Trends in breeding rice for high yield
1989
Yang, Shouren | Chen, Winfu (Shenyang Agricultural Univ. (China))
Chinese rice scientists increased rice 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 grain-straw ratio. Research efforts should aim at increasing leaf area and photosynthetic efficiency per unit leaf area; and at improving fertilizer responsiveness and lodging resistance. This will require combining ideal plant morphology with favorable vigor. Indica/japonica hybridization should meet the following objectives: the high stomata frequency in indicas combined the compact plant type, higher specific leaf weight, higher chlorophyll content per unit leaf area, and higher nitrogen and RUBPC content in japonicas. These characteristics are advantageous for close planting and for increasing photosynthetic efficiency of leaves and total biomass yield. Indica/japonica crosses should also have increased growth vigor. More than 30 years of research on crossing indicas and japonicas at Shenyang Agricultural University [China] have resulted in the development of rice strains that yield more than 10 t/ha. Exploiting the nucleus-cytoplasm interaction of indica/japonica crosses to increase yield potential is also proposed.
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