Agro-physiological performance of wheat genotypes under normal moisture and drought conditions

Scarcity of water for irrigation is an alarming issue of pakistan and the problem is being magnified rapidly with the passage of time. shortage of water is thus, a limiting factor in increasing per unit area wheat (triticum aestivum l.) yield that is staple food of most of the people. eventually, the gap between production and consumption is widening day by day and pakistan is now suffering from food crisis. hence, to find out the wheat genotypes having comparatively more drought tolerance, a field experiment was conducted during 2005-06 and 2006-07 on 497 wheat genotypes, which were subjected to drought conditions in addition to growing under normal soil moisture conditions. screening of the genotypes was done on the basis of some physiological and agronomic attributes such as, stomatal conductance, net photosynthetic rate, transpiration rate, photo active radiation, plant height, productive tillers, grains per spike, 1000-grain weight, biological yield, grain yield per plant and harvest index. drought stress adversely affected all these parameters, which expressed significant decrease in their values except harvest index, which was significantly increased irrespective of genotypes during both the years of study. the genotypes under study, on the basis of above physiological and agronomic attributes were grouped into high yielding drought sensitive, high yielding drought tolerant, low yielding drought tolerant and low yielding drought sensitive groups, employing cluster analysis. thus, out of 497 sixteen wheat genotypes were ranked as high yielding drought tolerant which can be successfully grown under drought conditions without substantial decrease in grain yield