Progress 10/01/18 to 09/30/19
Outputs
Target Audience:This project has reached lettuce growers at the Everglades Agricultural Area (EAA); there are mainly five growers at the EAA categorized as only growers General Management Inc, Roth Farm, Duda Fresh, company that are growers and packing, TKM-Bengard and VegPro. This project has reached other small-scale growers in the state of Florida. This includes hydroponics, aquaponics, and greenhouse leafy vegetable growers The project has also reached local vegetable extension agents in Palm Beach, Saint Johns, Hardee, Hillsborough, Miami Dade and Broward Counties. Other audience are collaborators in other states. Changes/Problems:We faced several challenges during the execution of experiments in the period 2018-2019. Failure on repeating an experiment for Phosphorus use efficiency lettuce cultivars due to mechanical errors of fertilizer application. Experiments were lost due to warmer temperatures during growing season and initial flooding before expected. The lack on qualified personnel to work in field settings and the unavailability of mechanical equipment able to perform several tasks The high abundance of weeds and the lack of approved chemicals to control them. Few methods to assess traits in lettuce did not work as expected. Therefore, we had to rework some of the protocols. ? What opportunities for training and professional development has the project provided?The first Ph.D. student continued to work in postharvest of lettuce and other leafy vegetables for production at the Everglades Agricultural Area (EAA). A second Ph. D. student worked on Phosphorus Use Efficiency in lettuce. One graduate student at the Master of Science level was recruited to work on Fusarium Wilt of lettuce. The student has experience working with the fungus in a different pathosystem. Three international interns were trained in lettuce breeding and genetics; two students were visitors from Brazil and one from Tajikistan who was awarded one year fellowship from Fulbright program Two high school students were trained in general research skills using lettuce breeding and genetics as models. How have the results been disseminated to communities of interest?In the present report period, the lettuce breeder at the EREC-UF-IFAS explained the advances of the lettuce program at the two annual Lettuce Advisory Committee Meeting. This venue reunites growers and other stakeholders in the state. Additional dissemination is done through face-to-face interaction with growers in a monthly base during the lettuce growing season. Lettuce Growers are informed in the advances of this project as the PI is invited by the growers to briefly explain the status of this project in one of the meetings with the Florida Fruit and Vegetable Association (FFVA) representative. We have participated in extension venues such as the Florida Seed Association Annual meeting. In Service Trainings (ISTs) through the dean of extension office at the University of Florida to train county extension faculty and other statewide extension agents. Other type of dissemination includes the participation of the lettuce breeding program at the South Florida Agricultural Annual Fair. On here, the PI of this project explained the work conducted at the lettuce breeding program of the University of Florida to the general public. In addition of explaining research activities to visitors at the University of Florida that includes general public, high schools, college students, legislators and others. What do you plan to do during the next reporting period to accomplish the goals?Goal 1. Lettuce Breeding and Genetics for Florida Production Developing resistant cultivars against Bacteria Leaf Spot (ongoing effort) We will continue the process of breeding lines for BLS resistance with romaine and iceberg background. We will select in field crosses of the resistant PI to BLS with butterhead lettuce and baby leaf. We will confirm sources of the resistance to Xanthomonas campestris pv. vitians. The crosses of Resistant x Resistant to BLS cultivars will be evaluated on an allelism test to determine the genetics of resistance in new identified sources We will continue to collect isolates of BLS over the 2018-19 season may an outbreak happens. They will be tested on any varieties found resistant or susceptible to Florida isolates.? Phenotypic characterization of the existent lettuce germplasm We will continue testing lettuce in sandy soils and their relationship to warmer temperatures. Phosphorus use efficiency and its implication in breeding We will screen for a third time 64 lettuce EREC breeding lines, Plant Introductions and cultivated varieties in field conditions to confirm preliminary results. These lines will be screened with non-application of Phosphorus, Half of the dose recommended by a certified laboratory and the standard dose needed. We will advance mapping populations into F3 for further phenotyping, genotyping and subsequent QTL identification. We will increase a GWAS population as well to likely do the same type of studies Study the genetics of several traits We will continue to screen lettuce seed germination at high temperature and then we will screen lettuce seedlings at high temperature. We will continue to screen lettuce planted at high temperature in field conditions. We will screen the University of Florida germplasm collection for Fusarium wilt of lettuce and determine pathogenicity in recent collected isolates. We will also screen newer introductions to our germplasm bank and as well wildtypes of the genus Lactuca Other collaborative efforts in lettuce breeding (controlled environments and red leaf lettuce under light conditions) We will explore other protected structures to establish preliminary experiments along the state of Florida. Goal 2. Other Lettuce Types and Leafy Vegetables 2.1. Explore the economic importance of other lettuce types and Leafy Vegetables for the EAA and Establish new breeding programs for leafy vegetables Nothing to be conducted in the next period
Impacts
What was accomplished under these goals?
