Control of Leaf angle1 (Cla1) Regulates Leaf Architecture in Elite Breeding Materials of Maize

Maize yields have increased dramatically in the U.S. since the late 1930’s and more recently in China thanks to both improved agronomic practices and selection by breeders for higher planting densities. The selection of upright leaf architecture enables plants to be grown at higher density while minimizing the shading of neighboring plants and increasing the efficiency of light capture. To identify genetic components of leaf architecture important for yield gains in China, we took advantage of a recombinant inbred line population developed from two elite lines, Shen137 and Yu82 that have contributed significantly to hybrid seed production in China. Fine mapping of a major effect QTL for leaf angle led to the identification of Control of leaf angle 1 (Cla1), a novel component of the leaf angle genetic program. Genome wide association studies (GWAS) confirmed the contribution of CLA1 in the control of leaf angle across a diverse germplasm collection. Variations in Cla1 expression likely regulate the extent of leaf auricle development through an auxin signaling cascade. These results suggest several new candidates for the manipulation of leaf architecture in maize in elite breeding materials to fine tune photosynthetic performance under increasing planting densities.