Horticulture Newsletter - October 2010

How hot is that pepper?

Do you have problems knowing how hot different chilli peppers are? One thing that the Professional Horticulture Group South West learned during a visit to Joy and Michael Michaud's nursery at West Bexington in Dorset was that you cannot tell by appearances. Joy demonstrated this by showing us two identical small fruited pepper plants (see right); one was a sweet pepper and the other 'dangerously' hot.

She explained that the 'heat' is measured by the Scoville scale invented by American chemist Wilbur Scoville. Sweet peppers have very low values while to most of us 50-100,000 Scoville units is approaching culinary dynamite. However, the hottest pepper that the Michaud's have bred, the famous Dorset Naga (pictured right), weighs in at up to 1.6 million units and is claimed to be one of the hottest peppers in the world. As a consequence they sell it with a safety warning attached! Nevertheless the fruit are highly desired by the Bangladeshis that run most Indian restaurants and the nursery cannot produce enough of them.

Chillies come from one of five species of Capsicum, a member of the potato and tomato family, the Solanaceae. Many of the familiar varieties are strains of Capsicum annuum, while some of the hotter varieties like tobasco are thought to be Capsicum frutescens and the hottest like Dorset Naga have at least some Capsicum chinense ancestry. Naga is a region of North West India but, despite these eastern connotations, all species of Capsicum come from tropical America and the word chilli from the Mexican Nahuatl language that also gave us the word tomato.

Joy explained that the 'heat' is produced by the chemical Capsaicin (8-methyl-N-vanillyl-6-nonenamide) which is synthesised in the interlocular septa of the fruit on which the seeds develop. Some seeps into the adjacent flesh but cleaned pepper seed is completely free of the chemical. No Capsaicin escapes to the surface of the fruit so even Dorset Naga is quite safe to handle - but break the skin at your peril!

Capsaicin
While we humans and other mammals have no problem detecting the presence of Capsaicin, birds and insects cannot taste it. Birds are thus the main distribution agents in the wild as the seeds pass undamaged through their guts, while mammals, whose crunching molars would damage the seed, wisely avoid eating the fruits. Why do we eat them then? It is thought the pungency gives us an endorphin rush, a 'high'.

Capsaicin is hydrophobic so, if you are unfortunate enough to get some on your hands, water will not remove it. The recommended agents to remove it from the skin are milk, yoghurt, ice cream and Swarfega.

Joy and Michael have bred a number of chilli varieties to suit differing tastes both culinary and visual. The common chillies pass from green to red as they ripen becoming hotter in the process. Others ripen to orange or yellow while one variety (pictured right) starts with a purple skin. The purple fades to reveal a pale yellow fruit which then ripens through orange to red. Since all stages can be present on one plant they are both highly ornamental and equally edible.

The Michauds continue to collect and test new varieties from around the world but have a firm philosophy of only selling varieties they deem worthy – some seed companies are happy to sell unsuitable varieties according to Joy. They grow and sell pepper fruits through their postal company, 'Peppers by Post' and promote their products and plants at shows and exhibitions.

They also sell the seeds of their peppers through their seed company Sea Spring Seeds. Here they produce and sell not only peppers but a variety of other vegetables all carefully selected to ensure they will perform well in UK gardens.

Plant of the Month

Cercidiphyllum japonicum, katsura tree, Japanese Judas tree, Cercidiphyllaceae
The katsura tree (pictured right at Bodnant) is native to Japan and China but has found a place in many beautiful gardens here in the United Kingdom. When I visit a garden for the first time I always want to know if they have one of these trees and if so where. Of course during the month of October there is often no need to ask these questions as the beautiful waft of caramel will greet you long before you can see the tree.

