Abstract

Stem rust, caused by Puccinia graminis f.sp. tritici (Pgt), is a major threat to wheat (Triticum aestivum L.) production due to increased susceptibility. This study aimed to identify wheat lines in the 16th Stem Rust Resistance Screening Nursery (SRRSN) with seedling and adult plant resistance (APR) to wheat stem rust. A two-season field experiment was conducted at (KALRO) Njoro using a 12×12 partially balanced lattice design under stem rust pressure. The results showed significant (p≤0.001) effects of season, genotype, and their interaction on plant height, 1000 kernel weight (TKW), biomass, and Area Under Disease Progress Curve (AUDPC). 54.86% of the wheat genotypes had an AUDPC of ≤200, 52.78% had a CI of ≤20, and 60.42% had FDS of ≤30 indicating resistant. Grain yield ranged from 0.8 to 9.05 t ha-1 and TKW from 20.03 to 46.42 g. Genotypes 6022, 6095, 6096, 6107, 6134, 6136, 6137, 6138, and 6139 showed APR and high yield potential. At seedling stage, about 72.7% of the lines were resistant to stem rust race TTKTT while 27.3% of the lines were susceptible. These high-yielding and APR lines can be valuable in breeding programs for stem rust resistance.

Key words: Genotypes, screening, stem rust, resistance, virulence.