Recent results from AHDB’s Recommended Lists (RL) trials for major winter crops are now available, revealing significant disease pressures and variable yields across the UK.
AHDB’s Jason Pole provides a concise summary of the latest findings from cereal and oilseed variety trials.
This growing season, winter combinable crops faced extended periods of wet and mild weather. Despite recent progress in the commercial harvest, many winter crops have recorded below-average yields. Challenging conditions have also led to delays in harvesting, particularly in winter wheat.
As more harvest results are released, the impact of this season on RL-listed varieties is becoming clearer.
While average yields for 2024 are close to historical trends, the tough growing conditions have resulted in elevated disease levels and inconsistent yields across the trial network. Additionally, some trials were abandoned due to poor crop conditions.
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Winter barley trials
Winter barley has performed relatively well in the RL winter crop trials. Overall, fungicide-treated yields are slightly above the five-year average control yield. The trials were established in favourable conditions before the weather took a turn and despite some localised waterlogging, they wintered well.
Brown rust and rhynchosporium were the most prevalent diseases in fungicide-untreated trials. Strong winds and heavy rain in the lead-up to harvest caused lodging and brackling in weaker-strawed varieties at some sites. Over half of the results for winter barley are now available.
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Winter oats trials
Winter oats were sown before the worst of the autumn weather, allowing them to establish well. Fungicide-treated yields are generally in line with the average.
However, some fungicide-untreated trials in southern England experienced very high levels of crown rust, sometimes so severe that the varieties failed to head properly. Lodging was also widespread, even in crops treated with plant growth regulators (PGRs). Most of the results for winter oats are now available.
Winter oilseed rape trials
This season has been particularly challenging for both commercial and RL oilseed rape crops. Nearly half of the fungicide-treated trials (9 out of 19) and almost all of the untreated trials (6 out of 7) had to be abandoned. Persistent wet weather, flea beetle damage, and pigeon grazing have all taken their toll. Additionally, clubroot and light leaf spot caused further complications, with the latter leading to severe plant stunting in some cases.
The surviving fungicide-treated trials have shown an average control yield of 4.92 t/ha, compared to a four-year average of 5.05 t/ha. The performance of winter oilseed rape is more variable than that of cereals, and this year’s results reflect that variability. For example, the control yield in Midlothian was 3.58 t/ha, while in two trials in Cambridgeshire, it reached 6.08 t/ha.
Winter Wheat Trials
The first RL harvest results for winter wheat were published in mid-August, with additional sites added at the end of the month, bringing the total number of reported fungicide-treated sites to nine.
Crops that were drilled after mid-October, when the weather deteriorated, struggled, leading to the loss of several trials due to waterlogging and flooding, particularly in central England. Disease pressure was high from the spring onwards, with brown rust appearing unusually early in RL trials and commercial crops at the start of May.
The RL is dominated by varieties with moderate disease resistance ratings (5, 6, and 7), and this season saw some of the highest levels of brown rust in untreated trials for many years. Septoria tritici was also prevalent. Previously, RL trials aimed to keep disease levels below 5% in fungicide-treated trials.
However, with current fungicide options, it is no longer feasible to maintain such low levels of disease, especially in a high disease-pressure year like 2024. As a result, data from fungicide-treated yield trials is now included even when disease levels exceed 10%, provided the fungicide protocol was followed.
This change in RL protocols allows for a more accurate assessment of genetic potential in the context of current fungicide efficacy.
The average yield of treated control varieties in the first reported sites is slightly below the five-year average of 10.95 t/ha, influenced by some low-yielding trials in the latest data release. With more than 20 trials yet to report, these results are still not complete.
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