Diversity level of genomic microsatellite among cultivated genotypes of Digitaria species in Nigeria

Abstract

Acha ( Digitaria exilis Kipps. and D. iburua Stapf.) are valuable indigenous food crops in West Africa. Despite several economic potentials of this crop, little or no attention is paid to its germplasm evaluation and improvement. In this study, we assessed genetic diversity and relationship among genotypes of cultivated acha in Nigeria, using Inter-Simple Sequence Repeat (ISSR) markers for the first time. Genomic DNA were extracted from the genotypes and we performed fragment amplification by Polymerase Chain Reaction (PCR). A total of 95 loci consisting of 790 bands were amplified by 13 ISSR primers, out of which 53.37% were polymorphic. Loci amplification per primer ranged from 5-10, with an average of 7.30 loci per primer. Eight of the primers had above 50% polymorphism. Cluster analysis separated the genotypes into two major groups; a group consisting of two D. exilis genotypes and the other comprising a mixture of genotypes. The D. exilis in the latter group were distant members and was only similar at 0.72 similarity index. The polymorphism we obtained in the present study showed that the ISSR markers are effective for assessment of genetic diversity of the genotypes. Clustering of D. exilis and D. iburua together suggests a common progenitor but could have been separated by geographical isolation mechanism.Les fonios ( Digitaria exilis Kipps. et D. iburua Stapf) sont des cultures alimentaires tr\ue8s importantes en Afrique de l\u2019Ouest. Malgr\ue9 les diff\ue9rentes potentialit\ue9s \ue9conomiques de cette culture, tr\ue8s peu ou aucune attention n\u2019est port\ue9e sur l\u2019\ue9valuation et l\u2019am\ue9lioration de son germplasm. Dans cette \ue9tude, nous avions \ue9valu\ue9 la diversit\ue9 g\ue9n\ue9tique et la relation entre les g\ue9notypes cultiv\ue9s du fonio au Nig\ue9ria, en utilisant les markers Inter-Simple SequenceRepeat (IISSR) pour la premi\ue8re fois. Les ADN g\ue9nomiques \ue9taient extraits des g\ue9notypes et nous avions utilis\ue9 la technologie de R\ue9action en Cha\ueene de la Polym\ue9rase (PCR). Un total de 95 loci contenant 790 bands \ue9taient amplifi\ue9es par 13 amorces d\u2019ISSR, sur lesquelles 53,37% \ue9taient polymorphiques. L\u2019amplification des loci par amorces variait de 5 \ue0 10, avec une moyenne de 7.30 loci per amorce. Huit des amorces ont plus de 50% de polymorphisme. L\u2019analyse typologique a s\ue9par\ue9 les g\ue9notypes en deux grands groupes\ua0; un groupe comportant deux g\ue9notypes de D. exilis et les autres comprennent un m\ue9lange de g\ue9notypes. Les D. exilis dans le dernier groupe \ue9taient membres distants et \ue9taient le seul similaire \ue0 0,72 d\u2019indice de similarit\ue9. Le polymorphisme que nous avons obtenu dans cette \ue9tude a montr\ue9 que les markers ISSR sont efficaces pour l\u2019\ue9valuation de la diversit\ue9 g\ue9n\ue9tique des g\ue9notypes. Le regroupement de D. exilis et D. iburua ensemble sugg\ue8re un parent commun mais pourrait \ueatre s\ue9par\ue9 par le m\ue9canisme d\u2019isolement g\ue9ographique