Variation in grain quality of pearl millet from Sahelian West Africa

Abstract

Agricultural intensification through the application of mineral fertilizers, the recycling of crop residues and animal manures and through plant breeding are the only means to increase food supply in the poverty ridden West African Sahel, where pearl millet ( Pennisetum glaucum (L.) R. Br.) is the dominant staple. Research on the effects of soil amendments on the quality of millet straw and grain is scarce, comparative studies of possible quality differences in traditional landraces versus improved varieties and hybrids are lacking. This paper reports results from 22 landrace populations, 22 improved varieties, six inbred×variety hybrids (IVHs, fertile inbred×open-pollinated varieties) and four topcross hybrids (TCHs, male-sterile line×open-pollinated varieties), whose grains were analyzed for protein concentration and amino acid composition, macro- and micronutrients (total and phytate P, K, Ca, Mg, Zn, Cu), metabolizable energy (ME), fat and β-carotene. At similar yield levels, landraces showed a 2.9 and 3.5% higher protein concentration compared with improved varieties and hybrids without a detrimental effect on protein quality as determined by the relative amount of lysine and threonine. Landrace populations also had the highest fat concentrations and the largest micronutrient densities. However, in-vitro digestibility and ME were (79.8% and 12.2 MJ kg −1 respectively) larger for both groups of hybrids. The concentration of β-carotene was (0.13 μmol kg −1) highest in the improved varieties, but appeared overall too low to significantly contribute to vitamin A nutrition in local diets. While the results of this genotype screening need to be verified in replicated multi-location trial studies, they underline the potential of including landraces in breeding programs to concurrently improve grain yield and grain quality in this area of the world.