Received March 17th 2011 // Accepted August 26th 2011 // Published online November 2nd 2011
GONZÁLEZ, J. 1; DE LA VEGA, A.J.2; MANCUSO, N.1; LUDUEÑA, P. 1
In Argentina, sunflower breeding led to constant genetic progress, resulting in better yields in every region where this crop was planted. In this study, we applied linear mixed models and multivariate analyses to an historical series of 17 years of trials from the sunflower territorial trial network (RET), conducted at the INTA Pergamino Experimental Station. The aim was to contribute to the knowledge of the variability observed for phenotypical traits in sunflower hybrids obtained from 1986 to 2006. Cluster analysis of the hybrid × attribute matrix allowed grouping the 64 tested hybrids, evaluated for at least 3 years, into 5 groups. These groups differ in the average number of years since the commercial release of their hybrids components. Component analysis showed a positive association between oil yield and its immediate determinants – grain yield and oil concentration -, lack of association between both determinants and positive association between time to flowering and height. Both traits were negatively associated with oil concentration, positively associated with grain yield and displayed lack of association with oil yield. Two groups of hybrids of different genetic origin converged through years of plant breeding into a new type, displaying high grain and oil yield and intermediate cycle and height.