Progress 01/04/02 to 01/03/07
Outputs
Progress Report Objectives (from AD-416) The goal of this research is to increase efficiency and allow profitable and sustainable operation of the United States sugarcane industry in a competitive environment by reducing the adverse impact of disease. The objectives for the next five years are to 1) identify and develop germplasm with resistance to the major diseases affecting sugarcane; 2) identify molecular markers that are linked to genes for disease resistance; 3) determine the effects of evolving agronomic practices such as the generation of residue blankets on fields following green-cane harvesting, on the epidemiology of sugarcane diseases and insect vectors; and 4) identify the genetic variability among pathogens populations and determine the distribution of races, strains, or other biotypes. Approach (from AD-416) To identify and develop germplasm with resistance to the major diseases affecting sugarcane in the United States, highly domesticated and wild clones of sugarcane and near relatives will be evaluated for resistance to the major sugarcane diseases following either natural infection or artificial inoculation. To identify molecular markers that are linked to genes for disease resistance, polymerase chain reaction (PCR) based methods such as RAPD, AFLP or SSR will be used to identify genetic markers closely linked to the resistance genes. Priority will be given to finding markers for ratoon stunting disease (RSD)and mosaic. Field studies will be conducted to determine the effects of evolving agronomic practices such as the utilization of post-harvest residue blankets to suppress weed development and reduce the need for cultivation on the epidemiology of sugarcane diseases. Genotypic and phenotypic expressions of variability within populations of pathogens and insect vectors will be used to identify the genetic variability among pathogen populations and determine the distribution of races, strains, or other biotypes. Significant Activities that Support Special Target Populations All 60 month milestones for this research project were met or substantially met as reported in FY 2006 annual report. Most objectives were continued in the new research project 6435-22000- 013-00D that became effective on 01/03/07. Progress during the final three months of this project is reported in the FY 2007 annual report of the new project. Accomplishments Experiments conducted during the final three months of this research project led to significant accomplishments in FY 2007 as reported in the Annual Report of the new project 6435-22000-013-00D. Technology Transfer Number of Non-Peer Reviewed Presentations and Proceedings: 1
Impacts
(N/A)
Publications
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? The efficiency of sugarcane production in Louisiana is limited by the attack of diseases. The goal of the research being conducted by the Agricultural Research Service (ARS), Southern Regional Research Center (SRRC), Sugarcane Research Unit's (SRU) scientists in this research project is to reduce the adverse impact of disease on the United States sugarcane industry through four integrated objectives. The first objective is to identify sugarcane plants resistant to the major diseases of sugarcane that can be used as parents for the next generation of sugarcane varieties. Disease resistant parents may be found among commercial-type varieties of sugarcane or plants of wild sugarcane relatives. The second objective is to identify genetic markers linked to genes for disease resistance.
Scientists can then use developed laboratory methods to identify plants with genes for resistance to diseases rather than conducting large-scale field tests that require the exposure of the plants to disease agents. A third objective is to determine how changing cultural practices, including changes in harvesting and planting methods, the elimination of burning, and an emphasis on reduced pesticide use, will affect the incidence and severity of sugarcane diseases. If the effect of diseases increases with the changes in cultural practices, research will be done to determine what actions are needed to reduce the threat. The final objective of this research is to determine the distribution of races, strains, or other genetically different groups among the populations of disease agents. Recently developed molecular approaches have enhanced the ability of scientists to study the genetics of disease agents and determine their ability to attack modern sugarcane varieties. The research falls
under National Program 303, Plant Pathology, and addresses primarily component 5, Host Plant Resistance to Disease. Facets of the project relate to Component 1, Identification and Classification of Pathogens, and Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors. All sugarcane varieties recommended for planting in Louisiana are susceptible to the disease that most sugarcane scientists agree is potentially the most important disease of sugarcane, ratoon stunting disease (RSD). Ratoon stunting disease has been estimated to cost growers in Louisiana approximately $20 million per year in direct loss of yield and in the expense of control. Among the nine varieties recommended for planting in Louisiana, most are resistant or moderately resistant to the other major diseases of sugarcane that occur in the United States including two fungal diseases (rust and smut), one viral disease (mosaic), and one bacterial disease (leaf scald).
Exceptions include two varieties which are highly susceptible to rust, one of which is also susceptible to smut. A third variety is highly susceptible to leaf scald. The major effect of these diseases occurs with the loss of susceptible breeding lines that are used as parents in the commercial varietal development program; however, each one has caused significant economic loss prior to the development of resistant varieties. 2. List by year the currently approved milestones (indicators of research progress) The milestones for the project are: Year 1 (FY 2002) Objective 1. Screen on-hand collection of wild clones for resistance to mosaic, smut, and leaf scald. Make new basic crosses. Second line trial (1,000 clones): inoculate for RSD and Ho (Houma) assignments (100 clones): inoculate for smut resistance and plant. Establish RSD and hot-water-treated nurseries (60-75 clones). Select clones to cross for heritability study of RSD resistance. Make crosses among clones with the highest
ratings for RSD resistance. Objective 2. Develop reference population (self pollinated progeny of variety LCP 85- 384 and variety LCP 82-89). Objective 3. Establish plots with research agronomist to monitor disease development in plots with different levels of organic residue removal. Plant large plot field experiment. Objective 4. Annually survey industry for introductions of new organisms that can cause diseases and for genetic changes among disease-causing pathogens that give them the ability to overcome disease resistance in the varieties being grown. Participate in annual variety advancement and release committee meetings and provide varietal ratings for disease response. Year 2 (FY 2003) Objective 1. Screen on-hand collection of wild clones for resistance to RSD. Make basic cross and plant progeny in field. Rate second line trials for RSD. Rate Ho assignments for smut and inoculate and rate same plants for leaf scald. Start new cycle of testing. Plant RSD yield effect and
spread experiment. Inoculate progeny and plant to field for testing. (Repeat experiment with new parents). Evaluate progeny and select the best for the next generation crosses. Initiate sugarcane yellow leaf disease (SCYLD) program. Objective 2. Inoculate and rate cuttings of progeny for different strains of mosaic and leaf scald. Inoculate for RSD and smut. Objective 3. Rate visual presence of disease such as rust, leaf scald, and other leaf diseases during course of growing season. Harvest plant-cane crop. Repeat experiment. Objective 4. Complete the genetic study of isolates of virus using a technique known as restriction fragment length polymorphism (RFLP) analysis that can detect small changes in the nucleic acid of the disease-causing virus. Publish results of mosaic survey. Modify screening protocols for mosaic resistance if necessary. Year 3 (FY 2004) Objective 1. Screen new collection of wild germplasm for resistance to mosaic, smut, and leaf scald. Screen first generation
(F1) progeny for disease resistance. Complete second cycle of testing second line trial and Ho assignment clones. Initiate third cycle of testing. Harvest and analyze plant-cane crop of yield test. Harvest spread test. Collect and analyze stalk tissue samples for RSD infection before first- ratoon crop harvest. Continue cycle of crossing and selection. Objective 2. Rate clones for RSD and smut. Initiate random amplification of polymorphic deoxyribonucleic acid/amplified fragment length polymorphisms (RAPD/AFLP) assays to identify markers for mosaic and leaf scald resistance. Objective 3. Repeat monitoring in first-ratoon crop. Monitor repeated experiment. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 1). Objective 4. Complete Koch's Postulates for unknown virus isolates. Report progress of attempts to identify probes for disease markers. Year 4 (FY 2005) Objective 1. Screen new collection of wild germplasm for resistance to RSD.
Continue screening F1 progeny and select clones for backcross with elite clone. Repeat cycle of testing. Harvest and analyze first-ratoon crop of yield test. Determine spread of RSD during plant-cane harvest. Collect tissue-blot data before second-ratoon crop harvest (1st trial). Continue cycle of crossing and selection. Objective 2. Complete RAPD/AFLP assays to identify markers for RSD and smut resistance. Develop new genetic markers. Identify the resistance genes. Objective 3. Repeat monitoring in second-ratoon crop. Monitor repeated experiment. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 2). Objective 4. Complete plant-cane phase of study to determine yield and cane quality effects of unknown virus. Transfer technology on effects of harvester type on RSD spread. Year 5 (FY 2006) Objective 1. With research geneticist, select wild clones with agronomic and disease and insect resistance traits. Make backcross and plant first
generation backcross (BC1) progeny in the field. Repeat cycle of testing. Harvest and analyze second-ratoon crop of yield test. Collect and analyze stalk tissue before second-ratoon crop harvest (1st trial) for RSD infection. Analyze data and prepare report. Identify best germplasm for use as RSD resistant parents. Objective 2. Further characterize resistant genes. Comparative study with other resistance gene analogs. Objective 3. Complete experiment, analyze data and transfer technology. Objective 4. Complete first-ratoon phase of study to determine yield and cane quality effects of unknown virus. Transfer technology regarding effects of organic residue on disease development. 4a List the single most significant research accomplishment during FY 2006. ASSESSING SUGARCANE VARIETIES FOR SUSCEPTIBILITY TO RATOON STUNTING DISEASE (RSD). Ratoon stunting disease is a major disease of sugarcane and the most effective method of control is the use of resistant varieties. The problem,
however, is that the current method for evaluating experimental varieties for RSD resistance does not provide the results in a timely manner. Because tissue-blot immunoassay (TBIA), the method most commonly used to evaluate sugarcane varieties for susceptibility to RSD, is performed on 7 to 8 month old stalk tissue, the results are available too late to affect the decision of which varieties to advance in the breeding program. A quantitative real-time polymerase chain reaction (PCR) protocol, which uses deoxyribonucleic acid (DNA) from leaves of sugarcane plants as young as 3 months old, was developed for the evaluating resistance to RSD. Application of this technology will provide a timely and reliable screening method for increasing the level of RSD resistance selection in the sugarcane breeding program as well as assisting breeding in identifying parental lines with resistance to RSD. This accomplishment addresses NP 303, Action Plan Component 5, Host Plant Resistance to Disease.
