Plant water relations, canopy temperature, photosynthesis and grain yield in wheat genotypes as affected by post-anthesis chemical desiccation

Afield experiment was carried out during rabi (winter) season of 1996–97 at Agronomy Research Farm, CCS Haryana Agricultural University, Hisar to study the plant water relations, canopy temperature and photosynthesis for screening wheat genotypes for post-anthesis moisture stress by chemical desiccant in normal irrigated field condition. Leaf water potential, osmotic potential, turgor potential, relative water content, photosynthetic rate and grain yield decreased, whereas canopy temperature increased under moisture stress condition. The reduction in these physiological characters and grain yield was much higher under desiccant sprayed treated plants than rainfed environment. Genotype UP 2338 maintained higher leaf water potential, turgor potential, relative water content, photosynthetic rate, grain yield and lower canopy temperature than other wheat genotypes under all the environments. Association between plant water relations, photosynthesis and grain yield was better at 12 days than six days after desiccant spray. This suggests that an inbuilt system of water economy in the cv. UP 2338 enables it to maintain vital physiological functions under adverse climatic condition to yield comparatively better.