Molecular diversity of Cuban cassava (Manihot esculenta Crantz) cultivars assessed by simple sequences repeats (SSR)

Abstract

A total of 36 microsatellites (SSR) markers were used to analyze the genetic diversity of 163 accessions of cultivated cassava (Manihot esculenta Crantz), 94 accessions of them from the Cuban Cassava Germplasm Collection and 69 genotypes from different countries and conserved at the International Center for Tropical Agriculture (Colombia). This study was carried out to determine genetic diversity within and between all accessions to promote their better use and conservation strategies. Thirty-four of those markers were used for the genetic diversity study based on their higher polymorphism. The Cuban cultivars showed the highest average allele number per loci with 5.8 and 100% of the loci were polymorphic, as well as those from Guatemala. The average proportion of individual heterozygocity observed (HO) was high (0.5918 ± 0.0351), while the highest HO rates were observed in groups of genotypes from Cuba (0.6016) and Tanzania (0.6459). The total heterozygocity (HT) was high (0.6538 ± 0.1770), but only 7.4% (GST = 0.0740 ± 0.0377) was due to differences between the five countries studied. Genetic differentiation coefficients (estimated by F-statistics) were low to moderate (FST > 0.04) and 17 unique alleles with low frequency were found in Cuban cultivars. The results provide the first molecular characterization of Cuban cassava genotypes and showed a wide diversity among landraces from Cuba. Application of this valuable information can be used for genetic diversity conservation and genotype identification studies for the genetic breeding program of cassava.

Keywords

• Manihot esculenta
• genetic variation
• genetic markers
• microsatellites
• germplasm