August 16, 2020
First-Ever Sustainability Ratings Established for Winter Cereal Varieties
The first-ever sustainability ratings for all today’s leading winter wheat and barley varieties have been published this season to help growers choose cereals offering them the greatest agronomic strength with the least production risk and environmental impact.
The ratings are provided as part of the 2020 Agrii Advisory List which complements the AHDB Recommended List with extra analyses and statistically-robust data from the company’s extensive national and regional variety testing programme. As well as helping individual growers in their variety selection, they form part of a concerted effort to improve the sustainability of UK cereal-growing as a whole.
In recent years, the Agrii Lists have revealed important weaknesses in the rust resistance and standing power of key winter wheat varieties not apparent in three-year average data from output-maximising, high input RL trials.
Indeed, almost 90% of the 32 winter wheat varieties also on the 2020/21 Recommended List have Agrii trials resistance scores a full point or more below their RL rating for at least one of the three main diseases. At the same time, just over half have untreated lodging scores at least a full point below the RL.
Clear differences from the RL in both disease resistance and lodging risk and are apparent too among the 19 Recommended winter barleys on the 2020 Agrii Advisory List.
“This is no criticism of the RL,” stresses Agrii head of agronomy, Colin Lloyd who oversees the variety testing programme alongside much of the company’s other trial work. “We are looking at performance under commercial farming regimes rather than primarily genetic potential.
“Our List complements the RL with disease ratings that take account of possible breakdowns in resistance at relatively few sites that can easily be lost in multi-site and multi-year averages.
“We deliberately include trial sites and treatments designed to put varieties under the greatest possible lodging pressure too. We have the only available scientific assessments of grassweed competitiveness from our comprehensive Stow Longa variety screening. And, we add to the breeders’ latest safe sowing date information on the RL with latest optimum sowing dates from our own evaluations.
“We also make the best possible use of RL data to provide assessments of the yield resilience of varieties under disease pressure and their yield consistency over the years,” he adds. “The key RL ratings are set out alongside our own intelligence in the Lists for completeness.”
Bringing all this intelligence together, the Agrii Advisory Lists clearly identify the winter cereals carrying the least risk from the most damaging diseases; those that are least prone to lodging, most reliable in their performance and best able to deal with grassweeds; and those that have the greatest flexibility in their agronomy, offer the best opportunity to economise on inputs and are least likely to disappoint in their bushel weights.
Even so, getting the best possible balance of these and other important characteristics is far from easy with varieties that excel in some areas having clear weaknesses in others and vice-versa. This is where the new sustainability ratings come in, combining all the key characters into a single score to indicate the overall agronomic strength of each variety.
“Of course, it’s vital to appreciate exactly where a variety’s particular strengths and weaknesses lie,” insists Colin Lloyd. “After all, the right agronomy can easily and economically deal with weaknesses in a wheat’s yellow rust susceptibility or protect a parentage suggesting greater risk of breakdown to strains of the disease currently circulating.
“Less-than-ideal resistance to Septoria in wheat, brown rust in both wheat and barley, mildew, net blotch and rhynchosporium in barley, and stem strength are equally manageable. But only if they are clearly recognised from the outset, so drilling dates, fertiliser regimes and crop protection programmes can all be tailored accordingly.
“In the same way, you can’t design and flex your agronomy as the season progresses to take full advantage of the specific strengths you have in your winter cereal variety mix to maximise your gross margins if you don’t know exactly where they lie and how robust they are.
“The sustainability ratings we have added to all these specifics from this season provide an unbiassed way of comparing the overall robustness and resilience of the available genetics to help growers and their agronomists narrow down their initial winter wheat and barley choices from the plethora of main varieties on offer today.”
So exactly which characteristics do the new ratings include, how are they calculated and what do they show us about today’s varieties?
Well, the sustainability scores for the 34 winter wheats on the 2020 Agrii Advisory List are calculated from their separate scores for 11 key characters – resistance to the three main foliar diseases, lodging (both treated and untreated) and orange blossom midge; yield resilience and consistency; grassweed competitiveness; specific weight; and, latest optimum sowing date.
Weighted according to their importance in offering performance reliability, management flexibility and the potential for reducing pesticide use and overall cost/tonne, these scores are added together, giving a maximum sustainability score of 37.
Individual wheat scores range from a high of 30 to a low of 14, with an average of 21. Some 62% of the main varieties for 2020 planting are rated as average or better, with 15% scoring 25 or more.
In the same way, sustainability scores for the 23 winter barleys on the 2020 Advisory List are derived from their separate scores for nine key characteristics. BYDV tolerance is included here alongside resistance to the four main diseases; lodging risk; disease resilience; grassweed competitiveness; and, specific weight.
Out of a maximum of 32, the barley sustainability scores range from a high of 25 to a low of 9 with an average of 16. Again, just over 60% are rated average or better, with 13% scoring 20 or more.
“We are at an early stage in developing these metrics,” Colin Lloyd points out. “Even though the individual merits of varieties will be the deciding factor for every one of our growers and agronomists alongside their own particular needs and experiences, the overall scores are already proving valuable in narrowing down initial selections for many.
“Setting a minimum sustainability score of 21 in wheat, for instance, cuts the number of qualifying varieties from 34 to a more manageable 21. What’s more, this includes at least three varieties within each NABIM Group, providing plenty enough choice for most situations. Interestingly too, it raises significant questions over four of the 20 most popular varieties currently in the ground.
“A minimum score of 17 similarly gives quite enough variety choice within the two and six-row feed and malting barley sectors too while also raising questions over several of the most popular.
“The scores further allow our agronomists and their growers to set targets to drive future sustainability improvements and benchmark their progress in doing so – both to themselves and to the outside world, if they wish.
“Every bit as importantly, as a leading seed merchant as well as agronomy provider, the metrics allow us to measure our own progress – overall and against others – in steering the industry towards the much greater environmental and economic sustainability essential for the future.
“Establishing these ratings is, we believe, a valuable step down the road we all need to travel,” concludes Colin Lloyd, “As we move ahead, we will be refining, improving and extending them with the most reliable intelligence available as part of the over-riding aim we’ve always had to keep farmers ahead in this fast-changing world.”