早籼稻品种遗传改良进程中群体质量的演变特征

以1934～2006年育成,在我国南方广泛种植的16个代表性早籼稻品种为材料,参照生产实践及品种演变阶段,按育成时间将供试品种划分为高秆品种、矮秆品种、矮抗品种、优超品种4种类型,采用常规栽培方法研究其群体质量的演变特征。结果表明,早籼稻品种改良进程中,花后群体光合生产能力增强,干物质积累增加,齐穗期总颖花量增加,高效叶面积率与颖花根流量略有下降,有效叶面积率与成穗率变化不大,单茎茎鞘重呈先下降后略有上升的趋势。早籼稻群体进一步改良的有效途径是增强根系活力,促进根系水分与矿物质的吸收及根系物质向籽粒的转运;提高高效叶面积率,增加花后光合产物积累和总颖花量,进而提高粒叶比,达到源库协调。

Evolution characteristics of population quality during genetic improvement in early season indica rice cultivars

Sixteen cultivars released during 1934~2006 and ever since widely planted in South China were classified into four rice types under conventional cultivation conditions according to evolution stages. The types include tall cultivar (TC), dwarf cultivar (DC), dwarf and resistant cultivar (DRC), and good-quality and super rice cultivar (QSC). A total of eight crop population quality indices were investigated in this study. The results indicate that photosynthetic ability and accumulated dry matter of rice population in post anthesis are reinforced with the evolution of early season indica rice cultivars. Total spikelet number at full heading stage increases, effective leaf area and spikelet-bleeding intensity slightly decrease, effective leaf area and ear-bearing tiller change slightly and single stem and sheath weight initially decreases but subsequently increases. To further improve population quality of early season indica rice it is important to enhance root activity facilitating absorption of water and mineral nutrients by root and root materials transformation to grains. Increasing effective leaf area rate, photosynthetic products in post-anthesis and total spikelet number are also the most effective ways of improving early season indica rice cultivars. This increases grain-to-leaf ratio and enhances coordinated source-sink balance.