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

Abstract

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.

Najznačajniji parametri atraktivnosti za oprašivače kod suncokreta su sadržaj nektara i dužina krunice cevastog cveta. Fenotipska i genotipska varijabilnost ovih svojstava je izučavana kod 4 komercijalno važna hibrida i njihove roditeljske komponente u ogledu sa 3 doze đubrenja, u dve godine. Rezultati istraživanja pokazuju da je na varijabilnost dužine krunice cevastog cveta bio najznačajniji uticaj godine (85.38-97.46%), ako se ona posmatra za pojedinačne genotipove. Pošto su godine istraživanja bile ekstremno različite fenotipska varijansa je izračunata za hibride i roditeljske komponente za svaku godinu posebno. U takvim okolnostima za sve kombinacije ukrštanja najveći udeo u fenotipskoj varijansi za dužinu krunice cevastog cveta je imao genotip: 57.27-61.11% (NS-H-45); 64.5l-84.84% (Velja); 96.74-97.20% (NS-H-702) i 13.92-73.17% (NS-H-111). Slično je bilo i sa fenotipskom varijabilnošću za sadržaj nektara, jer je takodje bio najznačajniji uticaj genotipa i to: 39.77-48.25% kod NS-H-45; 39.06-42.51% kod Velja; 31.97-72.36% kod NS-H-702162.13-94.96% kod NS-H-111.