Genetic Diversity for Biomass Yield, Plant Architecture, and Density Response in Sorghum.

Title: Genetic diversity for biomass yield, plant architecture, and density response in sorghum Sorghum is a vigorous, stress-tolerant crop that is an attractive option for biomass production. In corn, the development of varieties that maintain a high harvest index at high plant densities enabled vast yield increases.Ê Such a strategy may or may not prove useful in biomass crops in which all above-ground biomass is harvested. This project aims to 1) evaluate and exploit genetic diversity for biomass yield in sorghum under different planting densities; 2) assess correlations between biomass yield and plant architectural traits that may have higher heritabilities than yield. In one experiment, 200 inbred lines and their hybrids on a single tester were grown in 30-inch rows with four-inch spacing, phenotyped for biomass yield and plant architectural traits, and genotyped. Results from the first experiment identify markers associated with desirable variation in plant architecture. In a second experiment, six commercial biomass sorghum hybrids were evaluated for biomass yield and plant architecture under eight density treatments, including two row spacings (15Ó and 30Ó) and four within-row planting densities. Results from this second experiment identify optimal density treatments for different commercial hybrids and the plant architectural phenotypes correlated with yield under different densities. Together, these results will be used to guide a marker-assisted improvement strategy for biomass sorghum.