4b List other significant research accomplishment(s), if any. EFFECT OF SUGARCANE YELLOW LEAF VIRUS ON SUGARCANE YIELD AND JUICE QUALITY. Sugarcane yellow leaf virus (SCYLV) was first detected in Louisiana sugarcane in 1996; however, the effect of the virus on the productivity and processing of sugarcane in Louisiana, was unknown. This research demonstrated that cane and sugar yields were reduced in the third production year of LCP 85-384, the leading commercial variety in Louisiana and that excess starch accumulated in green leaves and the immature portions of the stalk of the SCYLV-infected plants of LCP 85-384 and Ho 95-988, another recently released variety, during all three production years. Elevated starch levels in the cane delivered to the mill reduces processing efficiency. The majority of green leaves and immature sections of stalks is normally removed when cane is harvested with chopper harvesters; however, these tissues may not be removed if the harvester is not being
operated at full extractor fan efficiency, when the stalks of cane are blown down by high winds, or when harvesting under rainy conditions. The results of this research contributed to the decision to establish a maximum level of SCYLV infection that would be tolerated in fields of seed cane certified by the Louisiana Department of Agriculture and Forestry. This accomplishment addresses NP 303, Action Plan Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host. DISEASE TESTING CONTRIBUTES TO THE RELEASE OF NEW VARIETIES. The availability of productive sugarcane varieties for planting in Louisiana is limited. Results of experiments associated with Objective 1 that addresses NP 303 Action Plan Component 5, Developing Host Plant Resistance to Disease, have contributed to the release of two varieties in 2006, L 99-226 and L 99-233, by the Louisiana Sugarcane Variety Advancement Committee composed of researchers from ARS, and Louisiana State
University, and farmers, millers, and staff of the American Sugar Cane League. The release of these two varieties was preceded by the release of HoCP 96-540 in 2003, and Ho 95-988 and L 97-128 in 2004. In experimental tests, the varieties met or exceeded the yield of the current leading variety, LCP 85-384, and were resistant or moderately resistant to the diseases (mosaic and leaf scald). Ho 95-988 and HoCP 96- 540 had higher levels of RSD resistance than any variety grown recently in Louisiana. The varieties should provide growers an excellent alternative to the planting of LCP 85-384 and lessen the vulnerability of the industry to the introduction of a new disease or different form of the disease already present in the industry. The greatest constraint to releasing a sugarcane variety with improved characteristics is the long testing cycle (12-14 years) and the difficulty of incorporating a large number of desirable traits into a single variety. 4d Progress report. The project
contributes to subordinate project 6435-21000-012-04T with the American Sugar Cane League, "Improving Sugarcane Production Efficiency," which is part of the parent project 6435-21000-012-00D, "Genetic Improvement of Sugarcane by Conventional and Molecular Approaches." Additional details of research can be found in the reports of the subordinate and parent projects. 5. Describe the major accomplishments to date and their predicted or actual impact. The introduction of new diseases is a threat to the profitability and efficiency of sugarcane growers and processors. Monitoring the sugarcane industry for exotic pathogens as proposed in Objective 4 which addresses Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors, of the NP 303 Action Plan uncovered a new sugarcane pathogen. In 1996, a new pathogenic virus, sugarcane yellow leaf virus (SCYLV), was discovered in Louisiana. Research was initiated to determine the effect of this
new pathogen on sugarcane grown in Louisiana and to develop disease management strategies to control the pathogen. Initially, research was limited because the known aphid vector (Melanaphis sacchari) required for transmission was not discovered in Louisiana until 1999. In the course of the current program cycle, a protocol for transmission of SCYLV by the aphid vector in the greenhouse was developed and differences in variety susceptibility to infection were demonstrated. Field experiments have also revealed differences in susceptibility of varieties to the virus and the effects of the virus on sugar and cane yields as well as changes in juice quality that can affect processing efficiency. The demonstration of the adverse effects of SCYLV infection on sugarcane contributed to the decision to inspect commercial seed cane fields and to establish a tolerance level of SCYLV infections in fields to be certified by the Louisiana Department of Agriculture and Forestry. Since most
growers used commercially available certified seed cane, this regulatory action will reduce the incidence of the virus disease and its impact on the crop and processing efficiency at the mills. Information about the susceptibility of varieties is shared with sugarcane breeders for the development of varieties with resistance to the SCYLV. Mosaic (a major disease caused by two different viruses) has caused significant losses in yield for sugarcane farmers in the past and, even though currently grown varieties are resistant to the disease, the possibility of new strains of the virus that can overcome the resistance remains a concern. An ongoing impact of the disease is that many promising varieties in the breeding program continue to be eliminated because of susceptibility to mosaic. We continue to monitor the sugarcane industry for new biotypes of mosaic and other pathogens as proposed in Objective 4 also addresses Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread
and Relationship with Host and Vectors, of the NP 303 Action Plan. A study of virus isolates collected from sugarcane exhibiting mosaic symptoms revealed that some isolates appear to be different from previously described strains and that some isolates may represent a virus not reported to cause mosaic in Louisiana sugarcane. The potentially new virus or virus strains are currently being characterized with molecular techniques and for their ability to attack different sugarcane varieties. The study also indicated that different strains of the viruses may become predominant at different times. As a result of this observation, a mixture of strains is used to screen new germplasm for mosaic resistance. The development of diagnostic procedures based on the unique nucleic acid (either DNA or ribonucleic acid, RNA) sequences of bacterial and viral pathogens in infected sugarcane tissue helps ensure disease-free seed cane for the sugarcane industry. Polymerase chain reaction (PCR)
assays and improved immunoassay techniques for the major bacterial and virus diseases of sugarcane in Louisiana that were developed in the preceding program cycle and validated during this program cycle are used in quarantine facilities to prevent diseased foreign sugarcane stalks from coming into the U.S.A. mainland and in local laboratories to safely permit interstate germplasm exchange. Accurate and quantitative diagnostic procedures are also critical to the evaluation of research being conducted in each of the four objectives of this project. During the current program cycle, a real-time RT-PCR protocol was developed for the detection and quantification of the sugarcane yellow leaf virus (SCYLV). These protocols are providing breeders and pathologists with better tools for monitoring disease epidemics and for evaluating breeding lines and experimental varieties for susceptibility to these diseases. The development of qualitative and quantitative diagnostic tools are needed for
research associated with Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors, and Component 5, Host Plant Resistance to Disease, of the NP 303 Action Plan. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? The research pathologist presented talks at fall and spring Extension/Research Sugarcane Training Meetings attended by Extension agents, specialists, and research scientists from ARS and Louisiana State University. He participated in the Terrebonne Parish Field Day attended by Extension agents, crop consultants, and growers where breeding for disease resistance was discussed. He was an invited presenter at the Contact Committee Meeting of the sugarcane commodity organization at which the
latest research advances are discussed with growers and mill personnel. He also participated in meetings with industry personnel, research scientists and administrators and certified sugarcane seed cane inspectors from the Louisiana Agriculture and Forestry Department concerning. More detailed scientific presentations were given at divisional and national commodity meetings of the American Society of Sugar Cane Technologists, attended by farmers, researchers, and agriculture industry personnel; and at the national meeting of the American Phytopathological Society. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Grisham, M.P. Sugarcane disease update. Extension/Research Sugarcane Training Meeting. December 2005 and May 2006. Grisham, M.P. 2006. Influence of soil fertility on incidence and severity of sugarcane rust. Bayouland Young Farmers
Meeting. January 23, 2006. Grisham, M.P. 2006. Research on sugarcane rust and smut. Contact Committee Meeting, American Sugar Cane League, June 28, 2006.
Impacts
(N/A)
Publications
- Grisham, M.P. 2006. Effect of ratoon stunting disease on yield of sugarcane cultivars recently released in Louisiana [abstract]. Journal of American Society of Sugar Cane Technologists. 46:49. Available: http://www. assct.org/journal/journal.htm
- Grisham, M.P., Johnson, R.M., Richard Jr, E.P. 2006. Effect of soil properties on sugarcane brown rust incidence and severity and associated yield loss [abstract]. Phytopathology. 96(6):S43.
- Grisham, M.P., Hoy, J. 2006. Effects of harvester type, inoculum source, and cultivar on spread of ratoon stunting disease. Sugar Cane International. 24(3):10-14.
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Progress 10/01/04 to 09/30/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The efficiency of sugarcane production in Louisiana is limited by the attack of diseases. The goal of the research being conducted by the Agricultural Research Service (ARS), Southern Regional Research Center (SRRC), Sugarcane Research Unit's (SRU) scientists in this research project is to reduce the adverse impact of disease on the United States sugarcane industry through four integrated objectives. The first objective is to identify sugarcane plants resistant to the major diseases of sugarcane that can be used as parents for the next generation of sugarcane varieties. Disease resistant parents may be found among commercial-type varieties of sugarcane or plants of wild sugarcane relatives. The second objective is to identify genetic markers linked to genes for disease resistance. Scientists can then
use developed laboratory methods to identify plants with genes for resistance to diseases rather than conducting large-scale field tests that require the exposure of the plants to disease agents. A third objective is to determine how changing cultural practices, including changes in harvesting and planting methods, the elimination of burning, and an emphasis on reduced pesticide use, will affect the incidence and severity of sugarcane diseases. If the effect of diseases increases with the changes in cultural practices, research will be done to determine what actions are needed to reduce the threat. The final objective of this research is to determine the distribution of races, strains, or other genetically different groups among the populations of disease agents. Recently developed molecular approaches have enhanced the ability of scientists to study the genetics of disease agents and determine their ability to attack modern sugarcane varieties. The research falls under National
Program 303, Plant Pathology, and addresses primarily component 5, Host Plant Resistance to Disease. Facets of the project relate to Component 1, Identification and Classification of Pathogens, and Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors. All sugarcane varieties recommended for planting in Louisiana are susceptible to the disease that most sugarcane scientists agree is potentially the most important disease of sugarcane, ratoon stunting disease (RSD). Ratoon stunting disease has been estimated to cost growers in Louisiana approximately $20 million per year in direct loss of yield and in the expense of control. Varieties recommended for planting in Louisiana are resistant or moderately resistant to the other major diseases of sugarcane that occur in the United States, smut, mosaic, and leaf scald, except for one variety which is highly susceptible to leaf scald. The major effect of these diseases occurs with the loss
of susceptible breeding lines that are used as parents in the commercial varietal development program; however, each one has caused significant economic loss prior to the development of resistant varieties. 2. List the milestones (indicators of progress) from your Project Plan. The milestones for the project are: Year 1 (FY 2002) Objective 1. Screen on-hand collection of wild clones for resistance to mosaic, smut, and leaf scald. Make new basic crosses. Second line trial (1,000 clones): inoculate for RSD and Ho (Houma) assignments (100 clones): inoculate for smut resistance and plant. Establish RSD and hot-water-treated nurseries (60-75 clones). Select clones to cross for heritability study of RSD resistance. Make crosses among clones with the highest ratings for RSD resistance. Objective 2. Develop reference population (self pollinated progeny of variety LCP 85- 384 and variety LCP 82-89). Objective 3. Establish plots with research agronomist to monitor disease development in plots
with different levels of organic residue removal. Plant large plot field experiment. Objective 4. Annually survey industry for introductions of new organisms that can cause diseases and for genetic changes among disease-causing pathogens that give them the ability to overcome disease resistance in the varieties being grown. Participate in annual variety advancement and release committee meetings and provide varietal ratings for disease response. Year 2 (FY 2003) Objective 1. Screen on-hand collection of wild clones for resistance to RSD. Make basic cross and plant progeny in field. Rate second line trials for RSD. Rate Ho assignments for smut and inoculate and rate same plants for leaf scald. Start new cycle of testing. Plant RSD yield effect and spread experiment. Inoculate progeny and plant to field for testing. (Repeat experiment with new parents). Evaluate progeny and select the best for the next generation crosses. Initiate sugarcane yellow leaf disease (SCYLD) program.
