CHARACTERIZATION AND AGRONOMIC VARIABILITY OF 125 ECOTYPES OF Bromus valdivianus Phil. COLLECTED FROM VALDIVIA PROVINCE

Abstract

Bromus valdivianus Phil. is a native species of southern Chile. It can be found on natural pastures of the X^th Region. The evolution of this species has created a wide diversity of ecotypes, which have not been characterized. The objective of this study was to characterize agronomically 125 ecotypes of B. valdivianus Phil., which were collected from four different areas of Valdivia province. Additionally through a multivariate analysis, groups of B. valdivianus Phil. ecotypes with similar agronomic characteristics were determinated. One hundred twenty five B. valdivianus Phil. ecotypes were studied from four different areas (north central valley, south central valley, north foofhills and south foothills). Ten variables were evaluated, from which dry matter was measured on spring, summer and autumn. A randomized block design with three replicatos was used. The average data from the ecotypes for the variables were analyzed by mean of multivariate analysis. The agronomic characterization allowed to show the phenotypic differentiation among ecotypes in relation to forage production. Principal components analysis and cluster analysis were used to observe the nature and degree of divergence of ecotypes, while the discriminant analysis allowed to determine if individuals in each group were well classified. Three principal components were choosen, which explained 56.7% of the total variation. The cluster analysis distinguished four groups clearly related with forage production and leaf morphology. According with discriminant analysis 94,4% of ecotypes were correctly classified and seven ecotypes (5,6%) were not. The geographic origin of the ecotypes did not show relationship with the cluster, because of some plants from different areas were observed in the same group.