Goal 1. Lettuce breeding and genetics for Florida production Developing resistant cultivars against Bacteria Leaf Spot (BLS) We continued the breeding of lettuce lines resistant to BLS. Three hundred and twenty breeding lines in several stages were produced, starting from F2 to F4. Only few lines are confirmed to be resistant to BLS and present an acceptable type of romaine or iceberg lettuce. We increased our breeding lines by making newer crosses of the resistant Plant Introduction (PI) 358001-1 to bibb, leaf and Latin lettuce types. These crosses are in F2 and are ready for plant selection. We screened 69 PIs requested to the National Plant Germplasm System (NPGS) of the USDA. These tests were conducted with three isolates of BLS in Florida. In collaboration with the USDA-ARS in California these PIs were also screened with two isolates of races 1 and 3 in California. Further testing is needed to verify the initial resistance found in a set of PIs. These putative sources of resistance were crossed to the PI358001-1 in a cross of Resistant x Resistant. Morphological characterization of the existent and introduced lettuce germplasm Several germplasm materials were characterized for other diseases and abiotic stresses including heat tolerance, lettuce in sandy soils. Phosphorus use efficiency and its implication in breeding During the season of 2018-2019, we repeated an experiment with 64 lettuce cultivars for phosphorus use efficiency. This experiment was fertilized using the recommended dose of Phosphorus (P), half of this dose and no application of Phosphorus. We collected soil and tissue sample to determine P uptake. Results indicate that few cultivars may efficiently uptake P. Further experiments will help to determine these initial findings. We crossed the most efficient P cultivars with no efficient cultivars to develop mapping populations. We advanced 20 of these crosses into a second generation of breeding. Eight commercial cultivars (4 iceberg and 4 romaine) in growers' field were evaluated to collect yield data. Cultivar Flagler had the highest yield, but low number of marketable heads and cultivar Chosen had slightly lower yield but less marketable heads. Romaine cultivar 'Manatee' and 'Okeechobee' had the highest yield and marketable heads. The same 8 commercial cultivars were evaluated under three Phosphorus doses as previously indicated. Within the scope of the same objective, 12 lettuce cultivars were grown in aeroponics under two different P sources (soluble and insoluble). Comparing the results from the 2 P treatments, 60183 had the lowest reduction in root and shoot fresh weight as well as in root and shoot dry weight to be considered as P efficient. Study the inheritance of traits of interests and design breeding strategies based on their genetic basis For Lettuce BLS We produced 10 different crosses combinations between newly identified resistant PIs x the most resistant PI 358001-1 to Florida strains thus far. We will study the inheritance of the resistance in a resistant x resistant combination using an allelism test inoculated with at least three Florida isolates. We initiated Genome Wide Association Studies (GWAS) of 500 lettuce accessions with three of our most representative isolates of Xanthomonas campestris pv. vitians. the causal agent of BLS For other traits Postharvest. - We started to work in pinking, a problem that affect lettuce growers in Florida. Initially we are setting protocols on how to measure pinking in lettuce in a few selected lines. Once the protocol is developed, we will screen the Florida germplasm collection. The protocol was developed using three lettuce cultivars with different self-life (high, intermediate and low) and evaluated for 10 days at 10?C and 15?C. The experiment was conducted twice in two different planting slots in Florida and confirmed that Okeechobee shelf life was 10 days which corresponds to a 28 day shelf life (high) at 1-5?C, 60182 shelf life was 8 days which corresponds to a 21 day shelf life (intermediate) at 1-5?C, and La Brillante shelf life was 4 days which corresponds to about 14 days at 1-5?C (low). We also measured chlorophyll fluorescence in lettuce and its relationship to postharvest parameters. Packaged romaine and iceberg lettuce were purchased and evaluated every 2 days for Fv/Fm and Y(II) fluorescence, color (Minolta), subjective ratings, and head weight at 10?C and 15?C. The objective was to determine if fluorescence could detect senescence rate prior to visual symptoms. We evaluated Y(II) for 24 hours after harvest to determine if the stresses on the photosystem II from harvest until adapting to storage was indicative of shelf-life. Our result was inconclusive. In addition, we are investigating in several compounds that may suppress pinking in lettuce. We tested the solubility of three plant-based compounds with DMSO and water. Iceberg lettuce was tested with these compounds and evaluated after 10 days of storage. All treatments showed moderate to severe discoloration at 4 days. An additional test with romaine lettuce was evaluated on individual leaves (with and without wounding) using an aniline blue solution to test uptake time and spread. We found that in wounded lettuce the aniline blue solution spread within 2 minutes and this