Breeding potential in quantitative characters of Paspalum dilatatum  Poir.  Populations from northeastern region of Buenos Aires province.

The aim of this work was to obtain more information on the variability in natural populations of P.dilatatum Poir. ssp. dilatatum, and to determine the breeding potential in traits of forage interest. Thirtynine genotypes from three sites in the province of Buenos Aires (Magdalena, Berazategui and La Plata) were analyzed. The experimental design consisted of a random block trial with two repetitions. The results show uniformity in most of the traits analyzed. When variances among and within populations for each character are pairwise compared, the F test show that in more than the 95% of comparations there are no significant differences. In spite of that homogeneity, the predominance of greater variances among populations should indicate a tendency for differentiation in the genetic composition related with each site. Data allow to distinguish, also, the phenotypic variance in the whole set of clones. In this source of variation a greater proportion of significant differences was found. Among them those related of forage yield (Lenght of flag leaf blade and Width of flag leaf blade) and seed production (Number of seed per basal spike) are of special interest in breeding projects. The results show that in the material analyzed the genetic variability available should allow to reach selection progress in components of both forage yield and seed production, without interference of significant negative correlations.

Key words: Paspalum dilatatum dilatatum, forage yield, apomixis.