Genetic diversity and molecular characterization of physic nut genotypes from the active germplasm bank of the Agricultural Research Company of Minas Gerais, Brazil

Abstract

The genetic diversity among 46 accessions of physic nut was estimated with Nei and Li’s similarity coefficient based on a collection of 69 random amplified polymorphic DNA (RAPD) sequences and 37 inter-simple sequence repeat (ISSR) polymorphic loci. The genetic distance between accessions ranged from 0.13 to 0.76, with an average genetic distance of 0.21. The most divergent genotypes were 86, 71 and 83. A dendrogram (generated by the unweighted pair group method with arithmetic mean, UPGMA) of the joint data matrix was constructed and presented only two phylogenetic groups, one of which contained only three individuals; the remaining group included 95.6% of the analyzed genotypes. The low genetic diversity measured in this study indicates the need to broaden the genetic base and increase the variability of this species. The amplification products generated by amplification of SSR primers were used to characterize toxicity alleles, and none of the accessions presented patterns characteristic of non-toxic accessions.