Contribution of different tillers within a plant to grain yield of rice

摘要

A greenhouse experiment was conducted to investigate the contribution of different tillers in a plant towards grain yield and also to evaluate the ideotype of a low tillering rice for increasing grain yield potential. Among the four rice cultivars,IR 36 and Pusa Basmati-I had an earlier and longer tillering period compared with Saket-4 and Basmati 370. Different tillering orders had varying tillering periods. Percent effective tillers was higher in low tillering cultivars than in high tillering ones. Based on spikelet number and grain weight of panicle, the panicles on the first formed 10 tillers in a plant (main culm, first 5-6 primary tillers and the first 2-3 secondary tillers) were larger than other panicles. These top 10 tillers were characterized by early initiation, early flowering, longer growth duration, heavier culm and greater flag leaf area. Panicles from primary tillers were larger than those from secondary and tertiary tillers. Tertiary and late secondary tillers contributed littleto grain yield and hence, selection of breeding lines without these tillers is recommended. Reduced tillering generally resulted in larger and heavier panicles with an increase in the number of panicle branches, spikelets and grain weight, compared to the corresponding tillers in plants with unrestricted tillering. The results suggest that the critical number of tillers for a low tillering rice ideotype must be around 10.