Assessment of Genetic Diversity in Sorghum Using Phenotypic Markers

Sorghum is an important grain crop in many parts of the world, especially in dry regions. It is an important crop for food and feed, and its role in energy production is currently growing. In Ethiopia, sorghum is a multi-purpose crop used for many different functions such as fuel, housing and animal feed. Information on genetic diversity levels among and within sorghum accessions will increase the efficiency of the sorghum improvement programmes. Field experiments were conducted in Potchefstroom, South Africa, during the summer growing seasons of 2009 and 2010, to estimate the level of phenotypic diversity among 22 sorghum accessions. The experiment was laid out in a randomised complete block design with three replications. Nine qualitative and 20 quantitative morphological traits were recorded. Analysis of variance for the quantitative traits revealed that differences among accessions were highly significant for all traits. Qualitative traits diversity index values varied from 31% (panicle compactness and shape) to 84% (glume colour). The pair-wise genetic distances based on phenotypic traits showed varying genetic distances. Cluster analysis of the phenotypic traits resulted in four distinct groups of accessions with genetic distances ranging from 0.40 to 1.59. Therefore, the phenotypic markers provide a useful measure of genetic distances among sorghum accessions to identify potential donors or parental material for future breeding efforts.