Influence of biotic and abiotic environmental conditions on sunflower (Helianthus annuus L.) grain yield

Abstract

Way of pollination in sunflower is allogamy and therefore the presence of insects is essential for successful production. Trial material was consisting of six sunflower hybrids that were grown on majority of sunflower’ s fields in Croatia. Trial was conducted on trial-field situated in Kneževi Vinogradi (Baranja region). Honey bees were transported in Langstroth-Rooth (LR) beehives to the trial field ; three days before sunflower’ s blooming. Impact of honey bee on selection and production traits of sunflower was expressed as a difference between results gained by free pollination and results under the condition of isolation. The most important pollinator of sunflower is a honey bee. Weather conditions (air temperature, relative air humidity and rainfalls) considerably influenced activities of honey bees during sunflower blooming. Honey bees were mostly active during the days without rain, at air temperature from 23 to 26 oC and relative air humidity from 65 to 75 %. The most attractive hybrid for honey bee was hybrid H4. Presence of pollinators resulted in improvement of selection and production traits of sunflower: number of flowers per head, number of full up field grains per head, percentage of pollination, 1000 kernel weight, hectolitre mass, oil content and oil yield.Considerable economic rationale was determined for the introduction of pollination with honey bee in agriculture practice.