compound barely spread on unwounded tissue. Fusarium wilt. - A never identified disease in Florida, Fusarium wilt, was detected for the first time in the state. We collected over 100 isolates in one of the ranches were the disease was first seen. Initially, we screened 34 Florida lettuce cultivars and breeding lines to identify locally adapted lettuce lines. Isolates were confirmed to be race 1 of Fusarium wilt indicated by lettuce differentials used for the test and by molecular markers in DNA extracted from these isolates. To date, we have increased our collection by 30 more isolates as new nearby plots are presenting the disease. Lettuce growers in Florida were trained to avoid further spread of the disease. We have conducted several experiments at the beginning and at the end of season in field conditions to identify heat tolerant lettuce cultivars. We have screened our lettuce collection for germination at high temperatures as well. Preliminary results indicate genetic variation for Florida lettuce to germinate at high temperatures. Lettuce Downy Mildew. - Bremia lactucae isolates from naturally infested Florida lettuce fields were collected and recovered in Green Towers seeds (universal susceptible to B. lactucae) in a tissue culture boxes on a filter paper placed in a growing chamber under 20°C and 12h light/ dark photoperiod; collection of material with Lettuce Downy Mildew (LDM) from the field and stocked on -80C; different experiments to find a methodology to increase the lesions sporulation to be inoculated and different experiments to adapt the inoculation methodology, several inoculations to obtain B. lactucae isolates; 20 differentials cultivars were planted on trays that later were transferred to pots, these pots were placed on a lettuce field infected by LDM. Of the total of 275 inoculations performed were found 11 viable isolates rescued in the season of 2018-2019. Other collaborative efforts in lettuce breeding (controlled environments and red leaf lettuce under light conditions) We retested 3 breeding lines of the University of Florida lettuce breeding program. Other experiments were also set in aquaponics and small hydroponic settings. We have crossed 10 red leaf lettuce lines with one cultivar that performs differently under different light settings. Few of the most advanced breeding lines were tested in hydroponics and aquaponics at growers' facilities Goal 2. Research on other lettuce types and Leafy Vegetables Explore the economic importance of other lettuce types and Leafy Vegetables for the EAA and Establish new breeding programs for leafy vegetables Nothing to report
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Hayes, R., G.V. Sandoya, B. Mou, I. Simko, K. Subbarao. 2018. Release of three iceberg lettuce populations with combined resistance to two soil borne diseases. HortScience 53: 247-250.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Wadlington, W p., G. Sandoya, C.F. Miller, J. Villegas, R.N. Raid. 2018. Stemphylium leaf spot in spinach: Chemical and breeding solutions for this threatening disease in Florida. Proceedings of the Florida State Horticultural Society 131:151-158.
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Miller C.F., G. Sandoya, W. Wadlington P, M. Bardin, E. McAvoy, R.N. Raid. 2018. Addressing the threat posed by Fusarium wilt of lettuce to Florida in an attempt to limit its spread. Proceedings of the Florida State Horticultural Society 131:148-150.
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Odero, D.C., G. Sandoya. 2018. Weeds and epidemiology of bacterial leaf spot of lettuce in the Everglades Agricultural Area. Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences. EDIS Publication SS-AGR-347. https://edis.ifas.ufl.edu/ag357 .
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Miller, C.F., G.V. Sandoya, W. Wadlington p, E. McAvoy, M. Bardin, R. Raid. 2018. Extension efforts to manage Fusarium wilt of lettuce, a new threat to Florida lettuce growers. Florida Association of County Agricultural Agents Mid-Year Meeting, Live Oak, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Miller, C.F., G.V. Sandoya, W. Wadlington p, E. McAvoy, M. Bardin, R. Raid. 2018. Extension efforts to manage Fusarium wilt of lettuce, a new Threat to Florida Lettuce Growers. National Association of County Agricultural Agents. Proceedings 103rd and Professional Improvement Conference. P74
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Sandoya G.V., W. Wadlington p, R.N. Raid, I. Simko, C.T. Bull. 2018. Novel sources of resistance to Florida isolates of Bacterial Leaf Spot in Lettuce (Lactuca sativa L.) American Society of Horticultural Sciences Annual Meeting. HortScience 53: S288.
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Raid, R.N., G.V. Sandoya, W. Wadlington p. 2018. Evaluation of Actigard, alone and in combination, for control of Stemphylium leaf spot on spinach, Winter 2017. Plant Disease Management Reports 12: V123. Online Publication doi: 10.1094/PDMR12.
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Raid, R.N., G.V. Sandoya, W. Wadlington p. 2018. Evaluation of strobilurin fungicides for control of Stemphylium leaf spot on spinach, Winter 2017. Plant Disease Management Reports 12: V122. Online Publication doi: 10.1094/PDMR12.
