关键词: 籼粳稻杂交, 理想株型, 光合效率

Abstract: Chinese rice scientists increased rice varietal yields during the 1950s and 1960s by improving the plant type and since the 1970s by exploiting the phenomenon of heterosis in developing F₁ hybrid cultivars. Both approaches seem to have reached a plateau, with yields of 8～9 t/ha. If still higher yields are to be achieved, total biomass yield has to be increased while maintaining a reasonable gram straw ratio. Research efforts should aim at:(1) increasing leaf area; (2) increasing photosynthetic efficiency per unit leaf area and (3) improving fertilizer responsiveness and lodging resistance. This would require combining ideal plant morphology with favorable vigor, Indica—japonica hybridization should meet this objectives. High stomata frequency of indicas could be combined with japonica traits of compact plant type, higher specificleaf weight, higher chlorophyll content per unit leaf area, and higher nitrogen and RUBPC content. All these characteristics are advantageous to close planting and to increasing photosynthetic efficiency of leaves and total biomass yield. Indtca japonica crossing would also result in ideal plant morphology and in increased growth vigor.

Key words: Indica-japonica hybridization, Ideotype, Photosynthetic efficiency