Stratified mass selection in sunflower in different environmental conditions

Abstract

An open pollinated cultivar of sunflower (Helianthus annuus L.) was mass selected in two successive growing seasons with the main objective of evaluating the genetic progress obtained with two cicles of selection per year involving one cicle in stress conditions. Selection was performed in the favorable environment only (spring), where sunflower is grown commercially, in the unfavorable environment only (summer), or continuously in both environments. The selection criteria were reduction of cicle and plant height and improvement of achene yield, with more emphasis given to cicle reduction. Tested in the favorable environment, spring selections were superior to Summer selections. The continuous selection was; superior to both others in cicle and plant height reduction, but resulted in higher yield reductions.