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United States Department of Agriculture

Agricultural Research Service

Research Project: SCREENING GERMPLASM AND BREEDING FOR RESISTANCE TO PHOMOPSIS SEED DECAY IN SOYBEAN
2011 Annual Report


1a.Objectives (from AD-416)
(1) Screen soybean lines for resistance to Phomopsis Seed Decay (PSD). (2) Breed high-yielding resistant cultivars and germplasm lines for North Central and Southern U.S. soybean production regions by incorporating new resistance genes and alleles. (3) Develop new and rapid screening tools that are correlated with the field screening method for the measurement of plant resistance.


1b.Approach (from AD-416)
Phomopsis seed decay (PSD) of soybean is a major cause of poor quality and poor germination of soybean seeds in the United States, especially in the mid-southern U.S. This research will be focus on two sides of the disease equation:.
1)screening untapped (not yet tested for PSD resistance) 123 MG 3-5 germplasm lines collected from 28 countries, and.
2)breeding lines and cultivars from southern U.S. with resistance to PSD. This research will provide tools and potential new resistance genes to increase breeding efficiency for high-yield PSD resistant lines.


3.Progress Report

Our first goal was to determine in 2010 field tests at the University of Missouri the percent seed infected by Phomopsis species (spp.) among 12 Maturity Group (MG) III, 12 MG IV, and 12 MG V plant introductions and to compare these results with results from similar tests conducted in 2009. Seeds from all plots were evaluated for visual appearance, percent germination, and percent seed infected by Phomopsis species. The results show that the following lines had very low percent of seed infected with Phomopsis spp. in 2009 and 2010: MG III lines 417361, 437482, 398697, 398752, and 88490; MG IV lines 346308, 346307, 87074, and 235335; and MG V lines 471938, and 381668.

Our second goal was to determine in 2010 field tests at the University of Missouri the effect of select plant introductions and cultivars, infurrow and foliar applications of the fungicide Quadris to Asgrow 4403, and a foliar application of the herbicide Cobra to Asgrow 4403 at flowering on the percent of seed infected with Phomopsis species. The results show that there were no differences among treatments in the percent of seed infected with Phomopsis species. There were differences in severity of bacterial blight, pod and stem blight, and charcoal rot among treatments.

The lines most resistant to this Phomopsis seed infection will be tested again in 2011, and the lines will be tested with and without inoculation by this pathogen. Tests to determine how infurrow and foliar applications of the fungicide Quadris and a foliar application of the herbicide Cobra, and of select plant introductions affected percent of seed infected with Phomopsis spp. were concluded in 2010.

The results of tests to determine the reaction of genotypes to Phomopsis spp. have not yet been confirmed by repeated trials. The results of tests to determine how infurrow and foliar applications of the fungicide Quadris, a foliar application of the herbicide Cobra, and of select plant introductions affect percent of seed infected with Phomopsis spp. have been concluded. ADODR used site visit, email and telephone conferences to monitor activities of the project.


Last Modified: 10/20/2014
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