Mapping of QTL Associated with Drought Tolerance in a Semi-Automobile Rain Shelter in Maize (Zea mays L.)

Drought is a major constraint in maize production worldwide. We studied quantitative trait loci (QTL) underlying drought tolerance for maize plants grown in two different environments. Traits investigated included ASI, plant height, grain yield, ear height, and ear setting. A genetic linkage map was constructed with 120 simple sequence repeat (SSR) markers based on an F(2) population derived from a cross between D5 (resistant parent) and 7924 (susceptible parent). Correlation and heritability were calculated. QTLs of these traits were identified by composite interval mapping combined with a linkage map covering 1790.3 cM. The markers were arranged in ten linkage groups. QTL mapping was made of the mean trait performance of the 180 F(2:3) population. The results showed five, five, six, four, and five QTLs for ASI, plant height, grain yield, ear height, and ear setting under full irrigation condition, respectively, and four, seven, six, four, and four QTLs for ASI, plant height, grain yield, ear height, and ear setting under severe late stress conditions, respectively. Especially the four QTLs detected for five traits in 2008 and 2009. The universal QTLs information generated in this study will aid in undertaking an integrated breeding strategy for further genetic studies in drought tolerance improvement in maize.