Effects of genotype and growing conditions on several parameters of sunflower attractiveness to bees

Abstract

Analyzed in the paper were the effects of genotype, fertilizer application and microclimate on nectar production and availability, bee attendance and sunflower seed yields. Four sunflower hybrids (Velja, NS-H-45, NS-H-111 i NS-H-702) and four fertilization treatments were analyzed. Disc flower corolla length and nectar content were studied in the hybrids and their parent lines. The monitoring of bee visitation at flowering was done on nine occasions every day. Nectar content and seed yield per head were determined. Weather conditions were also recorded at observation time. The flower nectar content differed significantly among the genotypes, ranging from 2 53 mg/20 flowers (Velja) to 15.57 mg/20 flowers (Ha-98B). The highest nectar content (7.36 mg/20 flowers) was found in the control treatment and the lowest (6.67 mg/20 flowers) in the 100:100:100 treatment. The largest bee attendance was recorded in NS-H-111 and the 150:150:150 treatment and the lowest in Velja and the 100:100.100 treatment. Corolla length in the treatments ranged from 9.11 mm (control) to 9.23 mm (100:100:100), while in the genotypes it ranged between 7.95 mm in Ha-26B and 11.14 mm in CMS-3-8B. The longest corollas were found in flowers whose pistils had not yet emerged (9.51 mm). Significant differences in yield were found among the hybrids as well as treatments. Bee attendance peaked at 25°C air temperature and 43.5% relative humidity. Bee presence was at its highest at 9.00 h.

Izvršena je analiza uticaja genotipa, đubrenja i mikroklimata na produkciju i pristupačnost nektara, posetu pčela i prinos semena suncokreta. Analizirana su 4 hibrida suncokreta (Velja, NS-H-45, NS-H-111 i NS-H-702), i 4 varijante đubrenja. Dužina krunice trubastog cveta i sadržaj nektara, ispitivani su kod hibrida i njihovih roditeljskih linija. Praćenje posete pčela tokom faze cvetanja, vršeno je svaki dan u 9 navrata. Utvrđen je sadržaj nektara i prinos semena po glavi. U vreme opažanja registrovani su vremenski činioci. Sadržaj nektara u cvetu značajno se razlikovao između pojedinih genotipova i kretao se od 2,53 mg/20 cvetova (Velja) do 15,57 mg/20 cvetova (Ha-98B). Najveći sadržaj nektara (7,36 mg/20 cvetova), konstatovan je kod varijante đubrenja kontrola, a najniži (6,67 mg/20 cvetova) kod varijante đubrenja 100:100:100. Najveća poseta pčela registrovana je kod hibrida NS-H-111 i varijante đubrenja 150:150:150, a najniža kod hibrida Velja i varijante đubrenja 100:100:100. Dužina krunice kod varijanti đubrenja kretala se od 9,11 mm (kontrola), do 9,23 mm (100:100:100), a kod genotipova od 7,95 mm (Ha-26B), do 11,14 mm (CMS-3-8B). Najduže krunice registrovane su kod cvetova kod kojih tučkovi još nisu bili izašli (9,51 mm). Utvrđene su značajne razlike u prinosu između hibrida, a takođe i između pojedinih varijanti đubrenja. Maksimalna poseta pčela zabeležena je pri temperaturi vazduha od 25°C i relativnoj vlažnosti vazduha od 43,5%. Najveća poseta registrovana je u 9 časova.