The katsura tree is one of the earliest to break bud in spring allowing its beautiful heart-shaped green leaves to emerge and be enjoyed in isolation. After a heavy dew or rain the leaves look like they are encircled by diamonds as tiny drops of water sit on each tooth around the leaf margin. Through the summer the tree is less showy but by the end of September the leaves are beginning to turn yellow and red and the warm caramel smell starts to float in the air. The green leaves contain maltol glucosides which break down as the leaves prepare to abscise releasing maltol (3-hydroxy-2-methyl-4H-pyran-4-one) which is the molecule responsible for the scent. I have heard the smell described as sticky toffee, burnt sugar and caramel – you'll know it if you smell it.

The tree provides a highly valued timber used for furniture and interior finishes of buildings but who could bear to cut one down? Not me.

All good gardens should have one!

Medicinal Plant of the Month

Colchicum autumnale, autumn crocus, naked ladies, meadow saffron, Colchicaceae
Colchicum autumnale (sometimes known as autumn crocus) contains an alkaloid called colchicine which like many chemicals can be a deadly poison or an effective medicinal agent depending on the quantity administered. Today Colchicine is used to treat acute cases of gout, a painful inflammatory disease of the joints as well as to relieve pain after joint replacement surgery. Colchicine also inhibits cell division and has therefore been considered as an anti-cancer agent. Unfortunately, the use of the drug for this purpose results in unacceptably severe side effects. It is, however, used as a tool in cancer research studies in the laboratory. These same properties have also resulted in its widespread use in the horticultural industry. Plant breeders use colchicine to interfere with dividing cells in plants and create mutants that have multiple copies of chromosomes. These plants will often produce larger or double flowers and vegetable plants treated this way may produce higher yields.

Colchicum autumnale (pictured right by Luc Viatour) is native to the British Isles and although they are commonly called autumn crocus they are actually not a crocus! The flowers appear directly from the ground in September and October without any leaves – hence the name naked ladies. The part of the flower we see that looks like the stem is in fact an extended perianth tube. The ovary of the flower remains below soil level. The leaves appear in late spring and then die down through the summer months before the flowers appear.

Due to the presence of the colchicine in all parts of the plant, Colchicum autumnale is toxic and can be fatal if ingested. There have been several cases where people have eaten the bulbs having mistaken them for wild garlic, Allium ursinum and not lived to tell the tale. Admire their beauty but do not be tempted to sample them.

Horticulture Industry News

Food Justice
This report by the Food and Fairness Inquiry is the result of a year-long investigation into social justice in food and farming, undertaken by a committee of respected and influential figures from across the food sector. The study found that producers, farm workers, the environment and consumers are all paying a high price for the food we eat and it calls on government to give farmers and growers a fair say in setting policies and research priorities. (Fruit Produce Journal, 30 July 2010)

Be resilient
Business should follow nature and focus on resilience rather than risk. So says the Royal Botanic Garden Kew and they have set up a 'Business shaped by Nature' web page, including some useful links, to encourage this philosophy.

The Autumn Colour Forecast
High hopes for a colourful autumn say experts at the National Arboretum, Westonbirt. As the days shorten leaves lose their green chlorophyll (C₅₅H₇₀MgN₄O₆) and the carotene (C₄₀H₃₆) that has been there all along becomes visible turning the leaves yellow. Many leaves also contain anthocyanins which give a purple colour if the sap is alkaline and red if it is more acidic. The concentration of anthocyanins is related to the amount of sugar available in the leaf. So a good season, such as the one past, combined with the acid soils at Westonbirt ensures one of the most spectacular autumnal displays. More and More

RAR Expands further in the UK
Vitacress, the water cress and leafy salad business has bought the Sussex based VHB herb production business from Humber VHB. Vitacress is part of the Portuguese RAR Group that also owns UK tomato grower, Wight Salads. The deal still requires the approval of the Office of Fair Trading before becoming final. More

Lord Sainsbury speaks out
Lord Sainsbury says science should have a better dialogue with the public. He cites the public debate on stem cells is an instance which has been handled well. The scientific community had identified potential problems and ethical issues well in advance and had engaged the public in what he called an open and honest debate. Conversely, with GM crops, the technology had already been foisted on the public and the debate ensued after it had been rejected. More

Fewer apples and pears
European apple output is forecast to plummet to one of the lowest levels in a decade, forcing prices higher. Inclement weather around the bloom period and a dry summer is claimed to be the main reason and one result is smaller fruits. Pears are similarly in decline (Fruit Produce Journal, 13 Aug 2010).