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:This project has reached lettuce growers at the Everglades Agricultural Area (EAA); there are mainly five growers at the EAA categorized as only growers General Management Inc, Roth Farm, Duda Fresh, company that are growers and packing, TKM-Bengard and VegPro. The project has also reached local vegetable extension agents in Palm Beach County. Additional collaborations were set with the North Florida Research and Education Center - Suwanee Valley extension agent. Other collaborations were set with extension agents in small farms, vegetables, water management in Broward, Hardee, Hillsborough, and Miami-Dade counties. Changes/Problems:The biggest challenge during this period was the lack of the precision to develop a molecular marker for marker assisted selection in the lettuce BLS program. We initially tested lettuce in a very late planting for heat tolerance but the experiment was lost due to abundant initial rains in May 2018. What opportunities for training and professional development has the project provided?During this period, one postdoctoral researcher was trained in lettuce breeding and genetics for improving Bacterial Leaf Spot resistance in lettuce. He has also worked in spinach diseases which are issues to leafy vegetable growers in Florida. One graduate student at the Ph.D. level continued to work in postharvest of lettuce and other leafy vegetables for production at the Everglades Agricultural Area (EAA). The student has a master in postharvest quality and a bachelor in food science; both topics are important to the lettuce industry in Florida and elsewhere. One graduate student at the Ph.D. level was recruited to work on Phosphorus Use Efficiency in lettuce. The student worked as crop scout prior to become a graduate. One graduate student at the Master of Science level was recruited to work on Fusarium Wilt of lettuce. The student has experience working with the fungus in a different pathosystem. Two high school students were trained in general research skills using lettuce breeding and genetics as models. The Following is reported in this period as professional development: Kreutz, G g., G. Sandoya, J. Bhadha, G. Liu, M. Resende, A. Wright. 2018. Screening lettuce genotypes for tolerance to low phosphorus inputs in the Everglades Agricultural Area. 6th Annual South Florida Graduate Research Symposium. Immokalee, FL. Kreutz, G g., G. Sandoya. 2018. Breeding lettuce genotypes for tolerance to low phosphorus inputs in the Everglades Agricultural Area. 2nd UF/IFAS Plant Improvement Retreat. Tampa, FL. Wadlington, W p., G. Sandoya, C.F. Miller, J. Villegas, R.N. Raid. 2018. Stemphylium Leaf Spot in Spinach: Chemical and Breeding Solutions for This Threatening Disease in Florida. Florida Society of Horticultural Sciences Annual Meeting. Fort Lauderdale, FL. Wadlington, W p., G. Sandoya, R.N. Raid. Spinach stemphyllium. A new threat to the baby leaf industry in Florida. Florida Seed Association 34th Annual Seed Seminar. 2018. Gainesville, FL Wadlington, W p., G. Sandoya. 2018. Molecular marker for lettuce BLS. Florida Lettuce Advisory Committee Meeting. Belle Glade, FL. How have the results been disseminated to communities of interest?In the present report period, Dr. German Sandoya, lettuce breeder at the EREC-UF-IFAS explained the advances of the lettuce program and what the future work is that needs to be accomplished during the first and second annual Lettuce Advisory Committee Meeting. Lettuce Growers are informed in the advances of this project as the PI is invited by the growers to briefly explain the status of this project in one of the meetings with the Florida Fruit and Vegetable Association (FFVA) representative. In addition, the PI and his team working on this grant had periodical meetings with the community of lettuce growers to inform them of the advances of this grant. In fact, we have agreed to meet and discuss in detail the objectives of future funding for BLS work to the Florida Department of Agriculture and Consumer Services and any other funding agency. Additional dissemination is done through face-to-face interaction with growers in a monthly base during the lettuce growing season. Other stakeholders such as one Seed Company tested their material for suitability at the Everglades Agricultural Area. Other venues are the Florida Seed Association Annual meeting and the Florida Foundation for seed producers where the PI was an invited speaker. On here the PI explained the objectives of this project to the stakeholders of the leafy vegetable industry. Other type of dissemination includes the participation of the lettuce breeding program at the South Florida Agricultural Annual Fair. On here, the PI of this project explained the work conducted at the lettuce breeding program of the University of Florida to the general public. What do you plan to do during the next reporting period to accomplish the goals?Goal 1. Lettuce Breeding and Genetics for Florida Production 1. Developing resistant cultivars against Bacteria Leaf Spot (ongoing effort) We will continue the process of breeding lines for BLS resistance with romaine and iceberg background. We will select in field crosses of the resistant PI to BLS with butterhead lettuce and baby leaf. We will confirm sources of the resistance to Xanthomonas campestris pv. vitians. The crosses of Resistant x Resistant to BLS cultivars will be advanced to F2 for further testing We will continue to collect isolates of BLS over the 2017-18 season may an outbreak happens. They will be tested on any varieties found resistant to older Florida isolates.? 2. Phenotypic characterization of the existent lettuce germplasm We will continue to test a set of EREC lettuce lines and we will start testing the EREC breeding lines in different conditions such as early planting, late planting, sandy soil conditions, lime rock conditions, nontraditional systems and others. 3. Phosphorus use efficiency and its implication in breeding We will start screening 60 lettuce EREC breeding lines, Plant Introductions and cultivated varieties in field conditions. These lines will be screened with non-application of Phosphorus, Half of the dose recommended by a certified laboratory and the standard dose needed. In addition we will start making crosses in cultivars that differ in the ability to perform well under non P or half of the P applied to make biparental populations. 4. Study the genetics of several traits We will continue to screen lettuce seed germination at high temperature and then we will screen lettuce seedlings at high temperature. We will continue to screen lettuce planted at high temperature in field conditions. We will screen part of our collection for Fusarium wilt of lettuce and determine pathogenicity in recent collected isolates. 5. Other collaborative efforts in lettuce breeding (controlled environments and red leaf lettuce under light conditions) We will explore other protected structures to establish preliminary experiments along the state of Florida. We will advance crosses of cultivar Annapolis with other red lettuces from the USDA GRIN system from F1 seed to F2 seed. Goal 2. Other Lettuce Types and Leafy Vegetables 2.1. Explore the economic importance of other lettuce types and Leafy Vegetables for the EAA and Establish new breeding programs for leafy vegetables Nothing to be conducted in the next period
Impacts
What was accomplished under these goals?