Objective 2. Inoculate and rate cuttings of progeny for different strains of mosaic and leaf scald. Inoculate for RSD and smut. Objective 3. Rate visual presence of disease such as rust, leaf scald, and other leaf diseases during course of growing season. Harvest plant-cane crop. Repeat experiment. Objective 4. Complete the genetic study of isolates of virus using a technique known as restriction fragment length polymorphism (RFLP) analysis that can detect small changes in the nucleic acid of the disease-causing virus. Publish results of mosaic survey. Modify screening protocols for mosaic resistance if necessary. Year 3 (FY 2004) Objective 1. Screen new collection of wild germplasm for resistance to mosaic, smut, and leaf scald. Screen first generation (F1) progeny for disease resistance. Complete second cycle of testing second line trial and Ho assignment clones. Initiate third cycle of testing. Harvest and analyze plant-cane crop of yield test. Harvest spread test. Collect and
analyze stalk tissue samples for RSD infection before first- ratoon crop harvest. Continue cycle of crossing and selection. Objective 2. Rate clones for RSD and smut. Initiate random amplification of polymorphic deoxyribonucleic acid/amplified fragment length polymorphisms (RAPD/AFLP) assays to identify markers for mosaic and leaf scald resistance. Objective 3. Repeat monitoring in first-ratoon crop. Monitor repeated experiment. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 1). Objective 4. Complete Koch's Postulates for unknown virus isolates. Report progress of attempts to identify probes for disease markers. Year 4 (FY 2005) Objective 1. Screen new collection of wild germplasm for resistance to RSD. Continue screening F1 progeny and select clones for backcross with elite clone. Repeat cycle of testing. Harvest and analyze first-ratoon crop of yield test. Determine spread of RSD during plant-cane harvest. Collect tissue-blot
data before second-ratoon crop harvest (1st trial). Continue cycle of crossing and selection. Objective 2. Complete RAPD/AFLP assays to identify markers for RSD and smut resistance. Develop new genetic markers. Identify the resistance genes. Objective 3. Repeat monitoring in second-ratoon crop. Monitor repeated experiment. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 2). Objective 4. Complete plant-cane phase of study to determine yield and cane quality effects of unknown virus. Transfer technology on effects of harvester type on RSD spread. Year 5 (FY 2006) Objective 1. With research geneticist, select wild clones with agronomic and disease and insect resistance traits. Make backcross and plant first generation backcross (BC1) progeny in the field. Repeat cycle of testing. Harvest and analyze second-ratoon crop of yield test. Collect and analyze stalk tissue before second-ratoon crop harvest (1st trial) for RSD infection.
Analyze data and prepare report. Identify best germplasm for use as RSD resistant parents. Objective 2. Further characterize resistant genes. Comparative study with other resistance gene analogs. Objective 3. Complete experiment, analyze data and transfer technology. Objective 4. Complete first-ratoon phase of study to determine yield and cane quality effects of unknown virus. Transfer technology regarding effects of organic residue on disease development. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Screen new collection of wild germplasm for resistance to RSD. Milestone Fully Met 2. Continue screening F1 progeny and select clones for backcross with elite clone. Milestone Fully Met 3. Repeat cycle of testing. Milestone Fully Met 4. Harvest and analyze first-ratoon crop of yield test. Determine spread of RSD during plant-cane harvest. Milestone Fully
Met 5. Collect tissue-blot data before second-ratoon crop harvest (1st trial). Milestone Fully Met 6. Continue cycle of crossing and selection. Milestone Fully Met 7. Complete RAPD/AFLP assays to identify markers for RSD and smut resistance. Develop new genetic markers. Identify the resistance genes. Milestone Substantially Met 8. Repeat monitoring in second-ratoon crop. Monitor repeated experiment. Milestone Fully Met 9. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 2). Milestone Fully Met 10. Complete plant-cane phase of study to determine yield and cane quality effects of unknown virus. Milestone Substantially Met 11. Transfer technology on effects of harvester type on RSD spread. Milestone Fully Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Year 5 (FY 2006) Objective 1. With
research geneticist and research entomologist, select wild clones with agronomic and disease and insect resistance traits. Continue on- going collaboration with research geneticists in screening basic germplasm, progeny of basic and commercial crosses, and near-release varieties for resistance to mosaic, smut, and leaf scald. In collaboration with research geneticists, make backcross and plant first generation backcross (BC1) progeny in the field. Repeat cycle of testing 2nd line trial for smut and leaf scald resistance. Harvest and analyze second-ratoon crop of RSD yield test. Collect and analyze stalk tissue before second-ratoon crop harvest (1st trial) for RSD infection. Analyze data and prepare report. Continue to evaluate first-line trial clones (approximately 1,000 clones per year) for RSD resistance and determine the effects of RSD on yield and cane quality of near-release varieties. Identify best germplasm for use as RSD resistant parents. Evaluate progeny of crosses with
RSD resistant parents for RSD resistance and inclusion in the next cycle of crossing and selection. Objective 2. As stated in 3a above, the milestones in this objective have been delayed by one year. Consequently, the milestone originally defined for year 4 will be pursued in FY 2006. RFLP/AFLP assays will be used to identify markers for major diseases of sugarcane. The milestone for year 5, further characterize resistant genes and comparative study with other resistance gene analogs, are proposed as a milestone for a new research project to be initiated in FY 2007. Objective 3. In cooperation with research agronomists and research plant physiologists, experiments on the effects of cultural practices on disease incidence and severity will be completed, data analyzed, and technology transferred. Objective 4. Complete first-ratoon phase of study to determine yield and cane quality effects of unknown virus causing mosaic of sugarcane. A greater number of potentially new strains of
sorghum mosaic virus (SrMV), the virus reported to cause mosaic in Louisiana, in addition to an unidentified virus causing mosaic on sugarcane in Louisiana has been found in the course of this study. Additional effort to molecularly characterize these virus isolates and determine their effect of sugarcane will be needed in year five and will be proposed as an objective for a new research project to be initiated in FY 2007. Continue surveys to determine if exotic pathogens or biotypes are introduced into the sugarcane industry. Transfer technology regarding effects of organic residue on disease development. (FY 2007 and FY 2008) The current research project will be completed before the end of FY 2007 and a new project will be developed. Some ongoing objectives will be renewed; however, new objectives will be developed to reflect new technologies and the disease control needs at that time. 4a What was the single most significant accomplishment this past year? EFFECT OF SUGARCANE
YELLOW LEAF VIRUS ON SUGARCANE YIELD AND JUICE QUALITY. In field experiments conducted between 2001 and 2004, sugarcane yellow leaf virus (SCYLV), first detected in Louisiana in 1996, reduced cane and sugar yields of LCP 85-384, the leading commercial variety in Louisiana, in the second-ratoon crop. No yield loss was observed in the plant cane- and first-ratoon crops of LCP 85-384 or Ho 95-988, a recently released variety; however, analysis of different plant tissues revealed an increased starch accumulation in green leaves and the immature portions of the stalk of the SCYLV-infected plants of both varieties in all three crops. SCYLV-infected sugarcane plants in Louisiana rarely show the typical late-season symptoms of midrib yellowing and dying tops associated with SCYLV infection and it was unknown how much of an effect the virus was having on Louisiana-grown sugarcane. The majority of green leaves and immature sections of stalks is normally removed when cane is harvested with
chopper harvesters; however, these tissues may not be removed if the harvester is not being operated at full extractor fan efficiency, when the cane is lodged, or when harvesting under rainy conditions. Elevated starch levels in the cane delivered to the mill could reduce processing efficiency. The results of this research contributed to the decision to establish a maximum level of SCYLV infections that would be tolerated in fields of seed cane certified by the Louisiana Department of Agriculture and Forestry. 4b List other significant accomplishments, if any. NEW METHODS TO DETECT RATOON STUNTING DISEASE EARLIER IN IMMATURE CANE. A real-time polymerase chain reaction (PCR) assay was developed that is able to detect Leifsonia xyli subsp. xyli (Lxx) in stalk sap of 4-month- old plants and in leaf tissue of one-month-old sugarcane plants. In Louisiana, a new crop of sugarcane is established by planting 5-6 month- old stalks. To prevent the introduction of ratoon stunting disease,
the stalks should be free of Lxx, the bacterium that causes the disease; however, the methods currently used to detect Lxx, tissue-blot immunoassay (TBIA) and conventional polymerase chain reaction (PCR), provide inconsistent diagnosis of plants younger than 6 months old. Detection of Lxx this early in plant development with an immunoassay or conventional PCR assay has not been previously successful. The method will be validated in field-grown cane of several varieties with different levels of susceptibility during the final year of this project cycle. Application of this detection method will provide a timely and reliable test for insuring the health of seed cane. 4d Progress report. The project contributes to subordinate project 6435-21000-012-04T, Improving Sugarcane Production Efficiency, which is part of the parent project 6435-21000-012-00D, Genetic Improvement of Sugarcane by Conventional and Molecular Approaches. Additional details of research can be found in the reports of
