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

Author： Silva Marcia F. Kiihl Romeu A.S. Almeida Álvaro M.R.

ISSN： 0014-2336

Source： Euphytica, Vol.135, Iss.3, 2004-01, pp. : 339-343

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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 under greenhouse 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: symptomless (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 Rsv₁ locus for resistance to SMV. However, the allele is different from those in Epps and Ogden. The symbol Rsv₁^d is a tentatively named for the newly detected allele in FT-10. This allele probably originated from Davis cultivar.