SCREENING OF SPRING WHEAT VARIETIES TOLERANT TO BROWN LEAF RUST (PUCCINIA TRITICINA) AND IDENTIFICATION OF ENVIRONMENTAL CONDITIONS CONDUCIVE TO DISEASE OUTBREAK

Abstract

In Pakistan, wheat production faces a significant challenge due to leaf rust disease instigated by the fungus Puccinia triticina. This affliction can diminish wheat yields by as much as 10%, a notable contrast to losses caused by other rust diseases like stem and yellow rust. The impact of leaf rust varies, influenced by the wheat plant's stage of growth and its inherent resistance. As Pakistan's staple and most nutritious crop, wheat thrives across varied environmental conditions, benefiting from the nation's diverse climate and the crop's genetic adaptability. The strategic breeding of resistant wheat varieties is the most cost-effective method for managing leaf rust. Nonetheless, this strategy demands continual effort because the pathogen can evolve, potentially breaching the defenses of resistant strains. Research at the University of Agriculture in Faisalabad assessed 25 wheat genotypes, including established commercial strains, emerging lines, and traditional local varieties, for their resilience to brown rust in 2022-23. Notably, three varieties, Arooj 2022, Nishan 21, and Subhani 21remained unaffected by the disease and demonstrated superior grain yields. In contrast, over the past three years, varieties such as Pakistan-81 and Galaxy 13 consistently exhibited vulnerability. Furthermore, an analysis of environmental patterns revealed that cooler temperatures ranging from 17 to 22℃, high humidity levels exceeding 80%, and abundant rainfall contribute to a heightened risk of leaf rust proliferation.