稀植条件下杂交稻分蘖成穗规律和穗粒结构研究

研究了19.5,13.5和7.5穴/m2 3个种植密度下杂交稻组合中优6号和两优培九不同时期的分蘖成穗规律和穗粒结构.结果表明,稀植促进分蘖发生,并导致最高分蘖期和有效分蘖期延迟,13.5和7.5穴/m2比19.5穴/m2的最高分蘖期分别推迟7和14 d;随种植密度下降,中后期发生的分蘖在茎蘖数中的比例提高,相应成穗率也提高;早期分蘖所成的穗与后期分蘖所成穗的每穗粒数差异较大,结实率差异较小,两者的产量差异主要由穗粒数差异引起;随种植密度下降,分蘖力较弱的组合产量显著下降,而分蘖力较强的组合产量没有差异.

Studies on the Tillering Dynamics,Panicle Formation and Composition of Panicles of Hybrid Rice under Sparse Transplanting Density

The tillering dynamics, composition of panicles and yield under different transplanting densities were studied with two hybrid rice combinations, Zhongyou 6 and Liangyou Peijiu as the materials. The results showed that sparse planting promoted the emergence of tillers and resulted in the delay of maximal tiller stage and elongation of the period of productive tillers. Compared with the planting density of 19.5 hills/m~2, the planting densities of 13.5 hills/m~2 and 7.5 hills/m~2 were delayed one and two weeks, respectively, in maximal tiller stage. With the decrease of planting densities, the percentage of the tillers emerged in the middle and late stages and their productive tiller rate increased. There was a great difference in the number of grains per panicle but not much difference in seed setting percentage between early tillers and late tillers, so the difference in yield was mainly resulted from the difference in the number of grains per panicle. With the decrease of planting densities, the yield of the hybrids with weak tillering capacity decreased dramatically while no yield difference was found in the hybrids with strong tillering capacity.