Goal 1. Lettuce breeding and genetics for Florida production Developing resistant cultivars against Bacteria Leaf Spot (BLS) We continued the breeding process of lettuce lines resistant to BLS. Three hundred and twenty breeding lines in several stages were produced, starting from F2 to F4. However, only few lines are confirmed to be resistant to BLS and present an acceptable type of romaine or iceberg lettuce. We increased our breeding pool of breeding lines by making newer crosses of the resistant Plant Introduction (PI) 358001-1 to other types such as bibb, leaf and latin lettuce types. These crosses are in F2 and are ready for plant selection by type. We screened 69 PIs requested to the National Plant Germplasm System (NPGS) of the USDA. These tests were conducted with three isolates of BLS in Florida. In collaboration with the USDA-ARS in California these PIs were also screened with two isolates of races 1 and 3 in California. Further testing needs to be conducted to verify the initial resistance found in a set of PIs. These putative sources of resistance were crossed to the PI358001-1 in a cross of Resistant x Resistant Morphological characterization of the existent and introduced lettuce germplasm We introduced the seed of 25 lettuce cultivars adapted to southwestern planting slots. These lines are romaine, iceberg and butterhead lettuce types that are the base material of the lettuce breeding program. We also introduced lettuce cultivars used as differentials for Fusarium wilt disease and for lettuce downy mildew in order to investigate in these diseases in Florida Phosphorus use efficiency and its implication in breeding During the season of 2017-2018 we planted an experiment with 64 lettuce cultivars of different types, geographical origin and adapted to different lettuce production. This experiment was fertilized using the recommended dose of Phosphorus (P) needed, half of this dose and no application of Phosphorus. We collected soil and tissue sample to determine P uptake. Preliminary results indicate that few cultivars may be able to efficiently uptake P. Further experiments will help to determine this initial findings. Study the inheritance of traits of interests and design breeding strategies based on their genetic basis For Lettuce BLS One PCR-based marker, called BLS_WW_15, designed from a variant detected in the GBS data has been validated in the population PI 358001-1 x Tall Guzmaine. In that population, BLS_WW_15 is effective at selecting the homozygous resistant individuals in the F2 from the cross 'PI358001-1 x Tall Guzmaine' with 85% accuracy. We suspected that the marker should be equally effective in identifying homozygous resistant individuals in other F2 populations as well with 85% accuracy; however, we were not able to design a 100% efficient marker to be used for marker assisted selection. In another research, we aligned our genetic map 'PI358001-1 x Tall Guzmaine' to a previous map developed by the USDA-ARS Salinas, CA 'Salinas 88 x La Brillante' with two new genetic maps coming from population Batavia Reine des Glaces (Reine des Glaces) x Eruption developed by the USDA-ARS Salinas, CA and Batavia Reine des Glaces x Delsay developed by the INRA-Avignon, France. For other traits We started to work in pinking, a problem that affect lettuce growers in Florida. Initially we are setting protocols on how to measure pinking in lettuce in a few selected lines. Once thr protocol is developed we will screen the Florida germplasm collection. In addition, we are investigating in several compounds that may suppress pinking in lettuce. We also initiated measuring the chlorophyll fluorescence in lettuce and its relationship to postharvest parameters. A never identified disease in Florida, Fusarium wilt, was detected for the first time in the state. We collected over 100 isolates in one of the ranches were the disease was first seen. Initially, we screened 34 Florida lettuce cultivars and breeding lines to identify locally adapted lettuce lines. Lettuce growers in Florida were trained to avoid further spread of the disease We have conducted several experiments at the beginning of season and at the end of season in field conditions to identify heat tolerant lettuce cultivars. Newer experiments are needed to identify possibly heat tolerant cultivars as well. Other collaborative efforts in lettuce breeding (controlled environments and red leaf lettuce under light conditions) We retested 3 breeding lines of the University of Florida lettuce breeding program. Other experiments were also set in aquaponics and small hydroponic settings. We have crossed 10 red leaf lettuce lines with one cultivar that performs differently under different light settings. Goal 2. Research on other lettuce types and Leafy Vegetables Explore the economic importance of other lettuce types and Leafy Vegetables for the EAA and Establish new breeding programs for leafy vegetables Nothing to report
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Sandoya, G., K.V. Subbarao, R.J. Hayes. 2017. Delayed wilt symptoms caused by Verticillium dahliae as a resistance characteristic in iceberg lettuce (Lactuca sativa). HortScience 52: 513-519.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Sandoya, G., S. Gurunj, D. Short, K.V., Subbarao, R. Michelmore, R.J. Hayes. 2017. Genetics of resistance in lettuce to races 1 and 2 of Verticillium dahliae from different host species. Euphytica 21: 3-20.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Lafta A., T. Turini, G. Sandoya, B. Mou. 2017. Field evaluation of green and red leaf lettuce genotypes in the Imperial, San Joaquin, and Salinas Valleys of California for heat tolerance and extension of the growing seasons. HortScience 52:40-48.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Puri, K., S. Gurung, D. Short, Z. Atallah, G. Sandoya, R.M. Davis, R.J. Hayes, K.V. Subbarao. 2017. Short-term host selection pressure has little effect on the evolution of a monoclonal population of Verticillium dahliae race 1. Phytopathology 107: 1417-1425.
