Characterization of Diverse Sorghum Genotypes for Traits Related to Drought Tolerance.

Grain sorghum (Sorghum bicolor L. Moench), a cereal that is grown in many semiarid regions of the world is very diverse in its genetic base. An association panel of 300 sorghum genotypes, which is believed to be representative of sorghum globally, has been developed for genetic studies in sorghum. The single greatest abiotic stress factor that limits crop growth worldwide is water availability. Evaluation of genetic resources and selection of drought tolerant germplasm and the understanding of the physiological and genetic responses to abiotic stress. The purpose of this study was to characterize the association panel for physiological traits associated with drought tolerance. The objectives were to (i) quantify the performance of the association panel under field conditions in Kansas, (ii) characterize the sorghum association panel for phenological, physiological and yield traits that might be associated with pre-flowering and post-flowering drought tolerance, and (iii) identify drought tolerant lines with higher yield potential that may be used in the sorghum breeding program. Results from the study showed significant differences in plant height, grain weight and numbers per panicle, harvest index and grain yield among and within races. There was a correlation between plant height and grain yield as well as grain numbers and yield. Harvest index and grain numbers were negatively affected by moisture limitation for all the races. From this study it can be concluded that there is a wide genotypic, phenotypic and yield variability within the diversity panel.