Evaluation of grain yield and its components in wheat cultivars and landraces under near optimal and drought conditions

In a 2-years experiment, 30 wheat cultivars and 21 landraces from different countries were tested under near optimum and drought stress conditions. Pl ant height, number of sterile spikelets per spike, number of spikelets per spike, number of kernels per spike, kernel weight per spike, 1000 kernel we ight and grain yield were evaluated. The number of kernels per spike, 1000 kernel weight and especially yield were more sensitive to drought stress in the cultivars than plant height and number of spikelets per spike, while i n the landraces these traits did not differ under drought stress compared t o near optimum conditions. The average yield of cultivars was significantly better than the average yield of landraces under near optimum as well as d rought stress conditions. Path coefficient analysis showed that for cultiva rs under near optimum conditions there was no significant direct associatio n of any of the analysed characters with yield, while under drought stress conditions, number of kernels per spike had a significant positive direct e ffect. Under drought stress conditions, the number of sterile spikelets dis played a negative direct effect, while kernel weight per spike had a positi ve direct effect on yield. Hierarchical cluster analysis was used as a tool to classify cultivars and landraces according to their yield ability under near optimum and drought stress conditions. Among the cultivars, two group s out of five and among one of three in the landraces were characterised by high yields in both near optimum as well as under drought stress condition s. These genotypes may serve as sources of germplasm for breeding for droug ht tolerance.