Genetic diversity and structure in Amorphophallus spp. Blume ex Decne. using morphological and ISSR markers

Abstract

ABSTRACTPopulations of many crop wild relatives are at risk and poorly conserved. Characterization of crop germplasm based on assessment of amount, and distribution of genetic diversity, is essential for proper utilization and conservation which could be achieved through morphological and molecular tools. Wild Amorphophallus relatives may be used in breeding to enhance palatability by eliminating tuber acridity, improve yield, and develop collar rot disease resistant varieties. Twenty-five accessions of Amorphophallus, including 7 wild species, 16 morphotypes of A. paeoniifolius var. paeoniifolius (Decne.) Sivad., and “Gajendra” (GJ) and “karunaikizhangu” (T10) – a medicinally important but poorly documented form – cultivars of A. paeoniifolius var. campanulatus (Decne.) Sivad., all collected from biogeographic zones of India, were evaluated using 48 morphological and 17 Inter Simple Sequence repeats (ISSRs) markers. There were differences among accessions for quantitative traits and Shannon-Wiener Diversity Index for qualitative characters. The first 2 principal components, accounting for 56% of variance, were corm and cormel characters. The Unweighted Pair Group with Arithmetic Averages cluster, based on morphological data, indicated two principal clusters with the first principal cluster represented by five wild species, and all A. paeoniifolius accessions in the second principal cluster with GJ and T10 placed far apart. In the ISSRs profile, all accessions of A. paeoniifolius, except T10, clustered together at a bootstrap value of 92.5% despite morphological variability observed in this complex. Within the A. paeoniifolius accessions, moderate diversity (45%) was observed. The accession T10 accounted for 60%–70% dissimilarity with all accessions. Cultivated accessions GJ and T10 evolved separately with anthropogenic intervention to elevate them as cultivated forms. Eight morphotypes of A. paeoniifolius were identified. The non-flowering, special type of the edible accession cv. karunaikizhangu, being placed between the wild species and A. paeonifolius complex provides a mechanism for delineation of taxonomic status of this particular genotype and indicates the need for its conservation.