- Type:
Other
Status:
Published
Year Published:
2017
Citation:
Truco, M.J. L. Bertier, G. Sandoya, A. Vargas, S. Reyes Chin-Wo, T. Gordon, R. Michelmore. 2017. Genetic Basis of Resistance Against Fusarium and Verticillium Wilts in Multiple Populations of Lettuce. XXV Plant and Animal Genome Conference. San Diego, CA. USA.
- Type:
Other
Status:
Published
Year Published:
2017
Citation:
Short, D.P.G., K.D. Puri, G.V. Sandoya, I. Simko, R.J. Hayes, K.V. Subbarao. Characterization of Verticillium dahliae disease reactions in lettuce differentials. American Phytopathological Society. San Antonio, TX. USA
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Progress 03/16/17 to 09/30/17
Outputs
Target Audience:This project has reached lettuce growers at the Everglades Agricultural Area (EAA); there are mainly five growers at the EAA categorized as only growers General Management Inc, Roth Farm, Duda Fresh, company that are growers and packing, TKM-Bengard and VegPro. During this period, two high school students from a local school have been trained in hands-on experience in lettuce breeding and genetics. The two students are females interested to become scientist in the future, one is working in resistance in lettuce against bacterial leaf spot and the other is screening lettuce seed germination at high temperature. The project has also reached the local vegetable extension agents in Palm Beach County. Additional collaborations were set with the North Florida Research and Education Center - Suwanee Valley extension agent as well. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?During this period, two postdoctoral researchers were trained in lettuce breeding and genetics for improving Bacterial Leaf Spot resistance in lettuce. The first postdoc under my supervision moved into an industry job working in breeding. The second postdoc is currently working under my supervision and he is developing an additional research topic in other leafy vegetables soon to be incorporated into this Hatch Project. One graduate student at the Ph.D. level was recruited to work in postharvest of lettuce and other leafy vegetables for production at the Everglades Agricultural Area (EAA). The student has a master in postharvest quality and a bachelor in food science; both topics are important to the lettuce industry in Florida and elsewhere. Two high school students were trained in general research skills using lettuce breeding and genetics as models. The two students will now be students of the University of Florida and will try to come back for summer internships at the EREC in lettuce breeding and genetics. The Following is reported in this period as professional development: Sandoya, G. Improving Lettuce for the challenges of the EAA. Specialty Crop Research Initiative (SCRI) Meeting with the project: Sustaining the supply of high quality lettuce in changing technological and climatic environment. Davis, CA. USA 2017 (Invited Speaker) Sandoya, G. (Presenter) 2017. Improving Lettuce for the Challenges of the EAA. Florida Seed Association 33rd Annual Seed Seminar. Immokalee, FL Sandoya, G. (Presenter) 2017. Breeding Lettuce for High Resistance to Bacterial Leaf Spot. Florida Lettuce Advisory Committee Meeting. Belle Glade, FL Wang, Y, and G. Sandoya (Contributor) 2017. Molecular Marker for Bacterial Leaf Spot resistance. Florida Lettuce Advisory Committee Meeting. Belle Glade, FL How have the results been disseminated to communities of interest?In the present report period, the lettuce breeder at the EREC-UF-IFAS and the Vegetables Extension Agent of Palm Beach County Extension Office organized a "field selection" meeting with the lettuce growers at the EAA. On February 2017, Dr. Sandoya explained the advances of the lettuce program and what the future work is that needs to be accomplished during the second annual Lettuce Advisory Committee Meeting. In addition, Dr. Yunwen Wang presented the work he accomplished during his time at EREC-UF-IFAS and the promising results of the grant. Lettuce Growers are informed in the advances of this project as the PI is invited by the growers to briefly explain the status of this project in one of the meetings with the Florida Fruit and