the subordinate and parent projects. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Results of experiments associated with Objective 1 that addresses NP 303 Action Plan Component 5, Developing Host Plant Resistance to Disease, have contributed to the release of two varieties, Ho 95-988 and L 97-128, in 2004 by the Louisiana Sugarcane Variety Advancement Committee composed of researchers from ARS and Louisiana State University, and farmers, millers, and staff of the American Sugar Cane League. In experimental tests, the varieties met or exceeded the yield of the current leading variety, LCP 85-384, and in addition to resistance or moderate resistance to mosaic, leaf scald, and smut; Ho 95-988 is resistant to rust and both varieties had higher levels of RSD resistance than any variety recently grown in Louisiana. The varieties should provide growers an excellent alternative to the planting of LCP 85-384 that currently
accounts for more than 90 percent of the area planted to sugarcane in Louisiana and lessen the vulnerability of the industry to the introduction of a new disease or insect pest or biotype of a disease or insect already present in the industry. The greatest constraint to releasing a sugarcane variety with improved characteristics is the long testing cycle (12-14 years) and the difficulty of incorporating a large number of desirable traits into a single variety. The introduction of new diseases is a threat to the profitability and efficiency of sugarcane growers and processors. Monitoring the sugarcane industry for exotic pathogens as proposed in Objective 4 which addresses Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors, of the NP 303 Action Plan uncovered a new sugarcane pathogen. In 1996, a new pathogenic virus, sugarcane yellow leaf virus (SCYLV), was discovered in Louisiana. Research was initiated to determine the
effect of this new pathogen on the sugarcane grown in Louisiana and to develop disease management strategies to control the pathogen. Initially, research was limited because the known aphid vectors required for transmission had not been reported in Louisiana. Melanaphis sacchari, a vector of SCYLV, was discovered in 1999. In the course of the current program cycle, a protocol for transmission of SCYLV by M. sacchari in the greenhouse was developed and differences in variety susceptibility to infection were demonstrated. Field experiments have also revealed differences in susceptibility of varieties to the virus and the effects of the virus on sugar and cane yields as well as changes in juice quality that can affect processing efficiency. The demonstration of the adverse effects of SCYLV infection on sugarcane contributed to the decision to inspect commercial seed cane fields and to establish a tolerance level of SCYLV infections in fields to be certified by the Louisiana
Department of Agriculture and Forestry. Since most growers used commercially available certified seed cane, this regulatory action will reduce the incidence of the virus disease and its impact on the crop and processing efficiency at the mills. Information about the susceptibility of varieties is shared with sugarcane breeders for the development of varieties with resistance to the SCYLV. Research related to the other aspect of Objective 4, the monitoring of the industry for new biotypes of endemic pathogens, has led to new discoveries about the viruses that cause mosaic disease of sugarcane. Mosaic, has cause significant losses in yield for sugarcane farmers in the past and, even though currently grown varieties are resistant to the disease, the possibility of new strains of the virus that can overcome the resistance remains a concern. An ongoing impact of the disease is that many promising varieties in the breeding program continue to be eliminated because of susceptibility to
mosaic. A study of virus isolates collected from sugarcane exhibiting mosaic symptoms revealed that some isolates of the mosaic virus appear to be different from previously described strains and that some isolates may represent a virus not reported to cause mosaic in Louisiana sugarcane. The potentially new virus or virus strains are currently being characterized with molecular techniques and for their ability to attack different sugarcane varieties. The study also indicated that different strains of the viruses may become predominant at different times. As a result of this observation, a mixture of strains is used to screen new germplasm for mosaic resistance. The development of diagnostic procedures based on the unique nucleic acid (either DNA or RNA) sequences of bacterial and viral pathogens in infected sugarcane tissue helps ensure disease-free seed cane for the sugarcane industry. Polymerase chain reaction (PCR) assays and improved immunoassay techniques for the major
bacterial and virus diseases of sugarcane in Louisiana that were developed in the preceding program cycle and validated during this program cycle are used in quarantine facilities to prevent diseased foreign sugarcane stalks from coming into the U.S.A. mainland and in local laboratories to safely permit interstate germplasm exchange. Accurate and quantitative diagnostic procedures are also critical to the evaluation of research being conducted in each of the four objectives of this project. During the current program cycle, a real-time RT-PCR protocol has been adapted for the detection and quantification of the sugarcane yellow leaf virus (SCYLV) and real-time PCR protocol has been developed for the detection and quantification of Leifsonia xyli subsp. xyli, the cause of ratoon stunting disease (RSD) of sugarcane. These protocols should provide breeders and pathologists better tools for monitoring the disease epidemics and for evaluating germplasm for susceptibility to SCYLV and
RSD. Monitoring the sugarcane industry for new biotypes of pathogens as proposed in Objective 4 also addresses Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors of NP 303 Action Plan. The development of qualitative and quantitative diagnostic tools are needed for research associated with Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors, and Component 5, Host Plant Resistance to Disease, of the NP 303 Action Plan. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? The research pathologist presented talks at fall and spring Extension/Research Sugarcane Training Meetings attended by Extension agents, specialists, and research scientists
from ARS and Louisiana State University. He participated in the Terrebonne Parish Field Day attended by Extension agents, crop consultants, and growers where management of insect pests and diseases was discussed. He also participated in meetings with industry personnel, research scientists and administrators and certified sugarcane seed cane inspectors from the Louisiana Agriculture and Forestry Department concerning. More detailed scientific presentations were given at divisional and national commodity meetings of the American Society of Sugar Cane Technologists, attended by farmers, researchers, and agriculture industry personnel; and at the national meeting of the American Phytopathological Society. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Grisham, M.P. 2005. Insuring availability of disease resistant sugarcane varieties for
Louisiana. The Sugar Bulletin 83(10):19-20. Grisham, M.P. Sugarcane disease update. Extension/Research Sugarcane Training Meeting. December 2004 and May 2005.
Impacts
(N/A)
Publications
- Grisham, M.P., Pan, Y. 2005. Detection and Quantification of Leifsonia xyli subsp. xyli in Sugarcane by Real-Time PCR. Phytopathology. 95(6) (Supplement):S36.
- Grisham, M.P. 2004. Ratoon Stunting Disease. In: Rao, G.P., Saumtally, A.S. , Rott, P., editors. Sugarcane Pathology Vol. III: Bacteria and Nematode Diseases. Enfield, NH: Science Publishers, Inc. p. 77-96.
- Grisham, M.P. 2004. Sugarcane Mosaic. In: Lapierre, H., Signoret, P., editors. Viruses and Virus Diseases of Poaceae (Gramineae). Paris: INRA. p. 703-707.
- Grisham, M.P. 2004. Sugarcane Mosaic Associated to Sorghum Mosaic Virus. In: Lapierre, H., Signoret, P., editors. Viruses and Virus Diseases of Poaceae (Gramineae). Paris: INRA. p. 707-708.
- Jensen, S.G., Grisham, M.P. 2004. Sorghum Mosaic. In: Lapierre, H., Signoret, P., editors. Viruses and Virus Diseases of the Poaceae (Gramineae). Paris: INRA. p. 547-548.
- Grisham, M.P., Hoy, J.W., Godshall, M.A., Eggleston, G. 2005. Effect of Sugarcane Yellow Leaf Virus on Sugarcane Yield and Juice Quality of LCP 85- 384 and Ho 95-988 [abstract]. Journal of the American Society of Sugar Cane Technologists. 25. Available: http://www.assct.org/journal/journal. htm
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Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? This project was certified through the OSQR process in 2002 with an entomological component. The entomological component was moved to a new CRIS Project 6435-22000-009-00D, "Developing Inegrated Weed and Insect Pest Management Systems for Efficient and Sustainable Sugarcane Production," effective October 1, 2003; accomplishments of the entomological component are included in that project's Annual Report. The efficiency of sugarcane production in Louisiana is limited by the attack of diseases. The goal of the research being conducted by the Agricultural Research Service (ARS), Southern Regional Research Center (SRRC), Sugarcane Research Unit's (SRU) scientists in this research project is to reduce the adverse impact of disease on the United State sugarcane industry through four integrated objectives.
