The factors influencing the pollinators visitation of the oilseed rape cultivars

Currently, the hybrid cultivars are predominant in the cultivation of winter oilseed rape in Europe. Cultivation of hybrid cultivars instead of the traditional line can affect the visitation of pollinators. Beekeepers and farmers claim that hybrid cultivars are not visited by pollinators as much as the line. Ten yellow and one white flowering oilseed rape cultivars were used to compare the visitation rates of pollinators (Apis mellifera L. and Bombus sp.) during flowering in the years 2015-2017. At the same time, the visitation of hybrid and line cultivars by pollinators was evaluated. Visitation of pollinators on each cultivar was calculated from observed visitations to flowering oilseed rape plants in an area 2.1 m2 from the edge of single plots for 20 s. The results from this study clearly show that the individual cultivars, whether hybrids or lines, did not have a major influence on the pollinators' visitation, either by honey bees or bumble bees. It is thus proved that hybrid cultivars do not affect the pollinator visitation and there is no need to worry about the prevalence of these cultivars in the Czech fields. However, a more significant effect for both pollinator groups appears to have been the color of the flower.