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 Sa helian West Africa where landraces have evolved in different ecologica l niches. These landraces have accumulated interpopulation diversity t hat has not been characterized. Evaluation of genetic diversity is a p rerequisite for successful germplasm exploitation through breeding. Th e objective of this study was to characterize morphological and agrono mic variability among African landrace populations of pearl millet. Te n pearl millet landrace populations widely grown in several African co untries and two experimental F-1 hybrids were evaluated at two locatio ns in Niger during the 1989 rainy season. Thirteen characters (downy m ildew [Sclerospora graminicola (Sacc,) Schroetl incidence, days to flo wering, primary spike length, peduncle exsertion, spike girth, Bag lea f 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 si gnificantly 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 clust er analyses revealed similarities between Niger and Senegal and betwee n Niger and Nigerian landrace populations. Four principal components w ere found to explain 92% of the total variation. Days to flowering, pl ant height, stem diameter, primary spike length, and grain and spike y ield per plot were the major sources of diversity among the landrace p opulations. These results could be useful in choosing potentially hete rotic pearl millet populations for intercrossing to develop improved c ultivars, synthetics, and hybrids for use in Africa.