Direct and indirect effects of morphophysiological traits on seed yield of sunflower (Helianthus annuus L.)

Abstract

In this paper, we have studied the interdependence of seed yield per plant and the following morphophysiological traits: total leaf number per plant, total leaf area per plant, plant height, total seed number per head, head diameter, weight of 1,000 seeds and oil content. Path coefficient analysis was used to separate direct and indirect effects of studied traits on seed yield, and to identify traits that could be used as selection criteria in sunflower breeding. The research was conducted during two vegetation seasons on 21 experimental sunflower hybrids, produced within the breeding program at the Institute of Field and Vegetable Crops. Among the large number of examined traits, significant and highly significant correlations were found. A strong positive correlation between the weight of 1,000 seeds and seed yield (0.791**) was determined. On the contrary, a strong negative correlation between oil content and seed yield was found (-0.649**). The biggest highly significant positive effect on seed yield was determined for the following traits: the weight of 1,000 seeds (0.789**), total seed number per head (0.473**) and total leaf number per plant (0.199**). Total leaf area per plant has demonstrated a significant direct positive effect on seed yield (0.139*). The weight of 1,000 seeds and total seed number per head were the most important traits for seed yield. Based on the coefficient of determination in F1 generation R2=0.92), it can be concluded that the influence of all traits involved in the study on total variability of seed yield per plant, was 92%.