Genetic control of the resistance of tomato genotypes Yoshimatsu and Hawaii 7996 to Ralstonia solanacearum

Abstract

Tomatoes are one of the most widely explored crops in breeding programs through hybridization and selection methods, with the aim of obtaining cultivars with better agronomic characteristics and resistance to diseases such as bacterial wilt caused by Ralstonia solanacearum, which causes major economic losses. One of the first steps in obtaining new cultivars is to know the genetic control of the characteristics. The aim of this work was therefore to determine the genetic control of the resistance of the tomato genotypes Yoshimatsu and Hawaii 7996 to Ralstonia solanacearum and to determine whether the resistance loci that govern the trait in these materials are the same. The Yoshimatsu and Hawaii 7996 genotypes and the F₁, F₂, BC₁₁ and BC₂₁ generations were evaluated in one experiment and 60 F_2:3 progenies in a second experiment. The severity of bacterial wilt was assessed using a descriptive scale of scores at 20 days after inoculation. Resistance to bacterial wilt caused by Ralstonia solanacearum has a distinct genetic control between the genotypes, being controlled by two genes of greater effect in recessive homozygosis in Yoshimatsu and only one gene with partial dominance action in Hawaii 7996.