Genetic analysis and QTL mapping of maize yield and associate agronomic traits under semi-arid land condition

Abstract

Drought is one of the major limiting factors in sustainable maize production all over the world. In order to develop maize variety with drought tolerance, it is necessary to explore the genetic basis and map
the quantitative trait loci (QTLs) controlling the yield and associate agronomic traits under semi-arid land condition. In this study the QTLs for flower time, plant height, yield and yield components were
characterized with recombinant inbred lines (RIL) derived from the cross 5003 × p138 under drought stress and well-watered regime in the years 2004 and 2005, respectively. A linkage map was
constructed based on 101 simple sequence repeat (SSR) markers covering a total of 1395.2 cM genetic distance, and an average distance of 13.81 cM between markers. A total of 51 QTLs were identified for 10 traits on 10 different chromosomes. Under the well-watered regime, 25 QTLs were identified for 9 traits, whereas under the water-stressed conditions, 22 QTLs were found for 7 traits. Four QTLs for drought tolerance index were found. Phenotypic variation associated with each QTL ranges from 1.68 to 13.3%. The results reveal that most related traits cluster in chromosomal blocks: bnlg1614-bnlg1083 on chromosome 1 and bnlg1634-bnlg1209 on chromosome 9 for plant height, bnlg1035-bnlg1564 on
chromosome 1 for yield and its components and drought insistence index, near NC012 and bnlg2907-bnlg1136 on chromosome 6 for flower time and anthesis-silking interval (ASI), and near bnlg1063 on
chromosome 5 and bnlg1241 on chromosome 4 for flower time. Four QTLs for male flower time were identified in marker bnlg1327-bnlg1812 on chromosome 8 under two water regimes. These QTLs may be
useful for the marker-assisted selection in maize breeding for drought resistance.