杂交水稻结实率的研究

STUDIES ON SEED SETTING PERCENTAGE OF HYBRID RICE

摘要:

对杂交水稻常规水稻在结实期间剑叶和谷粒中的蔗糖含量的变化，穗上不同部位的结实情况，实粒率和千粒重的动态变化以及它们之间的关系，结实率对有机营养供应变化的反应等方面进行了比较研究。结果表明，杂交水稻结实率较低主要是由于穗的中、下部尤其是稳下部出现较多的秕粒造成的；与常规水稻比较，杂交水稻在灌浆的前中期，剑叶和籽粒中的蔗糖含量高，籽粒增重快，后期则相反；穗上部和下部的结实率和千粒重皆差异大；在实粒增加过程中，千粒重与常规水稻相同时，实粒率低，在灌浆后期，实粒率对有机营养应给的变化较敏感，早、晚季及“库”“源”关系变化时，结实率和千粒重的变化幅度大。本文还对杂交水稻结实率较低和较不稳定的原因进行了探讨。

Abstract:

One cultivar (Teqing) and 3 hybrids (W6154s/Teqing, Weiyou 64 and Yayou Ⅱ) were used to study the changes of sucrose content in the flag leaf and grains, the seed setting percentage and grain dry weight, the grain weight in relation to the plump grain percentage, and the effect of organic nutrient on seed setting. The results indicated that seed setting percentage of hybrid rice was affected mainly by the number of imperfect grains in the middle and lower spikelet branches, especially by that in lower branches. In comparison with conventional rice, in hybrid rice, the sucrose contents in flag leaf and grains were high and the grain weight increased rapidly at early stage of grain filling, while those were lower and slowly at late stage, respectively. Hybrid rice showed much difference in seed setting percentage and grain dry weight between upper and lower branches. Low percentage of plump grains was shown in hybrid rice when the grain dry weight was the same as that in conventional rice. Plump grains of hybrid rice were more affected by the changes of organic nutrient at later stage of grain filling. The seed setting percentage and grain weight were much different in different growing season or in the case that the relationship between asource" and "sink" was changed as compared with conventional rice. The reason that the seed setting percentage of hybrid rice was lower and unstab1e was discussed.