Diversity among African Pearl Millet Landrace Populations

Pearl millet [Pennisetum glaucum (L.) R. Br.] is widely grown in arid to semi-arid regions of Africa. The crop is particularly adapted to Sahelian West Africa where landraces have evolved in different ecological niches. These landraces have accumulated interpopulation diversity that has not been characterized. Evaluation of genetic diversity is a prerequisite for successful germplasm exploitation through breeding. The objective of this study was to characterize morphological and agronomic variability among African landrace populations of pearl millet. Ten pearl millet landrace populations widely grown in several African countries and two experimental Fi hybrids were evaluated at two locations in Niger during the 1989 rainy season. Thirteen characters (downy mildew [Sderospora graminicola (Sacc.) Schroet] incidence, days to flowering, primary spike length, peduncle exsertion, spike girth, flag leaf width, stem diameter, spike number per plant, non-productive tillers per plant, plant height, spike yield per plot, grain yield per plot, and 1000-seed weight) were measured on six replicates of each landrace populations. In the pooled analysis, all landrace populations were significantly different for one or more of the characters evaluated. The Niger landrace populations showed much less variation than the other African landrace populations for most characters investigated. Ward's cluster and principal component analyses were used to investigate the nature and degree of divergence in the landrace populations. The cluster analyses revealed similarities between Niger and Senegal and between Niger and Nigerian landrace populations. Four principal components were found to explain 92% of the total variation. Days to flowering, plant height, stem diameter, primary spike length, and grain and spike yield per plot were the major sources of diversity among the landrace populations. These results could be useful in choosing potentially heterotic pearl millet populations for intercrossing to develop improved cultivars, synthetics, and hybrids for use in Afric