QTL mapping for leaf morphology traits in a large maize-teosinte population

Abstract

From its wild progenitor teosinte (Zea mays ssp. parviglumis), maize has experienced a dramatic morphological transformation. Although several critical genes controlling the changes in overall plant architecture during domestication have been identified, the genetic basis that controls the changes in leaf morphology, an important component of plant architecture, remains poorly understood. Here, using a large population of 866 maize-teosinte BC2S3 recombinant inbred lines genotyped with 19,838 SNP markers, we performed high-resolution quantitative trait locus (QTL) mapping for three leaf morphological traits, including leaf length, leaf width, and sheath length. We demonstrate that the three leaf traits were associated with distinct genetic architecture features and under relatively independent genetic control. This genetic independence was further validated by the analysis of near-isogenic lines for target QTLs. QTL characterization revealed that the three leaf traits might have experienced directional selection for increased leaf size since domestication. We found that known leaf development genes identified by mutagenesis were significantly enriched in the support intervals of leaf trait QTLs, potentially indicating their important roles in regulating natural variation in leaf traits. Our findings provide important insights into the genetic basis that controls maize leaf evolution.