Analysis on combining ability of major agronomic characteristics in two-line special hybrid rice with vitamin A.

Nine rich vitamin A two-line hybrid black rice parents rich in vitamin A,including 4 sterile lines and 5 restorer lines developed by this research center,were chosen to analyze the combining ability of 9 main agronomic characters by means of NCⅡ mating design.The results were as follows:(1)The mean squares of variance of the general combining ability (GCA) of all the characters determined were significant’ at a level of 1%.It means that both the 4 sterile lines and the 5 restorer lines had different effects on improving the agronomic characters.(2)The mean squares of variance of the specific combining ability (SCA) of all the characters determined for sterile line×restorer line were significant’ at a level of 1%.The analysis results showed that the non-additive effects were principal in the period from sowing to heading and the number of effective tillers per plant;plant height,panicle length,spikelets per panicle and full spikelets per panicle were controlled by the additive effects;and both the non-additive effects and the additive effects were principal on seed setting rate,1 000-grain weight and grain weight per plant.(3)In 25-11-9S,24-11-3S,R Tang 06-4 and R Yuheihai 07-4,the effect values of general combining ability were positive in most characters,and they had high effect values of general combining ability in spikelets per panicle,full spikelets per panicle and grain weight per plant.The four parents had been proved to have comparatively large potential in rice production,and strong heterosis combinations might be developed by abroad testcross.