Genetic diversity of Sudanese pearl millet (Pennisetum glaucum (L.) R. Br.) landraces as revealed by SSR markers, and relationship between genetic and agro-morphological diversity

Landraces are considered as storehouses of valuable genetic diversity. Understanding the structure of this diversity and identification of distinct clusters with complementary traits is an important goal for a sustained and successful pearl millet breeding program. In this study a collection of 214 pearl millet accessions from different geographical regions of Sudan, and 11 accessions from West Africa, were assessed for their genetic diversity using 30 simple sequence repeat markers (SSRs) and evaluated for 15 agro-morphological traits. The diversity of the studied pearl millet landraces was demonstrated by a large number (400) of detected SSR alleles. The average polymorphic information content (PIC), gene diversity and observed heterozygosity of the 30 SSRs were 0.77, 0.82 and 0.72 respectively. A total of seven phylogenic groups with variable sizes were identified. Low correlation was observed between the agro-morphological matrix and the genetic matrix (r = 0.20). The average PIC values obtained across the seven linkage groups varied significantly. Weak genetic differentiations were observed among the geographical regions, suggesting a high seed and pollen-mediated gene flow among the regions. Analysis of molecular variance revealed that the variation of pearl millet accessions within the regions was much higher than among the regions. The large divergence observed among the landraces of this study is promising for developing new cultivars and for development of heterotic groups which can be used to develop population and hybrid varieties with higher degrees of heterozygosity and therefore hybrid vigor and stability, as well as to intensify yield production in the harsh production environments of Sudan.