Identification of QTLS for yield and drought-related traits in maize: assessment of their causal relationships

Abstract

Drought is one of the most important factors contributing to crop yield loss. Developing maize varieties with drought tolerance requires exploring the genetic basis of yield and associated agronomic traits. In order to identify QTLs for yield and drought related traits and to determine their relationships, 116 F-3 families of the DTP79xB73 cross were evaluated in field trials. Phenotypic correlations between the traits were calculated using Pearson's coefficient. QTL detection was performed using ANOVA and composite interval mapping (CIM). Out of 64 QTLs identified using CIM for all analyzed traits 26 QTLs were also identified with ANOVA. For all the traits (except for EL, DS2 and RWC1) only a small proportion of phenotypic variation was accounted for by the identified QTL. The significant positive/negative phenotypic correlations between different traits and coincidence of markers with allelic differences in the expected direction show that they may be causally correlated. The above criteria were fullfilled for a subset of QTLs within all the traits. The overlap found between the QTLs for yield and those for the other traits suggests the presence of genes with pleiotropic effects on the investigated traits. Results will be used for further investigation and detection of possible candidate genes for drought tolerance in maize.