Host Resistance and Morpho-Physiological Responses of Wheat Genotypes to Stripe Rust Caused by Puccinia striiformis f. sp. tritici at Seedling and Adult Stages

ABSTRACT Wheat (Triticum aestivum L.) is an important cereal crop and one of the main factors for food security in most countries, including Pakistan. Its production is seriously threatened by stripe rust, one of the most devastating diseases that causes significant yield losses. Therefore, this study evaluated the resistance of 21 wheat genotypes to stripe rust at seedling and adult stages by artificial inoculation. The results showed that LLR-9 and WC-19 were resistant to yellow rust at both stages, while Mexi-Pak, Sarsabz, and Sonora were highly susceptible to the disease, and severe infections occurred in the adult stage. Mexi-Pak was found to be susceptible to the disease at both stages, while Sarsabz and Sonora were only affected at maturity. Based on analysis of genetic variability and ANOVA, high genetic diversity was found for PHT, FLA, GY, TGW, and CC, out of which PHT, GY, and TGW were the crucial factors associated with resistance to the disease. Principal component analysis revealed that PHT, GY, and TGW were the most influential traits in distinguishing between resistant and susceptible genotypes. In contrast, CC and FLA also contributed to higher photosynthesis efficiency and supporting disease resistance. High PCV and GCV values were found for traits such as awn length, showing great potential for genetic improvement of these traits. NTP, SD, and AL had high heritability and showed good genetic control, whereas, in the case of NGS and CC, the heritability was low and thus involved a stronger environmental influence. This study demonstrates the need for wheat genotypes with disease resistance and high agronomic traits in breeding programs. It highlights LLR-9 and WC-19 as sources of resistance and provides helpful information about genetic factors responsible for resistance to the disease and productivity.