Horticulture Group Newsletter - August 2012

Tomatoes and Cucumbers at Thanet Earth

A select group of members assembled at the Crown Inn, Sarre, before driving in convoy through the security barriers surrounding Thanet Earth. Our initial destination was the largest tomato glasshouse in the UK but, as we drove in, we passed two equally large glasshouses full of peppers and cucumbers as well as the packing shed that serves all three.

Thanet Earth is a collaborative venture between the Fresca group, who own 50% and three Dutch companies who own the other 50%. Fresca, the umbrella company for a number of growing and marketing companies the largest of which is M&M Mac, provides the packing and marketing for the site. The three grower companies each specialise in the three crops grown; Kaaij Greenhouses specialises in tomatoes and has units in Holland and Spain; A&A is run by two partners who moved their cucumber business from the Westland of Holland to Thanet Earth; and Rainbow Growers Group, a Dutch cooperative, growing and marketing a range of glasshouse crops but specialising in peppers at Thanet Earth.

The site can accommodate seven glasshouses and plans are advanced for the fourth. This will be a shared business with each of the four existing partners taking a 25% stake.

We were greeted by Gert van Straalen (picture upper right) who manages the tomato unit on behalf of Kaaij Greenhouses. He set the scene by outlining the history above and explaining that the primary objective for all three growers was to establish a base to market more easily into the UK. They are somewhat surprised by the attention the project has received for, as he points out, anyone who has visited the Westland of Holland will be very familiar with glasshouse growing on this scale.

He took us into his 10 hectare (25 acre) glasshouse where they grow around ten varieties of speciality tomatoes, many harvested 'on the vine'. They aim to be in production for 52 weeks a year using sodium growing lights to supplement the poor winter light levels. This continuity is achieved through interplanting. The plants are grown in shorter rockwool bags than a typical crop so that new plants can be added not just to the original bag but new bags can be inserted in the gaps between the old.

Two stems are taken from all plants at the propagation stage and additional sideshoots are taken on or stopped during the season to obtain an optimum shoot density for the prevailing light conditions. Coloured string is used to manage this ever-changing shoot density. Additional support wires also enable the older plants to be pulled wider apart to enable an interplanted crop to obtain more light.

A CHP unit provides heat and CO₂ to the glasshouse as well as supplying the national grid. Heat storage tanks are also used to balance power supply, heat demand and optimum income from the electricity sold.

We then moved on to A&A run by Addy Breugem and Arjen de Gier. Addy showed us round his glasshouse growing mainly standard slicing cucumbers on high wires; the only UK grower to use such a system.

Here the crop is grown on standard sized rockwool slabs and they do not attempt all year round production. The first crop is planted in mid-December and crops from mid-January to the end of July and the second crop continues until the start of November. This gives enough time for cleaning the glasshouse.

Instead of training the crop up strings, staff clip the stems to rigid wires suspended from the overhead crop wires. These clips are padded with foam rubber to minimise damage to the plant stem, and only two clips are required per plant.

Much of the basic structure was similar to that at Kraaij Greenhouses with a CHP power source and an impressive nutrient mixing and control unit (picture lower right).

Sadly, lack of time prevented us visiting Rainbow Growers peppers and as usual it is only possible in this short article to select just a few of the innovations we saw in our excellent visit. More information including videos can be found at www.thanetearth.com.

Plant of the Month

Asclepias syriaca, common milkweed, butterfly flower, silkweed, silky swallow-wort, Virginia silkweed, Apocynaceae

This herbaceous perennial is native to North America east of the Rocky Mountains, excluding the drier parts of the Prairies. It is one of approximately 70 species in the genus Asclepias which has its centre of diversity in North America. The flowers of this plant are grouped in several spherical umbels with numerous flowers in each umbel.

The seeds are attached to long, white flossy hairs and encased in large follicles. The plant has also been explored for commercial use of its bast (inner bark) fibre which is both strong and soft. The United States Department of Agriculture studies in the 1890s and 1940s found that milkweed has more potential for commercial processing than any other indigenous bast fibre plant, with estimated yields as high as hemp and quality as good as flax.

The seeds contain quantities of cinnamic acid, which is a very good sunscreen. The plants latex contains large quantities of poisonous glycosides which are toxic to most mammals. This plant is a host for Monarch butterflies, which are immune to the toxicity, but the poisonous chemicals are stored in their bodies making them toxic to birds such as jays.

Alison Foster
Oxford Botanic Garden

Medicinal Plant of the Month

Catharanthus roseus, Madagascar periwinkle, Apocynaceae

Catharanthus roseus, the Madagascar periwinkle (pictured right), is now widespread across the tropics and sub-tropics and is even considered an invasive weed in some areas. The leaves of the plant were traditionally made into a tea to treat diabetes. In the 1950s a physician in Jamaica sent a sample to his brother, a research scientist in Canada, to investigate further.

