Identification of QTL for leaf angle and leaf space above ear position across different environments and generations in maize (Zea mays L.)

The yield of maize (Zea mays L.) is affected by the plant architecture which is associated with the distribution of light within canopy and utilization of solar energy within population. Plant architecture of maize is mainly characterized by leaf angle (LA) and leaf space (LS). To analyze the genetic mechanism of LA and LS above ear position in maize, a genetic linkage map composed of 212 simple sequence repeat markers was constructed based on a F-2 population derived from the cross between the compact inbred line CY5 and the expanded inbred line YL106. The map spanned 1,153.39 cM in length with an average interval of 5.44 cM. By using the inclusive composite interval mapping method, QTLs for LA and LS above ear position were identified based on two field mapping populations consisted of 144 F-2:3 families in three environments and 144 F-4 families, respectively. In F-2:3 population, three consistent QTLs qSecLA1a, qThiLA1a, and qThiLS7 were detected in both single-environment analysis and joint-environment analysis. The qSecLA1a between bnlg1803 and bnlg1007 on chromosome 1.02 explained 26.99 and 18.51 % of the phenotypic variation, qThiLA1a between bnlg1803 and bnlg1007 on chromosome 1.02 explained 24.14 and 22.00 % of the phenotypic variation and qThiLS7 between bnlg1305 and umc1787 on chromosome 7.02/7.03 explained 13.77 and 9.96 % of the phenotypic variation in single environment analysis while the three QTLs explained 29.10, 31.86 and 11.20 % of the phenotypic variation, respectively in joint environment analysis. Moreover, there were major QTLs near bnlg1803 on chromosome 1 for SecLA and ThiLA stably expressing in F-2:3 and F-4 generations. The results of this study could provide references for genetic modification and molecular marker-assisted selection for LA and LS in maize.