Page 19 - Vol. 39-No.4 issue

CROP PROTECTION

NEW DSV PHOMA AND CLUBROOT RESISTANCES PROVIDE

ENHANCED DISEASE PROTECTION FOR UK OSR GROWERS

as the mainstay of their protection against start early destruction of OSR volunteers
this yield-robbing disease, clearly this is a and cruciferous weeds either chemically or
very worrying situation." mechanically is essential after the previous
crop is harvested, he says.
Additional layer of security
"Cruciferous weeds must be combated
RLMS provides some hope DSV Phoma as quickly and precisely as possible as weed
Blocker adds a much-required additional infestation in one field is often the reason
layer of security for the future, he believes.
New genetic resistances to two of the why clubroot still occurs after very long
UK's most serious and costly diseases "At the heart of Phoma Blocker is LepR1 breaks in cultivation."
affecting oilseed rape, should be availa- - a completely new type of genetic mech- "Volunteer rape is also a latent danger
ble to growers in the next few years, say anism for phoma resistance in Europe." with early control of OSR volunteers shown
breeders DSV. "Whilst LepR1 by itself has been shown to reduce intensity of clubroot and further
The company's Phoma Blocker trait, fea- to have the best resistance to the most multiplication of spores. Growing OSR no
turing a resistance mechanism for phoma common phoma strains in field trials across more than one year in five on the same
stem canker completely new to Europe, is Europe, we believe it is most effective when field is also important.
already featured in varieties currently going used in conjunction with other disease re- Enhanced clubroot protection
through the UK testing process with the sistance traits."
enhanced clubroot resistance CRE1 fol- "DSV Phoma Blocker is made up of In recent years, hybrid oilseed rapes
lowing closely behind. LepR1 with RLM7 and this combination with genetic clubroot protection have also
played an important role in keeping spread
According to Simon Kröger, DSV oil achieved an average of score of just 2.3 of the disease in check and also protecting
crops product management lead, phoma in the Dyngby trials - compared to the 7.5 yields for growers, he points out.
stem canker in oilseed rape is a disease for RLM7 by itself."
now costing UK producers £100M/year But the real advantage is that DSV now "DSV has been particularly successful in
through lost yield and the costs involved uniquely has varieties featuring all three this area with varieties such as DSV Crossfit
in trying to control it. different phoma resistance mechanisms - CR and DSV Crocodile CR offering good
"Resistance to phoma results in better RLM7, RLMS and now LepR1 - that can protection without yields being compro-
mised, which has usually been the case
and longer lasting plant health with bet- be rotated in the field to minimise major before such varieties were introduced."
ter lodging resistance as well as a longer breakdown of any one type of resistance,
and undisturbed assimilation process that Simon Kröger points out. "Breeding for clubroot resistance is com-
supports growth through tough climate "By being able to do this, DSV has taken plicated and time consuming with signifi-
conditions such as early summer drought." phoma resistance in oilseed rape several cant incompatibilities between species cre-
ating an additional challenge for breeders."
"It also underpins optimum harvest date stages further on."
and can lead to higher yields as well as "DSV already has Phoma Blocker varieties Despite this, DSV is now introducing a
reducing the general level of phoma spores moving through the UK testing process and new clubroot resistance mechanism called
in the field." it fully anticipates the first of these will CRE1 (Clubroot Resistance Enhanced 1)
with a broader protection against more
But while RLM7 has been the main ge- be commercially available in 2024 after pathotypes, Alex Doering says.
netic disease resistance mechanism for completing NL2 testing this year."
many years there is growing evidence that According to DSV UK managing director "CRE1 is a novel trait that has been cre-
its effectiveness is reducing, he explains. Dr. Alex Doering, new genetics to improve ated by crossing from B. rapa. Laboratory
infection studies using various P. brassi-
"In DSV trials in Dyngby in Denmark, for resistance against the growing threat of cae isolates show CRE1 to be an enhanced
example, on a scale of 0 - 10 with 0 being clubroot are also being introduced by the resistance mechanism compared to the
excellent resistance and 10 being high sus- company. classical resistance."
ceptibility to Phoma, varieties without any "Clubroot, caused by the pathogen Plas-
qualitative resistance showed an average modiophora brassicae (P. brassicae), is a "The first DSV CRE1 resistant variety is
score of 7.5 with a range of 6.5 to 8.5." highly infectious, yield-robbing disease of expected to be registered during winter
"Varieties with the RLM7 gene showed a growing concern across Europe." 2023/24 in the EU, but it will take a few
more years until it is available in the UK."
wider range of phoma susceptibility scores "In the UK, Scotland has experienced
- from 4 to 9 - but of real concern is that heavy infestation in recent years, but there "In the meantime, we are launching a
the average was the same 7.5 as varieties is growing evidence that the problem now new variety (RAP637) which as well has
with no disease resistance at all." exists in many other regions including the a clubroot protection using the established
common source of partial resistance, will
"When you consider 53% of oilseed rape South East of England." also be TuYV resistant with Verticillium wilt
varieties on the current 2023/24 AHDB Strategies to control clubroot involve a tolerance and a very good lodging resist-
Recommended List for the UK rely on RLM7 combination of different approaches. For a ance score."

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