[Freeze resistance analysis of different wheat cultivars based on the relationships between physiological indices and grain yield].

A pot experiment with twenty wheat cultivars was conducted to investigate the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities and the MDA, soluble protein and soluble sugar contents of functional leaves as well as the grain yield, 1000-grain weight, and grain morphological characters under low temperature stress. Low temperature (-4 degrees C) stress at stem elongation stage resulted in the changes of grain morphology and yield characters. For most of test cultivars, their grain length-width ratio, grain roundness, and sterile spikelets increased, and their grain equivalent diameter, grain area, 1000-grain weight, and grain yield decreased.