February 6, 2017
Prioritise important traits for winter OSR consistency
The latest Masterseeds research underlines the importance of prioritising a number of vital traits alongside high gross output in the oilseed rape mix to achieve consistently good farm performance – most importantly, autumn and spring vigour, all-round disease resistance, pod shatter resistance and, where needed, herbicide tolerance.
Agrii seed technical manager, David Leaper pointed out that National and Recommended List testing shows almost every modern variety is well able to deliver high gross outputs in small plot trials. However, to deliver consistently above average performance under commercial farming conditions he stressed they must have more than just a high output potential.
“In particular, winter rape crops have to be resilient enough to cope with stresses like later-than-ideal sowing, less-than-ideal seedbeds and spray timings, persistent pest problems and, increasingly, extreme weather variations,” he stressed.
“In our experience, this means they need to develop rapidly in both the autumn and spring, be as resistant as possible to phoma and light leaf spot – not to mention turnip yellows virus, clubroot and verticillium – and stand-up well through to harvest with minimal seed shedding.
“The varieties that do so invariably seem to come out at or near the top of the large scale trials we run across the country under typical farm regimes. They are also proving much more popular and, crucially, longer-lasting with our growers.
“We record substantial differences between the 30+ varieties we trial each year in the vigour with which they establish and develop ahead of winter and the earliness with which they grow away in the spring,” explained David Leaper. “The better varieties in both respects are better able to grow away from flea beetle, slug and pigeon attack and tolerate early phoma and light leaf spot infections.”
High levels of combined phoma and light leaf spot resistance also make an important contribution to performance consistency, with Agrii trials highlighting their clear association with the highest levels of untreated yield. This gives the greatest possible leeway in both the extent and timing of fungicide treatment from late autumn to early spring when spray days are at their most limited.
“As well as phoma and light leaf spot resistance, we see growing value in the clubroot, TuYV and verticillium resistance traits becoming much more available in modern, high gross output genetics,” David Leaper added.
“Replicated small plot trials are allowing us to categorise varieties clearly by their level of verticillium wilt. Our involvement in a national assessment of the impact of TuYV is highlighting how much yield we may be losing from this disease and the value of the resistance now available. At the same time, the increased incidence of clubroot our agronomists are encountering across the country these days is demonstrating the growing importance of addressing this issue with the best genetics.”
Pod shatter resistance, which can protect crops against inclement weather in the run up to harvest and make a major contribution reducing OSR volunteer problems in the rotation, is another valuable characteristic David Leaper welcomes for its much wider availability. Originally confined to varieties from Dekalb, he’s now seeing it in hybrids from at least three other breeders.
Finally, he is finding the Clearfield system – involving hybrids conventionally bred to be resistant to the herbicide, imazamox – invaluable where cruciferous weeds are a problem, both in robbing yield and in high erucic acid contamination. With erucic acid contents of over 30% in charlock and wild mustard and 10% in cranesbill, he has no doubt that these weeds can be an important factor in claims and rejections.
“The Masterseeds 2017 winter OSR portfolio is based firmly on varieties we have selected for the combination of traits they bring alongside high gross outputs to improve the consistency of farm performance,” concluded David Leaper. “It extends to nine mainline ‘double low’ varieties – six hybrids and three conventionals – and five specialist types – one club root resistant, one Clearfield, one HOLL and two HEAR varieties.
“Together, we believe this provides everything our growers need to make the most of the undoubted value the crop offers with the least possible agronomic risk.”