Some Ecological Factors Affecting Winter Wildfowl Distribution on Inland Waters in England and Wales, and the Influence of Water-Based Recreation

Abstract

Taking thirty six wheat cultivars bred in different era and ecological regions as test materials, their seedlings growth under water stress was investigated, and their drought resistance was evaluated by gray correlation grade analysis. Significant difference was observed in the drought resistance among the cultivars. The weighted drought resistance index ranged from 0.6580 to 0.2434. Among the test seventeen morphological and physiological traits, shoot dry mass had the greatest correlation degree (0.9473) with drought resistance, while SPAD had the smallest one (0.5356). The test cultivars were clustered into three groups, among which, eight cultivars belonged to strong drought resistance group, twenty three cultivars belonged to medium drought resistance group, and five cultivars belonged to drought-sensitive group. The shoot dry mass, root dry mass, plant dry mass, plant height, root nitrogen accumulation, leaf area, and tiller number per plant differed significantly among the three groups, which could be used for evaluating the drought resistance of wheat cultivars at seedling stage.