MULTIVARIATE EVALUATION OF WHEAT GENOTYPES AND MICROBIAL INOCULATION FOR ENHANCED PERFORMANCE UNDER WHEAT LEAF RUST PRESSURE Authors: Ameer Hamza Aslam, Rabia Irshad, Muhammad Faheem Khan, Aqib Ali, Fatima Tu Zahra Huma Abbas, Amjad Abbas, Muhammad Amjad Ali Journal: Journal of Animal and Plant Sciences (JAPS) ISSN: 1018-7081 (Print), 2309-8694 (Online) Volume: 37 Issue: 1 Year: 2027 DOI: https://doi.org/10.36899/JAPS.2027.1.0003 URL: https://doi.org/https://doi.org/10.36899/JAPS.2027.1.0003 Publisher: Pakistan Agricultural Scientists Forum Abstract:

Wheat leaf rust (WLR) caused by Puccinia triticina remains an important constraint to wheat productivity and microbial seed treatment may complement host resistance by reducing disease development while sustaining plant growth and yield. However, genotype-dependent responses to individual and combined microbial treatments under field WLR pressure remain insufficiently characterized. Therefore, the present study was carried out to investigate the efficacy of beneficial microbes, Trichoderma harzianum and Bacillus sp. MN54, in managing WLR and enhancing growth and yield of wheat under field conditions. Twenty-five wheat genotypes were initially screened for disease response, and three representative genotypes, namely Galaxy-13 (moderately susceptible), Subhani-21 (moderately resistant), and Arooj-22 (resistant), were selected based on their contrasting responses to WLR severity. These genotypes were further evaluated using seed priming with T. harzianum, Bacillus sp. MN54, and their combination in a randomized complete block design (RCBD). The combined application of T. harzianum + Bacillus sp. MN54 significantly improved morpho-physiological and yield traits, resulting in increases of up to 13.0% in plant height, 17.9% in root length, 26.1% in fresh root weight, 50.0% in dry root weight, 35.1% in spike length, 61.1% in spike weight, 22.7% in grains per spike, 28.5% in 1000-grain weight, and 45.5% in grain yield per plant compared to the control. Microbial treatments significantly reduced disease severity, with the lowest values in Arooj-22 (12.0%) and Subhani-21 (17.3%) after seed priming with T. harzianum. Compared with the respective untreated controls, disease severity was reduced by approximately 37.8% in Arooj-22 and 45.4% in Subhani-21. Significant genotypic variation was observed, with Arooj-22 exhibiting superior resistance and responsiveness to microbial treatments. Correlation analysis revealed strong positive relationships among growth and yield traits, while WLR severity showed significant negative associations with yield components (r = −0.80 to −0.82). Principal component analysis (PCA) confirmed that yield traits and disease severity were the primary drivers of variation. These findings demonstrate that microbial seed treatments, particularly in combination, can effectively suppress WLR, enhance host growth, and improve grain yield and grain biomass in wheat, providing a sustainable approach for integrated disease management.

Keywords: Wheat leaf rust, Bacillus sp. MN54, Puccinia triticina, seed priming, Triticum aestivum; Trichoderma harzianum.