Patterns of molecular and phenotypic diversity in pearl millet [Pennisetum glaucum (L.) R. Br.] from West and Central Africa and their relation to geographical and environmental parameters

Five sub-groups were detected within the entire germplasm set by STRUCTURE. We observed that the phenotypic traits flowering time, relative response to photoperiod, and panicle length were significantly associated with population structure but not the environmental factors which are expected to influence these traits in natural populations such as latitude, temperature, or precipitation.Our results suggested that for pearl millet natural selection is compared to artificial selection less important in shaping populations.Pearl millet [Pennisetum glaucum (L.) R. Br.] is an annual, diploid, highly allogamous cereal with seven chromosome pairs [1]. It can be grown in a vast range of environmental conditions including environments that are characterized by frequent drought events and poor soil fertility [2]. This is one reason that pearl millet is one of the most important staple food crops in West and Central Africa (WCA) [3]. The other reason is that pearl millet grain has relatively high nutritional values for a cereal. Its grain has higher protein and fat content than wheat or rice and its amino acid composition is more appropriate for human nutrition than that of wheat or polished rice [4-6].Cultivated pearl millet displays tremendous phenotypic variability for traits such as flowering time, panicle length, grain and stover characteristics, tolerance to drought, pests, and diseases, as well as nutritional value (e.g., [7]). Efficient and systematic exploitation of this diversity is the key to any crop improvement program [8]. This, however, requires in a first step the assessment of genetic diversity and population structure of the species under consideration.For pearl millet, several studies have examined these issues. [9] determined the influence of farmer management on pearl millet landrace diversity in two villages in North-Eastern Nigeria. [10] assessed the genetic diversity within and between ten Indian pearl millet landraces. The genetic diversity of 46 wild