Coancestry analysis of the germplasm used for breeding in Uruguay

Abstract

The study of the genetic diversity and the relationships existing within the available germplasm constitute an essential element in the decision-making process in a plant breeding program. The coefficient of coancestry (f),
defined as the probability of two random alleles within two individuals being identical by descent, is the classic measure of genetic diversity. In this study, the coancestries of twenty-nine barley genotypes (varieties and experimental lines), representative of the germplasm used by breeders in Uruguay, were analyzed and the genotypes grouped according to their values. A second clustering procedure was carried based on the parentage relationship with a set of twenty-five ancestors of importance as sources of variability or quality, frequently
detected in the studied pedigrees. The average coancestry ((f = 0.072 for the whole group; f = 0.080 when genotypes with incomplete pedigree were discarded) was intermediate when compared with reported values from different regions. The clustering based on these values showed a strong association with region of origin in the introduced genotypes, whereas the genotypes of national origin had a wider dispersion. The use of the coancestry with the set of ancestors detected different clusters, mainly explained by a limited number of ancestors with worldwide importance (Hanna, Haisa, Prior). The key factors in the conformation of the different groups were studied, as well as potential relationships with traits of interest.