QTL Analysis And Genetic Dissection Of Grain Weight And100-kernel Weight In Maize Under Different Water Regimes

Grain weight and100-kernel weight are two important traits for maize. Much attention has been paid to investigate the genetic mechanisms of grain weight and100-kernel weight for improving grain yield. To elucidate the genetic basis of the two traits, a recombinant inbred lines (RIL)populations derived from the crosses of Lv28×Huangzaosi were used as materials in the present study. The objectives were to indentify QTL conferring grain weight and100-kernel weight under different water regimes and estimate their effects;to dissect the stability of QTL, the QTLx Environment interaction cross environments and the epistatic effects involved in controlling grain weight and100-kernel weight; and to provide references for effective utilization in maize improvement program.The main results were as follows:1. QTL for grain weight and100-kernel weight were mapped in a recombinant inbred lines (RIL)populations derived from the crosses of Lv28×Huangzaosi with184families which were evaluated under two diverse environments in Xinjiang China in the year of2009. The two traits were mapped under a single environment and across environments. Meanwhile, epistasis among QTL and QTL by environment interaction (QEI) were analyzed. The mapping results showed that a total of3and7QTL were identified for grain weight and100-kernel weight, respectively. The major QTL located in bin4.08,bin4.05,bin5.06and bin10.04can be detected across environments.Most of the detected major QTL exhibited high stability across the two different environments. Several major QTL were detected with large and consistent effect across two water regimes (bin4.08-4.09,bin4.05and bin7.04-7.05), These QTL may be particularly useful in maize breeding programs.2. Particularly, two major QTL were detected with large and consistent effect (bin4.05, bin4.08-4.09), and had quite high phenotypic variance explained.The major QTL located in chromosome4also can be detected in the two environments. To narrow down the two QTL intervals, SSR markers were designed from the bin4.05and bin4.08-4.09regions of chromosome4. The QTL interval was narrowed down to 4.9-17.4cM by targeted enrichment of the two regions.The QTL stably expressed under different environments may play an important role in controlling maize grain yeild-related traits, which may be candidates for fine mapping and positional cloning.