The first objective is to identify sugarcane plants resistant to the major diseases of sugarcane that can be used as parents for the next generation of sugarcane varieties. Disease resistant parents may be found among commercial-type varieties of sugarcane or plants of wild sugarcane relatives. The second objective is to identify genetic markers linked to genes for disease resistance. Scientists can then use developed laboratory methods to identify plants with genes for resistance to diseases rather than conducting large-scale field tests that require the exposure of the plants to disease agents. A third objective is to determine how changing cultural practices, including changes in harvesting and planting methods, the elimination of burning, and an emphasis on reduced pesticide use, will affect the incidence and severity of sugarcane diseases. If the effect of diseases increases with the changes in cultural practices, research will be done to determine what actions are needed to
reduce the threat. The final objective of this research is to determine the distribution of races, strains, or other genetically different groups among the populations of disease agents. Recently developed molecular approaches have enhanced the ability of scientists to study the genetics of disease agents and determine their ability to attack modern sugarcane varieties. The research falls under National Program 303, Plant Pathology, and addresses primarily component 5, Host Plant Resistance to Disease. Facets of the project relate to Component 1, Identification and Classification of Pathogens, and Component 4, Pathogen Biology, Genetics, Population Dynamics, Spread and Relationship with Host and Vectors. All sugarcane varieties recommended for planting in Louisiana are susceptible to the disease that most sugarcane scientists agree is potentially the most important disease of sugarcane, ratoon stunting disease (RSD). Ratoon stunting disease has been estimated to cost growers in
Louisiana approximately $20 million per year in direct loss of yield and in the expense of control. Varieties recommended for planting in Louisiana are resistant or moderately resistant to the other major diseases of sugarcane that occur in the United States, smut, mosaic, and leaf scald, except for one variety which is highly susceptible to leaf scald. The major effect of these diseases occurs with the loss of susceptible breeding lines that are used as parents in the commercial varietal development program; however, each one has caused significant economic loss prior to the development of resistant varieties. 2. List the milestones (indicators of progress) from your Project Plan. The milestones for the project are: Year 1 (FY 2002) Objective 1. Screen on-hand collection of wild clones for resistance to mosaic, smut, and leaf scald. Make new basic crosses. Second line trial (1,000 clones): inoculate for RSD and Ho (Houma) assignments (100 clones): inoculate for smut resistance and
plant. Establish RSD and hot-water-treated nurseries (60-75 clones). Select clones to cross for heritability study of RSD resistance. Make crosses among clones with the highest ratings for RSD resistance. Objective 2. Develop reference population (self pollinated progeny of variety LCP 85- 384 and variety LCP 82-89). Objective 3. Establish plots with research agronomist to monitor disease development in plots with different levels of organic residue removal. Plant large plot field experiment. Objective 4. Annually survey industry for introductions of new organisms that can cause diseases and for genetic changes among disease-causing pathogens that give them the ability to overcome disease resistance in the varieties being grown. Participate in annual variety advancement and release committee meetings and provide varietal cultivar ratings for disease response. Year 2 (FY 2003) Objective 1. Screen on-hand collection of wild clones for resistance to RSD. Make basic cross and plant
progeny in field. Rate second line trials for RSD. Rate Ho assignments for smut and inoculate and rate same plants for leaf scald. Start new cycle of testing. Plant RSD yield effect and spread experiment. Inoculate progeny and plant to field for testing. (Repeat experiment with new parents). Evaluate progeny and select the best for the next generation crosses. Initiate sugarcane yellow leaf disease (SCYLD) program. Objective 2. Inoculate and rate cuttings of progeny for different strains of mosaic and leaf scald. Inoculate for RSD and smut. Objective 3. Rate visual presence of disease such as rust, leaf scald, and other leaf diseases during course of growing season. Harvest plant-cane crop. Repeat experiment. Objective 4. Complete the genetic study of isolates of virus using a technique known as restriction fragment length polymorphism (RFLP) analysis that can detect small changes in the nucleic acid of the disease-causing virus. Publish results of mosaic survey. Modify screening
protocols for mosaic resistance if necessary. Year 3 (FY 2004) Objective 1. Screen new collection of wild germplasm for resistance to mosaic, smut, and leaf scald. Screen first generation (F1) progeny for disease resistance. Complete second cycle of testing second line trial and Ho assignment clones. Initiate third cycle of testing. Harvest and analyze plant-cane crop of yield test. Harvest spread test. Collect and analyze stalk tissue samples for RSD infection before first- ratoon crop harvest. Continue cycle of crossing and selection. Objective 2. Rate clones for RSD and smut. Initiate random amplification of polymorphic deoxyribonucleic acid/amplified fragment length polymorphisms (RAPD/AFLP) assays to identify markers for mosaic and leaf scald resistance. Objective 3. Repeat monitoring in first-ratoon crop. Monitor repeated experiment. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 1). Objective 4. Complete Koch's Postulates
for unknown virus isolates. Report progress of attempts to identify probes for disease markers. Year 4 (FY 2005) Objective 1. Screen new collection of wild germplasm for resistance to RSD. Continue screening F1 progeny and select clones for backcross with elite clone. Repeat cycle of testing. Harvest and analyze first-ratoon crop of yield test. Determine spread of RSD during plant-cane harvest. Collect tissue-blot data before second-ratoon crop harvest (1st trial). Continue cycle of crossing and selection. Objective 2. Complete RAPD/AFLP assays to identify markers for RSD and smut resistance. Develop new genetic markers. Identify the resistance genes. Objective 3. Repeat monitoring in second-ratoon crop. Monitor repeated experiment. Collect and analyze stalk tissue samples to determine spread of RSD during plant-cane harvest (trial 2). Objective 4. Complete plant-cane phase of study to determine yield and cane quality effects of unknown virus. Transfer technology on effects of
harvester type on RSD spread. Year 5 (FY 2006) Objective 1. With research geneticist, select wild clones with agronomic and disease and insect resistance traits. Make backcross and plant first generation backcross (BC1) progeny in the field. Repeat cycle of testing. Harvest and analyze second-ratoon crop of yield test. Collect and analyze stalk tissue before second-ratoon crop harvest (1st trial) for RSD infection. Analyze data and prepare report. Identify best germplasm for use as RSD resistant parents. Objective 2. Further characterize resistant genes. Comparative study with other resistance gene analogs. Objective 3. Complete experiment, analyze data and transfer technology. Objective 4. Complete first-ratoon phase of study to determine yield and cane quality effects of unknown virus. Transfer technology regarding effects of organic residue on disease development. 3. Milestones: A. List the milestones that were scheduled to be addressed in FY 2004. How many milestones did you
fully or substantially meet in FY 2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. The milestones listed below were scheduled for completion in FY 2004. Most milestones were completed or substantial progress was made toward their completion. The status of each milestone is indicated. Objective 1. Screen new collection of wild germplasm for resistance to mosaic, smut, and leaf scald. (Partially met). Expected new germplasm has been delayed because the quarantine facilities in Beltsville, MD, have not been operational since 2001. Testing of on-hand wild germplasm for resistance to RSD was completed in FY 2003. Testing of the germplasm for mosaic resistance. (Fully met) Selected F1 progeny from the basic breeding crosses were included in smut and leaf scald inoculated tests and the progeny were visually rated for natural infection by viruses that cause mosaic. (Fully met) Second cycle of testing second line trial and
Ho assignment clones and initiate third cycle of testing. (Fully met) Harvest and analyze plant-cane crop of yield test. Harvest spread test. (Fully met) Collect tissue-blot data before first-ratoon crop harvest. (Fully met) Continue cycle of crossing and selection. (Partially met). Substantial progress has been made on the selection and testing for RSD resistance. The selection and testing for SCYLD has progressed more slowly because an insect is needed to inoculate the virus into the plant. An artificial greenhouse protocol has been developed in collaboration with the research entomologist and field trials dependent on natural inoculation have been established. Objective 2. Rate clones for RSD and smut. Initiate RAPD/AFLP to identify markers for mosaic and leaf scald resistance. (Partially met). This project was initiated with the approval of the CRIS at the end of FY 2002 rather than at the start date of the CRIS (January 2002); therefore, the milestones as listed are delayed
by one year. The reference population was established in FY 2003 (originally a FY 2002 milestone). The genetic purity of the population was verified in FY 2003 and FY 2004, a critical step before disease resistance testing could begin. Substantial progress has been made in testing the population for disease resistance to mosaic and leaf scald. Objective 3. Repeat monitoring in first-ratoon crop. Monitor repeated experiment. (Fully met) Collect tissue-blot samples to determine spread of RSD during plant-cane harvest (trial 1). (Fully met) Objective 4. Complete Koch's Postulates for unknown virus isolates. (Partially met) Substantial progress. Tests for virus isolate pathogenicity need to be repeated. Also, the number of unknown virus isolates is greater than anticipated; therefore, some isolates remain to be tested. Transfer technology regarding attempts to identify probes for disease markers. (Partially met). This milestone is delayed because of the reasons given above under
the milestones for Objective 2. B. List the milestones that you expect to address over the next 3 years (FY 2005, 2006, and 2007). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Year 4 (FY 2005) Continue on-going collaboration with research geneticists in screening basic germplasm, progeny of basic and commercial crosses, and near- release varieties for resistance to the mosaic, smut, and leaf scald. Continue to evaluate second-line trial clones (approximately 1,000 clones per year) for RSD resistance and determine the effects of RSD on yield and cane quality of near-release varieties. Recommend crosses of parental germplasm based on resistance to RSD. Evaluate germplasm in the greenhouse and in the field under natural infection for resistance to the SCYLV. Inoculate and rate clones in the reference population for genetic markers for mosaic and leaf scald resistance. Inoculate clones for RSD and smut to be rated in FY 2006. Continue
evaluation of effects of organic residue management on diseases in ratoon crops. Complete a four year study on the effects of harvesting system and variety on the spread of RSD. Continue genetic analysis of strains of sorghum mosaic virus (SrMV) not previously described and of potentially new viruses found infecting sugarcane. Establish disease nurseries of plants infected with new SrMV strains. Surveys will continue to determine if exotic pathogens or biotypes are introduced into the sugarcane industry. Year 5 (FY 2006) Continue on-going collaboration with research geneticists in screening basic germplasm, progeny of basic and commercial crosses, and near- release varieties for resistance to mosaic, smut, and leaf scald. Continue to evaluate first-line trial clones (approximately 1,000 clones per year) for RSD resistance and determine the effects of RSD on yield and cane quality of near-release varieties. Evaluate progeny of crosses with RSD resistant parents for RSD resistance and
inclusion in the next cycle of crossing and selection. Continue evaluation of germplasm for resistance to the SCYLV and identify resistant clones as parents in the next cycle of crosses. Conduct RAPD/AFLP studies to identify genetic markers associated mosaic resistance. Continue evaluation of effects of organic residue management on diseases in ratoon crops. Establish field trials to determine the effect of new SrMV strains on yield and cane quality. Continue surveys to determine if exotic pathogens or biotypes are introduced into the sugarcane industry. Year 6 (FY 2007) The current CRIS project will be completed before the end of FY 2007 and a new project will be developed. Some ongoing objectives will be renewed; however, new objectives will be developed to reflect new technologies and the disease control needs at that time. Continue on-going collaboration with research geneticists in screening basic germplasm, progeny of basic and commercial crosses, and near- release varieties
