Evaluation of commercial wheat cultivars for resistance to Wheat yellow mosaic virus in Henan Canopy Architecture and Photosynthetic Characteristics in Two Winter Wheat Culti vars with Different Spike Type Chlorophyll diagnoses of N nutrition for different winter wheat cultivars on dryland Effects of all-day warming on growth, development and yield of winter wheat cultivars bred in different periods. THE DROUGHT-RESISTANCE AND HIGH-PRODUCTIVITY CHARACTER OF SHAANXI MAIN WINTER WHEAT CULTIVARS