26-06-2014 10:50 AM | News

Measuring vigour gives interesting results



NIABTAG has been running a 3 year, multi-site experiment looking at different sowing dates for a set of diverse winter oilseed rape varieties and as part of this research has been measuring vigour using three specific criteria – plant height, number of leaves and ground cover. Simon Kightley of NIABTAG explains that is important for crops to be vigorous so that they can get big enough to survive pigeon damage and the winter weather. “In most situations, including the HGCA Recommended list, vigour has been a subjective characteristic, but in this research it is actually measurable.”

“These measurements show that vigour is something that varies tremendously from variety to variety and it also shows that conventional rape varieties are just as, and in some cases more vigorous, than hybrid varieties. Results illustrate that you have to look at the individual variety itself, not just whether it is a conventional or a hybrid.”

“One of the varieties that we have included in this project is Es Alienor, a conventional type. In all three years, it has shown autumn vigour as good as or better than any of the hybrids. Even in the difficult 2012 autumn this came through well whilst the hybrids in general showed no significant advantage over the rest of the conventional pack. Alienor is a prime variety with good early vigour. It did impress in these trials, by getting away well both in the autumn and spring.”

He also concludes that the project indicates no particular argument to say that hybrids are more suited to the later sowings.

Simon points out that conventional varieties offer other practical advantages which could be more advantageous this coming autumn. “Conventional varieties have more flexibility in their seed rates. Seed is less expensive and, especially if faced with difficult seed bed conditions and no seed insecticidal treatments, this gives the grower more leeway to increase the seed rate to allow for potential field losses.”

However he warns that using high seed rates means growing a variety with good standing ability. “If your worst fears don’t come true and all the seed germinates, you may be running into a lodging risk. Choosing stiff-strawed vigorous varieties is a vital part of this autumn’s strategy.”

“With the loss of the major seed dressing products, a shift back towards higher seed rates could well be part of growers’ strategy, too. I would say that researchers and growers will need to make a rapid assimilation and understanding of how crops perform this autumn without seed dressings. It could be a steep learning curve but good establishment of the crop remains important whatever the season brings.”

Neil Groom, Technical Director of Grainseed, says the loss on neonicotinoids will certainly increase the importance of autumn vigour and the need for higher seed rates. “Autumn vigour could make sure that the rape out runs any insect damage from flea beetles or aphids and the impact of viruses - real threats to this autumn’s crops. Seed vigour is essential to ensure rapid germination and good development of the root system and seedling growth. Rapid germination and vigour are going to be key requirements now that seed treatment options are limited.”

“When oilseed rape seed was treated with Chinook many growers drilled at 6 kg per ha of seed, which is approximately equivalent to 120 seeds per square metre. With a better understanding of seedbed requirements, tillage trains, consolidation and improved placement of seed, I think many growers will opt for increased seed rates this season, but maybe not as high as 120 seed per square metre.”

“Alienor has been proven in trials and in commercial use to have these characteristics in spades. It also is a low biomass conventional variety that performs consistently well, as do all our other autumn rape varieties, Es Alegria, Es Cubic and Es Astrid. All these varieties have top stem stiffness, resistance to lodging and multigene resistance to stem canker. Being low biomass means that they are easily managed and harvested, which is what growers are looking for.”

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