Progress of Super Hybrid Rice Breeding in South China

摘要

Rice is one of the most important crops providing staple food for more than half the population in China. The wide utilization of semi - dwarf varieties and hybrid rice has led to two major breakthroughs in rice yield. Since 1990's, however, the yield level has re-mained stagnant for a long time. To meet the future demand for rice, the focus of the rice breeder in the new century is how to further increase the yield potential. Chinese scientists have designed a set of model for breeding high - yielding rice based on different ecological conditions and theories, such as the erect panicle type model of japonica rice designed by Yang Shou - ren in northern China, the bushy type and early rapid - growing model proposed by Huang Yao - xiang in South China, thfe indica rice- growing region, and the heavy panicle model constructed by Zhou Kai - da in Southwest China, as well as the super hybrid rice model designed by Yuan Long - ping for Yangtze River rice - growing region. As one of the main rice - growing regions, South China has its particular ecological conditions and hence should have specific plant model and breeding strategies for breeding high - yielding hybrid rice. After years of practice, a new strategy for super hybrid rice breeding, based on the models of Huang and Yuan, was put forward as follows: ①middle growth duration of 105 - 130 d , ②rapid growth at seedling and tillering stage to form larger leaf area and make full use of the solar energy , ③moderately compact plant type, with high LAI, long leaf blade at early growth stage, and then lower LAI and erect leaf,.at the late growth stage, ④better tillering capacity with 10 ～ 13 panicles per hill, ⑤droopy panicles, ⑥harvest index of 0. 55 or more. According to the new strategies, great progress has been achieved and a super hybrid rice combination Yueza 122 and Yueza 889, with daily yield of more than 100 kg/hm~2·d, were successfully developed.