%0 Journal Article %A CAO Shu-qing %A DENG Zhi-rui %A ZHAI Hu-qu %A TANG Yun-lai %A HAN Guo-biao %A ZHANG Rong-xian %A SHENG Sheng-lan %A GONG Hong-bing %A YANG Tu-nan %T Analysis on Heterosis and Combining Ability for Root Activity and Its Declined Properties in Indica Hybrid Rice %D 2002 %R %J Chinese Journal OF Rice Science %P 19-23 %V 16 %N 1 %X The heterosis and combining ability of root activity and its declined properties in indica hybrid rice were investigated by way of 4×4 incomplete diallel cross design with four sterile lines and four restorer lines. The results showed that hB2 in root activity and its declined value was higher than 85 percentage, suggesting that they may be used as the indexes of selecting excellent root in rice breeding. The estimates of both combing ability (GCA and SCA) variances were highly significant for two traits, showing root activity and declined value existed for both additive and non-additive effects, but the former was affected mainly by non-additive effect, while the latter mainly by additive effect. Longtefu A and Zhenhui 048 had higher GCA and larger variance values of SCA, which implies that they can be utilized as superior parents in rice breeding. The mean heterosis of root activity and declined value were positive (it was excellent for the negative mean heterosis of the latter), showing it was difficult to improve root physiological activity trait, but the quality hybrid might be obtained because of the difference among crosses. %U http://www.ricesci.cn/EN/abstract/article_1015.shtml