We are urgently developing research requirements with other European laboratories to make sure we understand and the disease (Schmallenberg) better.Seed Varieties: Early start needs careful handling
After last autumn’s difficulties growers are expected to plan for an early start to their 2009 drilling campaign. However early drilling has its pitfalls as well as pluses. TERESA RUSH reports.
Early drilling is very much on the arable agenda at the moment. After the experiences of last autumn – when wet weather wreaked havoc on harvest and drilling schedules – growers further north in particular, are expected to aim for an early start to planting.
Added to that, there are a few new winter varieties coming into their first full season of commercial planting which are being pitched as suitable for the early drilling slot.
All sounds reasonable enough and most would agree that, managed properly, early drilling can pay off. But, warns one leading wheat breeder, those opting to drill early must be aware of the risks posed by a series of ‘elephant traps’.
Suitability for early drilling is an agronomic trait Nickerson wheat breeder Bill Angus has observed, selected for and developed variety management guidelines over the years, but while he acknowledges there are benefits to be had from making an early start to the drilling programme, he is quick to point out early-drilled crops require a step-change in terms of management.
“Nine out of ten farmers believe they can manage an early-drilled crop, while in fact only one in ten actually can,” he maintains.
It may be stating the obvious, but the main benefit from early drilling is not drilling too late, he says. Early drilled crops may have a higher yield potential but capturing this yield can be fraught with difficulties.
These include an increased lodging threat, increased disease pressure, the risk of reduced ear fertility and weed management challenges. Early drilled crops will be around 10cm taller and more lush than their later-drilled counterparts. “As a rule of thumb early drilling will reduce a straw strength rating by at least one point,” says Mr Angus.
In terms of disease pressure, early drilling can transform first wheats into pseudo second wheats. Even first wheats will succumb to eyespot when sown early, so treatment for this disease should be routine.
Infection risk
Septoria tritici pressure will be higher and yellow rust-susceptible varieties will run the risk of early spring infections – an important consideration for autumn 2009-drilled crops, given the expected increase in disease pressure following this season’s outbreaks and the breakdown in resistance of some varieties.
A yellow rust-active seed treatment will be essential on early-drilled, susceptible varieties, says Mr Angus. “We already know we are going to get yellow rust next year and a lot of the varieties which are perceived as resistant, are, in fact, susceptible as juvenile plants.”
One aspect of early drilling which is often overlooked, is its effect on crop growth and development, he adds. Varieties drilled early will pass through growth stages much more quickly and those which initiate their ear primordia early will be at high risk of reduced ear fertility caused by stress events such as drought or cold spring temperatures. In the field, this is manifested as reduced yields, blind grain sites, deformed ears, or, in some varieties, ergot.
The robustness of a variety’s flowering biology plays a big part here, says Mr Angus. And with new varieties as yet unproven in the early drilling slot, it is possible to make an initial assessment of their suitability by looking at the performance of their parent lines as early drilled varieties, he adds.
These risks can be alleviated to some extent through variety choice. Amongst the Nickerson varieties, Mr Angus singles out are the Recommended List varieties Alchemy and Claire as proven varieties. Two further varieties within the company’s portfolio, Exsept and Orator are also worth considering, he says.
Further approaches to minimising the risks associated with early drilling, include reducing seed rates and delaying nitrogen applications.
“There is no standard seed rate for any situation. Growers must consider the seedbed conditions, threat from slugs, previous cropping and prevailing weather patterns. Seed rates as low as 125-150 seeds per square metre from the beginning of September would be appropriate in good conditions,” says Mr Angus.
Insure against
Openfield arable technical manager Lee Bennett is advising growers across the country to plan to drill a proportion of their wheat area in early September but with a variety which can equally well be sown late if conditions dictate.
“If the seedbed and weather conditions are right, starting your wheat drilling in the first week of September can be a very valuable way of insuring against subsequent weather problems,” he says. “Especially so if you have large amounts of winter cereals to get into the ground with limited labour and machinery.
“Early drilling can also more fully exploit wheat yield potential by improving establishment and early crop development. But only with varieties which don’t get too far ahead in their development before the winter sets in, or put on too much vegetative growth and have both good lodging and disease resistance. Otherwise there’s a very real danger of getting things badly wrong.”
The key essential for early-drilled wheat in Mr Bennett’s book is slow apical development. Given the particular lodging risk posed by early sowing, he also favours varieties which have good lodging resistance, are relatively short-strawed and don’t tiller especially freely. Strong all-round disease resistance is a further characteristic he considers important to combat the increased risk from rusts, septoria and eyespot, in particular.
Given these key considerations he identifies three main contenders for early drilling this season - Group 2 variety Battalion; old favourite biscuit wheat, Claire; and newly-recommended feed variety, Grafton.
“Battalion ticks all the right boxes for early drilling. It’s a slow developer from early September sowing, relatively short, and offers about the best combination of lodging and all-round disease resistance on the Recommended List, including the Pch1 eyespot gene.
The variety has the added advantage of being a relatively fast developer from later sowings too, as well as an awesome second wheat. So it scores very well in terms of sowing date flexibility.
Classic choice
“Claire may be getting a little long in the tooth these days and is slightly weaker in the stem than Battalion, but its very slow apical development has long made it the classic choice for early drilling. It’s proved its value in broad acre production and there’s a ready market for its milling value, so growers who know it and can grow it, will continue to stick by it.
“It’s too soon for RL data on apical development, but initial indications suggest new feed wheat, Grafton is also suitably slow to develop from early sowings,” says Mr Bennett.
“Alchemy and Scout also look useful as early drillers. But for my money it’s really down to one of the three main contenders,” he concludes.
An early start to the 2010 crop drilling schedule is pretty much inevitable given last autumn’s difficulties and rightly so, says independent variety consultant Richard Fenwick. But he urges growers to choose their varieties for early drilling carefully.
Claire has traditionally been the variety for early drilling and while its yields are trailing more recent variety introductions, some growers will stick with it, says Mr Fenwick.
Using HGCA’s RL Plus to identify varieties suitable for early drilling, highlights Oakley, Viscount, JB Diego and Grafton as the first four on the list. However, RLPlus classifies ‘early’ as before October 6 and so is not particularly useful in this respect, says Mr Fenwick. But a new series of RL trials which got underway last autumn should provide growers with more information. With drilling dates between August 30 and September 21 at sites across the country, these should start to provide some information on the performance of varieties from early plantings as harvest results start to emerge.
New data
One of the key considerations for an early-drilled variety is speed of development to GS31 and HGCA last week issued new data for Recommended List varieties. Varieties taking longer than average to reach GS31 – ie: slow developers – from an early September sowing include Scout, Grafton, Claire, Cassius and Oakley.
“Grafton has good yield potential, exceptionally stiff straw and generally good disease resistance, with the exception of a slight problem with brown rust. It’s one which farmers should be considering for the early drilling slot.
“Scout is a soft biscuit wheat. A lot of farmers want to grow a soft wheat because they market well and they can get a premium. If you’ve been growing Claire, I would go for Scout.
“Grafton and Scout are two new varieties which growers should be looking at, but with 662 hectares of Grafton entered for certified seed, and 938ha of Scout, seed is likely to be limited,” says Mr Fenwick.
“What growers definitely must not do is choose one of the varieties which develop very rapidly - Einstein, Xi19, Gallant, for example,” concludes Mr Fenwick.
