Screening of elite germplasm of wheat against Bipolaris sorokiniana disease resistance under terminal heat stress

Abstract

Spot blotch (Bipolaris sorokiniana) and terminal heat stress are critical biotic and abiotic stresses that substantially limits wheat (Triticum aestivum L.) yields in the Eastern Indo-Gangetic Plains (EGP) of South Asia. The present study evaluated 104 wheat genotypes, sourced from both national and international sources, for their resistance to spot blotch disease and tolerance to terminal heat stress under field conditions. A range of physiological parameters, including disease severity, SPAD index, NDVI, canopy temperature, and canopy temperature depression, were monitored on a weekly basis, and their correlations with Area Under Disease Progress Curve (AUDPC) and yield were statistically analysed. AUDPC demonstrated a significant negative correlation with yield. Based on these findings, genotypes such as ACC-311 and ACC-306 emerged as promising genotypes exhibiting resistance to spot blotch and tolerance to heat stress. These genotypes hold considerable potential for use in breeding programs aimed at developing heat-and disease-tolerant wheat varieties, thereby contributing to enhanced wheat productivity in the region, particularly in the context of climate change-induced challenges.