Inheritance of Protein Content and Digestibility in Grain Sorghum.

Sorghum (Sorghum bicolor (L.) Moench) is cultivated as one of the major food and feed grains throughout the world. It has wider ecological adaptation with remarkable tolerance to marginal growing conditions including drought stress, low nutrient supply, and heat stress. In terms of nutrient content, sorghum is similar to other major cereals and even better in certain minerals such as calcium. However, the digestibility of sorghum protein compared to that of other cereals is low. This reduces its value as food and feed grain. Similar to other traits, there is significant genetic variability for protein digestibility and content among sorghum germplasm. A recent screen of sorghum diversity panel involving 300 genotypes revealed wide genetic variability for protein digestibility (PD) which ranged from about 20% to 80%. Protein content (PC) also ranged from as low as 5% to a high of 20%. Knowledge of the genetic basis of such variability and inheritance of the traits is the first step towards genetic improvement of the crop for these traits. The objective of this study was to determine the inheritance of protein content and digestibility in grain sorghum. Six pollinator genotypes with contrasting protein content and digestibility were crossed to 4 public female parents using a design II mating scheme. The resulting progeny were grown in the field and seeds harvested from the F1 plant were evaluated using near infrared reflectance spectroscopy to predict the protein content. Protein digestibility was determined using standard laboratory procedure. Analysis of the data revealed significant variation among the entries. General combining ability (GCA) for PC was significant for pollinator parents indicating that the traits are controlled by additive genes. The specific combining ability (SCA) effect was not significant along with the location effect and its interaction with both GCA and SCA.