Analysis of combining ability heritability of major agronomic traits of two-line super hybrid rice

Abstract

4 different photo-thermo-sensitive sterile lines(i.e.Y58S,etc.) and 8 restorers(i.e.9311,etc.) were utilized by the method of incomplete diallel cross(NCⅡ) to make 32 crosses,which was used to observe and evaluate 10 agronomic traits such as plant height,number of panicles per plant in F1hybrid rice,in order to analyze the combining ability and heritability.Results were ①The general combining ability and the specific combining ability variances were significantly different in major agronomic traits at 0.05 and 0.01 levels,respectively.In addition to general combining ability variance of number of empty grains per panicle,seed setting rate,yield per plant,the other 7 traits contributed more than that of specific combining ability to F1hybrid rice,which showed that the general combining ability was more important than the specific combining ability for hybrids yield potential.②The plant height,straw length,panicle length,number of empty grains per panicle,seed setting rate,yield per plant of hybrid rice F1were mainly influenced by female lines,while number of panicles per plant,number of grains per panicle,number of filled grains per panicle,1 000–grain weight were mainly affected by restorers.To increase the super hybrid rice yield,the key method should be the improvement of both parents.Breeding for female lines should emphasize the large sink and raise the ratio of sink/source,breeding for restorers should focus on enlarging the size of source and sink.③Sterile lines Y58S,Guangzhan63S and restorers Yuanhui2,R0293 were the better parents for F 1 yield improvement because of their better the general combining ability in all parents.④The order of h n 2 of 10 yield traits was panicle length,1 000–grain weight,number of filled grains per panicle,plant height,straw length,number of grains per panicle,seed setting rate,number of empty grains per panicle,number of panicles per plant,yield per plant.And these characters,panicle length,1 000–grain weight,number of filled grains per panicle,plant height were important supporting points for promoting the yield potential in super hybrid rice breeding.