Genetic analysis of organogenesis in the cotyledons of zygotic embryos of sunflower (Helianthus annuus L.).

Crosses were made between five cytoplasmic male-sterile and five restorer sunflower inbred lines. Twenty-five F1 hybrids and their parents were studied for their organogenesis ability in a randomized block design with four replications. Each replication per genotype consisted of ten petri dishes with four expiants. Regeneration medium consisted of full MS medium modified by the addition of hormones and solidified with 6 g/l agar. Statistical analysis showed that both general and specific combining abilities were significant for all of the organogenesis parameters studied, and both showed several significant positive or negative values. General combining ability values were usually higher than those of specific combining ability, indicating the importance of additive genetic control for organogenesis parameters in sunflower. Narrow-sense heritability for the number of explants producing shoots and roots was 65.8%, which suggests that organogenesis of currently inferior inbred lines in sunflower should be improved in a crossing program.