OSR beyond the RL (2) 25-Jun-2019

At Agrii, seed technical manager, David Leaper sees the Recommended List as a good starting point for evaluating OSR varieties. But he and his colleagues look well beyond the information it provides in their recommendations, basing them on trial work designed as much to highlight varieties’ relative weaknesses as their inherent production potential.

 

David Leaper, Seed Technical Manager at Agrii

“Most modern varieties have the genetic potential to deliver well over the sort of gross outputs most growers are likely to see in commercial practice,” he points out.

“So what we want to do in our extensive trials with around 70 varieties across the country each year is identify the best from a grower’s point of view and tease out their particular agronomic strengths and weaknesses. That way we can complement the RL information with practical advice based on sound science to help growers make better variety and agronomy decisions.

“We replicate farm practice as closely as we can in our trials and drill at a standard 50 seeds/m2 and 70 seeds/m2 rates for hybrids and conventional varieties, respectively. This ensures we don’t discriminate against generally better-branching hybrids by sowing them too thickly and allows us to make the most meaningful comparisons of their autumn and spring growth habits and vigour.

“We find huge differences between varieties in their rate of autumn development – which isn’t measured in RL trials – enabling our growers and agronomists to match them far better to drilling slot and conditions for the best establishment,” explains David.

“This season too, we have seen clear correlations between levels of Cabbage Stem Flea Beetle damage and varieties’ speed of autumn and spring development. In both cases the most vigorous, faster-developing hybrids appear to have an important edge over the rest in their ability to tolerate infestations.

“We also know how important a good level of pod shatter resistance is in safeguarding yields and minimising volunteer problems. Verticillium wilt resistance is another area where we have to look beyond the RL for information. As is Clearfield variety performance and agronomy.”

ADM Agriculture head of seed, Chris Guest also looks beyond the RL to find varieties that will give his growers the year-in, year-out performance consistency they seek above everything else. Especially so in the face of the extra challenges the crop is facing from flea beetle these days.

“What we want is varieties that cope best with things like later sowing, difficult autumn or spring conditions, and slugs and pigeons as well as flea beetle rather than purely those that top the output charts when everything goes right,” he insists. “With today’s climate, we also want varieties that can survive summer storms or harvesting delays with minimal seed losses.”

 

Chris certainly finds RL ratings for phoma, light leaf spot and lodging resistance valuable, and agrees that the system has the advantage of independence. However, he finds small plot trials can be a poor predictor of how hybrids, in particular, perform on farm. This is mainly due to the fact that they need sufficient space to develop the most productive canopies and the opportunity to show the superior abilities to compensate for setbacks he knows the most robust varieties have.

“Autumn vigour and the ability to grow away from pest problems in the spring are key things we need in varieties today,” stresses Chris. “DK Exalte is a great example of a variety that has really delivered for our growers here, as well as in disease and pod shatter resistance and standing power. Yet we’d completely have missed it if we were just relying on data from the RL.

“So, we keep a close eye on what the breeding programmes we trust are coming-up with; identify the varieties that have the things we’re looking for at an early stage; and work with our growers to try them out alongside their current favourites.

“At the moment we’re particularly excited by DK Exstar. It really ticks our boxes for its all-round strength and robustness. We can see it becoming another farmer favourite for these reasons.”