Evaluation of advanced bread wheat genotypes for resistance to stem rust and yield stability

Abstract

Stem rust (Puccinia graminis f. sp tritici) poses a major threat to wheat (Triticum aestivum L.) production worldwide. The interaction between wheat and pathogen in presence of favorable environment can cause a complete crop failure. This study was conducted with the objective to identify wheat genotypes with resistance to stem rust with high and stable yield under four environments in Kenya. Forty wheat genotypes were tested in two consecutive growing seasons, using an alpha lattice design with three replications. Host response to stem rust was recorded based on the modified Cobb scale. The disease severity was recorded on scale of 0 to 100%. The results of the coefficient of infection indicated that about 30% of genotypes were moderately resistant. Yield and disease data were subjected to statistical analyses to estimate the stability parameters. The top three genotypes in yield performance were G25, G18 and G29 with 2.07, 1.98 and 1.97 t ha-1 respectively. Considering both stem rust and yield stability G5, G16, G18, G24 and G36 were the best genotypes which could undergo further testing for future release. Key words: Wheat, stem rust, resistance, stability, genotype × environment interaction.