NIAB TAG has set up a taskforce to investigate the 2012 yield performance issues in winter wheat, with the aim of understanding and explaining the drop in yield across much of the country as well as significant local yield variations.

The investigation forms part of NIAB TAG’s ongoing work on the causes of wheat yield stagnation and the steps needed to drive yield improvement going forward. NIAB specialists in genetics, plant breeding, variety performance, agronomy and pathology have been recruited into the team, demonstrating the range of factors involved in the project. The conclusions will include guidance and strategies that growers could adopt in the future.

Work has already begun on analysing yield data from across the NIAB TAG trials network and the HGCA Recommended List data. NIAB TAG will also be surveying its members to determine the level of variability in yield performance on farms across the UK and the factors involved.

Checking plant physiology is one part of the project. “We knew early on that yields could be low so pre-harvest samples were taken from some sites for whole crop analysis,” explains Bill Clark, NIAB TAG commercial director.

The NIAB TAG taskforce will be looking at environmental factors affecting plant growth, including rainfall and light radiation levels.

“For example, low light levels can impact on the build-up of stem carbohydrates, the number of grain sites and grain filling. Light radiation only reached 60-70% of normal levels in June and July so grain filling was always going to be compromised as even green healthy crops struggled to fill grain sites,” says Mr Clark.

Another consideration is disease control. Although very variable this year it was only part of the story. In trials, high fungicide inputs achieved good disease control, but did not always result in high yields. Even with 100% green leaf area, the plant cannot compensate for low radiation levels.

Summer waterlogging in some soils, with anaerobic conditions around the roots, may have also contributed to poor grain fill, and with rainfall in June at least 200% of normal in some areas, fusarium ear blight was practically uncontrollable in many crops. With extended flowering and high disease pressure, one spray was not enough this year. “Fusarium had a significant effect on yield in its own right but it may also have contributed to a reduction in grain sites and poor grain filling,” says Mr Clark.

The taskforce is expected to report its findings to members at the annual NIAB TAG Winter Results Conferences starting in late November.

More on this topic

Read more about this year’s HGCA Recommended List harvest results