早籼稻品种更替过程中农艺性状的演变特征

以南方稻区品种更替过程中大面积推广的18个早籼稻代表品种为材料，按高秆品种、矮秆品种、矮抗品种、优超品种4个演变阶段，采用常规栽培方法研究其农艺性状的演变特征。结果表明，随着品种的演变，产量、收获指数、每穗粒数均有提高；有效穗、结实率、千粒重变化不大。进一步分析表明，每穗粒数的增加是着粒密度改良所致。农艺性状与年代的回归分析表明，生物量与株高在1980年后有增加的趋势，生育期有缩短的趋势。相关分析表明，决定早籼稻产量的农艺性状为生物量、株高、收获指数和每穗粒数。

Evolution Characteristics of Agronomic Traits in Cultivar Replacement of Early Season Indica Rice

Eighteen leading cultivars released from 1934 to 2006 and widely planted ever in south China were used, and classified into four rice genotypes, i.e. high-stalk cultivar (HC), dwarf cultivar (DC), dwarf and resistant cultivar (DRC), high-quality and super cultivar (QSC) in the present study conducted at 2006 and 2007 under conventional cultivation conditions. Plant height and growth duration as typical agronomical traits and grains per panicle, effective panicles and 1000-grain weight as main yield parameters were investigated in the study. Results showed that grain yield was increased with the increase of harvest index, grains per panicle and grain density in the evolution of the cultivars. The results further indicated that higher grains per panicle were closely related to the higher grain density. The regression analysis results showed that plant height and biomass tended to increase after 1980, while growth duration decreased. The correlation analysis showed that there were four key factors, biomass, plant height, harvest index, and grains per panicle, affecting grain yield.