DISSIMILARIDADE GENÉTICA ENTRE POPULAÇÕES DE AZEVÉM ANUAL DO RIO GRANDE DO SUL GENETIC DISSIMILARITY AMONG ANNUAL RYEGRASS POPULATIONS FROM THE RIO GRANDE DO SUL STATE, BRAZIL

The objectives of this work were to characterize at morphological and molecular levels the genetic variability in 26 ryegrass populations collected in four different areas from Rio Grande do Sul state - Brazil. Plants were sowed with 0.30 m space within and between rows for the morphological characterization. The variables evaluated were: tiller number, canopy diameter and vegetative cycle. Analysis of variance, test of comparison of means and correlation analysis among the characters were performed. For the molecular evaluation two independent extractions of DNA were obtained from two bulks of ten plants each per population, which were used for the molecular characterization with the RAPD technique. A total of 130 primers were tested, and the 15 most polymorphic were used. Main components and clustering analyses were performed using the average linkage method from the SAS statistical program. For tiller number, the populations Dom Pedrito - 2 and Dom Pedrito - Guatambu were superior, with average of 36.9 and 31.9 tillers per plant, respectively. For canopy diameter, the populations Cruz Alta, Santo Ângelo and Sarandi, with averages of 55.01; 53.82 and 90.99 cm, respectively, presented the higher means. The population Santo Ângelo had the smallest vegetative cycle with 136 days. At the molecular level all the 26 studied populations were able to be discriminated. The molecular differences showed a good association with the morphological characters tiller number and canopy diameter.