title: Pollination of rapeseed (Brassica napus) by Africanized honeybees (Hymenoptera: Apidae) on two sowing dates.
abstract: In this study, performed in the western part of the state of Paraná, Brazil, two self-fertile hybrid commercial rapeseed genotypes were evaluated for yield components and physiological quality using three pollination tests and spanning two sowing dates. The treatments consisted of combinations of two rapeseed genotypes (Hyola 61 and Hyola 433), three pollination tests (uncovered area, covered area without insects and covered area containing a single colony of Africanized Apis mellifera honeybees) and two sowing dates (May 25th, 2011 and June 25th, 2011). The presence of Africanized honeybees during flowering time increased the productivity of the rapeseed. Losses in the productivity of the hybrids caused by weather conditions unfavorable for rapeseed development were mitigated through cross-pollination performed by the Africanized honeybees. Weather conditions may limit the foraging activity of Africanized honeybees, causing decreased cross-pollination by potential pollinators, especially the Africanized A. mellifera honeybee. The rapeseed hybrids respond differently depending on the sowing date, and the short-cycle Hyola 433 hybrid is the most suitable hybrid for sowing under less favorable weather conditions.
authors.affiliation: Centro de Ciências Agrárias, Campus Universitário de Marechal Cândido Rondon, Universidade Estadual do Oeste do Paraná, Marechal Cândido Rondon, PR, Brasil.
authors.forename: Emerson D
authors.initials: ED
authors.lastname: Chambó
authors.affiliation: Centro de Ciências Agrárias, Campus Universitário de Marechal Cândido Rondon, Universidade Estadual do Oeste do Paraná, Marechal Cândido Rondon, PR, Brasil.
authors.forename: Newton T E
authors.initials: NT
authors.lastname: De Oliveira
authors.affiliation: Centro de Ciências Agrárias, Campus Universitário de Marechal Cândido Rondon, Universidade Estadual do Oeste do Paraná, Marechal Cândido Rondon, PR, Brasil.
authors.forename: Regina C
authors.initials: RC
authors.lastname: Garcia
authors.affiliation: Centro de Ciências Agrárias, Campus Universitário de Marechal Cândido Rondon, Universidade Estadual do Oeste do Paraná, Marechal Cândido Rondon, PR, Brasil.
authors.forename: José B
authors.initials: JB
authors.lastname: Duarte-Júnior
authors.affiliation: Genética e Biologia Celular, Departamento de Biotecnologia, Centro de Ciências Biológicas, Universidade Estadual de Maringá, Maringá, PR, Brasil.
authors.forename: Maria Claudia C
authors.initials: MC
authors.lastname: Ruvolo-Takasusuki
authors.affiliation: Programa de Pós-Graduação em Zootecnia, Universidade Estadual de Maringá, Centro de Ciências Agrárias, PR, Brasil.
authors.forename: Vagner A
authors.initials: VA
authors.lastname: Toledo
mesh_terms: D000818:Animals; D001516:Bees / Q000145:classification / Q000502:physiology*; D001522:Behavior, Animal; D029688:Brassica napus / Q000254:growth & development*; D001938:Brazil; D054817:Pollination / Q000502:physiology*; D012621:Seasons