Inheritance of resistance to Soybean mosaic virus in FT-10 soybean

Abstract

The occurrence of a new isolate from the G5 strain of Soybean mosaic virus (SMV), which broke the resistance of soybean cultivar FT-10, was first reported in Brazil in 1995. Cultivar Davis is an ancestor of ‘FT-10’ and the likely source of resistance to the virus. Diallel crosses among resistant cultivars Epps (PI 96983), Ogden and FT-10, and susceptible cultivar Hill were made to investigate the inheritance of SMV resistance in FT-10. The experiments for genetic studies were performed undergreen house conditions. Plants of the F2 population and F3 families from each cross and the parents were inoculated with SMV G1 and G5 strains. Plants were classified as: symptom less (R), susceptible with typical symptoms of mosaic (S), and systemic necrosis (N). Plants showing necrosis or no symptoms were classified as resistant. Each F3 family was classified as resistant (homozygous),susceptible (homozygous), or segregating (heterozygous). The results of both F2 and F3 were analyzed by Chi-square tests. The results suggested that FT-10 carries an allele at the Rsv 1 locus for resistance to SMV. However, the allele is different from those in Epps and Ogden. The symbol Rsv 1 d is a tentatively named for the newly detected allele in FT-10. This allele probably originated from Davis cultivar.