Canopy Temperature an Effective Measure of Drought Stress Tolerance in RIL Population of Wheat
Field experiments were conducted for evaluating recombinant inbred lines (RILs) of wheat cross of C518 and PBW343 under rainfed conditions by using plant water related traits viz; canopy temperature and stomatal density during rabi seasons 2012-13 and 2013-14. Both parents belonging to distinct adaptation group, offer several morpho-physiological contrasting traits. Canopy temperature (CT) and stomatal density (SD) were recorded under irrigated and rainfed conditions. Analysis of variance showed that CT and SD differed significantly under both conditions, indicating the existence of sufficient genetic variability among the populations. Frequency distribution for canopy temperature at anthesis among RIL population showed transgressive segregation under irrigated and rainfed conditions. Skewness (0.22) and kurtosis (0.27) was higher under rainfed conditions. Stomatal density does not vary greatly under water-deficit conditions. However, reduction in stomatal density was found under water stress conditions and recorded minimum stomatal density suggesting less transpiration rate under drought conditions resulting in minimize of loss of water. Under irrigated environment, canopy temperature at anthesis (CTA) showed non-signification correlation with stomatal density. While, under rainfed condition, canopy temperature among RILs showed significant negative correlation with stomatal density and yield attribute characters. This indicated that the selection for traits viz, canopy temperature and stomatal density may be effective measure of drought tolerance of wheat cultivars and yield improvement under drought stress conditions.