Following a recently published report on the UK’s shifting climate, septoria should remain a key focus when selecting varieties, believe experts.

The ‘State of the UK climate’ report was published by the Meteorological Office earlier this year. Reflecting on the information provided, Niab’s regional agronomist for the North, Patrick Stephenson, notes the continued risk factors for septoria.

“Although we’re a maritime country with a temperate climate largely influenced by the gulf stream, it’s evident that the UK’s winters are becoming milder and wetter, with summers trending hotter and drier. UK climate projections also tell us that the frequency of extremely wet months has roughly doubled in recent years,” he says.

“With warmer winters and early springs potentially up to 30% wetter, we unfortunately now have a perfect environment for Septoria tritici – the most economically-damaging wheat disease,to survive and proliferate in UK wheat crops.”

Disease resistance ratings

As the current chair of the Recommended List committee, Patrick highlights that most winter wheat varieties have a septoriarating of 6. “While I believe breeders have done a good job in improving the background resistance of varieties, I still have some concerns.

“Firstly, in a sustained period of warm, wet conditions, the best fungicide programmes, even when applied quickly, will still let some septoriainto the crop. Secondly, when we assess RL varieties on their septoria ratings, we’re basing them on a drilling date in early October. Any farmer drilling earlier than that has to understand that the varietal rating is automatically lowered.

“While early drilling can offer benefits, it’s also a way of building up a potential reservoir of disease that can subsequently become a yield robber in the spring and summer months if, and when, the disease gets its optimum weather conditions,” he explains.

Conversely, Patrick believes growers have been ‘pretty lucky’ to experience historically lower septoria pressure across much of the UK in three of the past five seasons due to extended hot, dry conditions.

Equally, farmers have also generally been able to spray quickly when they’ve wanted to. “However, it’d be very dangerous to accept this as the ‘new normal’ and forget the septoriarisk based on unusually favourable weather.

“Taking all these factors into account, I’d certainly advise every grower to include at least one variety with a septoriascore of 7 or more in their winter wheat rotation, with growers in higher rainfall regions such as the North and West potentially opting for two varieties with robust disease packages,” comments Patrick.

Group 4 wheats

With an annual area of around 750,000ha – equating to 45% of the total winter wheat area – the Group 4 sector is currently the most popular category among UK wheat growers.

Factoring in key elements such as overall disease resistance, yield potential, flexibility of drilling date, and first versus second wheat positioning, Patrick believe a variety like Sparkler could be a robust option.

“With a 7.2 for septoria and a 7 for yellow rust, it offers higher overall resistance against the two key disease challenges that effect most growers. Given it’s also the highest yielding Group 4 soft wheat, there’s no trade off on yield either,” he suggests.

Ben Urquhart, technical manager for Elsoms Seeds, agrees that shifting seasonal windows away from the UK’s traditional seasonal calendar is a major challenge for arable farmers. “It’s clear that the UK has been moving away from four defined seasons for many years now.

“These looser, less defined seasonal weather windows impact significantly on farmer decisions around drilling dates. For instance, are farmers now drilling earlier to avoid the risk of prolonged wet weather in late Autumn? Equally, inclement weather also creates an issue linked to the chemistry we use to support our varieties – can it still be applied to the crop in a timely fashion to get the maximum efficacy from the product?”

Being in control

One of the few things that farmers still have total control over is the varieties they want to grow, stresses Ben. “When assessing any variety against key diseases, growers have access to a five-year data set, so they’re getting a significant amount of information to base their decision on.

“Balancing higher resistance scores – particularly on septoriaand yellow rust – against potential yield has to be a sensible move for growers right now.”

Ben hopes that Sparkler will enter conversations for those growing winter wheat for the feed or distilling markets. “Whether it’s drilled early or late, on heavy or light land, or in a first or second wheat position, it delivers consistently high yields. And for those who prefer a later drilling slot then Sparkler also offers excellent fusarium resistance too,” he concludes.