Universities too focused on research
Addressing vice chancellors, Science Minister David Willetts said he was shocked by how little teaching was valued in lecturers' career promotions. More

Crops for cold climates
Researchers from the Universities of Edinburgh and York have shown for the first time that a gene - known as Spatula - limits the growth of plants in cool temperatures, possibly helping them adjust to cool conditions. They believe that by manipulating the gene, they could produce the opposite effect - enabling development of crops that grow well in cold climates.

Strawberries and cream… lavender
Chemical compounds found in lavender could be the solution to a major problem faced by the UK's strawberry growers in combating Verticillium wilt – ACT Publishing, 'Lavender to lift strawberry growers' blues', 20 Sep 2010

More UK grown vegetables
Specialist glasshouse grower Stubbins Marketing has begun the production of UK okra and baby aubergine for Asda. The products are being grown at its development nursery in Waltham Abbey (Fruit Produce Journal, 30 July 2010) Melons grown in Lichfield and Evesham have also been in the news and Waitrose launched a new flowery salad 'Garden Salad with Nasturtium Leaves' (Fruit Produce Journal, 27 August 2010).

Totally Tomato
The British Tomato Growers Association held its annual tomato event at West Dean College in West Sussex. The college grows one of the widest ranges of tomato and pepper varieties in the country. The Tomato Growers Association will be holding its Annual Conference in Coventry on 30 Sep 2010 as we go to press. Pictures

High definition view
HortiMaX has developed a high-definition system to enable growers to monitor their crops. CropView is designed to monitor crop development throughout the day, making it a remarkable solution for observing and fine-tuning the management of glasshouse crops. The CropView camera takes both overall and detailed photographic images of a crop and stores these, enabling the grower to view current and past images of crop responses in unrivalled detail; even condensation (promoting fungi growth), pollen or minute differences in flowering or stem size (important in rose production) are captured in perfect detail.

HortiFair 2010
The theme of this year's Horti Fair is 'earning sustainably'. Some things to see:

• Horticoop has produced a machine and gel to fix bark to the surface of pots to prevent it spilling out during transportation. It is not phytotoxic and the surface remains permeable to water.
• Koppert Biological systems will introduce Aphipar-M. a new parasitic wasp Aphidius matricariae to combat aphids on sweet pepper and Citripar to combat the Citrus mealybug (Planococcus citri) and the vine mealybug (Planococcus ficus) in citrus crops, grapes and ornamentals. (Floraculture International, September 2010)

Evening lectures
This year's first evening lecture was 'Peoplequake' by Fred Pearce. The world's population boom is coming to an end as birthrates decline around the world. However, expansion is set to continue for a decade or so yet, so the challenge of feeding them will not go away quickly. This topic will be debated in our Can we feed 9 billion? event in Cambridge on 21 October 2010. The next evening lecture is 'A little light relief' on 21 October 2010. More Evening Lectures

Quotes of the Month

'If we wish to make a new world we have the material ready. The first one, too, was made out of chaos'.

Robert Quillen

Events Calendar

South West Growers
6 Oct 2010, South West Growers Group
Matford Centre, Exeter, UK

Planning Updates
7 Oct 2010, British Institute of Agricultural Consultants
Stoneleigh Park, Kenilworth, UK

The Botanic Garden - Your Modern Medicine Cabinet
11 Oct 2010, Lecture by Alison Foster
Oxford Botanic Garden, Oxford, UK

Peat in Horticulture
11 Oct 2010, International Society for Horticultural Science
Amsterdam, The Netherlands

International Conference on Organic Greenhouse Horticulture
11 -14 Oct 2010, International Society for Horticultural Science
Bleiswijk, The Netherlands

