Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) The objective is to evaluate the resistance of public and private soybean varieties and breeding lines to the most serious diseases present in the southern United States. Approach (from AD-416) The Delta Research and Extension Center, Mississippi Agricultural and Forestry Experiment Station, Stoneville, Mississippi, will obtain seed from the entries in the Mississippi Soybean State Variety Trials, which averages 205 entries in Maturity Groups IV-VI. Additional seed of Maturity Group III and breeding lines from the USDA soybean breeder at Stoneville will also be obtained. These varieties and breeding lines will be screened for resistance to the following diseases: (1). Stem Canker -- The Toothpick method of inoculation will be used to evaluate resistance to this disease; (2). Frogeye Leaf Spot -- Spores from selected races which are prevalent in Mississippi will be sprayed on the soybeans; (3). Cercospora blight, purple leaf stain -- Leaves and immature pods will be inoculated; (4). Charcoal rot -- Plants will be grown in field infested with the casual fungus; and (5). Soybean rust -- Entries planted in replicated plots will be evaluated for natural infection. Other foliar diseases of soybean will be evaluated if present in field plots. The entries in the Mississippi Soybean Variety Trials were evaluated for resistance to frogeye leaf spot in the greenhouse and for resistance to black root rot in the growth chamber. These entries will be retested. Entries were evaluated in inoculated greenhouse trials for resistance to frogeye leaf spot. Chambers were constructed to periodically mist the inoculated plants. Four plants per replication were planted in four inch square pots in Sunshine LG3 potting mix. The plants were inoculated with 100,000 spores per ml of the frogeye fungus when they had one-two sets of true leaves. They were placed in mist chambers until symptoms developed on the susceptible checks and were evaluated. There were a large number of entries which were completely resistant to frogeye leaf spot. Ratings ranged from resistant to very susceptible. Mature green pods were harvested and placed in humidity chambers and inoculated with the purple pod rot fungus. However, the isolate we inoculated with was not virulent and no disease developed. We have been unable to isolate the fungus from soybean roots or leaves. Therefore, we are screening a collection of seed isolates of the fungus to determine if any of them are pathogenic to soybean leaves. Entries to be evaluated for reaction to the Black Root Rot fungus were planted in EM4 containers filled with Sunshine LG3 potting mix. The inoculated seed were placed in a growth chamber (75- 85�F) for 2-3 weeks. There were very few entries which were rated resistant to black root rot. The plants were dug up and washed and the amount of black root rot was determined. Evaluation for reaction to stem canker will be conducted in the field under a new agreement. ADODR used site visit, email and telephone conferences to monitor activities of the project.
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) The objective is to evaluate the resistance of public and private soybean varieties and breeding lines to the most serious diseases present in the southern United States. Approach (from AD-416) The Delta Research and Extension Center, Mississippi Agricultural and Forestry Experiment Station, Stoneville, Mississippi, will obtain seed from the entries in the Mississippi Soybean State Variety Trials, which averages 205 entries in Maturity Groups IV-VI. Additional seed of Maturity Group III and breeding lines from the USDA soybean breeder at Stoneville will also be obtained. These varieties and breeding lines will be screened for resistance to the following diseases: (1). Stem Canker -- The Toothpick method of inoculation will be used to evaluate resistance to this disease; (2). Frogeye Leaf Spot -- Spores from selected races which are prevalent in Mississippi will be sprayed on the soybeans; (3). Cercospora blight, purple leaf stain -- Leaves and immature pods will be inoculated; (4). Charcoal rot -- Plants will be grown in field infested with the casual fungus; and (5). Soybean rust -- Entries planted in replicated plots will be evaluated for natural infection. Other foliar diseases of soybean will be evaluated if present in field plots. The objective of this cooperative research project is to evaluate the resistance of public and commercial soybean cultivars and breeding lines to other most serious diseases present in the southern United States. All of the entries in the Mississippi Soybean variety trials were evaluated for resistance to stem canker using the toothpick method. A stem canker infested toothpick was inserted into the upper 1/3 of the soybean plant five weeks after planting. Plants were rated at the R5-R6 growth stage. There continues to be about 5-10% of the entries which are susceptible to stem canker. These results are published in the Mississippi State Variety Publication and are sent to soybean pathologists in several southern states. All of the entries in the Mississippi Soybean variety trials were evaluated for resistance to frogeye leaf spot in field and greenhouse studies. In the field, the entries were sprayed with spore suspensions of the fungus. The trial was conducted under a lateral move irrigation system and the plots were watered frequently to encourage disease. In greenhouse studies, the 3-4 week old soybean plants were inoculated with a spore suspension of the fungus and placed in a misting chamber which misted them for 30 seconds every 6 minutes. In both trials, the plants were rated for disease when the susceptible checks had symptoms of the disease. Several of the commercial soybeans varieties were susceptible to the disease. All of the entries in the Mississippi Soybean variety trials were evaluated for resistance to purple leaf stain in greenhouse studies. The inoculation methods were the same as for frogeye leaf spot. All of the entries in the Mississippi Soybean variety trials were evaluated for resistance to purple pod rot in small moist chambers. Ten green mature soybean seed were placed in a moist humidity chamber and inoculated with a spore suspension of the fungus and, as a control, sterile water. The chambers were incubated for 2 weeks and were rated for the presence of the disease. Weather conditions were not favorable for the development of charcoal rot and soybean ruts and none was observed in the plots. In 2010, we initiated a screen of the entries in the Mississippi Variety Trials using the black root rot fungus. ADODR used site visit, email and telephone conferences to monitor activities of the project.