Vegetable Association (FFVA) representative. In addition, the PI and the new postdoc working on this grant had periodical meetings with the community of lettuce growers to inform them of the advances of this grant. In fact, we have agreed to meet and discuss in detail the objectives of future funding for BLS work to the Florida Department of Agriculture and Consumer Services and any other funding agency. Additional dissemination is done through face-to-face interaction with growers on a monthly basis during the lettuce growing season. Other stakeholders such as one Seed Company tested their material for suitability at the Everglades Agricultural Area. Other venues are the Florida Seed Association Annual meeting where the PI was an invited speaker. Here the PI explained the objectives of this project to the stakeholders of the leafy vegetable industry. Other type of dissemination includes the participation of the lettuce breeding program at the South Florida Agricultural Annual Fair. Here the PI of this project explained the work conducted at the lettuce breeding program of the University of Florida to the general public. What do you plan to do during the next reporting period to accomplish the goals?Goal 1. Lettuce Breeding and Genetics for Florida Production 1. Developing resistant cultivars against Bacteria Leaf Spot (ongoing effort) We will continue the process of breeding lines for BLS resistance with romaine background. We will make more crosses with iceberg background as well. Additional breeding efforts will include crosses of the resistant PI with butterhead lettuce and baby leaf. We will look for additional sources of the resistance to Xanthomonas campestris pv. vitians. We will first concentrate our efforts sources of resistance to the California strains and other untested sources to the Florida strains; our goal is to have more than one source of resistance for breeding lettuce against the disease. These putative sources of resistance will be crossed to the PI358001-1 in a cross of Resistant x Resistant New isolates of BLS could be collected in Florida over the 2017-18 season if an outbreak happens. They will be tested on any varieties found resistant to older Florida isolates.? 2. Phenotypic characterization of the existent lettuce germplasm We will choose a set of EREC lettuce lines and we will start testing the EREC breeding lines in different conditions such as early planting, late planting, sandy soil conditions, lime rock conditions, nontraditional systems and others. 3.Phosphorus use efficiency and its implication in breeding We will start screening 60 lettuce EREC breeding lines, Plant Introductions and cultivated varieties in field conditions. These lines will be screened with non-application of Phosphorus (P), Half of the dose recommended by a certified laboratory and the standard dose needed. We will measure the total P concentration and soluble P in plant and soil samples. In addition we will start making crosses in cultivars that differ in the ability to perform well under non P or half of the P applied to make biparental populations. 4. Study the genetics of several traits We will continue to screen lettuce seed germination at high temperature and then we will screen lettuce seedlings at high temperature. We will start making crosses of biparental populations based on results from these experiments. In postharvest we will set the protocol to measure pink rib in lettuce and other leafy vegetables such as escaroles and endives. We will set a protocol to measure ascorbic acid and chlorophyll fluorimeter as an indicators of postharvest in lettuce. 5. Other collaborative efforts in lettuce breeding (controlled environments and red leaf lettuce under light conditions) We will set up new experiments in a hydroponic NFT system in a replicated trial and repeat the experiment in a different season (summer). Additionally we will explore other protected structures to establish preliminary experiments along the state of Florida. We will start making crosses of cultivar Annapolis with other red lettuces from the USDA GRIN system. The F1 seed then will be planted to produce the F2 seed.
Impacts
What was accomplished under these goals?
