On the annual strawberry walk at East Malling Research (EMR), Produce Business UK learns how the site’s Strawberry Breeding Club programme is striving to come up with berries that meet the needs of the supply chain, buyers and the end consumer
It’s that time of year again when strawberry crops are bursting onto the retailers’ shelves at roughly the same velocity as a tennis ball being whacked down the line on Wimbledon’s hallowed centre court.
However, the nation’s fortnight of focus on top-class tennis pales in comparison with the year-round dedication of the strawberry breeding club at Kent-based EMR, which continues to develop new, and improved, cultivars [cultivated varieties] for the fresh produce sector.
Adam Whitehouse leads this breeding club and also hosts AHDB Horticulture (formerly the Horticultural Development Company) and East Malling Research Association’s annual strawberry walk, which gives visitors the chance to find out more about the process involved in developing some of the UK’s most popular strawberry varieties.
From crosses to cultivars
Whitehouse begins the strawberry walk by explaining to the group that it can take as long as a decade to develop a new variety. As visitors trundle past fields full of strawberries, he points out that the breeding club produces 13,000 young strawberry plants (seedlings) a year. He says: “We then visually pick out the best 1% of these. We have to make that judgment.” These 130 plants are then whittled down to just eight or 10, which are then further trialed.
It sounds like a brutal process and it has to be. Those selections that outperform the other plants at the East Malling test plot are further trialed by commercial growers – first on a small scale and then (for those selections deemed to have the most commercial potential) in large-scale trials.
Whitehouse says: “It’s a hugely important step in assessing the commercial viability of a new strawberry, and for getting a feel for what growing systems and locations they work best in. This whole process can take four to six years – approximately 50% of the time needed to get a new selection from cross to cultivar.” He adds that three marketing organisations – namely CPM Retail, Mack Multiples and Berry Gardens Growers host trials for the breeding club.
The perfect fruit
Bearing in mind the varying requirements of growers, packers, retailers and consumers, Whitehouse tells the group that there are a total of 25 different traits that he and his team are assessing as part of their quest to find new cultivars. These traits include, for example, the fruits’ flavour, appearance, size, and firmness. They also include the amount of Class I fruit a plant produces, what time of year it bears fruit, and whether or not the plant is capable of producing sufficient ‘runners‘ for commercial breeding. Members of the tour group, which include commercial growers, are invited to help rate 20 of Whitehouse’s best selections of June bearing cultivars. They assess them for their appearance, flavour and firmness – rating each characteristic on a scale from one (poor/very soft) to nine (excellent/very firm).
The group is also asked to assess how these selections compare to some of the industry “standards,” including Elsanta, Vibrant and Malling Centenary – a cultivar that was launched by the club in 2013 to mark the 100th anniversary of East Malling.
Whitehouse says: “In here are some advanced selections that have gone through the grower trials – predominantly the back end of the early ones and a couple of mid-season [cultivars]. There are also some newer selections that need lots of data in terms of yields.”
Whitehouse reveals that a selection named EM2379 is looking particularly promising as it is an early variety that has so far yielded more than 95% Class I fruit, with 90% of this fruit deemed “large” (35-40mm]. He explains that those selections, like EM2379, that are code-named are the ones that have not yet been officially given plant variety rights. He says: “Once we get a variety we think is going to be successful we apply for plant variety rights. When it’s accepted as a unique variety we are then allowed to give it a name and permitted to produce the plants. Plant propagators have licenses to produce the plants, and for every plant that’s produced there’s a royalty levied against it. That money goes back to the club.”
An ideal partnership
Malling Centenary remains the latest variety to be released by the breeding club. “We don’t have any new releases planned for this year, but we have a number of advanced lines, both June bearer and everbearer, that are currently in growers’ trials that have cultivar potential,” says Whitehouse, adding that, up until last year and due to the low number of plants originally available, Malling Centenary was marketed only through Sainsbury’s. This year, however, Malling Centenary has become available to all growers and is appearing on more retailer lists.
“It looks likely to be a real success story for both the EMSBC programme and EMR, mainly due to its excellent fruit quality (flavour, appearance and size) and the fact that it can be cropped slightly earlier than the main-season standards such as Elsanta and Sonata,” he says.
One of the main reasons why the breeding club first started in 1983 was to help extend the UK season. “Now there’s only two months of the year when we don’t produce [strawberries] in the UK,” Whitehouse says. Since 2008, the breeding club has been funded by a public-private partnership. This sees its research supported by private investment from the UK soft-fruit industry and by money from AHDB Horticulture – which is a shareholder representing all UK growers. “This ensures that this material is open to all UK growers,” says Whitehouse.
Breeding for the future
The EU’s strict stance on pesticide use, and the anticipated removal of more pesticides from the market, has encouraged EMR’s scientists to identify genetic markers in cultivated strawberry plants that they claim will lead to new varieties resistant to verticillium wilt – a disease for which there is only one chemical treatment available. Whitehouse reveals: “We have made a rather exciting step forward this year. Being based at East Malling we benefit from all of the other research projects that are going on, including some of the work on genetics. And so, we have started a breeding programme that ties into the club selections, looking to use [genetic] markers that have been identified to breed for wilt resistance.”
Given the club’s unique location at East Malling – one of the world’s most renowned horticultural research centres – it is not surprising that more than 40 of its cultivars have been a hit, in different measures. They have enjoyed success in the US and Asia, as well as the UK and the rest of Europe.
Buyers can therefore feel confident that the UK has a breeding programme that will ensure that strawberries continue to be a key part of the fresh produce sector – and, indeed, the British summer.