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) The objective is to evaluate the resistance of public and private soybean varieties and breeding lines to the most serious diseases present in the southern United States. Approach (from AD-416) The Delta Research and Extension Center, Mississippi Agricultural and Forestry Experiment Station, Stoneville, Mississippi, will obtain seed from the entries in the Mississippi Soybean State Variety Trials, which averages 205 entries in Maturity Groups IV-VI. Additional seed of Maturity Group III and breeding lines from the USDA soybean breeder at Stoneville will also be obtained. These varieties and breeding lines will be screened for resistance to the following diseases: (1). Stem Canker -- The Toothpick method of inoculation will be used to evaluate resistance to this disease; (2). Frogeye Leaf Spot -- Spores from selected races which are prevalent in Mississippi will be sprayed on the soybeans; (3). Cercospora blight, purple leaf stain -- Leaves and immature pods will be inoculated; (4). Charcoal rot -- Plants will be grown in field infested with the casual fungus; and (5). Soybean rust -- Entries planted in replicated plots will be evaluated for natural infection. Other foliar diseases of soybean will be evaluated if present in field plots. Significant Activities that Support Special Target Populations Two hundred and seventy-four soybean entries were screened from the Mississippi State Soybean Variety Trials. The entries were from maturity group III through V. Entries were screened for stem canker resistance using the toothpick method in which toothpick infested with the stem canker fungus was inserted into the stem 5 weeks after planting. Twelve plants were inoculated per replication and 4 replications were evaluated per entry. Results from the trials from last year were published in the Mississippi State Variety trial booklet and in Plant Disease Management Reports. The plots have been inoculated this year and the results will be published in the same two publications. Entries are in the process of being screened for frogeye leaf spot resistance in greenhouse and field trials. Field studies consist of plots which have been inoculated with spore suspensions of the fungus. After inoculation, the plants are being periodically sprinkler irrigated to encourage disease development. In the greenhouse, misting chambers have been set up and entries are being inoculated with the fungus and incubated in the mist chambers. In both trials the entries are evaluated when the susceptible checks show symptoms of the disease. Results will be published in the publications previously mentioned. Entries are also being screened for purple leaf and pod rot by inoculating plants in the R5 growth stage or mature green pods with a spore suspension of the fungus. Entries are screened for charcoal rot by mixing charcoal rot infested seed with the soybean seed at planting. An attempt will be made to screen for aerial blight by inoculating the entries with the aerial blight fungus suspended in sodium algenate pellets. All of the trials will be monitored for the development of soybean rust and will be rated if rust is present. Foliar fungicide trials were conducted to evaluate the efficacy of experimental and commercial late season applied foliar fungicides. Early planted maturity group IV�s and early and late planted maturity group V soybeans will be sprayed at different times with different fungicide rates. Some trials will be inoculated with frogeye leaf spot, purple leaf stain, and aerial blight. All fungicide trials will be taken to yield and the seed quality of some trials will be determined. ADODR used site visit, email and telephone conferences to monitor activities of the project.
