华南地区水稻品种发展中产量及有关性状的演变研究

对华南地区50年代以来先后推广的水稻品种早造16个、晚造17个作了研究,新复极差测定表明:产量呈现明显的递增趋势。但近期品种间产量差异不显著。产量构成因子,早稻经历了从高秆大穗型到早期矮秆多穗型又到近期半矮秆的改良大穗型的品种发展过程。晚稻近期品种向着大穗多穗型的方向发展,与同化产物分配有关的千粒重与结实率,早、晚稻近期品种均未得到较大的发展。近期品种株高,早稻向半矮秆方向发展,基部节间加粗,茎壁增厚。晚稻的变化趋势不明显。近期品种冠部功能叶,早稻略有减小,晚稻稍有增大。

STUDIES ON THE EVOLUTIONARY CHANGES IN YIELD AND RELATED CHARACTERS OF RICE CULTIVARS GROWN IN THE SOUTH-CHINA REGION

The evolutionary changes in yield and related characters of rice cultivars grown in the South-China region since 1950's were studied. 16 cultivars in early season and 17 in late season, representative of current and proceeded ones were planted in 1985, and were evoluated for grain yield and relatad morphological characters. It was shown by the SSR result that yield of rice in the South-China region were substantially increased over the last thirty years but no significant difference in yield among the current cultivars.In early ricet the yield components were developed from the panicle-weight type of the tall stature to the panicle-number type of the short stature in early 1960's, and to the impoved penicle-weight type of the current semi-dwarf cultivars. The cultivars with weighty panicles and more panicle numbers had been developed in late rice. There was no much impovement in weight of grain and fuil-grain percentage of the current cultivars both in the early and late rice The semi-dwarf cultivars with thicker base internodes and wall of stem were developed in early rice.Except the hybrid rice, the leaves size in canopy of the current cultivars were smaller and eracter in early rice but greater and eracter in late rice than those of the proceeded ones.Results from present studies suggest that further yield advances could be attained by combining higher biological yield and higher harvest index, greater grain numbers per pancile, higher full-grain percentage and higher weight of grain in rice breedlig programmes.