Some of the nation’s favourite brassica vegetables, such as broccoli and cauliflower, are available all year round. This is because growers plant different crop varieties that flower at different times of year – known in the world of horticulture as the “heading date”. Crop varieties with different heading dates are usually the result of a long process of selective breeding based on cross breeding plants with a desired trait or set of characteristics.
In new research published in The Plant Journal, Professor Caroline Dean and her research team explored the molecular basis for this heading date variation in broccoli.
“When we use selective plant breeding to develop a new crop variety, we can grow the plants and see the effects of that process, but we don’t really know what’s going on at the genetic level; what genes we’re actually selecting for,” said Professor Dean.
Through a series of laboratory, greenhouse and field-based experiments using both broccoli and the reference plant Arabidopsis thaliana (a relative of the brassica vegetable family), Professor Dean and her team were able to show that small changes in a gene called FLOWERING LOCUS C (FLC) are responsible for the range of heading dates found in different broccoli varieties.
FLC is a gene that blocks flowering so necessitating overwintering in many flowering plants. Professor Dean said:
“In previous work, we showed that the reference plant Arabidopsis has adapted to many different climates by modulating how quickly the FLC gene is switched off during winter. Here we have shown that when we breed broccoli varieties to head at different times of the year, we’re actually selecting the same gene in broccoli, BoFLC.C2. Different versions of the Brassica gene require more or less cold before the gene is switched off and flowering can begin.”
Dr Judith Irwin, a crop geneticist at the John Innes Centre and first author of The Plant Journal paper said:
“Identifying that the BoFLC.C2 gene is involved in heading time variation means we now have a target for plant breeding programs to develop new brassica varieties. This will be especially important in the face of climate change, because our weather patterns and climate conditions are changing and we need new vegetable varieties to be resilient to this change.”