Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems
© 2017 The Authors. Global Change Biology Bioenergy Published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited
Oilseed rape (OSR; Brassica napus L.) is a major crop in temperate regions and provides an important source ofnutrition to many of the yield-enhancing insect ﬂower visitors that consume ﬂoral nectar. The manipulation ofmechanisms that control various crop plant traits for the beneﬁt of pollinators has been suggested in the bid toincrease food security, but little is known about inherent ﬂoral trait expression in contemporary OSR varieties orthe breeding systems used in OSR breeding programmes. We studied a range of ﬂoral traits in glasshouse-grown, certiﬁed conventional varieties of winter OSR to test for variation among and within breeding systems.We measured 24-h nectar secretion rate, amount, concentration and ratio of nectar sugars per ﬂower, and sizesand number of ﬂowers produced per plant from 24 varieties of OSR representing open-pollinated (OP), genicmale sterility (GMS) hybrid and cytoplasmic male sterility (CMS) hybrid breeding systems. Sugar concentrationwas consistent among and within the breeding systems; however, GMS hybrids produced more nectar and moresugar per ﬂower than CMS hybrid or OP varieties. With the exception of ratio of fructose/glucose in OP vari-eties, we found that nectar traits were consistent within all the breeding systems. When scaled, GMS hybridsproduced 1.73 times more nectar resource per plant than OP varieties. Nectar production and amount of nectarsugar in OSR plants were independent of number and size of ﬂowers. Our data show that ﬂoral traits of glass-house-grown OSR differed among breeding systems, suggesting that manipulation and enhancement of nectarrewards for insect ﬂower visitors, including pollinators, could be included in future OSR breeding programmes.
This work was fundedby the BBSRC, including support from an Insect Pollinators Ini-tiative grant awarded to GAW (BB/I000968/1) that was jointlyfunded by the BBSRC, NERC, the Wellcome Trust, Defra, andthe Scottish Government. Support was also received from HighWycombe Beekeepers’ Association. Rothamsted Researchreceives strategic funding from the Biotechnology and BiologicalSciences Research Council (BBSRC) of the UK.
This is the final version of the article. Available from the publisher via the DOI in this record.