Genetic Analysis of Resistance to Sudden Death Syndrome Caused by Fusarium virguliforme in Hartwig Soybean

摘要

Host resistance is the most effective strategy for soybean TGlycine max j sudden death syndrome (SDS) management. The objective of this study was to determine the inheritance of resistance to SDS in soybean cv. Hartwig under greenhouse conditions. One-hundred and fifty p2:i lines derived from the cross of the SDS-resistant cultivar ‘Hartwig’ with the SDS-susceptible cultivar ‘Camp’ were inoculated with sorghum seeds colonized with a F. virguliforme reference isolate from Arkansas (AR-171). The experiment was arranged in a randomized complete-hlock design with two replications. Each block included a pot of each p2:i line and two pots of each parent with eight plants per pot. The experiment was repeated to give a total of four replications. Disease incidence (DI) and disease severity (DS) were rated on a pot basis at 21 and 28 days post-inoculation. A disease index (DX) was calculated as ((DI x DS)/11). The 95% confidence intervals (Cl) for DX of the parents were calculated and used to classify the F2:3lines as susceptible, resistant or segregating. Segregating lines were scored on an individual plant basis. Chi-square tests determined the goodness-of-fit of observed F2:3 segregation data to the expected genetic ratios. Hartwig (SDS-R) and Camp(SDS-S) consistently had low and high DX ratings, respectively. The DX of SDS foliar ratings of the F_(23) lines segregated in a 7:8:1 (resistant:segregating:susceptible) ratio (x~2 = 4.514, F = 0.1046), indicating that Hartwig carries two dominant genesconferring resistance to SDS and can serve as a good source of resistance for crossing in a breeding program.