Multivariate analysis of genetic diversity of peach and nectarine cultivars

In breeding programs, satisfactory results are rapid and easily obtained when in the base population a great genetic variability is combined with a high average for the character to be selected. Genetic diversity among 26 peach cultivars (Tropical, Regis, Centenario, Premier, Marli, Aurora 1, Aurora 2, Reliquia, Setembrino, Alo Docura, Maravilha, Okinawa, Cristal, Talisma, Ouro Mel, Colibri, Perola de Itaquera, Real, Biuti, Lake City, Campinas 1, UFV 186, UFV 286, Rei da Conserva, Bolao and Flordasun) and three nectarine cultivars (Sunred, Centenaria and Josefina) was analysed through multivariate technics (principal components and standart media Euclidean distance), with the aim to identify promising parents for a breeding program. The cultivars Tropical, Regis, Sunred, Centenario, Premier, Aurora 1, Josefina, Setembrino, Alo Docura, Maravilha, Real, Campinas 1 and Rei da Conserva were considered as elite due to the superiority of their phenological characteristics and fruit quality. Through principal component analysis and Tocher's method of grouping, based on standart Euclidean distance, it was possible to identify a consistently similar group (Real, Josefina, Aurora 1, Premier, Setembrino and Regis) and two pairs of consistently divergent cultivars (Rei da Conserva and Sunred, Rei da Conserva and Tropical). These divergent cultivars are promising parents for crossing, because of the great genetic variability in a segregant population derived from the genetic divergence between their parents.