Breeding oilseed rape varieties for pollinator-friendly traitsStaff Writer | March 17, 2017
In recent years, some beekeepers have suggested that hybrid varieties of OSR may provide inferior nectar for pollinators compared with traditional open-pollinated varieties.
Farming OSR may provide inferior nectar
The researchers demonstrated that while the amounts and sugar content of nectar were similar in varieties within the same breeding system, they varied between the breeding systems. The study has been published in the journal Global Change Biology Bioenergy.
Professor Juliet Osborne, of the Environment and Sustainability Institute on the University of Exeter’s Penryn Campus in Cornwall, said: "We got the idea for this study from beekeepers.
"Several approached us to ask if we knew why some varieties of oilseed rape didn't seem to give as good a honey crop from their hives as they expected.”
Oilseed rape is an important component of many farmers’ arable crop rotations and the nectar and pollen produced by their distinctive yellow flowers provide a key source of nutrition for insect pollinators.
The UK has around 250 bee species, including the domesticated honey bee.
Like many other insect pollinators, these bees need sources of nectar and pollen.
The declines in pollinator abundance in farmed landscapes is the result of several factors with the lack of available food resources thought to be a major contributor.
In this study, varieties produced with three different methods were tested. The scientists compared OSR varieties representing open-pollinated (OP), genic male sterility (GMS) hybrid and cytoplasmic male sterility (CMS) hybrid breeding systems.
Dr Jonathan Carruthers, previously a PhD student from Newcastle University working at Rothamsted Research explained: “We measured a range of floral traits in varieties of winter OSR grown in a glasshouse to test for variation within and between breeding systems.
“Specifically, we quantified 24-hr nectar secretion rate, the amount, concentration and ratio of nectar sugars per flower, and the sizes and number of flowers produced per plant from 24 varieties.”
Analyses of the data demonstrated that while the amounts of nectar and sugar were similar in varieties within the same breeding system, they varied between the breeding systems, being significantly greater in GMS hybrids than in CMS hybrids and open-pollinated varieties.
The researchers concluded that plant breeding could be used to create crop varieties with pollinator-friendly traits, benefitting both pollination services and crop production. ■