Wednesday, November 4, 2009
Convention Center, Exhibit Hall BC, Second Floor
Worldwide, cyst nematode (SCN) Heterodera glycines Ichinohe is the most destructive pathogen on cultivated soybean (Glycine max (L.) Merr.). In the USA recent annual yield losses were estimated to be nearly 60 million dollars. Crop losses are primarily reduced by the use of resistant cultivars. Nematode populations are variable and have adapted to reproduce on resistant cultivars overtime because resistance primarily traces to two soybean accessions PI 88788 and Peking. Cultivar Hartwig was released which has comprehensive resistance to most SCN populations. Recently, a virulent population was selected for its reproduction on Hartwig. Soybean PI567516C, a recent introduction from China was found resistant to the virulent population however, it is agronomically highly undesirable. Hartwig was crossed to PI567516C to develop agronomically desirable soybean germplasm JTN-5109 that is resistant to virulent nematode population. Breeding methodology included a combination of pedigree and mass selection. Resistant progeny was identified in the greenhouse evaluations and confirmed using SSR markers associated with nematode resistance. In the greenhouse evaluations indicator lines, susceptible control and cv. Hartwig produced each a Female Index of 60% or more (Susceptible) whereas JTN-5109 and PI 567516C both had less than 10% Female Index (Resistant). Three SSR markers, Satt 592, Satt 331, and Sat_274 on Linkage group O have confirmed resistance with a combined efficacy of 90%. JTN-5109 is a maturity group V soybean with purple flowers and grey pubescence. Seeds are slightly greenish in color and plant height is approximately 31 inches. JTN-5109 has combined nematode resistance from Peking, PI 437654 and PI 567516C. This is being released.