Abstract

Drought stress is a major constraint to wheat production globally, particularly in arid and semi-arid regions. A diverse panel consisting of 300 wheat (T. aestivum L.) genotypes was evaluated under normal and drought conditions across two consecutive growing seasons using a randomized complete block design with three replications. Drought was imposed by withholding irrigation after the first watering. Data were recorded for key agronomic, physiological, and yield-related traits including chlorophyll content (SPAD), flag leaf length (FLL), flag leaf width (FLW), plant height (PH), peduncle length (PL), extrusion length (EXT.L), number of spikes per plant (NOS/P), number of spikelets per spike (SPKLTS/S), spike length (SL), thousand-grain weight (TGW), number of grains per spike (No.G/S), yield per plant (Y/P), days to 50% heading (DTH 50%), physiological maturity (PM), relative water content (RWC%), canopy temperature (CT) and awn length (AWN.L). Significant variation was observed among genotypes, as well as across treatments and years, as revealed by analysis of variance. Principal component analysis (PCA) was employed to understand the structure of trait variability and to distinguish genotypes with contrasting responses to drought. More than 50% of variation was accounted by first 5 PCs under both conditions. PCA and biplot analysis facilitated the identification of drought-tolerant genotypes such as Pothwar, Darabi-11, C-273, T-9, C-250 and BW/SH-118, which consistently performed well under drought stress. Conversely, genotypes like Sandal-73, FSD-85, DN-40, and PAK-81 were found to be highly sensitive to drought. The study highlights genetic diversity for drought resilience and provides potential breeding material for the development of climate-resilient wheat cultivars suited for water-limited environments.