First Double Resistance Rhizo-Beet Variety Makes New Recommended List

Trials confirm that this new gene can help minimise problems being encountered in parts of Norfolk, Suffolk and Essex from a more aggressive strain of the virus.

“Rz2.0 Double Resistance has already been widely tested across continental Europe,” says KWS UK sugar beet manager, Simon Witheford. 

“We expect UK growers to widely test this new technology now available in Isabella KWS for the first time next year.

“It will be particularly welcome for those in areas where Rhizomania pressures are greatest or where the virus is known to be resistant.

“Growing Isabella brings no yield penalties and, through reducing the availability of potentially susceptible host plants, the development and multiplication of any resistant strains of rhizomania is reduced,” he says.

With a sugar yield of 100.8%, Isabella KWS sits fifth on the new UK Recommended List, just 1.3% behind front runner Rosalinda KWS. 

It is also backed by strong agronomic characteristics particularly for disease – including the highest rating on the list for resistance to powdery mildew at 8 – plus the third highest rating for rust of 6.  Bolting scores are middle of the pack.

“Indeed, Isabella KWS could easily be selected as a first choice variety in its own right – without anyone even casting an eye over its additional Rhizomania resistance protection profile,” he says.

According to Mr Witheford, Isabella KWS’ Rz2.0 Double Resistance is as a result of introducing the existing widely utilised Holly gene, which continues to provide strong protection against the disease, with a new C48 gene from a wild beet source.

Intrials last year, the new C48 gene technology tested at a site at Woodbridge where the mutated rhizomania strain has been detected, gave an average yield increase of 36% over beet containing the Holly gene alone.

“By combining both major gene sources into the same variety, growers can be sure that they have the best protection possible against root madness which can cut yields by 70% rendering crops almost unprocessable,” he says.

“And, while only a handful of fields have so far been identified as having resistance breakdown issues, the industry needs the better protection these new varieties offer.

  “This is particularly relevant in areas where Rhizomania has been long established and where the pressures from the disease are greatest.  These situations are most likely to be more at risk of the occurrence of resistant strains.

 “In effect, by growing second generation rhizomania resistant varieties such as Isabella KWS, growers can insure against the further development of resistant strains of the disease and be confident that they will gain the rhizomania protection needed to maintain best possible beet crop performance wherever they farm,” says Mr Witheford.

KWS admit that the mechanism with which the C48 gene provides rhizomania resistance is not completely understood though it is similar to that of the Holly gene and is typically characterised by reduced accumulation of the rhizomania virus in the tap root of the beet plant.

In addition to the two major genes for Rhizomania resistance, Isabella KWS also has minor genes on the same chromosome from both sources which also offer some additional resistance benefits.  As a result Rz2.0 Double Resistant varieties offer the best possible rhizomania protection whatever strains are found in growers’ soils.