水稻大穗形成机理的研究（3）品种间每穗颖花现存数与颖花分化和抽穗期物质生产的关系

１９８９～１９９０年在大田条件下，对杂交籼稻和常规籼、粳稻等１２个品种每穗颖花现存数等穗部性状进行了观察，结果表明，不同品种每穗颖花现存数差异很大，其差异主要由２次颖花现存数的变化所致。每穗颖花现存数高的品种，２次颖花现存数的比例大。每穗１，２次颖花现存数分别主要决定于１，２次枝梗现存数。每穗颖花现存数随每穗颖花分化数的增加而提高，但颖花现存率却随之降低。每穗颖花现存数可分解为抽穗期单茎干物重和每克干物质形成现存颖花能力２个因素，只有两者同时提高，每穗颖花现存数才能大幅度地增加。

FORMATION OF LARGE PANICLE IN RICE(3)VARIETAL DIFFERENCE OF SURVIVED SPIKELET NUMBER PER PANICLE AND ITS RELATIONS WITH DIFFERENTIATED SPIKELET NUM-BER AND BIOMASS AT HEADING

rice varieties including indica,japonica and hybrid indica were selected ln analysing thespikelet number per panicle and its relation with differentiated and retrograded spikelet number. Resultsshowed that the varietal difference of survived spikeiet number per panicle was significant,mainly due to thevariation of the number of survived spikelets on secondary branches. The bigger the number of survivedspikelets per panicle,the higher the percentage of the number of spikelet on secondary branches. The sur-vived spikelet numbers on primary and secondary branches were mainly subjected to the numbers of prirnaryand secondary branches respectively.With the increment of the differentiated spikelet number per panicle,the number of survived spikelets increased, but the surviving rate of spikelet decreased.The survived spikeletnumber was the product of two components:dry matter accumulated at heading and spikelet surviving ability(the ratio of survived spikelet number per panicle to the dry matter weight per stem).Only with the incre-ment of both of them, the survived spikelet number per panicle could be raised drastically.