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Solanaceae offer feast or fatality

When Martyn Cox came across a plant growing on the headland of a potato field his curiosity was aroused. He dug it up, took it home and identified it as highly toxic henbane, one of several unsavoury members of the genus Solanaceae. ADAM CLARKE takes up the story.

Most of Britain’s arable fields are filled with a predictable range of crops and weeds, especially if you know the region like the back of your hand, so it came as a shock to find such an unsavoury weedy guest on the headland of a potato field in Norfolk this summer. After poking and prodding it, then pulling it up to take a sample home, the aforementioned weed turned out to be Hyoscyamus niger or henbane (pictured), a member of the Solanaceae family that is highly toxic.

Known also as stinking nightshade due to its pungent smell, it was made infamous by American homeopath Hawley Harvey Crippen who allegedly used hyoscine (an alkaloid extracted from henbane) to kill his wife in London in early 1910. In some cultures Henbane was used for ritual and recreational purposes due to its hallucinogenic properties, but it can also cause a wide range of unpleasant symptoms. These include dry mouth, thirst, difficulty in swallowing and speaking, warm flushed skin, dilated pupils, blurred vision and photophobia, vomiting, urinary retention…the list goes on. In severe cases, there may be hypertension, coma and convulsions or even death.

So why are some Solanaceae plants toxic? The 2,000-plus strong family is an unusual collection of species, containing some of the most harmful plants and some of the most widely consumed crops, including pepper, tomato, aubergine, potato and tobacco. All plants produce nitrogenous substances called alkaloids which can have significant physical effects on animals, even in small quantities. The Solanaceae are known to produce a particularly wide range of these compounds, including cholinesterase-inhibiting glycoalkaloids and steroid alkaloids.

Woody nightshade, Solanum dulcamara. Picture: Blackthorn Arable.

Woody nightshade, Solanum dulcamara. Picture: Blackthorn Arable.

These can be desirable to humans at low concentrations, with nicotine giving the stimulating, addictive effect of tobacco, while capsaicin gives chilli peppers their heat.  Nicotine is also found at low levels in potatoes, tomatoes and peppers and its purpose is to provide a natural defence mechanism against herbivores and insects – hence its use as an agricultural insecticide over many years.

Potatoes, aubergines and tomatoes contain solanine and although concentrations in tomato fruit and potato tubers aren’t harmful, they are known to cause gastro-intestinal disorders such as irritable bowel syndrome. Elevated levels of solanine in potato berries and green tubers left exposed to sunlight can, however, be very toxic and cause headaches, abdominal pain, shock and diarrhoea if eaten by humans.

Read the full article in our January/February edition

UK growers need world-class seed

 

Melody seed potatoes in chitting trays- Lincolnshire, January

Melody seed potatoes in chitting trays – Lincolnshire, January

Without a top quality seed supply chain ware growers would be at the mercy of imports, warned Norfolk farmer Tony Bambridge, speaking at AHDB’s Seed Industry Event in St Andrews. They could survive on imported stocks, he said, but that would not be a good place to be.

High levels of expertise, well-resourced businesses and the availability of excellent scientific support provide British ware growers with high-grade seed, said Tony Bambridge of B&C Farming, Marsham, Norfolk. By buying seed in the UK, there are no exchange rate uncertainties, providing better economic security for both ware growers and their customers.

‘There are still some untapped opportunities which could help our industry grow,’ he insisted, but he warned that the industry is vulnerable because of its reliance on just 30 pre-basic seed producers who have outstanding expertise but do not have time on their side.

‘Money attracts talent and the industry needs to attract younger members who will learn their skills from them. We are becoming a sexy industry which is both dynamic and science led, so we need to signpost and encourage young people to enter our industry.’

Finding solutions to the challenges facing the potato sector will need to start with a long, hard look at the supply chain, Mr Bambridge suggested. ‘Trading has got us where we are today but to continue to grow we need to take risks…we also need to ensure a sustainable return.

‘Seed production needs to be at the heart of the industry as a platform for business and high on the agenda of packers, processors and the final customer. However, in many cases, it is almost an afterthought,’ he continued. ‘We need to be on the front foot, talking to the retailers, raising our profile and influence so others understand more about the seed production chain.’

Longevity of the seed industry is of real concern. Mr Bambridge sees Scotland as being the best place in the UK for growing seed potatoes, and well supported by scientific capability, but the fly in the ointment is the fact that the sector is limited by finite land availability as more growers move to producing ware.

‘There is increasing pressure from disease resulting from closer rotations and also the proximity of other crops,’ he argued. ‘Once land is damaged by potato cyst nematodes (PCN), soil-borne pathogens and non-persistent viruses vectored by aphids, it cannot go back to producing high-grade seed.’

Short term gains for a few which were impacting on the long-term interests of the seed sector are also an area of concern. ‘We need to consider how we get security and rigour of the protected regions once the legislation is lost.’

See our January/February edition for the full article

Teamwork helps Pepsico meet targets 

pepsico

Potato growers, many of them among the top tier of innovators, have been working with academics from NIAB CUF, ADAS, the University of Aberdeen and Cranfield to halve the amount of water and carbon used to produce Walkers crisps in just five years. Heather Briggs reports.

There is no instant recipe to reduce the environmental impact of potato production but thanks to teamwork growers and scientists have developed tools to help deliver crops with lower carbon and water footprints. Progress is being made towards a more sustainable way of producing food, according to Mark Pettigrew, PepsiCo’s agricultural sustainability manager for Europe, who led the company’s ‘50-in-Five’ initiative.

Reducing waste at all levels means every farm procedure needs to be involved, from choosing the right variety and sourcing healthy seed to cultivation practices, agronomy, lifting and storage.

Efficiency and sustainability go hand in hand, and Mr Pettigrew is pleased that the sector saw the links between productivity and sustainability by year two of the project, realising that there were advantages to be had from being more efficient with the use of energy, fuel, fertiliser and water.

‘By measuring fertiliser use a number of the growers found they were using 17% too much nitrogen,’ says. ‘Using less fertiliser meant lower costs but with no yield penalty.’

Variety choice is important; not only do varieties need the right taste, texture and colour for consumers, they must also have the right agronomic characteristics, they must yield well and not create waste.

‘The better the yield, the lower the carbon and water footprint per tonne,’ explains Mr Pettigrew. ‘However, you still have to take into account the vulnerability of each variety under consideration to damage and consequently waste.

‘For example, some are more susceptible to damage at harvest, during storage and processing, and one of the key issues about sustainability is that we have to reduce waste right along the food chain.

‘The good news is that we have some really good varieties, with good yields of a uniform size which helps keep waste to a minimum, and helps growers achieve economically sustainable yields. And there are even better varieties on the way, which provide practical solutions as they need less nitrogen, and use less energy, too.’

One of the many challenges comes from potato cyst nematodes (PCN), partly because of a lack of varieties with resistance to Globodera pallida. As a result, crispers such as Agrico’s Arsenal have been well received because they have the added benefit of being among a handful which are resistant.

Developing a new variety is the very long process, Mr Pettigrew points out, usually taking up to 15 years to create a line that will fulfil all the necessary criteria for the company. ‘The first thing we look for is the right taste – if the consumer doesn’t actively prefer it then we do not even keep it in a trial.’

See our January/February edition for the full article

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