Developing resistant cultivars against Bacteria Leaf Spot In the last year, substantial progress has been made towards breeding resistance to Bacterial Leaf Spot disease (BLS) into economically desirable lettuce. We have continued the ongoing work and also added new avenues of research stemming from the background and expertise of the new PI and new post doc. Initially 33 F5 breeding lines from the crosses PI358001-1 x Tall Guzmaine (11 lines) and Okeechobee x PI358001-1 (22 lines) were evaluated for Bacterial Leaf Spot Resistance using the isolate L7 of Xanthomonas campestris pv. vitians in a controlled environment experiment. The controls in this experiment were the resistant parent PI358001-1 and the susceptible romaine cultivars Tall Guzmaine and Okeechobee. Three lines from the cross of PI358001-1 x Tall Guzmaine showed little to no disease; these three lines are currently planted this season for additional selection. We planted the F3 of the crosses 10168-1 x PI358001-1 and 10207 x PI358001-1 to reselect F3 plants that will become F4 families. As we lost a significant amount of families for selection, especially the ones with iceberg background we planted again the F2 of the crosses described in the previous paragraph. In 2017 We have collected seed of 136 potentially BLS resistant F3 families of the following crosses Okeechobee x PI358001-1, 50100 x PI358001-1, Terrapin x PI358001-1, 60182-1 x PI358001-1, 60182-2 x PI358001-1, 70096 x PI358001-1, 10179 x PI358001-1, 10198 x PI358001-1, 10207 x PI358001-1, 10380 x PI358001-1, 10168-1 x PI358001-1, 10168-2 x PI358001-1, 10178 x PI358001-1 and 10221 x PI358001-1. The selection method called "pedigree method" has been used in this case. We reported that a single dominant gene seems to be controlling resistance against BLS in lettuce but unfortunately we have observed that segregation of several crosses produced mostly unacceptable, leafy lettuce plants that have poor horticultural traits in the field. We have started a backcross selection method to increase the favorable alleles of horticultural traits in the cross of the resistant PI with our breeding lines. We have crossed the resistant PI 358001-1 to 59 EREC lettuce breeding lines. We concentrated our efforts on producing more crosses to our iceberg breeding lines. Nineteen of these crosses are in the F2 stage and further breeding could be accomplished in the future. 2. Morphological characterization of the existent and introduced lettuce germplasm We increased the seed of 145 Everglades Research and Education Center breeding lines. These lines are romaine, iceberg and butterhead lettuce types that are the base material of the lettuce breeding program of the University of Florida. 3. Phosphorus use efficiency and its implication in breeding We preliminary evaluated in greenhouse settings 5 lettuce cultivars adapted to Florida conditions. Two cultivars were commercial cultivars (Hialeah and Chosen) and three were breeding lines (60168, 70096 and Floricos 83) from the germplasm bank of the EREC. These 5 cultivars were grown under no application of P, half of the dose, or the standard dose recommended by lettuce growers. The commercial cultivar Chosen and the breeding line 60168 seem to perform better with half of the recommended dose than with the standard dose. Another challenge facing growers has been the steady increase in soil pH. This is partly due to the fact that the soil is being lost to oxidation, via a process commonly known as "soil subsidence". As these soils get shallow their pH rises because of the calcium carbonate associated with the underlying limestone bedrock. Increase in soil pH can bind elements like P and other micronutrients making them less bioavailable for plant uptake. In lettuce little to none work has been conducted to investigate lettuce with low input of Phosphorus. Preliminarily we tested the lettuce romaine cultivar Sawgrass in different soil compositions (muck + lime rock and muck + sand) at different soil pHs. We found that Phosphorus uptake is limited in the combinations of muck + lime rock at higher pHs that go above 7.0. This tendency was not as clear in the soil combination of muck + sand. 4.Study the inheritance of traits of interests and design breeding strategies based on their genetic basis For Lettuce BLS Initial data from genetic crosses indicated resistance in PI 358001-1 was controlled by a single dominant gene. The gene was mapped in Linkage Group 2 in the mapping population 'PI358001-1 × Tall Guzmaine'. However, the distance between the gene and the closest marker positioned in the genetic map was bigger than expected and therefore no marker has been useful so far. This year we regenotyped the population 'PI 358001-1 x Tall Guzmaine' using next generation sequencing. We have sequenced the 163 F2 DNA samples that comprise our mapping population using Genotyping by Sequencing (GBS). The GBS libraries were sequenced to produce marker data to map resistance.Once again, analysis of the GBS data revealed that resistance was controlled by a single dominant resistance locus on Linkage Group 2 (LG2). We analyzed the data to find the correct Single Nucleotide Polymorphisms (SNPs) by saturating the genetic map with newer and better markers to get closer to the gene of interest. This strategy should allow us to fine-map the gene and develop the marker for MAS. We have developed one PCR-based marker, called BLS_WW_15, designed from a variant detected in the GBS data has been validated in the population PI 358001-1 x Tall Guzmaine . In that population, BLS_WW_15 is effective at selecting the homozygous resistant individuals in the F2 from the cross Tall Guzmaine x PI 358001-1 with 85% accuracy. The marker should be equally effective in identifying homozygous resistant individuals in other F2 populations as well with 85% accuracy. we are working to design markers which will more perfectly select the homozygous resistant individuals in F2, BC1F2, BC2F2 and F3 populations. In order to move forward to study the genetic for other traits listed initially in this project (resistance to Cercospora Leaf Spot, seed germination at high temperature, heat tolerance and others such as postharvest quality of lettuce), during this period I started to work in seed germination at high temperature. We have started to screen the EREC lettuce seed germination at high temperatures and initially set protocols for postharvest quality of lettuce and other leafy vegetables. 5. Other collaborative efforts in lettuce breeding (controlled environments and red leaf lettuce under light conditions) We set initial collaborations with the North Florida Research and Education Center - Suwanee Valley Vegetable Extension Agent to establish an initial trail in a hydroponic NFT system for north Florida production. In this test we initially evaluated 31 lettuce cultivars in the NFT system (27 EREC breeding lines plus 4 control cultivars). Results from this first experiment helped us to choose three EREC breeding lines that will further tested in the system.
Publications
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