Onion variety field trials

Approximately 8,885 hectares of onions, yielding 357,000 tonnes, were harvested in the UK in 2019. In the same year, onion dry bulb production was worth £142m to the UK economy.

Varieties can perform very differently in the UK from other parts of mainland Europe. AHDB’s funded variety trials provide independent performance evaluation for new onion varieties propagated from seed to meet grower requirements i.e. high marketable yield, disease resistance, good quality and storage potential.

These requirements need to be balanced and compared over a number of years due to seasonal variation. Relatively small differences between varieties can have a significant impact on profitability so results are of great value to growers. The use of appropriate varieties is also considered to be the cornerstone of good IPM

Since 2000 over 333 drilled and 50 set varieties have been tested.

Strategic Centre for Field Vegetables – Onions

The 2020 season has seen the previous year’s onion variety trials continue at our trial sites in Norfolk and Essex on different soil types.  Funded by AHDB Horticulture and seven seed companies, the trials focused on early varieties with the crops being sown on 11^th March in Norfolk and 23rd March in Essex and harvested on the 26^th August and 3^rd September.

The selection of the grower-led trials is driven by discussions with the British Onion Producers Association (BOPA) who have a steering group specifically to guide these trials. The work is designed to deliver practical, applicable outputs.

This season 22 brown and 11 red varieties of drilled onions were evaluated in the main trial with three replications; and two red varieties and one pink variety were evaluated in the preliminary trial with two replications.

The onion crops are assessed for:

• Maturity
• Yield (by size and weight)
• Storage rots – base rot, neck rot
• Bacterial rot and penicillium and total defects including rots,
• Bulb quality – skin colour/protection
• Bulb shape
• Uniformity and firmness
• Plant establishment and vigour
• Onion ring data (for processing)
• Storability as % sound bulbs coming out of store for both ambient and cold storage and at different dates.

Dr Dawn Teverson, Knowledge Exchange Manager at AHDB, explains: “Our trial sites provide the opportunity for us to show research in practice to encourage the industry to adopt new ideas. And it’s also an important way for us to work in partnership with growers to run demonstration trials showcasing solutions to the issues and challenges that are most pressing for them.

“The Strategic Centres create the perfect opportunity for grower-to-grower learning by allowing us to informally share and discuss our experiences from the current season with each other. The demonstration trials and events look at the whole crop management, from nutrients, water use, to pest management and are intended to help the industry improve productivity.”

The grower-led work in 2020 also consisted of herbicide trials for onions. Trials have been carried out on two different soil types assessing treatments for control of weeds. This is particularly important for onion crops as there are patches of bare soil around the crops which encourages weed growth.

Results of both the variety and herbicide trials were presented to onion growers on 5 and 12 November and the trial report will be available on the AHDB website in early 2021.