Role of seed flow on the pattern and dynamics of pearl millet (Pennisetum glaucum [L.] R. Br.) genetic diversity assessed by AFLP markers: a study in south-western Niger

Abstract

We studied the regional genetic diversity and seed exchange dynamics of pearl millet landraces in south-western Niger. The genetic study was based on AFLP markers. We found significant genetic differentiation between landraces in different geographical areas of south-western Niger. However, the degree of differentiation was low insofar as only 1.9% of the total molecular diversity was due to regional differentiation, suggesting a relatively high gene flow. Anthropologic studies on farming practices have suggested that seed exchanges between farmers on a large geographical scale probably make a considerable contribution to this result. In order to test this hypothesis, the effects of seed exchange on the genetic diversity of landraces was analyzed on seed samples from two distant villages in contrasting areas of south-western Niger. Seeds imported by farmers into the southern village of Sina Koara did not differ significantly from locally grown landraces. By contrast, in the northern village of Alzou, several samples were genetically different from locally grown landraces and closer to southern accessions. These data suggest that the seed flow is preferentially from south to north, i.e. from an area with more favorable rainfall conditions. The potential consequences for the genetic diversity and adaptation of northern pearl millet landraces are discussed.

Unexpected pattern of pearl millet genetic diversity among ethno-linguistic groups in the Lake Chad Basin

“…This was especially observed in the western side of the lake and when comparing landrace populations sampled in the same ethno-linguistic group. This result is fully in agreement with those of Busso et al (2000) in North-eastern Nigeria, and of Allinne et al (2008) in the Zarma-Songhay area. Farming practices have been invoked to explain this pattern.…”

“…Seeds of non-local landraces acquired from outside sources (markets or NGOs) are mainly consumed, being sown only infrequently (Robert et al , 2005). Allinne et al (2008) have confirmed this preference, showing that seeds, imported for sowing by farmers in two villages of the Zarma-Songhay area in Niger, were genetically much more similar to landraces grown in the same region than to landraces from neighbouring countries. The mechanisms responsible for the relative isolation between pearl millet genetic pools is likely effective nowadays since its fingerprint is still detectable.…”

An Heuristic Framework for Identifying Multiple Ways of Supporting the Conservation and Use of Traditional Crop Varieties within the Agricultural Production System

“…Molecular methods, which can now provide significant additional insights into the extent and distribution of diversity and on the ways in which it is correlated with important social, environmental, and management variables have yet to be undertaken on the scale needed except perhaps for sorghum and pearl millet in Africa (e.g. Barnard et al, 2008;Bezancon et al, 2009;Busso et al, 2000;Sagnard et al, 2008;Allinne et al, 2008). With the rapid improvements in methods over the last decades this is now possible on the required scale.…”

New Genetic Insights into Pearl Millet Diversity As Revealed by Characterization of Early- and Late-Flowering Landraces from Senegal

“…Flowering time in pearl millet is derived from a common domestication event and a strong gene flow between early- and late-flowering landraces is observed (Dussert et al, 2015). The level of gene flow would depend on cycle overlapping, agricultural practices and spatial distribution (Mariac et al, 2006b; Allinne et al, 2007; Lakis et al, 2012). …”