MOLECULAR AND GENETIC ANALYSIS OF AXILLARY BUD DORMANCY AND OUTGROWTH IN SORGHUM AND MAIZE TO IDENTIFY SHOOT BRANCHING GENES

The major goal of this project is to identify genes that control shoot branching in sorghum and maize using molecular (RNA sequencing/gene expression) and genetic (gene loci/QTL mapping) approaches. To achieve the goals of the project, we will work on the following three objectives:Objective 1: Identify genes controlling axillary bud transition from growth to dormancy. Sorghum, sweet corn, and teosinte (a wild ancestor of maize) develop axillary buds that grow into branches. We will apply shade or defoliation treatments and induce bud dormancy in these species. We will identify genes associated with growing (control) and dormant (shade or defoliated treated) buds using RNA sequencing (RNA-seq) methods.Objective 2: Identify genes controlling axillary bud transition from dormancy to growth. Some buds in sorghum, maize, and teosinte remain dormant and grow when conditions are favorable. We will identify genes associated with the dormancy to growth transition using RNA-seq.Objective 3: Identify quantitative trait loci (QTL) that control genetic variations in shoot branching. Using recombinant inbred line (RIL) populations derived from diverse sorghum genotypes selected for variations in shoot branching, we will identify QTLs associated with shoot branching.