Two new Elsoms swede varieties will be the first ever to include genetic resistance to the yield and quality-sapping disease Brown Heart.
Teviot and Derwent, available to growers in 2022,have been tested extensively in field conditions across the UK and have achieved consistently high yields and quality without any incidence of Brown Heart, the company revealed.
“Brown Heart has been a problem for growers for many years with potentially devastating losses including unmarketable roots and field yield reductions of up to 40 per cent being commonplace,' said Elsoms brassica crop manager David Clay.
“The problem is the disease cannot be seen until the crop is harvested and by then it is too late to do anything about it. Brown Heart results from stress conditions, particularly lack of moisture at key times of the growing cycle, and with summer droughts now becoming more prevalent in many parts of the country, it is a problem that is likely to get worse.
“For some swede growers, production has unfortunately become a bit of a gamble and every variety bred to date is susceptible.”
Once in the crop, there is little that can be done to prevent the condition in terms of crop management, Clay pointed out. “Slower-growing varieties have suffered less historically, and boron deficiency is also thought to contribute to the problem, but even if you add boron its uptake is seldom efficient so the condition persists.
“Over the years we have managed to breed swedes that have significantly improved quality, colour, shape and yield but Brown Heart resistance has eluded the industry until now.”
Elsoms’ head of R&D, Richard Tudor, explained that building Brown Heart resistance into the new varieties has taken many years of talking to growers, patient plant breeding and transferring promising trial results into consistent field success.
“It all starts with the customer,' he said. 'We listened to their views about Brown Heart, how it affected them and the problems it gave them with marketing the crop. All said the condition was the number-one problem they faced with commercial swede production.
“The first step was, therefore, to screen all the material we could source to find the lines least affected and establish why this was the case. This enabled us to select the best parent lines to create a new generation of hybrids with Brown Heart resistance.
“Working with York University we were then able to identify candidate genes we believe are providing resistance to Brown Heart.
“The great news for growers is that in seven years of trials in various conditions, in multiple locations and even when trying to force the condition on crops, we have never seen a single case of Brown Heart in Teviot or Derwent.
“In one really challenging trial in the Borders five years ago, every commercial variety developed Brown Heart apart from Teviot and Derwent. In pre-commercial trials of the new varieties involving 300,000 plants grown in the field, not one has developed Brown Heart.”