Studies on some physiological traits in wheat under water stress condition

Abstract

Wheat is one of the most important crops of the world and is cultivated in more than 250 million hectares, with an average annual production of 80 M tons. India is the second largest producer of wheat in world, with cultivation area of 28 million hectares and an average productivity of approximate 27 q/ha. Wheat demand of growing population is increasing with no change in area. To meet the ever increasing demand of wheat production and challenges to be faced for increasing productivity without scope of increasing the area, there is prime need to follow the advanced physiological tools, which may be useful in formulating the breeding programme. The Central and Peninsular Zones account for 1/3rd of total area in India. On all India basis only 1/3rd area receives desired irrigation and rest receives 2-3 irrigation or limited irrigation. There is need to improve yield gains under limited irrigation using reliable physiological traits which may be dependable for selecting genotypes having higher tolerance to water and heat. Breeding programmes are generally focused on rainfed as well as irrigated environments. There is urgent need to develop varieties which are responsive to limited irrigation. Breeding strategies for these regions should aim at reduced irrigation requirement and high yielding capacity. For this various recent physiological techniques need to be adopted, which will help to improve water use efficiency (WUE) and higher tolerance to water and heat stress. Several morpho physiological traits are traditionally used as screening criteria for drought tolerance such as relative water content (RWC), stomatal index, water use efficiency (WUE) etc. Crop WUE can be improved by optimizing crop transpiration. Several workers have proposed carbon isotope discrimination (CID), ash content and canopy temperature depression (CTD) as selection criteria for transpiration efficiency (TE), which may serve as the surrogate measures for improvement in grain yield.