Genetic analysis of karnal bunt resistance in 14 Mexican bread‐wheat genotypes

Abstract

Abstract Fourteen Mexican genotypes of bread wheat ( Triticum aestivum L.) with good to moderate levels of resistance to Karnal bunt ( Tilletia indica (Mitra)) were crossed with the highly susceptible cultivar WL711 to determine the genetic basis of resistance. The parents, F 1 F 2 and backcross populations of the 14 crosses were evaluated under artificial epiphytotic conditions during the 1993–94 season for Karnal bunt resistance. The F 1 data suggested that the resistance was dominant to partially dominant over susceptibility. The F 2 analysis of the segregation ratios in the F 2 and backcross generations indicated that the resistance in the wheat genotypes Luan, Attila, Vee #7/Bow, Star, Weaver, Milan, Sasia and Turacio/Chil is controlled by two genes. The resistance in genotypes Cettia, Irena, Turaco, Opata, Picus, and Yaco was found to be conditioned by a single dominant gene. The genotypes with two genes for resistance expressed a higher level of resistance than those with a single gene and, therefore, are better sources of resistance to Karnal bunt.