M Francisca Perera, Andrea N Peña Malavera, Aldo S Noguera, Josefina Racedo and Santiago Ostengo
Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA), Estación Experimental Agroindustrial Obispo Colombres (EEAOC) – Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CCT NOA Sur. Av. William Cross 3150. Las Talitas, Tucumán, R. Argentina, T4101XAC; franciscaperera@yahoo.com.ar
Understanding the genetic diversity and population structure of sugarcane germplasm banks provides valuable information to produce progenies with maximum variability. To this end, 350 accessions of the EEAOC´s germplasm bank were genotyped at 74,969 biallelic SNP loci using DArT-seq technology. Genotyping data were analyzed to assess the genetic diversity and the genetic structure of all the collection through a Bayesian method and a principal coordinate analysis (PCoA), and its variability through an analysis of molecular variance (AMOVA). Finally, core collections of different sizes were suggested. Across all the accessions, the mean observed heterozygosity (HO) of all SNPs was 0.28 (ranging from 0 to 1) while their expected heterozygosity (HE) ranged from 0 to 0.5, with a mean of 0.3. The polymorphism information content (PIC) of the SNPs varied from 0 to 0.38, with a mean value of 0.22 and a mean of their discrimination power (Dj) of 0.28. Genetic structure analysis and PCoA revealed that accessions clustered in three groups (I: 71 genotypes; II: 243 genotypes and III: 34 genotypes). AMOVA suggested a greater percentage of variation inside each subpopulation (89.75%) than among them (10.25%; p <0.0001), whereas the ΦFST value of 10% indicated a moderate genetic differentiation among these three groups. Different sizes of core collections were tested; a core collection of 35 genotypes (10%) captured almost 96% of diversity, while including 104 genotypes (30%) more than 98% of diversity was captured. Results will allow the efficient exploitation of genetic diversity of sugarcane germplasm, and the development of strategies to obtain new cultivars with superior characteristics.