Yieldsfrom all winter oilseed rape trials are now in, reports the HGCA. Thisnewsletter has analysis of the results by Ellie Marshall, HGCA Research and KTManager, from different regions of the UK as well as the thoughts of Tim Isaac,HGCA Regional Manager East.
Theyields are expressed as gross output, which takes into account seed yield andoil content. Gross outputs for 2014 provide a good guide to variety performanceduring this season, but the four-year average values give a betterrepresentation of variety performance over several seasons.
TheRecommended List for oilseed rape is divided into two regions the ‘North’ whichis effectively all of Scotland, Northern Ireland and England down to Teesside.The East/West region is all of the rest of England and Wales. In this resultsround-up, the East/West region has been divided in half to give more detailedinformation. The West is all of Wales and the wetter part of England fromHampshire in the south to Cumbria in the north. The drier East is all theremaining parts of England.
Recommended List results in the OSR EastRegion
Inthe East, the 2014 average gross output from HGCA Recommended List trials was5.16 t/ha which is the same as the four-year average for the East. Gross outputis represented as a percentage of the yields of the control varieties which areExcalibur, Vision, PR46W21 and DK Cabernet.
Thereare seven trials in the East region. These include two in Suffolk whereverticillium wilt was diagnosed. Incentive has performed well with a grossoutput in 2014 of 108% and a four-year average gross output of 106% Othervarieties which have performed well in 2014 include Charger 104% (4-year 104%),Harper 104% (4-year 104%), Rivalda 104% (4-year 102%), and DK Camelot 104%(4-year 101%).
Candidatevarieties for the new HGCA Recommended List have yielded well. V316OL, a higholeic, low linolenic HOLL variety, was the highest yielding variety with agross output in 2014 of 115%. Campus achieved a high gross output of 110% andArrazo 109% in 2014. Looking at the four-year average values, which are abetter reflection of variety performance over several seasons, the highestyielding candidate varieties include V316 OL (108%), Campus (108%), Arazzo(107%), SY Harnas (106%) and Popular (106%).
Onthe whole, the growing conditions for this years harvest were very goodthroughout and a welcome improvement over the previous year. Autumn sown cropsgot away well and continued to grow through the mild winter. For the first partof harvest, when people were bringing in winter barley and oilseed rape,conditions were pretty much ideal meaning harvest was ahead of previous yearswith very little need for drying.
However,on-farm oilseed rape yields were a little disappointing, the winter OSR lookedgreat all year having got away so well and expectations were high. On the wholethough, the results have been about average (3.5 to 4t/ha) it would seem thatall the vegetative growth did not translate into pod numbers.
RL results from other regions West
Inthe West, average gross output from HGCA Recommended List trials was 6.01 t/hawhich is 0.3 t/ha above the four-year average for the West of 5.71 t/ha. Information is limited to two trials in Oxfordshire and one in Herefordshirefor the West results.
Incentiveand Charger both achieved high yields for varieties on the HGCA RecommendedList with a gross output of 113%. Both have performed well over the four-yearaverage with gross outputs of 109% and 108% respectively.
Harperalso performed well in 2014 with a gross output of 109%. Top yielding varietiesbased on the four-year average include Incentive, Charger, PT211, Harper andTrinity.
Theclubroot resistant variety Cracker yielded 102% in 2014, which was higher thanits four-year average gross output of 97%. The clubroot resistant candidatevariety Mentor achieved a gross output of 107% in 2014 and 105% in thefour-year average, which compares favourably with Cracker.
Candidatevarieties for the HGCA recommended List for 2015 were amongst the highestyielding varieties. These include V316 OL, the High oleic low linoleic acidvariety with a gross output of 119%, Popular (117%), SY Harnas (115%) andCombiner (111%).
RL results from other regions North
Resultsin the North will also be of particular interest to growers with concerns aboutlight leaf spot, since varieties selected for this region have higher levels ofdisease resistance, with a lower emphasis on resistance to Phoma stem canker.
Harvestresults for North oilseed rape trials in 2014 show average gross output yieldsof 5.41 t/ha. This is 0.39 t/ha above the four-year average gross output.
Anastasiaperformed well in 2014 and in the four-year average with a gross output of 114%in 2014 and 109% in the four-year average. Incentive, too, has performed wellwith a gross output of 110% in 2014 and 109% in the four-year average. Bohemehas also performed well in 2014 with a gross output of 114% and a four-yearaverage value of 107.
Theclubroot resistant variety Cracker is a specialist variety. Its gross output in2014 is 91% (when grown in situations where clubroot is not an issue), whilstthe four-year average figure is 97%. One candidate variety also has clubrootresistance Mentor. The four-year gross output of Mentor compares favourablywith Cracker at 102%.
Ifshort-stemmed varieties are important, Troy is a semi-dwarf variety with agross output in 2014 of 95% and a four-year average value of 100%.
Newvarieties under test as candidates for the 2015 HGCA Recommended List includeSY Harnas with a gross output of 118%, Campus with a gross output of 116%,V316OL with a gross output of 115%, and DK Explicit with a gross output of 115%in 2014. The imidazolinone tolerant candidate variety DK Imagis CL has a grossoutput of 108% in 2014. This compares favourably with the described varietywith the same tolerance DK Imagine CL which has a gross output of 84% in 2014.
Lightleaf spot resistance is a tough standard for varieties to meet in the North,but all these varieties are rated 6 or above. Observations from HGCAsmonitored untreated varieties last season show that in Aberdeenshire light leafspot can infect varieties with good resistance. This was identified in Crackerwhich, due to its specialist clubroot resistance, is likely to be grown inregions where oilseed rape is grown in short rotations where disease pressureswill be high.