Oilseed rape growers should put as much priority on varietal stability and consistency as outright yield potential, suggests a 2012 harvest study published by the HGCA.The results (which can be accessed here: http://www.farminguk.com/KnowledgeCentre/HGCA-2012-harvest-study-results_210.html) for over 30 varieties in HGCA’s East/West region show oilseed rape yields dropped by 0.7 tonne/ha in 2012 compared to the previous four years with widely differing varietal ability to withstand changeable growing conditions over the four years evident.Highest yielding and most consistent performer over the period was the hybrid Marathon with an average 105% seed yield. It was also the highest performer in 2012 with 104% of the group’s average yield for the year.All in all, the results show an average yield of 4.5 tonnes/ha for 2012 compared to an average 5.2 tonnes/ha for 2009 – 2012 in the region.The study underpins the growing need for growers to focus on genetic stability and consistency of performance when making varietal decisions in the future, says Sarah Lockhart of OSR specialists DSV Ltd.“With reports from the Environment Agency and others warning of increasingly variable growing seasons ahead, a variety’s track record of consistency and resilience is arguably more important than its outright yield potential. If you can combine both, then these are the varieties to choose.
“Some big hitters performed very poorly this year due to lodging, the effects of early flowering and the low levels of light experienced.“The cold, wet conditions experienced in 2012 are precisely the types of conditions the scientists say we can expect more of in the years ahead. Growers, therefore, must factor an element of risk management in to their varietal selection strategy in the future.”Simon Kightley of NIAB TAG, agrees many existing varieties and new recommendations on the HGCA East West list have failed to meet expectations this year.“DK Expower has dropped right down due to lodging, but it may be that it had a particularly good season last year. DK Camelot and Thorin haven’t done anything special and are currently 7% or so behind Marathon.“Marathon is has done very well overall and is currently equal top in the HGCA recommended list and the semi dwarf Troy is also sticking in there.”