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qEL7.2 is a pleiotropic QTL for kernel number per row, ear length and ear weight in maize (Zea mays L.)

Zhou, Guangfei, Zhu, Qiuli, Yang, Guliang, Huang, Jun, Cheng, Shuiyuan, Yue, Bing, Zhang, Zuxin
Euphytica 2015 v.203 no.2 pp. 429-436
quantitative trait loci, substitution lines, isogenic lines, Zea mays, microsatellite repeats, loci, seeds, pleiotropy, corn ears, genetic improvement, corn, agronomic traits, genes, grain yield, phenotypic variation, screening, genetic markers
In maize (Zea mays L.) breeding, high grain yield is the most important breeding goal. Maize grain yield is strongly correlated with kernel number per ear, kernel weight, ear weight, among other factors. Unveiling the genetic basis of these yield-associated traits is useful for guiding the genetic improvement of maize. In this study, we found that a chromosome segment substitution line, SL17-1, showed that approximately 92.3 % of the genome of SL17-1 was recovered from its original elite parental line, Ye478, based on the simple sequence repeat marker screening, but it significantly diverged in ear length (EL), kernel number per row (KNR) and ear weight (EW). Moreover, we developed two sets of narrow-based F₂:₃families derived from a cross of Ye478 × SL17-1, and we detected a QTL on maize chromosome 7.02 bin (designated as qEL7.2) responsible for EL, KNR and EW, which accounted for 21.6–51.8 % of the phenotypic variation observed in these populations. Furthermore, qEL7.2 was validated using QTL isogenic lines. These results suggest that qEL7.2 is a pleiotropic QTL with large effects and, thus, is an important locus for improvement of maize grain yield and cloning of the yield-associated gene.