Visitas de abelhas e produtividade do girassol (Helianthus annuus L.)

Abstract

With the objective of studying the effect of bees’ visits over the sunflower yeld (Helianthus annuus L) an experiment was installed in Experimental Station of Universidade Federal da Fronteira Sul in Cerro Largo, Rio Grande do Sul State, Brazil, in August 2013. The experiments evaluation were arranged on randomized at random block design, in a split plot arrangement, with four treatments and ten replicates. The treatments were constituted by the combination of two hybrids of sunflower (Syn 034A e CF 101) and two pollination tests: free insect visitation and exclusion of floral visitors. The variables evaluated were: diâmero chapter, mass of the chapter mass of the achenes by inflorescence, mass of the 1000 achenes, the number of achenes by inflorescence and total productivity of achenes. The exclusion experiment revealed that sunflower bees` visitors significantly contributed to pollination and sunflower reproduction. Except for the M1000, all variables of sunflower heads that had been isolated from flower visitors being significantly lower (P < 0.05) than of those heads exposed to normal insect activity. These findings also demonstrate the economic importance of pollination services to maximize the productivity and reduce the need for cropland expansion, contributing towards sustainable agriculture.