RESPONSE OF DURUM WHEAT CULTIVARS TO WATER STRESS IN THE FIELD AND GREENHOUSE
Experiments were conducted in the field and in the greenhouse to measure differences in drought resistance among durum wheat (Triticum turgidum L.) cultivars. Nine cultivars were tested in 1976 and 12 in 1977 in duplicate tests grown adjacent to each other under rainfed and irrigated conditions in the field. The drought resistance of the cultivars was measured as the difference in their performance under the two water regimes. For yield, there was no significant interaction between the cultivars and the water regimes in either year. Thus, the cultivars did not appear to differ significantly in drought resistance. They did differ significantly in the effect of water stress on the yield components. However, the performance of the cultivars was not consistent either for the yield components or between years. In one greenhouse experiment, six cultivars were grown in large containers. One set of plants was watered at regular intervals while a second set was watered only until 5 days after anthesis in the main spikes. Water stress caused major, correlated reductions in grain yield, 1000-kernel weight, and length of the growing period. However, the differences among the cultivars largely depended on their vegetative growth under nonstress, those with the most growth showing the largest reduction from stress. In a second greenhouse experiment, the 12 cultivars were grown in 15-cm pots at three moisture levels. For yield, there was no interaction between cultivars and moisture levels. Overall, the data provided little evidence of consistent differences among cultivars in resistance to moisture stress.Key words: Drought resistance, components of yield, yield, durum wheat (Triticum turgidum L.).