Rhizomania-resistant varieties top the Recommended List for beet

Five new sugar beet varieties were added to the BBRO/NIAB Recommended List for 2011. Philip Case looks at the new additions

Rhizomania tolerance should be the first characteristic growers should look for when selecting a sugar beet variety for the 2011 crop, according to experts.

The disease needs to be taken seriously, says Simon Kerr, NIAB’s sugar beet expert. “It is continuing to build up through the best beet growing areas in the UK.”

All five new varieties on the 2010/11 BBRO/NIAB Recommended List are rhizomania-tolerant, he says. “From 2012, we will not be recommending any non-resistant varieties to the List.”

Broom’s Barn‘s Pam Chambers says BBRO advice is to focus on rhizomania tolerance. Choosing a rhizomania-tolerant variety will help maintain yields where there are known infections and prevent the build-up of inoculum, she explains.

Less common, but also potentially very damaging to yield, are fields infested with beet cyst nematode. The recent introduction of tolerant varieties has increased grower options for dealing with the pest, but are only needed where the pest is known to be an issue, Ms Chambers says.

Once the correct pest or disease tolerance has been decided, growers should then consider varieties on the RL with the highest yields or with good bolting resistance where early drilling is being considered, she advises.

Don’t discount older varieties completely, Mr Kerr adds. “Selecting some varieties that already performed well with commercial seed is a safer option.”

Best all round newcomer – Rosalinda KWS.

Rosalinda KWS is the new highest yielding variety on the Recommended List at 105% of the control varieties. That puts it 3% ahead of last year’s top variety, Carissima on both sugar yield and adjusted tonnage.

It also has the best disease combination of any variety – seven for rust and nine for powdery mildew – and the equal highest establishment (96%) with Topper and Levi.

It has moderate bolting resistance, at 224 bolters/ha for early sown crops, just under the List average of 244 bolters/ha, although its 4/ha for normal sowing above average.

KWS’s UK sugar beet manager Simon Witheford says: “With the best disease resistance combination of any variety and the equal highest establishment percentage on the List, Rosalinda is arguably the best all-round selection for 2011.”

Best alternative all-round newcomer – Valeska

Nickerson‘s Valeska is a good alternative to Rosalinda KWS with only slightly lower yield – 103% of the control for sugar yields and adjusted tonnage. That puts it 1% ahead of Carissima.

Disease resistance is weaker than Rosalinda, scoring three for rust and six for powdery mildew. But its bolting resistance is slightly better, scoring 205/ha for early sowing and 2/ha for normal sowing.

Mr Kerr says Valeska is a useful variety for growers who do not want to rely on just one variety. “You cannot argue that Valeska’s data closely matches to Rosalinda. But the only proviso I would have is that it’s a first year recommendation,” he notes.

“Growers may be better advised to mix their varieties up. They could have some Valeska, Rosalinda and a couple of proven performers from the list like Bobcat and Bullfinch.”

Best newcomer for early drilling – Cheetah

Elsoms’ Cheetah is the fourth highest yielding variety on the new RL – just 0.5% below Carissima on adjusted tonnage.

Its main advantage, though, is its low bolting level. At 180 bolters/ha for early sowing and 0/ha for normal sowing, it is the best of the rhizomania-tolerant varieties.

The variety is attracting strong interest from growers looking to sow early, according to Ian Munnery of Elsoms.

But growers should consider the higher yielding varieties for mid to late drillings, Ms Chambers suggests.

Best BCN-tolerant variety drilling at a normal time – Sentinel or Annouschka

Of the three beet cyst nematode tolerant varieties now on the RL, Sentinel from Syngenta Seeds, offers the highest yields on non-infested lands. At over 99% of the controls it shows the yield drag for these varieties is narrowing all the time.

Where trials have been carried out under beet cyst nematode infested conditions, yield benefits of 10-85% have been recorded, depending on levels of infestation and prevailing conditions, according to Syngenta.

“We have seen the trial data from Syngenta and under infected conditions it seems to be good,” notes Mr Kerr. “But growers who have a high level of infection may consider Annouschka as an alternative. Sentinel does not have as high a level of tolerance and disease resistance as the KWS material.”

Sentinel does, however, offer by far the best bolting resistance – 169 bolters per/ha for early sowing and 1 for normal sowing – of any rhizo resistor, making it most suitable for early drilling.

Best BCN-tolerant variety where lifting late – Annouschka KWS

Annouschka KWS is around 5% lower yielding than Sentinel in non-infested conditions, but 5% higher than last year’s initial beet cyst nematode tolerant variety, Fiorenza KWS.

In trials on BCN-infected soils last year, Annouschka out-yielded its stablemate by an average of between 4-5%.

As well as perhaps better tolerance to beet cyst nematode than Sentinel, it also has better rust resistance, scoring a six compared with two for Sentinel. That might make it a better fit where growers know the disease is an issue, or perhaps when late lifting is expected.