Protein Content and Amino Acid Composition among Selected South African Sorghum Genotypes

Abstract

The presence of genetic diversity is essential for quality improvement to achieve balanced protein and amino acid levels in sorghum. The objective of this study was to determine the genetic diversity present among selected South African sorghum genotypes for protein and amino acid content and to select candidate lines for breeding or direct production. Fifty nine selected South African sorghum genotypes grown at two localities were analysed for crude protein content using near-infrared spectroscopy (NIR). Nineteen genotypes with high crude protein content from each location were selected and analysed for amino acid profiles using protein hydrolysates. The crude protein content of the genotypes varied from 7.69 to 16.18% across the two sites with a mean of 13.07%. The genotypes that had high crude protein content at both sites were Mammopane, AS16 M1, Macia-SA, AS19, Maseka-a-swere, and AS4. The genotype AS16cyc was the best candidate for high phenylananine content at 5.99%. Overall, the studied lines had great variability in their protein and amino acid profiles. Accessions with high protein content or amino acid values can be used in sorghum breeding programmes to increase grain nutritional quality.