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Making use of ‘Natural Dormancy’

DormFresh technical specialist Ajay Jina first worked on 1,4-dimethylnapthalene (DMN) twenty plus years ago at Sutton Bridge Experimental Unit in Lincolnshire. Since then, the sprout suppressant which is produced by tubers has progressed slowly along the development pipeline.

Work on DMN began back in the early 1960s when researchers extracted a range of volatile compounds from potatoes to determine which ones were responsible for initiating and maintaining dormancy. Some of these chemicals were either too toxic, too volatile or simply not volatile enough, but DMN stood out as a promising candidate for further development.

Subsequent trials in the 1980s, led by Dr Harry Duncan at Glasgow University, highlighted the commercial opportunities for the compound while work at Sutton Bridge examined the use of alumina powder formulations as a possible replacement for Tecnazene to be applied during store loading.

‘DMN is actually produced by the potato where it is present at very low concentrations in the skin,’ explains Ajay Jina, who now works for DormFresh, the Perth company which, along with Harry Duncan, will provide technical support throughout Europe.

‘It’s a dormancy enhancer which puts the tubers to sleep. It is naturally occurring and it’s the fact that it is produced by potatoes themselves which is the key.

‘We now know that the earlier you apply it the better its efficacy will be, we know that it has no impact on curing or wound healing, it reduces respiration rate, shrinkage and weight loss,’ he continues. ‘There is also some anecdotal evidence from commercial use in the United States that treatment may produce a better bloom and skin finish.

‘DMN will work on its own as a stand-alone product, though used in that way it will be more expensive than CIPC. Applied as it is in the US, however, where it has been used for 15 years or more, you would put it on early to get the benefits and then follow treatment up with CIPC. So it’s a dual-purpose suppressant which can be used on its own if the market requires CIPC-free potatoes.

‘I started working on DMN in 1999 at Sutton Bridge with Adrian Briddon,’ Ajay Jina recalls. ‘Now BASF and DormFresh are funding new trials aimed at answering some of the key questions that the industry has raised since then. We have carried out a whole range of studies to provide efficacy data and we know that it works on many varieties for the processing and fresh markets.

‘DormFresh wants to make sure that DMN is used as effectively as possible,’ he adds. ‘Their mantra is that we’re not just here to sell product and I am really looking forward to getting out onto farms and working closely with growers, store managers and applicators so that we can get the best out of it.’

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