Some parts of the UK are struggling to finish harvest and consequently to get their winter oilseed rape drilled. Those that have been pushed into later drillings should try to compensate by choosing a variety with proven, measurable vigour.
NIABTAG has been running a 3 year, multi-site experiment looking at different sowing dates for winter oilseed rape varieties and has been actually measuring vigour using three criteria – plant height, number of leaves and ground cover. Simon Kightley of NIABTAG says that crops must be vigorous so that they can grow away in the autumn and get big enough to survive pigeon damage and the winter weather. “These three measurements show that vigour varies tremendously from variety to variety and that conventional rape varieties are just as, and in some cases more vigorous, than hybrid varieties. Results confirm that you have to look at the individual variety itself, not just whether it is a conventional or a hybrid.”
“In all three years, the conventional variety Es Alienor showed autumn vigour with more leaves and was as good as or better than any hybrid. It impressed in these trials, by getting away well both in the autumn and spring.” Simon concludes that the project shows no particular argument to say that hybrids are more suited to the later sowings.
Neil Groom, Technical Director of Grainseed, points out that the loss on neonicotinoids will increase the importance of autumn vigour. “Autumn vigour will ensure that the rape can outgrow insect damage from flea beetles or aphids. Seed vigour is essential for rapid germination and good development of the root system and seedling growth. Alienor has been proven in these trials and in commercial use to have exceptional autumn vigour. It also is a low biomass conventional variety that performs consistently well, as does another of our varieties Es Alegria. Both Alienor and Alegria would be good candidates for the later sowing slot.”
“They both 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.”
Neil Groom also advises growers to grow rape varieties with a good combined disease resistance package. “And this means good known resistance to Verticillium, Phoma and Light Leaf spot. Alienor has a 7 rating for Phoma stem canker and a 6 rating for Light Leaf Spot, giving it an excellent overall disease resistance package. Alegria has a 7 rating for Phoma and a 5 for Light Leaf Spot. Alienor and Alegria show good resistance to Verticillium as well as exceptional vigour which will help them grow away from diseases and pests. Their genetic resistance to Phoma and Verticillium is multi-gene and stable.”
