Abstract:

Experiments with thirty mid-season hybrid rice combinations were conducted to study the relationship between the seed setting rate and climatic conditions at flowering stage and sink-source characteristics of varieties with high temperature resistant by applying different sowing dates. The results showed that the main reason of low seed setting rate were low daily minimum temperature, minimum relative humidity, daily rainfall and sunshine at heading stage and the highest number of seedlings, higher LAI and the rate of spikelets to leaf. The low daily rainfall is the direct cause of higher daily maximum temperature. There were positively correlation between high temperature resistant at heading and numbers of the highest seedling or productive panicle, but negatively correlated with spikelets per panicle and spikelets-leaf ratio, the hybrid combinations with more productive panicles and strong tillering ability were stronger in high temperature resistant at heading. Chuanxiang 858, Taiyou 99, Xianglvyou 727, Mian5you 5240, Neixiangyou 2550, Chuanguyou 202 were suitable for planting in high temperature-drought areas.

Key words: mid-season hybrid rice, heat resistant coefficient, climatic condition, sink-source characteristics

摘要：

以30个大面积推广的杂交中稻组合为材料，在大田条件下通过分期播种，研究了杂交中稻结实率与开花期气候条件的关系及耐高温组合的库源特征。结果表明，抽穗期间的日最低气温、最低相对湿度、日降雨量、日照时数相对较低，最高苗数少，LAI和粒叶比较高，是导致结实率下降的重要原因。日降雨量少是导致日最高气温较高的直接因素，因此高温是引起结实率下降的根本原因。抽穗期耐热系数分别与最高苗数、有效穗数呈显著正相关，与穗粒数和粒叶比呈显著负相关，分蘖力强的穗数型组合抽穗期耐高温能力较强。川香858、泰优99、香绿优727、绵5优5240、内香2550、川谷优202可作为高温伏旱区的推荐品种。

关键词: 杂交中稻, 耐热系数, 气候条件, 库源特征