两系杂交稻两优培九粒重因子的环境模型解析及生态特征分析

为探究两系杂交稻两优培九粒重对气候的反应和生态适应性，用2006年和2007年在南方稻区8个生态点29点次的田间种植试验资料，将粒重解析为谷粒长、宽、厚和比重4个因子，组建了谷粒面积(S)、厚度(H)和比重(ρ)的环境预测模型。相关分析表明，谷粒面积S的影响期在颖花分化期(III~IV期)至花粉母细胞减数分裂期(VI~VII期)，温度是其主要影响因子，有利于谷粒长度和宽度发育的日平均气温( )为27~29℃，最高气温(T_max) 34℃，最低气温(T_min) 24℃。谷粒厚度H与抽穗后1~30 d的Tmax呈二次曲线关系，与 呈负相关。谷粒比重ρ与日照时数(SH)呈正相关，影响时期在抽穗后1~10 d；与Tmax呈负相关，影响时期在抽穗后1~30 d。有利于增加ρ的气象指标是SH达到8 h，T_max低于30℃。用1951—2002年的气候资料模拟计算了95个地区的两优培九千粒重，按7个水稻生态区归纳，平均值变化在25.93~28.01 g之间。千粒重的区域分布明显随纬度而递增，由于地形影响，在湘、赣、粤北地区还表现出一定的经向影响。晚季稻的千粒重则比早季稻高1.39 g。幼穗分化期的温度和灌浆结实期的温度、日照时数是造成两优培九粒重区域和季节特征的主要生态原因。

Modeling with Climatic Factors and Analysis on Ecological Characters for Grain Weight Dissected Factors of Two-Line Hybrid Rice, Liangyoupeijiu

To understand the grain weight variation with climatic factors and exert its ecological potential of grain yield for a two-line hybrid rice Liangyoupeijiu, grain weight was carefully calculated with dissected indices of grain length, width, thickness and specific gravity. In an effort to correlate ecological factors to such indices during growing stages, a set of data from eight ecological plots in Southern China rice area in 2006 and 2007 were used to establish ecological model. Equations with climatic and biological factors were established for grain area (S), thickness (H) and specific gravity (ρ). Correlation analysis showed that growing stages strongly affected S from glumes differentiation (stage III–IV) to pollen mother-cell meiosis (stage VI–VII), and the most important meteorological factor was temperature. Furthermore, daily average temperature ( ) of 27–29℃, daily maximum temperature (T_max) of 34℃，and daily minimum temperature (T_min) of 24℃ were favorable to growth in grain length and thickness. Thickness showed quadratic relation with Tmax and linear negative relation with at 1–30 d after heading. Specific gravity positively correlated with sunshine hours (SH) during 1–10 d after heading, and negatively correlated with Tmax during 1–30 d after heading, and 8 h of SH, Tmax<30℃ were favorable to the development of ρ. By modeling with climate data of 95 cities which was grouped into seven rice cropping areas in Southern China during 1951–2002, the mean 1000-grain weight of Liangyoupeijiu was 25.93–28.01 g, which mainly varied with the latitude. However, grain weight in Hunan, Jiangxi and Guangdong Provinces was presented a certain extent of varying trend with longitude because of the tremendous difference of altitude. 1 000-grain weight of late season rice was 1.39 g larger than that of early season rice. The key factors affecting the ecological and seasonal characters of grain weight were temperature during panicle differentiation, subsequently, the temperature and sunshine hours during grain filling period.