COMBINING ABILITY FOR OIL CONTENT AND ITS CORRELATIONS WITH OTHER YIELD COMPONENTS IN SUNFLOWER (Helianthus annuus L.) / HABILIDADES DE COMBINACIÓN PARA EL CONTENIDO DE ACEITE Y SUS CORRELACIONES CON OTRAS COMPONENTES DE RENDIMIENTO DE GIRASOL (Helianthus annuus L.) / APTITUDE COMBINATOIRE POUR LE CONTENU D’HUILE ET CORRÉLATIONS AVEC D’AUTRES COMPOSANTES DU RENDEMENT CHEZ LE TOURNESOL (Helianthus annuus L.)

Oil yield is a major characteristic of each sunflower hybrid (Škorić et al., 2005). To be able to develop new high-oil sunflower hybrids by the method of interspecific hybridization, it is necessary to have information on mode of inheritance and combining abilities of inbred lines used. When selecting prospective lines as components of future hybrids, it is important to know correlations between yield components on one side and oil content on another.Seven new divergent cytoplasmic male sterile lines (A) developed by interspecific hybridization, three Rf-restorer lines used as testers and 21 F₁ hybrids have been subjected to the line × tester analysis. Significant differences have been obtained in mean values for all characteristics under study.Significant differences were found between A lines and R lines on one side and their F1 hybrids on the other in oil content, plant height, head diameter, total number of seeds per head, 1000-seed weight and seed yield per plant. The line NS-GS-4 exhibited a highly significant positive GCA value for oil content. The line NS-GS-5 had a highly significant negative GCA value for oil content. The hybrid NS-GS-6 × RHA-R-PL-2/1 had a highly significant positive SCA value for oil content. Non-additive component of genetic variance played the main role in the inheritance of oil content, as indicated by the analysis of variance of combining abilities and the analysis of components of genetic variance. Further confirmation was the ratio GCA/SCA for oil content in the F₁ generation which was smaller than unity (0.33). The highest average contribution to the expression of oil content (77.3%) was exhibited by the A lines. Highly significant negative correlations were found between oil content on one side and head diameter, total number of seed per head, 1000-seed weight and seed yield per plant on the other.