for resistance to mosaic, smut, and leaf scald. Evaluate progeny of crosses with RSD resistant parents for RSD resistance and inclusion in the next cycle of crossing and selection. Continue evaluation of germplasm for resistance to the SCYLV and identify resistant clones as parents in the next cycle of crosses. Conduct RAPD/AFLP to identify genetic markers for leaf scald and RSD resistance. Complete study of effects of organic residue management on diseases in ratoon crops. Harvest field trials to determine the effect of new SrMV strains on yield and cane quality. Continue surveys to determine if exotic pathogens or biotypes are introduced into the sugarcane industry. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004. Shifts in mosaic strains detected. A survey of virus isolates collected from sugarcane exhibiting mosaic symptoms revealed a shift in strain dominance among the naturally infected plants. In
contrast to viruses collected from diseased plants between 1990 and 1995 in which more than 90 percent were SrMV strain H and the remainder strains I and M, approximately 68, 10, and 2 percent of the viruses collected between 2001 and 2004 were strains I, H, and M, respectively; 13 percent was an unknown strain of SrMV; and 8 percent appeared to be strains of a virus other than SrMV or sugarcane mosaic virus that causes mosaic in other locations. Among the 693 plants with mosaic symptoms, 18 were found to contain two virus strains, and two plants were infected with three virus strains. These results demonstrate the ability of the different strains of the SrMV to become predominant, for new strains to emerge, or for a new virus to infect Louisiana sugarcane; and suggest that a mixture of strains be used to screen new germplasm for mosaic resistance. B. Other Significant Accomplishment(s). Disease resistant sugarcane varieties released for commercial planting. The most effective
method of controlling diseases of sugarcane is the planting of varieties with combined resistance to the major disease agents. ARS scientists at the SRU screen tens of thousands of progeny each year for resistance to diseases and for their yield potential in an effort to find that rare individual that is better adapted to the Louisiana environment than varieties currently grown by farmers and has resistance to all the major diseases. Two new varieties of sugarcane, Ho 95-988 and L 97-128, were released for commercial production in 2004. Both have resistance to mosaic and leaf scald, moderate resistance to smut, and Ho 95-988 has resistance to rust. Importantly, both have a higher level of resistance to infection by the RSD bacterium than any recently grown variety in Louisiana. Both varieties will help the farmer improve efficiency by providing them with additional varieties that have equal or better yield potential and disease resistance to variety LCP 85- 384 that currently
occupies 90 percent of the sugarcane production area in Louisiana. C. Significant Accomplishment/Activities that Support Special Target Populations. None. D. Progress Report. This project contributes to subordinate project 6435-21000-006-07T, "Improving Sugarcane Productivity by Conventional and Molecular Approaches to Genetic Development," which is part of the parent project 6435-21000-006-00D of the same name. Additional details of research can be found in the reports of the subordinate and parent projects. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Accomplishments of previous project (1997-2002) for which this project is primarily a continuation include: Disease surveys uncover new sugarcane disease. Since the late 1970s, three major diseases have been introduced into the Louisiana sugarcane industry: smut, rust, and leaf scald. All had economic significance either from direct loss to the grower or from the
loss of promising germplasm. In 1996, a new pathogenic virus was discovered in Louisiana, sugarcane yellow leaf virus (SCYLV). Initially, research was limited because the known aphid vectors required for transmission had not been reported in Louisiana. Melanaphis sacchari, a vector of SCYLV, was discovered in 1999. A protocol for transmission of SCYLV by M. sacchari in the greenhouse was developed and differences in variety susceptibility to infection were demonstrated. National Program 303 Action Plan Component I and IV. The development and implementation of diagnostic procedures based on the unique nucleic acid (either DNA or RNA) sequences of bacterial and viral pathogens in infected sugarcane tissue help ensure disease-free seed cane for the sugarcane industry. These protocols are used in quarantine facilities to prevent diseased foreign sugarcane stalks from coming into the U.S.A. mainland and in local laboratories to safely permit interstate germplasm exchange. National
Program 303 Action Plan Component I. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Two varieties, Ho 95-988 and L 97-128, were released in 2004 by the Louisiana Sugarcane Variety Advancement Committee composed of researchers from ARS, and Louisiana State University, farmers, and staff of the American Sugar Cane League. In experimental tests, the varieties met or exceeded the yield of the current leading variety, LCP 85-384, and in addition to resistance or moderate resistance to mosaic, leaf scald, and smut; Ho 95-988 is resistant to rust and both varieties had higher levels of RSD resistance than any variety recently grown in Louisiana. The varieties should provide an excellent alternative to the planting of LCP 85-384 that currently accounts
for 90 percent of the area planted to sugarcane in Louisiana and lessen the vulnerability of the industry to the introduction of a new disease or insect pest or biotype of a disease or insect already present in the industry. The greatest constraint to releasing a sugarcane variety with improved characteristics is the long testing cycle (12-14 years) and the difficulty of incorporating a large number of desirable traits into a single variety. The research pathologist presented talks at fall and spring Extension/Research Sugarcane Training Meetings attended by Extension agents, specialists, and research scientists from ARS and Louisiana State University. He participated in the Terrebonne Parish field day attended by Extension agents, crop consultants, and growers where management of insect pests and diseases was discussed. He also participated in the training of Louisiana Agriculture and Forestry Department certified sugarcane seed cane inspectors. More detailed scientific
presentations were given at a national commodity meeting, the Joint Meeting of the American Society of Sugar Cane Technologists, attended by farmers and researchers; and the national meeting of the American Phytopathological Society. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Grisham, M.P. An example of why growing a single variety is risky. American Society of Sugar Cane Technologists, Louisiana Division, February 3, 2004, Baton Rouge, Louisiana. Review of presentation included in article by Herman Waguespack, Jr., Sugar Journal 66(10):19-20. Grisham, M.P. Sugarcane disease update. Extension/Research Sugarcane Training Meeting. December 2003 and May 2004. Dufrene, E.O., Grisham, M.P., White, W.H., Bischoff, K. New varieties: fitting them in. Presentation at the Terrebonne Parish and Area Sugarcane Field Day. 2004.
Impacts
(N/A)
Publications
- Hoy, J.W., Grisham, M.P., Comstock, J.C. 2004. Summary of ISSCT Pathology Workshop VII. Sugar Journal. 66(9):16-18.
- Grisham, M.P., Pan, Y. 2004. A genetic shift in the predominant virus strain causing mosaic in Louisiana sugarcane [abstract]. Phytopathology. 94, No. 6 (Supplement):S36.
- Grisham, M.P. 2004. Evaluation of Ho 95-988, HoCP 96-540, and L 97-128 for susceptibility to ratoon stunting disease [abstract]. Journal of the American Society of Sugar Cane Technologists. 24:110.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The efficiency of sugarcane production in Louisiana is limited by the attack of diseases and insect pests. The goal of the research being conducted by Agricultural Research Service (ARS), Southern Regional Research Center (SRRC), Sugarcane Research Unit's (SRU) scientists in this CRIS project is to reduce the adverse impact of disease and insect pests on the United State sugarcane industry through four integrated objectives. The first objective is to identify sugarcane plants resistant to the major diseases and insect pests of sugarcane that can be used as parents for the next generation of sugarcane varieties. The disease and insect resistant parents may be found among commercial-type varieties of sugarcane or plants of wild sugarcane relatives. The second objective is to identify genetic markers linked to genes for disease and insect resistance. Scientists can then use developed
laboratory methods to identify plants with genes for resistance to diseases and insects rather than conducting large-scale field tests that require the exposure of the plants to disease agents and insect pests. A third objective is to determine how changing cultural practices, including changes in harvesting and planting methods, the elimination of burning, and an emphasis on reduced pesticide use, will affect the incidence and severity of sugarcane diseases and insect pests. If the effect of diseases and insect pests increases with the changes in cultural practices, research will be done to determine what actions are needed to reduce the threat. The final objective of this research is to determine the distribution of races, strains, or other genetically different groups among the populations of disease agents and insect pests. Recently developed molecular approaches has enhanced the ability of scientists to study of the genetics of disease agents and insect pests and determine their
ability to attack modern sugarcane varieties. 2. How serious is the problem? Why does it matter? All sugarcane varieties recommended for planting in Louisiana are susceptible to the disease that most sugarcane scientists agree is potentially the most important disease of sugarcane, ratoon stunting disease (RSD). Ratoon stunting disease has been estimated to cost growers in Louisiana approximately $20 million per year in direct loss of yield and in the expense of control. Varieties recommended for planting in Louisiana are resistant or moderately resistant to the other major diseases of sugarcane that occur in the United States, smut, mosaic, and leaf scald, except for one variety which is highly susceptible to leaf scald. The major effect of these diseases occurs with the loss of susceptible breeding lines that are used as parents in the commercial varietal development program. The sugarcane borer is the most destructive insect pest in the Americas. In Louisiana, this insect is
capable of causing yield losses approaching $2.5 million with an additional $5.5 million spent for insecticide applications. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? Research aimed at detecting and managing diseases to minimize their economic impact on sugarcane production contributes to the Plant Diseases National Program 303(60%). Research on the development of integrated pest management practices to limit the impact of insect pests in sugarcane production contributes to the Crop Protection and Quarantine National Program 304(40%). 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2003: Blastobasis graminea, an insect pest of sugarcane in Columbia and Venezuela, has in recent years been found in Costa Rica and Mexico indicating a northward movement that could threaten sugarcane production in the southeastern United States. In 2003, a team lead
by USDA-ARS scientists and included members from Louisiana State University, Texas AM University, Mexico, and private industry conducted a survey at 31 sites in the northeastern Gulf Coast of Texas and southern Louisiana to determine if B. graminea is present and, if present, its distribution. The only observation of B. graminea, the first record of the insect in the United States, was in Louisiana where it was found to be feeding on smooth cordgrass, a coastal marsh grass, but not on sugarcane. Concerns associated with this first report of B. graminea in Louisiana are that the insect may affect the smooth cordgrass which is planted in wetland stabilization projects and that the smooth cordgrass may serve as a source of the insect pest to spread into sugarcane. B. Other Significant Accomplishments: 1. The most effective method of controlling insect pests and diseases of sugarcane is the planting of varieties with combined resistance to the major pests and disease agents. ARS
scientists at the SRU screen tens of thousands of progeny each year for resistance to insect pests and diseases and for their yield potential in an effort to find that rare individual that is better adapted to the Louisiana environment than varieties currently grown by farmers and has resistance to all the major insect pests and diseases. A new variety of sugarcane, HoCP 96-540, with resistance to mosaic, smut, and leaf scald was released for commercial production in 2003. Variety HoCP 96-540 will help the farmer improve efficiency by providing them with a variety that has equal or better yield potential and disease resistance to variety LCP 85-384 that currently occupies 85 percent of the sugarcane production area in Louisiana. 2. Recently, several varieties of sugarcane believed to be resistant to mosaic, a serious disease of sugarcane in Louisiana caused by sorghum mosaic virus (SrMV), developed the disease during the final stages of testing before release to commercial growers.
