摘要： 选择生育期相近的迟熟高产杂交稻组合或水稻品种（品系），在自然条件下分期播种，寻找水稻抽穗期冷害相关的形态评价指标，并对参试材料进行抽穗期耐冷生态适应性评价。抽穗期遭受低温冷害胁迫后，主要农艺性状中受冷害程度大小顺序依次是每穗实粒数、单蔸产量、结实率、每穗总粒数、株高、穗长、千粒重；单蔸产量相对受害率（RDP）与每穗实粒数RDP、结实率RDP、剑叶叶色分、抽穗期延迟天数分成极显著正相关。在低温冷害胁迫条件下，水稻不同基因型的抽穗期耐冷能力存在明显的差异。将判别水稻抽穗期耐冷能力的形态指标——每穗实粒数RDP、结实率RDP、剑叶叶色、抽穗期延迟天数、苞穗率增加值进行量化，综合判别参试材料抽穗期对低温冷害的生态适应性。研究结果表明：籼粳交材料95LR102后期耐冷能力强；带有部分粳稻血缘、正在生产中大面积种植的杂交稻组合V644，V46耐冷能力较强。

关键词: 晚籼稻, 抽穗, 低温冷害, 生态适应性

Abstract: To screen high-yield rice varieties or hybrids with good tolerance to low temperature at flowering stage, the ecological adaptability of 12 late-maturing, high-yield rice hybird and varieties(line) with similar growth duration had been evaluated at flowering stage by 3 times of sowing under natural conditions. Under low temperature stress at flowering stage, relative damage degree values of major agronomic traits were as following order. grains per panicle, yield per plant, seed-setting rate, spikelets per panicle, plant height, panicle length, 1000 seed weight;and relative cold damage percent (RDP) of yield per plant was very significantly positive correlated with RDP of grains per panicle, RDP of seed-setting rate, score for color of flag leaf, score for delayed time of heading period. Cold tolerance differs distinctly in rice genotypes at flowering stage. The morphological indexes, e. g. RDP of grain-setting rate and grains per panicle, color of flag leaf, delayed time of heading period, bract panicle rate had been used to evaluate tolerance to low temperature at flowering stage.95LR102, a line derived from the cross of an indica variety and a japonica variety, has strong tolerance to chilling injury. Some hybrids, e. g, V644, V46, which have been popularly planting as late rice in Hunan, have better adaptability.

Key words: Rice, Flowering stage, Chilling injury, Ecological adaptability