Assessment of Grain Protein in Tropical Sorghum Accessions from the NPGS Germplasm Collection

The development of higher nutritional sorghum varieties requires the identification of high protein content germplasm that expands the genetic diversity of breeding programs. Therefore, a near-infrared (NIR) spectroscopy method was developed to predict the protein concentration of whole-grain sorghum with R-2 = 0.83, root-mean-square error of prediction = 1.44%, and bias = 0.16%. We evaluated 228 tropical accessions from West and Central Africa maintained by the National Plant Germplasm System (NPGS) of the United States for protein content for three years. The analysis found that the protein concentrations among accessions varied from 5.05 to 15.00% with an average of 10.24%. Correlation analysis between years revealed changes in protein content and ranking across years for multiple accessions. However, heritability of protein concentration was moderately high (H-2 = 0.81) indicating most of the observed variation could be determined by genetic differences among accessions. Sixteen tropical accessions with the highest protein concentration (>12.84%) may be used in breeding programs for the development of new and improved nutritional varieties. This assessment documented the range of natural variation for protein content in the NPGS sorghum tropical germplasm collection that could be used to enhance breeding programs focused on biofortification.

Automated summary

The development of higher nutritional sorghum varieties requires the identification of high protein content germplasm that expands the genetic diversity of breeding programs. A near-infrared spectroscopy method was developed to predict the protein concentration of whole-grain sorghum. Evaluation of 228 tropical accessions found high variation in protein content among accessions, with heritability indicating genetic differences play a significant role. Sixteen tropical accessions with high protein concentration have potential for breeding new nutritional varieties.