Correlation between heterosis and genetic distance based on SSR markers in sunflower (Helianthus annuus L.)

Abstract

The objective of this study was to determine the correlation between SSR based genetic distance (GD) of new NS sunflower inbred lines and heterosis for six agronomic traits. Twenty three sunflower inbred lines (20 restorer lines and three female lines used as testers) and their hybrids were examined for plant height, head diameter, thousand seed mass, oil content, seed yield per plant and oil yield per plant. Significant heterosis was observed in hybrid combinations for all examined traits except oil content. Genetic distance between pairs of tested sunflower inbred lines ranged from 0.13 to 0.8. There was no significant positive correlation between genetic distance and mid- and better-parent heterosis, specific combining ability and mean value in any of the examined traits for all 60 hybrids. A highly significant negative correlation was found between GD and mean oil percentage (r=-0.33 p<0.01). Although GD was generally a poor predictor of heterosis, better results are obtained if hybrid combinations for each tester and each trait are analyzed separately.