%D 2011 %0 MEDLINE %T Cytoplasm affects grain weight and filled-grain ratio in indica rice . %J BMC Genet %V 12 %P 53 %A Tao D %A Xu P %A Zhou J %A Deng X %A Li J %A Deng W %A Yang J %A Yang G %A Li Q %A Hu F %M pub21631950 %X BACKGROUND : Cytoplasmic effects on agronomic traits--involving cytoplasmic and nuclear genomes of either different species or different cultivars--are well documented in wheat but have seldom been demonstrated in rice ( Oryza sativa L ) . To detect cytoplasmic effects , we introgressed the nuclear genomes of three indica cultivars--Guichao 2 , Jiangchengkugu , and Dianrui 449--into the cytoplasms of six indica cultivars - Dijiaowujian , Shenglixian , Zhuzhan , Nantehao , Aizizhan , and Peta . These 18 nuclear substitution lines were evaluated during the winter season of 2005 in Sanya , Hainan , China , and during the summer season of 2006 in Kunming , Yunnan , China . The effects of 6 cytoplasm sources , 3 nucleus sources , 2 locations and their interactions were estimated for plant height , panicle length , panicle number per plant , spikelet number per panicle , grain weight , filled-grain ratio , and yield per plot . RESULTS : For five of the seven traits , analysis of variance showed that there were no significant cytoplasmic effects or interactions involving cytoplasmic effects . The effect of cytoplasm on 1000-grain weight was highly significant . Mean 1000-grain weight over the two locations in four of the six cytoplasms clustered close to the overall mean , whereas plants with Nantehao cytoplasm had a high , and those with Peta cytoplasm a low mean grain weight . There was a highly significant three-way interaction affecting filled-grain ratio . At Sanya , cytoplasms varied in very narrow ranges within nuclear backgrounds . Strong cytoplasmic effects were observed only at Kunming and in only two of the three nuclear backgrounds ; in the Jianchenkugu nuclear background , there was no evidence of strong cytoplasmic effects at either location . In the Dianrui 449 and Guichao 2 nuclear background evaluated at Kunming , filled-grain ratios of the six cytoplasms showed striking rank shifts CONCLUSIONS : We detected cytoplasmic variation for two agronomically important traits in indica rice . The cytoplasm source had a significant effect on grain weight across the two experimental locations . There was also a significant cytoplasmic effect on filled-grain ratio , but only in two of three nuclear background and at one of the two locations . The results extend our previous findings with japonica rice , suggesting that the selection of appropriate cytoplasmic germplasm is broadly important in rice breeding , and that cytoplasmic effects on some traits , such as filled-grain ratio , can not be generalized ; effects should be evaluated in the nuclear backgrounds of interest and at multiple locations .