Plant Height, Internodes, Ear Traits, General Combining Ability Analysis And Their QTLs Mapping Using Double Haploid Lines Of Maize

A total of 79 DH lines derived from Nongdan5 was used to test QTL which controlled plant height, ear height, and internodes under two densities (60,000 plants hm-2 and 90,000 plants hm-2) in 2007, 2008 respectively. The plant height and its component traits were mapped to discuss molecular genetic mechanism of plant and its component traits. The aim of this study was to provide academic reference for the genetic improvement of plant height in maize. Ear traits were mapped to find QTL which controlled ear traits under two densities (60,000 plants hm-2 and 135,000 plants hm-2) and two replications, respectively. It was useful for the genetic improvement and improving yield. A,B population induced from DH8×DH40,DH86×S137 respectively were used to analyze the general combining ability and QTL of main yield traits. It was expected it would be useful to explain the genetic mechanism of combining ability. The main resule were as follow:1 Data of the plant and internodes were analyzed and mapped, the main conclusion were as follow: The plant height, ear height were controlled mainly by internodes located under ear especially basal internodes; the adjacent internodes were cooperated with each other or affected by common element mainly. There might be common mechanism in the course of growth. 67 QTLs which controlled plant height, ear height, internodes were detected and the genetic variation illustrated by individual QTL ranged from 0.97% to 18.83% The importment gene(s) which controlled plant height was(were) located in the umc1962-umc2067 on the 10th chromosome. Gene(s) controlling plant height or internodes was(were) located in umc1962-umc2067 on the 1st chromosome.There were many QTLs affecting different traits respectively which were located in the common interval, such as QTLs controlling plant height, subtractive first internode length and subtractive second internode length were located in bnlg1144-phi036 on the 3rd chromosome. It might be the same gene affecting differert traits or different genes linking closely. The QTLs could be divided into three types according to the effect of Q×E: QTL which did not have interaction with environment, QTL which did not have significant interaction with environment, QTL which had significant interaction with environment.2 Data of ear traits were analyzed and mapped, the main conclusion were as follow: The ear traits of Nongdan5 DH population were mapped under two densities (60,000 plants hm-2 and 135,000 plants hm-2) and the results indicated that there were in total 30 QTLs detected under the two densities, the genetic variation illustrated by individual QTL ranged from 3.26% to 31.59%, there was complicated interaction between QTL and environments. qEL2a (umc1165-umc1261) and qEL2b (umc1165-umc1261) might be the common site detected under two densities respectively. qRN4a (umc2135-bnlg292a),qRN4b (bnlg292a-bnlg292b) qRN4a (umc2135-bnlg292a),qRN4b (bnlg292a-bnlg292b)和qED4 (bnlg292a-bnlg292b) and qED4 (bnlg292a-bnlg292b) might be the common site also.Genes controlling row number or gain per row which were between umc2135 -bnlg292b were located in 4.08bin. 3 The general combining ability of yield traits of A, B population were analyzed and mapped, the main conclusion were as follow: The GCA of many traits of lines ( A11-2,A7,B15,B27) is high after analyzing the data of A,B population. The GCA of yidld traits of A,B DH population were mapped and the results indicated that there were in total 62 QTLs detected, the genetic variation illustrated by individual QTL ranged from 6.72% to 59.11%, there was complicated interaction between QTL and environments. qGW8b and qGPR8 might be the same site detected in B DH population. It was in bnlg1056-phi233376 which existed an importment gene controlling the GCA of grain width or the GCA of grain production rate.