Mode of inheritance and heritability of disc flower corolla length and nectar content in sunflower

Since disc flower corolla length and nectar content are the two most important parameters of attractiveness to pollinators in sunflower and we monitored them in the parental lines F[ hybrids, we thought it would be interesting to determine the mode of inheritance and heritability of these two traits. The mean values of disc flower corolla length ranged between 7.23-10.22 mm. Differences among most of the genotypes were significant Year had significant influence on the expression of this trait. In the inheritance of the corolla length, partial dominance of the parent with the smaller corolla length (NS-H-702) was observed when determining mode of inheritance relative to the parents. Relative to the parental average however it was not possible to determine the mode of inheritance in any of tile hybrid combinations. The nectar content means ranged from 2.08 to 15.54 mg/20 flowers and differences among most of the genotypes were significant. Partial dominance of the parent with the smaller nectar content mean was recorded in the inheritance of this trait (NS-H-702): Negative heterosis was found in the hybrid NS-H-45.

Phenotypic and genotypic variability of disc flower corolla length and nectar content in sunflower

The nectar content and disc flower corolla length are the two most important parameters of attractiveness to pollinators in sunflower. The phenotypic and genotypic variability of these two traits was studied in four commercially important hybrids and their parental components in a trial with three fertilizer doses over two years. The results showed that, looking at individual genotypes, the variability of disc flower corolla length was affected the most by year (85.38-97.46%). As the study years were extremely different, the phenotypic variance of the hybrids and parental components was calculated for each year separately. In such conditions, looking at all of the crossing combinations, the largest contribution to phenotypic variance of the corolla length was that of genotype: 57.27-61.11% (NS-H-45) 64.51-84.84% (Velja); 96.74-97.20% (NS-H-702) and 13.92-73.17% (NS-H-111). A similar situation was observed for the phenotypic variability of nectar content, where genotype also had the largest influence, namely 39.77-48.25% in NS-H-45; 39.06-42.51% in Velja; 31.97-72.36% in NS-H-702; and 62.13-94.96% in NS-H-111.