Combining ability of main agronomic traits in early-maturing maize inbred lines

ObjectiveCombining abilities of 11 agronomic traits in 8 early-maturing maize inbred lines were determined to provide reference for selection of early-maturing maize premium combinations in Guangxi.MethodNCII genetic cross design was used to determinate and analyze general combining ability of 11 agronomic traits in four new-bred early-maturing maize in-bred lines and four early-maturing maize core inbred lines applied in production,as well as the specific combining ability of 16 cross combinations with the above mentioned maize lines as parents.ResultThe 16 cross combinations sowed and sprouted at the same time,but their silking stages were different,and the maximum difference was 6 d.The silking stage of South 6047× M0502 occurred first.The mature stages varied within 5 d at most,and the earliest one was South 6047×M0502.The average growth period was 99 d,South 31×M0340,South 31×South 783,M12-5×MWC5 and M12-5×South 783 had the longest growth period(average 101 d).There were significant differences in grain yield per plant,stem diameter,ear length,length of bald tip,ear diameter,kernel number per row,kernel number per row and grain rate among different cross combinations(P<0.01).General combining ability of 11 agronomic traits in South 31 had the optimal performance.Their effect values of general combining ability in plant height,ear height,stem diameter,ear length,length of bald tip,ear diameter,ear row,kernel number per row,100-grain weight,grain rate and grain yield per plant were 0.42,4.95,-2.86,2.85,-22.36,6.13,7.68, 5.58,6.15,4.60 and 12.02 respectively.Using these two as parents could increase grain yield per plant of F1 generation,and the possibility of high yield cross combinations was great.The highest effect value of specific combination in grain yield per plant appeared in cross combination M12-5×South 783,and effect values of specific combination in grain yield per plant of South 31×M0502 and South 6047×MWC5 were 13.45 and 13.16 respectively.ConclusionSouth 31,M0502 and M12-5 can be used as the idealest parents for the combination of early-maturing and high-yield hybrids.The general combining abilities in bald tip of M12-5,South 31 and South 783 present great negative effects,which can be used to improve bald tip. M12-5×Southe 783,South 31×M0502 and South 6047×MWC5 as super combination can be promoted after tests and identifica-tion in multiple sites.