Study On The Basic Characteristics Of Indica Rice(Oryza Sativa.L.)Varieties With Large Panicle And Their Effect On Grain Yield

24 conventional indica rice (Oryza Sativa.L) varieties from different years and areas, which with near growth duration were employed in solution-cultured experiment to investigate yield and its components, dry matter production and partition, root morphological traits and root activity. The varieties were clustered into 3 types by panicle weight, using hierarchical cluster method to analyze the basic characteristics of large panicle in conventional indica rice varieties and their effect on grain yield. The purpose of this study is to provide valuable bases for selecting and breeding high-yielding rice varieties. Result showed as follows:(1) The ratio of maximum/minimum of traits aboveground ranged from 1.40 to 5.94 and 1.47 to 13.39 , respectively; And that of root traits ranged from 1.54 to 11.71 and 1.51 to 13.39, respectively, in 2002 and 2003.(2) The varieties were clustered into 3 types by panicle weight, using hierarchical cluster method, and result showed that the average of high, medium and low panicle weight was 2.75g, 1.96g and 1.17g, respectively, in 2002; and 2.48g , 1.79g and 1.20g, respectively, in 2003.(3) The varieties with high panicle weight have higher yield and lower coefficient of variation (CV), and the contrary result was observed in varieties with low panicle weight.(4) The characteristics of yield components , biomass accumulated and partitioning , and root traits of varieties with high panicle weight were as follows: Smaller number of panicles per unit area, larger number ofspikelets per panicle, higher spikelet fertility, higher 1000-grain- weight, larger number of spikelets and larger sink potential per unit area; Dry matter accumulated before or after heading , the biomass and the harvest index (HI) were higher; Longer length of adventitious root per plant, higher root dry weight per plant, longer length per adventitious root, higher dry weight per adventitious root.( 5 ) The yield of rice was significantly correlated with spikelets per panicle, spikelet fertility, the number of spikelets per unit area and sink potential per unit area; and it has no close relation with the number of panicles per unit area and 1000-grain- weight. There existed remarkable relationship between yield and biomass, harvest index. The contribution of biomass to yield was higher than that of harvest index.(6) The yield significantly correlated with length of adventitious root per plant, dry weight of root per plant, dry weight per adventitious root and length per adventitious root. And it has no close relation with other root traits.