WITH WHEATS
NIAB HOSTS A FRIENDLY JOUST
WITH WHEATS
Six winter wheats managed
by their breeders for
maximum gross margin
add spice to trials at
NIABs Cambridge
headquarters this year.
Andrew Blake reports
FOUR stables eagerly await harvest in the NIAB Variety Challenge.
The new replicated plot feature (Arable, Mar 19) is fundamentally a friendly competition, says cereals specialist Richard Fenwick. But it also addresses a more serious side, namely how to match fertilisers, growth regulators and fungicides more precisely to individual varieties strengths and weaknesses.
"It is very important for growers to think about inputs and to see what differences they make," he says. "There is increasing interest in managing individual varieties in more specific ways to get that little bit extra from them."
The winner will receive a Shield trophy at a celebratory dinner in February.
NIAB chose the site, a medium loam field after winter beans, and drilling date. It also took care of weeds and pests with a standard programme. All other inputs were largely dictated by the breeders but applied by NIAB.
Main niggle was the restriction on sowing date. Oct 15 clearly did not suit all varieties equally, Mr Fenwick acknowledges. "But the problems of drilling separate plots on different dates were too great, and all competitors accepted that."
The first 40kg/ha (32 units/acre) of N, in mid-March, was also a universal application made with all-round consent.
The varieties were all 1999 Recommended List candidates, only Aardvark and Shango failing to get listed.
By the end of June all plots appeared in good order with disease and lodging well controlled. "Personally I would be hard put to predict which is going to give the highest gross margin."
* Breeder strategies
With both high quality and feed types vying for maximum reward, growing strategies vary considerably, especially with nitrogen applications ranging from 200kg/ha (160 units/acre) to 290kg/ha (232 units/acre).
Advantas Ros Twemlow was well pleased with the mid-October slot for potential breadmaker Shamrock. "It was ideal because its not an early driller. We went for 325 seeds a sq m because it is quite a shy autumn tillerer and you need to keep the rate up."
Total N input, at 210kg/ha (168 units/acre), included a late 40kg/ha (32 units/acre) of foliar N to boost grain protein.
Shamrocks short stiff straw required no more than a single growth regulator spray – 3C Cycocel (chlormequat) at 1.75 litres/ha. "Maybe we could have got away with 1.5."
Temptation to cut T1
With the highest untreated yield on the recommended list the temptation was to cut out the T1 fungicide. "The disease resistance is there. But with only a provisional 4 for eyespot we chickened out even though it was a first wheat."
Brown rust justified the late Amistar (azoxystrobin) treatment, she says.
CPB Twyford is two-handed with Aardvark and Malacca both sown at 300 seeds a sq m. "Seed rate is not as critical as other factors," says agronomy services manager, Kerry Barnes.
The Oct 15 slot was fine for Aardvark, which lacks Malaccas winter dormancy, he says. "We do not recommend drilling Aardvark until the end of September because it may produce too much leaf which can get hit by frost. Good eyespot resistance also makes it an ideal second wheat."
By contrast Malaccas potential was probably reduced by the delayed sowing and a relatively poor seed-bed, he believes. "It is ideal for early sowing, from Sept 1. It was certainly the furthest behind in March, though it then roared through its growth stages."
A single hit of 5C Cycocel regulator was deemed sufficient for both varieties.
Plenty of residual N
Three splits of N, totalling 200kg/ha (160 units/acre), were also probably enough to achieve good bread-making samples, Mr Barnes believes. "There should be plenty of residual N after the beans, but there might have been an argument for a bit more to boost the protein after the wet."
In a more normal season nitrogen would not be advocated on either variety until April, he notes.
Fungicide inputs were strongly linked to individual disease resistances, Aardvark offering scope for a slightly cheaper programme. Even though it is a first wheat Malacca merited Unix (cyprodinil) because of its 5 eyespot resistance rating, he says.
Nickerson Seeds also has two winning chances in Buchan and Claire, sown at 200-220 seeds a sq m. Given the choice neither would have been drilled so late, says the firms breeder Bill Angus.
"We would not drill Buchan after September because you start losing yield potential and it is then better to switch to a quality variety." Baytan (fuberidazole + triadimenol) seed dressing was "an absolute must" to counter yellow rust.
At 290kg/ha (232 units/acre) stiff-strawed Buchan received by far the most N, an input which remains the most economic, says Mr Angus. "We thought we should push it a bit more to create some debate. A lot of people do not operate at their peak for fear of lodging."
Split 3C Cycocel, at a slightly higher rate on Claire, was a cheap, adequate building block, he says.
Unlike the other camps Nickerson insisted that the main N dressing went on at terminal spikelet, about a week later than first node detectable (GS31) in the other varieties.
"We take the view that far too much N is used too early. That simply increases tiller survival, enhances disease pressure and raises the risk of lodging."
Mildew control was the main aim of the fungicide programme on Claire, its otherwise good all-round disease defences needing no more than two sprays. Buchan merited three, including plenty of triazole to keep rust at bay and an Amistar ear wash. "It is not as clean ripening as Claire," says Mr Angus.
Multimin trace element sprays, which have proved their value in other Nickerson work, were key inputs.
PBICs John Howie hopes competition success for Shango could offer some compensation for the variety not being recommended last autumn.
Oct drilling was no problem, though establishment was quite poor because of the poor seed-bed. "We drilled 275 seeds a sq m, but the stand was only 180, although it was quite even."
The varietys relatively weak straw saw it as the sole entry requiring a late growth regulator in Terpal (ethephon + mepiquat chloride). It also was the only variety receiving a four-spray fungicide programme including what Mr Cowie calls a pre-T1 anti-mildew treatment. *
Aardvark Buchan Claire Malacca Shamrock Shango
40@23 40@24 40@25 40@23 40@23 40@23
80@31 160@T spk 140@T spk 80@31 90@31 120@31
80@33 90@37 60@37 80@33 40@32 60@33
40@73
200 290 240 200 210 220
Growth stage
Aardvark 31 5C Cycocel (1.2) + Opus (0.5) + Bravo 1.0)
39 Mantra (0.75)
59 Folicur (0.3)
Buchan Glume primordia 3C Cycocel (1.0)
31 3C Cycocel (0.5) + Opus Team (1.0)
37 Amistar (0.75) + Opus (0.25)
59 Amistar (0.25)
30 & 37 Multimin (1.0)
Claire Glume primordia 3C Cycocel (1.5)
30 3C Cycocel (0.75) + Corbel (0.5) + Fortress (0.3)
39 Mantra (1.0)
30 & 37 Multimin (1.0)
Malacca 31 5C Cycocel (1.2) + Unix (0.5)
39 Amistar (0.4)
60 Folicur (0.3) + Amistar (0.3)
Shamrock 31 3C Cycocel (1.75) + Opus (0.25) + Bravo (0.5)
39 Landmark (0.5)
61 Amistar (0.3)
Shango 30 5C Cycocel (1.75)
31 5C Cycocel (0.75) + Fortress (0.1)
32 Opus Team (0.25) + Bravo (1.0)
33 Terpal (0.75)
39 Landmark (0.75)
59 Folicur (0.25) + Amistar (0.25)