Abstract
<jats:p>The determination of wheat resistance to leaf rust is an important research priority both in Kazakhstan and worldwide. Leaf rust (Puccinia recondita) is one of the most destructive wheat diseases, causing significant yield losses and economic damage. The pathogen exhibits high adaptability to diverse soil and climatic conditions, which contributes to its broad geographical distribution. Consequently, leaf rust epiphytotics are frequently reported across many continents, leading to substantial reductions in wheat productivity. In Kazakhstan, the disease is particularly widespread in the northern and eastern regions. The aim of this study was to conduct a phytopathological evaluation under natural field conditions to assess the resistance of 52 spring wheat lines grown in the Kostanay region to leaf rust and drought stress. Based on the phytopathological assessment, 11 genotypes showed an immune reaction (IT-0) to leaf rust, including Tertia, Astana-2, Lutescens KS 963, Lutescens 1193, Lutescens 1296, Lutescens 1300, Sibirskaya 21, Lutescens 443, Lutescens 449, Silach, and Erythrospermum 24841. Eight genotypes with a high biomass index were identified, with NDVI values ranging from 0.55 to 0.62. Early heading (1 July) was observed in six genotypes: Standard early-maturing (Kazakhstanskaya 4), Lutescens 1193, Novosibirskaya 16, Novosibirskaya 41, OmskGAU-100, and Erythrospermum 24841. Structural analysis revealed 12 genotypes with plant heights of 90-100 cm and 12 genotypes with ear lengths of 9-10 cm. Twenty genotypes were characterized by a high number of spikelets per spike, while five genotypes exceeded 40 grains per main spike. High grain weight per main spike (>1.30 g) was recorded in 17 genotypes, and the highest thousand-kernel weight (44 g) was observed in SPChS-69. Overall, most spring wheat genotypes evaluated in the Kostanay region were susceptible to leaf rust, emphasizing the importance of identifying resistant genotypes for breeding and agricultural use.</jats:p>