Genetic Analysis of Resistance to Leaf Rust and Yellow Rust in Spring Wheat Cultivar Kenya Kongoni.

ABSTRACT

The Kenyan wheat (Triticum aestivum L.) 'Kenya Kongoni' exhibits high levels of adult plant resistance (APR) to leaf rust (LR) and yellow rust (YR). We determined the genomic regions associated with LR and YR resistance in a population of 148 recombinant inbred lines generated from a cross between 'Avocet-YrA' and Kenya Kongoni. Field experiments to characterize APR to LR and YR were conducted in four and two Mexican or Uruguayan environments, respectively. A linkage map was constructed with 438 diversity arrays technology and 16 simple-sequence repeat markers by JoinMap 4.1 software. Genetic analyses showed that resistance to both rusts was determined by four to five APR genes, including Lr46/Yr29 and Sr2/Lr27/Yr30. Quantitative trait loci (QTL) analysis indicated that pleiotropic APR loci QYLr.cim-1BL corresponding to Lr46/Yr29 and QYLr.cim-7BL that is a putative novel QTL accounted for 5 to 57% and 12 to 35% of the phenotypic variation for resistance to LR and YR, respectively. These loci, in combination with another three LR QTL and two YR QTL, respectively, conferred high levels of resistance to both LR and YR in wheat under Mexican and Uruguayan environments. Among other detected QTL, QLr.cim-1DS, QLr.cim-2BL, and QYLr.icm-7BL may be new loci for APR to both rusts in common wheat.