Because of this observation and the development of atypical symptoms on susceptible plants, scientists from the SRU, collected and identified a large number of SrMV isolates from field-infected sugarcane plants to determine if there had been a change in the strains of the virus causing the disease. In contrast to a collection of isolates collected between 1990 and 1995 in which more than 90 percent were SrMV strain H and the remainder other described strains, approximately 60 and 18 percent of the isolates collected between 2001 and 2003 were strains I and H, respectively; 15 percent an unknown strain of SrMV; and the remaining 7 percent appeared to be strains of a virus other than SrMV or sugarcane mosaic virus that causes mosaic in other locations. These results demonstrate the ability of the different strains of the SrMV to become predominant, for new strains to emerge, or for a new virus to infect Louisiana sugarcane; and suggest that a mixture of strains be used to screen new
germplasm for mosaic resistance. 3. The only known method of moving the sugarcane yellow leaf virus (SCYLV) that causes sugarcane yellow leaf disease from a disease plant to a healthy plant is by a group of insects known as aphids that feed on the diseased plants then move the virus to the healthy plants. To uniformly test sugarcane varieties for susceptibility to sugarcane yellow leaf disease, the ARS research entomologist and research pathologist at the SRU transferred aphids that had colonized diseased plants to healthy test varieties under controlled greenhouse conditions following protocols they had developed earlier. All tested varieties were susceptible to infection by the virus; however, the rate of disease expression and the percent of plants that became infected indicated a difference in susceptibility of the varieties. This information will assist sugarcane breeders avoid making crosses between parents that are highly susceptible to sugarcane yellow leaf disease. 4. To be
effective as a biological control agent, insects that feed on the sugarcane borer must be able to survive the Louisiana winters and do not have to be reintroduced. The ARS research entomologist at the SRU introduced a new strain of Cotesia flavipes, a very small wasp that feeds on and kills the sugarcane borer, monitored their parasitizing sugarcane borers that had infested stalks of cane, and then observed the following spring to determine if the parasitic wasp survived the winter and was again attacking the destructive sugarcane borer. The new strain of the wasp survived the winter; however, further testing will be needed to determine if they can survive throughout the sugarcane growing region and through different winter conditions. The results are encouraging that a biological control method can be developed and reduce the dependence on chemical control of this major pest. C. Significant Accomplishment/Activities that Support Special Target Populations: None. D. This project
contributes to subordinate project 6435-21000-006-07T (Improving Sugarcane Productivity by Conventional and Molecular Approaches to Genetic Development) which is part of the parent project 6435-21000-006-00D of the same name. Additional details of research can be found in the reports of the subordinate and parent projects. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. The increased proportion of experimental varieties in the commercial breeding program that are resistant to mosaic, smut, and leaf scald is the result of identifying and incorporating disease resistance into breeding lines. New sources of germplasm have been introduced into the program from wild relatives of sugarcane. Four of the last five varieties released and recommended for planting in Louisiana are the result of a basic breeding program designed to incorporate genes from wild relatives of sugarcane into commercially adapted varieties. A total of
seventeen breeding lines resistant to the sugarcane borer have been registered and released through the Crop Science of America. Commercial varieties with borer resistance obtained from crosses of this germplasm are possible in the next four to five years. A high yielding variety with even a moderate level of sugarcane borer resistance could reduce insecticide usage by as much as 50%. The development and implementation of nucleic acid-based protocols that detect and identify the bacterial and viral pathogens in infected sugarcane tissue help ensure disease-free seed cane for the sugarcane industry. These protocols are used in quarantine facilities to prevent diseased foreign sugarcane stalks from coming into the U.S.A. mainland and in local laboratories to safely permit interstate germplasm exchange. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2004: With the verification of techniques to conduct controlled SCYLV transmission studies using the aphid,
Melanaphis sacchari, response of additional sugarcane varieties and breeding lines to SCYLV infection will be determined. Resistant varieties and clones will be recommended for incorporation into the commercial breeding program. A reference population for the identification of genetic markers for disease and insect resistance was developed in FY 2002 and FY 2003. Clones rated resistant to mosaic in FY 2003 will be verified in FY 2004. The population of clones will be rated for resistance to ratoon stunting disease, leaf scald, and the sugarcane borer in FY 2004. The effects of organic residue management practices on plant pathogens and insect pests will be determined. Research will continue in FY 2004 to discover the factors that affect the predominance of one strain of SrMV over another and to determine the identification of unknown virus isolates causing mosaic in sugarcane during surveys conducted in 2002 and 2003. As results are obtained from studies replicated over time and
environments, reports will be prepared and the results presented at grower and scientific meetings and in scientific journals. FY 2005: Continue on-going collaboration with research geneticists in screening and recommending germplasm and varieties for inclusion or continued evaluation in the sugarcane breeding program. Identify genetic markers associated with borer resistance and mosaic resistance. Verify clones resistant to ratoon stunting disease and screen clones for resistance to sugarcane yellow leaf virus. Ratoon crops of tests to determine effects of sugarcane yellow leaf and ratoon stunting disease on yield and quality of sugarcane will be harvested. Continue evaluation of effects of organic residue management on diseases and insect pests in ratoon crops. Continue genetic analysis of strains of sorghum mosaic virus not previously described and of potentially new viruses found infecting sugarcane. Surveys will continue to determine if exotic pathogens or biotypes are introduced
into the sugarcane industry. FY 2006: Continue on-going collaboration with research geneticists in screening and recommending germplasm and varieties for inclusion or continued evaluation in the sugarcane breeding program. Verify and further characterize genetic markers associated with borer resistance and mosaic resistance and identify markers for other diseases and insect pests including ones for leaf scald and ratoon stunting disease. Continue evaluation of clones resistant to ratoon stunting disease and sugarcane yellow leaf virus. Ratoon crops of tests to determine effects of sugarcane yellow leaf and ratoon stunting disease on yield and quality of sugarcane will be harvested. Continue evaluation of effects of organic residue management on diseases and insect pests in ratoon crops. Surveys will continue to determine if exotic pests or disease agents are introduced into the sugarcane industry. 7. What science and/or technologies have been transferred and to whom? When is the
science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? A variety, HoCP 96-540, was released by the Louisiana Sugarcane Variety Advancement Committee composed of members from ARS and Louisiana State University research scientists and farmers and staff of the American Sugar Cane League, in 2003. In experimental tests, the variety meets or exceeds the yield of the current leading variety, LCP 85-384, and has resistance to mosaic, leaf scald, smut, and moderate levels of susceptibility to rust and ratoon stunting disease. Although susceptible to the sugarcane borer, the infection processes have been fully characterized and an integrated pest management program has been developed for control of borers in this variety. The variety should provide an excellent alternative to the planting of LCP 85-384 that is currently accounts for 85 percent
of the area planted to sugarcane in Louisiana and lessen the vulnerability of the industry to the introduction of a new disease or insect pest or biotype of a disease or insect already present in the industry. The greatest constraint to the releasing a sugarcane variety with improved characteristics is the long testing cycle (12-14 years) and the difficulty of incorporating a large number of desirable traits into a single variety. The research entomologist and research pathologist presented talks at fall and spring Extension/Research Sugarcane Training Meetings attended by Extension agents, specialists, and research scientists from ARS and Louisiana State University. They participated in several parish field days and grower meetings attended by Extension agents, crop consultants, and growers where management of insect pests and diseases was discussed. The ARS research entomologist organized and chaired a session between crop consultants and ARS researchers to discuss research
information developed by the researchers and the application of the knowledge to resolve grower problems and to gain a perspective of research needs from the consultants. More detailed scientific presentations were given at a national commodity meeting, American Society of Sugar Cane Technologists, attended by farmers and researchers; an international workshop of sugarcane pathologist sponsored by the International Society of Sugar Cane Technologists; and the International Congress of Plant Pathology attended by peer scientists. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Grisham, M.P. Sugarcane disease update. Extension/Research Sugarcane Training Meeting. December 2002 and May 2003. White, W.H. Impact of Cotesia sp. on Sugarcane Borer. Extension/Research Sugarcane Training Meeting. 2003. Grisham, M.P. Old Diseases/New
Diseases/ New Old Diseases. Presentation at the Terrebonne Parish and Area Sugarcane Field Day. 2003. White, W.H. Response of the new variety, HoCP 96-540, to the sugarcane borer. Presentation at the Terrebonne Parish and Area Sugarcane Field Day. 2003.
Impacts
(N/A)
Publications
- Grisham, M.P., Pan, Y. 2003. Identification of virus isolates causing mosaic of sugarcane in Lousiana [abstract]. 8th International Congress on Plant Pathology, February 2-7, 2003, Christchurch, New Zealand. 2(23.31) :308.
- Grisham, M.P., Pan, Y.-B. Variability of the sugarcane mosaic virus complex in Louisiana. Proceedings of International Society of Sugar Cane Technologists Pathology Workshop. 2003. Paper No. 13.
- Grisham, M.P., Pan, Y., Dufrene Jr, E.O. 2003. A potential new strain of sorghum mosaic virus in Louisiana [abstract]. Sugar Journal. 66(1):33.
