Evaluation of winter wheat cultivars for drought resistance

Abstract

Cultivars of winter wheat (Triticum aestivum L. em. Thell.), considered by wheat breeders to be drought sensitive or drought resistant, were grown under two irrigation regimes (daily or weekly waterings) to determine physiological responses to drought and to evaluate methods to use in screening for drought resistance. Leaf water potential, stomatal resistance, plant resistance to water flow, and soil water potential were measured for three weeks on vernalized plants in a growth chamber. When water was lacking, drought-sensitive plants had a lower leaf water potential than did drought-resistant plants. With both daily and weekly waterings, stomatal resistance was higher in drought-resistant plants than in drought-sensitive plants. Plant resistance to water flow, calculated as the difference between the soil water potential and leaf water potential divided by the amount of water used by the plant, was usually higher in drought-resistant plants than in the drought-sensitive plants. The results showed that, when screening for drought resistance, stomatal resistance was a better method to use than determinations of leaf water potential or plant resistance to water flow.