Mapping QTLs for Component Traits Influencing Drought Stress Tolerance of Maize (Zea mays L) in India

The present study was aimed at mapping of Quantitative Trait Loci (QTL) for various traits influencing the performance of maize genotypes under drought stress conditions in India. A set of 210 Recombinant Inbred Lines (RILs) developed at CIMMYT (Mexico) was analyzed in drought trials undertaken at Karimnagar (2002-03) and Hyderabad (2003-04). Analyses of the RIL datasets using Composite Interval Mapping (CIM) models led to the detection of 52 QTLs, including 22 QTLs under the control conditions and 30 QTLs under drought stress conditions at Karimnagar, and 14 QTLs influencing various characters under drought stress conditions at Hyderabad. A significant digenic epistatic QTL effect, other than the main effect QTLs, was detected for kernel number per ear under drought stress conditions. A comparison of the QTL information obtained from independent analyses of the Karimnagar and Hyderabad datasets revealed colocalization of QTLs on chromosomes 1, 2, 8 and 10 in the RILs influencing specific characters under drought stress conditions. Comparison of the QTL information with that reported from previous analyses of the same set of RILs at Mexico, Kenya and Zimbabwe revealed some ‘consensus QTLs’, which could be of significance in molecular marker-assisted breeding for drought tolerance in maize, besides functional genomics.