HortiFair
12 -15 Oct 2010
RAI, Amsterdam, the Netherlands

World Emulsions Congress
12 - 14 Oct 2010,
Lyon, France

Food Skills Symposium
13 Oct 2010, City University
London, UK

Cactus Pear and Cochineal
17 Oct 2010, International Society for Horticultural Science
Agadir, Morocco

Streptomyces in Nature and Medicine: The Antibiotic Makers
18 Oct 2010, Lecture by Sir David Hopwood
Oxford Botanic Garden, Oxford, UK

National Fruit Show
20 - 21 Oct 2010, Marden Fruit Show Society
Detling, Kent UK

Workshop on Biological Control of Postharvest Diseases
25 - 28 Oct 2010, International Society for Horticultural Science
Leesburg, Virginia, USA

A Spoonful of Sugar
25 Oct 2010, Lecture by Professor Robert Nash
Oxford Botanic Garden, Oxford, UK

Crop World
1 - 3 Nov 2010, United Business Media and British Crop Protection Council
ExCel, London UK

The Artemisinin Supply for Malaria Control
1 Nov 2010, Lecture by Professor Diane Bowles
Oxford Botanic Garden, Oxford, UK

Planning to Achieve/More from Less
2 Nov 2010, British Institute of Agricultural Consultants
Kenilworth, UK

Predicting and Controlling the Shelf-Life of Foods
3 - 4 Nov 2010, Food Chain CIC
Leatherhead, Surrey, UK

Know Your Plants - Developing skills for better science, horticulture and communication
3 - 5 Nov 2010, Botanic gardens education Network
Royal Botanic Gardens, Edinburgh, UK

The Roots of a Cure
8 Nov 2010, Lecture by Professor Monique Simmonds
Oxford Botanic Garden, Oxford, UK

Advances in Biological Control
17 Nov 2010, Association of Applied Biologists
Marston, Lincs, UK

Towards 2013. An agriculture fit for purpose
17 - 18 Nov 2010, British Institute of Agricultural Consultants
Wellesbourne, Warwick, UK

Bananas, Genetics and Appropriate Biotechnology
18 Nov 2010, Society of Biology
Nottingham, UK

Tropical Horticulture
22 - 26 Nov 2010, International Society for Horticultural Science
Kingston, Jamaica

Oatridge Conference and Exhibition
25 Nov 2010, Scotgrow
Ecclesmachan, Nr Edinburgh, UK

Innovative ideas in pest and weed control in field vegetables
25 Nov 2010, Association of Applied Biologists
Rothamsted Research, Harpenden, UK

What makes an alien invasive?
7 Nov 2010 - 8 Nov 2010, Association of Applied Biologists
Edinburgh, UK

Ideotypes - is the understanding of physiology relevant to the future of plant breeding?
7 Dec 2010, Association of Applied Biologists
Reading, UK

Water and nitrogen use efficiency in plants and crops
15 -16 Dec 2010, Association of Applied Biologists
Grantham,UK

Stress Responses – molecules, organisms, environments
4 - 7 Jan 2011, British Ecological Society, Society for Experimental Biology, Biochemical Society
London, UK

Interaction of Pesticide Application and Formulation on Residues in Fruit and Vegetables
9 Feb 2011, Association of Applied Biologists
Jealotts Hill, UK

Crop Protection in Southern Britain
23 Feb 2011, Association of Applied Biologists
Impington, Cambridge, UK

• If you would like to advertise a forthcoming event please contact scihortigroup@btinternet.com

Horticulture Group Contact Details

For submitting ideas or to volunteer to be part of a committee or a group, please contact:

Acting Chairman - Peter Grimbly
Meetings Secretary - Marion Stainton
Minutes Secretary - Margaret Waddy
Newsletter co-ordinator - Sue Grimbly, E: scihortigroup@btinternet.com
SCI contact - communications@soci.org T: +44(0)20 7598 1500