Similaridade Genética entre clones de cana-de-açúcar (Saccharum spp) usando genotipagem de alto rendimento e pedigree

Abstract

The knowledge of the genetic variability of the available germplasm is an important requirement for the success of the plant breeding program. This study aimed to evaluate the genetic similarity among accessions/genotypes of the sugarcane germplasm bank of the CTC company through dense genotyping and pedigree data; and to investigate the correlation between different similarity coefficients calculated based on this genetic relationship information. There were genotyped 1,230 genotypes using 81,309 SNPs markers, and then estimated Jaccard similarity coefficient and Van Raden additive genomic kinship coefficient from the marker data. The Malecot kinship coefficient was computed based on the pedigree data. The genetic similarity estimated by the Jaccard coefficient ranged from 0.14 to 0.92, with a mean of 0.46. The Malecot coefficient ranged from 0 to 0.75, and mean equal to 0.02, The Tocher optimization grouped the genotypes into 83 groups based on the Malecot coancestry coefficient and 6 groups when Jaccard's similarity coefficient was used. The principal component analysis using the marker-based genetic dissimilarity structured the genotypes in consonance to the sugarcane evolutionary history. The Jaccard and Van Raden coefficients presented higher correlation (r = 0.45) than those marker-based coefficients with the Malecot kinship coefficient, indicating pedigree data was less informative about the actual genetic similarity in the assessed germplasm. The most divergent genotypes were MOL1032 (Saccharum spontaneum) and IK7635 (Saccharum officinarum).