Regresar

Genetic diversity of sweet potatoes [Ipomoea batatas (L) Lam.] in Ecuador

Abstract:

The present work considered collecting and characterizing the genetic diversity of sweet potato [Ipomoea batata (L.) Lam.] in Ecuador through morphological and molecular descriptors (SSRs). Germplasm collections were made to assemble a national sweet potato collection for Ecuador. Characterization of the genetic diversity of this species was done through 34 morphological descriptors (24 qualitative and 10 quantitative), plus 12 exclusive descriptors for flowering and 8 microsatellites (SSRs). Three hundred and sixty-eight sweet potato accessions were collected in 18 provinces of Ecuador. Morphological characterization showed seven morphological groups and the variables with the greatest discriminating power for the description of the germplasm (p <.001) were the color, shape and defects of the reservoir root, in addition to the shape of the profile and lobes of the leaves. Principal component analysis determined the association of the main quantitative morphological features to the components. Eight microsatellite markers detected 89 alleles, with an average of 11.12 allele/locus and average polymorphism (PIC) of 0.848. STRUCTURE software revealed the formation of 4 different genetic groups. Morphological and molecular data did not show the formation of any group defined according to the province of origin. Factors such as the sweet potato reproductive system (cross-pollination), random sweet potato mutations and farmer exchange, contributed to the greater genetic diversity present. High genetic diversity and low number of duplicates were identified. This collection could provide outstanding genotypes to be used in breeding programs. Local landraces still in the hands of local farmers suggest that in situ conservation projects must be put in place.