THE RELATIONSHIP BETWEEN HETEROSIS AND GENETIC DISTANCES BASED ON SSR MARKERS IN HELIANTHUS ANNUUS

Identifying the best inbred combinations for the development of commercial hybrid of sunflower remains the main challenge to sunflower breeders. In the present research the level of heterosis of F₁ hybrids, genetic diversity of parental lines based on SSR markers, as well as its connection with specific combining ability of sunflower were studied. Ten sunflower elite inbred lines (3 restorer lines and 7 cytoplasmic male sterility lines) and their hybrids were examined for plant height, seed yield, thousand seed mass, oil content and husk content. Field tests were carried out in 5-6 seasons. The level of heterosis was calculated using measurement of midparent heterosis. Genetic distance between pairs of tested sunflower inbred lines ranged from 0.45 to 0.74. Significant positive correlation was found between genetic distances among lines, measured using SSR markers and midparent heterosis for seed yield of hybrids (r = 0.79 p<0.05). The correlation between genetic distances and the level of midparent heterosis for other studied agronomic traits was not reliable. The dependence of seed yield of hybrids on genetic distances among parental lines may be used for planning of effective crossbreeding of sunflower. Further research is needed to determine the best inbred combinations for the development of commercial hybrid of sunflower.