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Progress 10/01/07 to 09/30/08
Outputs
Progress Report Objectives (from AD-416) The objective is to evaluate the resistance of public and private soybean varieties and breeding lines to the most serious diseases present in the southern United States. Approach (from AD-416) The Delta Research and Extension Center, Mississippi Agricultural and Forestry Experiment Station, Stoneville, Mississippi, will obtain seed from the entries in the Mississippi Soybean State Variety Trials, which averages 205 entries in Maturity Groups IV-VI. Additional seed of Maturity Group III and breeding lines from the USDA soybean breeder at Stoneville will also be obtained. These varieties and breeding lines will be screened for resistance to the following diseases: (1). Stem Canker -- The Toothpick method of inoculation will be used to evaluate resistance to this disease; (2). Frogeye Leaf Spot -- Spores from selected races which are prevalent in Mississippi will be sprayed on the soybeans; (3). Cercospora blight, purple leaf stain -- Leaves and immature pods will be inoculated; (4). Charcoal rot -- Plants will be grown in field infested with the casual fungus; and (5). Soybean rust -- Entries planted in replicated plots will be evaluated for natural infection. Other foliar diseases of soybean will be evaluated if present in field plots. Significant Activities that Support Special Target Populations Three hundred and seventy soybean entries were screened from the Mississippi State Soybean variety trials. The entries were from maturity group III through V. Entries were screened for stem canker resistance using the toothpick method in which a toothpick infested with the stem canker fungus was inserted into the stem about 5 weeks after planting. Twelve plants were inoculated per replication and 4 replications are evaluated per entry. Entries were also screened for frogeye leaf spot resistance by inoculating plants with spore suspensions of the fungus. After inoculation, the plants were periodically sprinkler irrigated to encourage disease development. Additionally, entries were screened for purple leaf and pod rot by inoculating the plants in the R5 growth stage with a spore suspension of the fungus. Entries were screened for charcoal rot by mixing charcoal rot infested seed with the soybeans at planting and by spraying the fungus later. Entries were also screened for soybean rust by planting the entries late and waiting for natural rust infection. Foliar fungicide trials were conducted to evaluate experimental fungicide efficacy on late season foliar disease. Some trials were planted late after wheat to determine efficacy for soybean rust control. ADODR used site visit and telephone conferences to monitor activities of the project.
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Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) The objective is to evaluate the resistance of public and private soybean varieties and breeding lines to the most serious diseases present in the southern United States. Approach (from AD-416) The Delta Research and Extension Center, Mississippi Agricultural and Forestry Experiment Station, Stoneville, Mississippi, will obtain seed from the entries in the Mississippi Soybean State Variety Trials, which averages 205 entries in Maturity Groups IV-VI. Additional seed of Maturity Group III and breeding lines from the USDA soybean breeder at Stoneville will also be obtained. These varieties and breeding lines will be screened for resistance to the following diseases: (1). Stem Canker -- The Toothpick method of inoculation will be used to evaluate resistance to this disease; (2). Frogeye Leaf Spot -- Spores from selected races which are prevalent in Mississippi will be sprayed on the soybeans; (3). Cercospora blight, purple leaf stain -- Leaves and immature pods will be inoculated; (4). Charcoal rot -- Plants will be grown in field infested with the casual fungus; and (5). Soybean rust -- Entries planted in replicated plots will be evaluated for natural infection. Other foliar diseases of soybean will be evaluated if present in field plots. Significant Activities that Support Special Target Populations This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Mississippi Agricultural Forestry & Experiment Station (MAFES). Additional details of the research can be found in the report of in-house project 6402-21220-007-00D, "Genetic and Cultural Methods to Reduce Soybean Yield Losses to Diseases and Environmental Stress." Three hundred and fourteen entries in the Mississippi State Soybean variety trials were evaluated for resistance to the following diseases: 1. Stem Canker; Entries were inoculated with toothpicks infested with the stem canker fungus and were rated for disease resistance. Early and late planted trials were conducted. Results were reported in Plant Disease Management Reports. 2. Frogeye leaf spot; Entries were sprayed with a spore suspension of frogeye leaf spot. In 2006, environmental conditions were not favorable to disease development and there was very little frogeye development in the trials. 3. Purple Pod Rot; Mature green pods were collected from each entry and sprayed with the fungus. Pods were incubated in a moist chamber and rated for disease development after two weeks. 4. Charcoal rot; Entries were inoculated with charcoal rot by incorporating charcoal rot infested grain in with the seed at planting. Plots were rated at harvest. Seed treatment fungicides were evaluated for control of Rhizoctonia and Pythium. Some trials were inoculated at planting. A trial was conducted to determine if seed treatment with a trizole fungicide would delay the onset of soybean rust or charcoal. There were some differences in charcoal rot development between the treatments. However, no rust developed in the trial. A series of five foliar fungicide trials were conducted to evaluated foliar fungicides. Environmental conditions were not favorable for disease development and very little disease developed in the trials. Foliar fungicide treatment did not significantly increase yields in 2007. There was no soybean rust present in the trials. ADODR used site visit and telephone conferences to monitor activities of the project.
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 4d Progress report. This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Mississippi Agricultural Forestry & Experiment Station (MAFES). Additional details of the research can be found in the report of inhouse project 6402-21220-007-00D, Genetic and Cultural Methods to Reduce Soyberan Yield Losses to Diseases and Environmental Stress. This project started June 10, 2006 and replaces project number 6402-21220-007-01S with all programs.
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