- Kimbeng, C.A., White, W.H., Miller, J.D., Legendre, B.L. Sugarcane resistance to the sugarcane borer: performance among progeny derived from resistant and susceptible parents. Sugar Journal. 2003. v. 66(1):Abstract p. 30.
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Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The efficiency of sugarcane production in Louisiana is limited by the attack of diseases and insect pests. Agricultural Research Service (ARS) researchers are approaching the control of these major disease and insect pests primarily through the development of integrated management systems with a major component of these systems being the development and planting of resistant varieties and the use of nonchemical management strategies. 2. How serious is the problem? Why does it matter? All varieties recommended for planting in Louisiana are susceptible to ratoon stunting disease. Even with efforts to control the disease with cultural practices, losses are estimated to cost growers approximately $20 million per year. Varieties recommended for planting in Louisiana are resistant or moderately resistant to smut, mosaic, and leaf scald, except for one variety which is highly susceptible to
leaf scald. The major effect of these diseases occurs with the loss of susceptible breeding lines that are used as parents in the commercial varietal development program. The sugarcane borer is the most destructive insect pest in the Americas. In Louisiana, this insect is capable of causing yield losses approaching $2.5 million with an additional $5.5 million spent for insecticide applications. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? Research aimed at detecting and managing diseases to minimize their economic impact on sugarcane production contributes to the Plant Diseases National Program 303(60%). Research on the development of integrated pest management practices to limit the impact of insect pests in sugarcane production contributes to the Crop Protection and Quarantine National Program 304(40%). 4. What was your most significant accomplishment this past year? A. This new bridging research project
established 01/04/02 replaced research project 6435-22000-007-00D entitled "Disease and Insect Control Mechanisms for the Enhancement of Sugarcane Germplasm Release." The only known method of moving the virus that causes sugarcane yellow leaf disease from a disease plant to a healthy plant is by a group of aphids that feed on the diseased plants then move the virus to the healthy plants. To test sugarcane germplasm for susceptibility to sugarcane yellow leaf disease, the ARS research entomologist and research pathologist at the SRU used greenhouse techniques developed earlier to place aphids on diseased plants and then move them to different varieties of healthy test plants. All tested varieties were susceptible to infection by the virus; however, the rate of disease expression and the percent of plants that became infected indicated a difference in susceptibility of the varieties. This information will assist sugarcane breeders in attempting to avoid making crosses between parents
that are both highly susceptible to sugarcane yellow leaf disease. B. Other Significant Accomplishments: 1. The ARS research entomologist at the SRU has been attempting to find a strain of Cotesia flavipes, a parasitic wasp that feeds on sugarcane borers, that can survive the Louisiana winters and not have to be reintroduced. A new strain of C. flavipes was introduced in different location, monitored during the same year to verify that they were parasitizing sugarcane borers that had infested stalks of cane, then observed the following spring to determine if the parasitic wasp survived the winter and was again attacking the destructive sugarcane borer. The new strain of the wasp survived the winter; however, further testing will be needed to determine if they can survive throughout the sugarcane growing region and through different winter conditions. The results are encouraging that a biological control method can be developed and reduce the dependence on chemical control of this
major pest. 2. The most effective method of controlling insect pests and diseases of sugarcane is the planting of varieties with combined resistance to the major pests and pathogens. ARS scientists at the SRU screen tens of thousands of progeny each year for resistance to insect pests and diseases and for their yield potential in an effort to find that rare individual that is better adapted to the Louisiana environment than varieties currently grown by farmers and has resistance to all the major insect pests and diseases. Progress in developing potential varieties with superior insect and disease resistance was demonstrated at each stage of the 12 to 14 year testing process. Although only a few varieties will ultimately be released to and grown by the farmers, they will help the farmer improve efficiency through improved insect and disease control. C. Significant Accomplishment/Activities that Support Special Target Populations: None. 5. Describe your major accomplishments over
the life of the project, including their predicted or actual impact? The increased proportion of experimental varieties in the commercial breeding program that are resistant to mosaic, smut, and leaf scald is the result of identifying and incorporating disease resistance into breeding lines. New sources of germplasm have been introduced into the program from wild relatives of sugarcane. Three of the last four varieties released and recommended for planting in Louisiana are the result of a basic breeding program designed to incorporate genes from wild relatives of sugarcane into commercially adapted varieties. A total of seventeen breeding lines resistant to the sugarcane borer have been registered and released through the Crop Science of America. Commercial varieties with borer resistance obtained from crosses of this germplasm are possible in the next four to five years. A high yielding variety with even a moderate level of sugarcane borer resistance could reduce insecticide usage
by as much as 50%. The development and implementation of nucleic acid-based protocols that detect and identify the bacterial and viral pathogens in infected sugarcane tissue help ensure disease-free seed cane for the sugarcane industry. These protocols are used in quarantine facilities to prevent diseased foreign sugarcane stalks from coming into the U.S.A. mainland and in local laboratories to safely permit interstate germplasm exchange. 6. What do you expect to accomplish, year by year, over the next 3 years? FY 2003: Unique deoxyribonucleic acid (DNA) markers associated with resistance to the sugarcane borer will be identified within a reference population, one with individuals that have very similar characteristics except for a trait of interest. A reference population for the identification of DNA markers for mosaic resistance will be developed. Offspring of crosses between wild relatives of sugarcane with resistance to borers and commercial varieties will be evaluated.
Biological control research and research on how the sugarcane yellow leaf virus (SCYLV) spreads and survives on LCP 85-384, which occupies 85 percent of Louisiana sugarcane industry will continue. Release sites will be monitored for over wintering parasites. The characterization of new strains of sorghum mosaic virus (SrMV), including nucleic acid sequence analysis and the pathogenicity testing will be conducted. Field plots will be established to determine the effect of the leaf trash blanket created from cutting unburned cane with the combine harvester on soil microflora. Preliminary studies indicated that these need to be plots that can be continuously evaluated for several years. FY 2004: With the development of techniques to conduct controlled SCYLV transmission studies using the aphid, Melanaphis sacchari, response of additional sugarcane varieties and breeding lines to SCYLV infection will be determined. Resistant varieties and clones will be recommended for incorporation
into the commercial breeding program. Favorable results of biological control of borer research in FY 2003 will result in an increased number of release sites and potential industry impact studies in FY 2004 and FY 2005. Borer-resistant progeny from crosses made in FY 2003 will be used as parents for crosses. Research to discover the factors that affect the predominance of one strain of SrMV over another will continue. Changes in soil microbial populations will be determined in FY 2004 and FY 2005. The effects of trash management practices on soil microbial populations will be determined. FY 2005: Verification of DNA markers for borer resistance and mosaic resistance will continue. The application of biological control of borers will be evaluated. Genetic studies of the variability of SrMV will continue. The long-term effects of trash-management practices will also continue. As results are obtained from studies replicated over time and environments, reports will be prepared
and the results presented at grower and scientific meetings and in scientific journals (FY2003, FY2004, and FY2005). 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Results of experiments to determine the susceptibility to the major insect pest, the sugarcane borer, and to the major diseases, mosaic, rust, leaf scald, and ratoon stunting disease of varieties being tested for possible release to the Louisiana sugarcane industry were presented to the Louisiana Sugarcane Variety Advancement Committee. The committee is composed of representatives of ARS and Louisiana State University research scientists and farmers and staff of the American Sugar Cane League. The results are a portion of the information used by the committee to determine which varieties will be advanced for another year of
testing and finally if the variety will be released to the Louisiana sugarcane farmer. The most advanced variety in the testing program is to be considered for release in 2004 and has superior yield characteristics and is resistant to the major diseases. The greatest constraint to releasing a sugarcane variety with improved characteristics is the long testing cycle (12-14 years) and the difficulty of incorporating a large number of desirable traits into a single variety. The research entomologist and research pathologist presented talks at the spring Extension/Research Sugarcane Training Meeting attended by Extension agents, specialist, and research scientists from ARS and Louisiana State University. They also participated in several parish field days and grower meetings attended by Extension agents, crop consultants, and growers where management of insect pests and diseases was discussed. A popular article was written for the commodity journal, Sugar Bulletin, that is subscribed
to by farmers, consultants, Extension agents, agribusiness personnel, and sugarcane researchers. It describes changes in the virus that causes mosaic and how this could ultimately affect varieties currently being grown by the farmers. A more detailed scientific presentation of the results of this research was presented at a national commodity meeting, American Society of Sugarcane Technologists, attended by farmers and researchers and at the Annual Meeting of the American Phytopathological Society attended primarily by peer scientists. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not replace your review publications which are listed below) Grisham, M.P., Pan, Y.-B. Molecular identification of virus isolates causing mosaic in Louisiana. Extension/Research Sugarcane Training Meeting. 2002. Grisham, M.P. Gotcha! Presentation at the Terrebonne Parish and Area Sugarcane Field Day. 2002. White, W.H. Debugging the
Louisiana Industry. Presentation at the Terrebonne Parish and Area Sugarcane Field Day. 2002. Grisham, M.P., Y.-B. Monitoring mosaic. Sugar Bulletin. 2002. v. 80(9). p. 29-31.
Impacts
(N/A)
Publications
- 1. Grisham, M.P., Pan, Y.-B. Molecular identification of virus isolates causing mosaic in Louisiana. Sugar Journal. 2002. v. 64(1): Abstract p. 26- 27.
- 2. Grisham, M.P., Pan, Y.-B. A shift in the strains of sorghum mosaic virus causing mosaic in Louisiana. Phytopathology. 2002. v. 92(Suppl. 6): Abstract p. S32.
- 3. Grisham, M.P. International testing for genetic variability of sugarcane smut. XIII Biennial Workshop on Smut Fungi. 2002. Paper No. 2.
- 4. Pan, Y.-B., Tew, T., Grisham, M.P., Richard, E.P., White, W.H., Veremis, J.C. Selection of interspecific sugarcane hybrids using microsatellite DNA markers. Sugar Journal. 2002. v. 65(1): Abstract p. 27- 28.
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