用7个BT型晚粳不育系和7个粳稻恢复系按NCⅡ交配设计配成49个杂交组合，研究10个重要农艺性状的杂种优势及亲本的配合力。结果表明,各性状的优势有正有负，其中每穗总粒数的优势最为明显，竞争优势和超高亲优势平均值分别为22.6%和8.6%；产量性状的超高亲优势最大，平均值为9.5%，变幅为－38.0%～43.9%，竞争优势平均值变幅为－54.8%～10.3%。在产量性状上配合力较优的不育系有852-77A、后36A和9522A，恢复系有161-10、3402、HP121，优良组合有9522A/161-10、9522A/C166、852-77A/3402。
Late-maturing japonica rice (Oryza sativa L.) is planted 10×104 hectares annually in Suzhou region, Jiangsu Province. Average yield is about 9t/ha, which is the highest yield in Jiangsu province. At the beginning of 1990’s, the hybrid rice was popularized, and the planting area was enlarged gradually, increasing by 10%. However, as the continuous improvement of pure line variety, superiority of the hybrid has not been conspicuous. If this question cannot be solved well, the planting area of hybrid rice will be reduced. This study was conducted to evaluate parents of combinations used currently in the south of Jiangsu Province and the heterosis of late-mature japonica rice and combining ability of their parents. Seven CMS lines with BT cytoplasm and seven restorers were used as parents. CMS lines were newly bred in Wuzhong Institute of Agricultural Sciences. Restorers were introduced from other provinces or newly bred in Suzhou. With NCⅡ genetic design, 49 combinations (7×7) were made by paper bag isolation in Hainan. The plots of F1s and parents were arranged in the field in a randomized complete block design with 3 replications in Suzhou. Ten agronomic characters were investigated. Research results were as follows: ⑴ Both positive and negative heterosis existed in all the 10 characters. Among them, heterosis of spikelets per panicle was the highest，showing the average heterosis over 22.6% of the control and over 8.6% of high parents. The average value of the heterosis over high parent in yield per plant was 9.5%, the highest among ten characters, ranging from －38.0% to 43.9%. The competitive heterosis of yield per plant ranged from －54.8% to 10.3%(Table 3). ⑵For character of yield, 852-77A, Hou 36A and 9522A were elite CMS lines(table 5); 161-10, 3402, HP121 were excellent restorers(Table 6); 9522A/161-10, 9522A/C166、852-77A/3402 were superior combinations.
全 文 ：