超级杂交稻结实期根系活力与籽粒灌浆特性研究

本文以两系超级杂交稻粤杂122、粤杂889和粤杂922及其亲本为试验材料，研究了超级杂交稻及其亲本在结实期的根系活力与籽粒灌浆特性关系。结果表明，（1）各供试材料根系伤流强度最大值出现的时期各不相同。其中，粤杂889、粤杂922和恢复系R122最大值出现在始穗期；粤杂122和W922的最大值是在抽穗后5天，而W889与GD-1S则是在抽穗后10天。此后，除母本GD-1S外，其它均迅速下降，到抽穗后15天伤流强度下降到拐点。（2）超級杂交稻的受精颖花根活量与其父母本的受精颖花根活量之间呈显著或极显著正相关，说明利用根系活力强的亲本组配可望获得根系活力强的超级杂交稻组合；（3）超级杂交稻及其父本恢复系都存在不同程度的两段灌浆现象，强势粒灌浆速率高峰出现在抽穗后15天左右，而弱势粒的灌浆速率高峰则出现在抽穗后30-35天；（4）强势粒的灌浆速率与伤流量、颖花根活量和受精颖花根活量在抽穗15天左右均呈极显著相关；弱势粒的灌浆速率与受精颖花根活量在抽穗后10天、15天和20天均相关达到极显著水平，而与伤流强度和颖花根活量在抽穗后15天和20天呈显著或极显著相关。因此，选育出根系活力强的超级杂交稻组合，以及从栽培上维持和提高超级杂交稻中后期根系活力，是解决超级杂交稻的两段灌浆明显和充实度差等问题的根本途径。

Root Vigor and Grain-filling Characteristics in Super Hybrid Rice

In the present paper , the relationship between root vigor and grain-filling characteristics were studied, in which three two-line super hybrid rice，Yue-za 122,Yue-za 889,and Yue-za 922, as well as their restorer lines R122, W889,W922 and P/TGMS line GD-1S were used. The results showed that, a) The maximum root bleeding intensity was achieved at different grain-filling stage for the rice hybrids and their parental lines. It occurred at heading for Yue-za 889 and Yue-za 922 and the restorer line R122, and at 5 days after heading(DAH) for Yue-za 122 and W922, but 10 DAH for W889 and GD-1S. The root bleeding intensity consequently declined for all the hybrids and their parental lines except for GD-1S, and its sharp-down point occurred at 15 DAH. b) The fertilized grain-root activity of hybrids was positively and significantly correlated with their parental lines. It suggested that hybrids with high fertilized grain-root activity can be developed by using parental lines with high fertilized grain-root activity. c) The super hybrid rice and their restorer lines had two-period grain-filling phenomenon to some extent, and the maximum grain-filling rate was at about 15 DAH for the superior grains, but at about 30-35 DAH for the inferior grains. d) The grain filling rate of superior grains was significantly correlated with three root vigor indices, ie. root bleeding intensity, spikelet-root activity, and fertilized spikelet-root activity, respectively, only at 15 DAH. The grain-filling rate of inferior grains was significantly correlated with the three root vigor indices at 10, 15 and 20 DAH. Developing super rice hybrid with strong root vigor and maintaining and enhancing its root vigor at the grain-filling period through cultivation measures, could be helpful in solving the problems of two-period grain-filling phenomenon and poor grain filling of super hybrid rice.