No anti-diabetic activity was found but it was observed that the test animals suffered from depleted white blood cell levels. This suggested that the plant could have potential as an anti-cancer agent and so the search began for the active constituent(s). The two main chemicals responsible for the activity were identified as vincristine (left) and vinblastine (right), and these two drugs have since been rigorously tested and proven to be very effective.

Vincristine was approved by the FDA in 1963. Both molecules work by inhibiting the assembly of microtubule structures which arrests the cell cycle in the metaphase. These drugs are important components of many chemotherapy regimes. Vincristine is especially important for the treatment of childhood leukaemia. The chemical structures are very complicated and, although total synthesis has been achieved in the laboratory, it is not a commercially viable process. Even though the plants only contain very small quantities of the chemicals, they are farmed commercially in places such as Texas, USA in order to extract the chemicals. Vincristine makes up 0.0003% of the dry weight of the plant with vinblastine more abundant at 0.01%. Fortunately vinblastine can be transformed into vincristine by chemical transformation.

Alison Foster
Oxford Botanic Garden

News from our Associates

Commercial Horticultural Association
The CHA is continuing to recruit UK Companies interested in exporting for three major trade shows in the coming autumn - HortiFair in Amsterdam (30 Oct - 2 Nov), IPM in Essen (22-25 Jan 2013) and Fruit Logistica (6-8 Feb 2013). Grants of between £1,000 and £1,400 are available to eligible companies. HortiFair focusses on technology, IPM on pot plants and nursery stock while Fruit Logistica, as its name implies is about fruit.

Grow Careers
We have been working on a redraft of the Science and Technology Section of the Grow Careers website to make it more representative of the wide range of careers available in Horticultural Science. Thanks to all those who have sent their comments. The website should be updated with the revised text shortly.

Society of Biology
The Society of Biology has made a response to the Department for Education's consultation on Career Guidance. This supports the concentration on 14-18 year olds, is undecided on the value of extending it to 12-14 years olds, but is strongly in favour of extending career advice well beyond 18.

Horticulture Industry News

For the very latest horticultural news follow us on Facebook and or Twitter.

Green walls cut pollution cost effectively
Research shows that planting living 'green walls' of vegetation could provide a faster and cheaper way of cleaning up the air in cities than large-scale initiatives such as congestion charging. Reductions of street level pollution of as much as 30%t could be achieved at a low cost simply by growing trees, bushes, and other greenery amid the concrete and glass 'street canyons' that characterise modern cities. 'Green walls emerged as clear winners in pollutant removal. Street trees were also effective, but only in streets where the tree crowns did not cause pollution to be trapped at ground level,' said Professor Rob MacKenzie from Birmingham University. More and More

Green light for Irish GM potatoes
The Irish Environmental Protection Agency (EPA) has given the go-ahead for a genetically modified blight-resistant potato crop to be tested on lands in Co Carlow. Two hectares will be planted over the next four years to assess how the GM potatoes cope with less fungicidal spray than conventional varieties. The agency said scientists will continue to monitor the land, run by Teagasc, at Oak Park in the county, for four years after the trial. Opponents of GM now have a three month window to lodge a judicial review of the licence. More

Sinclair expands green waste growing media production
Lincoln-based horticultural supplier William Sinclair is to increase its manufacturing capacity and reduce its cost base following the purchase of a new production site in Cheshire for £4.75m. The new site, two miles from the motorway network near Ellesmere Port, includes 41 acres of freehold land with approximately 380,000 sq ft of industrial buildings. William Sinclair said it anticipated a phased occupation of the new site, as it expanded its operations into new areas including increasing production levels of peat free product SuperFyba. Other group operations would be transferred over the next five years.

Legumes give bacteria a special access pass
A 120-year debate on how nitrogen-fixing bacteria are able to breach the cell walls of legumes has been settled. John Innes Centre (JIC) scientists now report that plants themselves allow the bacteria in. Whether the bacteria breach the cell walls by producing enzymes that degrade it, or the plant does the work for them, has been contested since an 1887 paper in which the importance of the breach was first recognised. 'Our results are so clear we can unequivocally say that the plant supplies enzymes to break down its own cell walls and allow bacteria access,' said JIC's Professor Allan Downie.

US carrot giant Bolthouse Farms sold to Campbells for a billion pounds
Campbells, best known in this country for its soups, is to buy natural foods maker Bolthouse Farms in a $1.55 billion cash deal. Campbells says Bolthouse's line of juices will complement its 'V8' beverage unit, and Bolthouse's packaged carrots will deepen its healthy snack offerings. Campbells wants to strengthen its presence in the refrigerated sections of supermarkets. Most of its products are currently found in the centre aisles, where shelf-stable items are sold. CEO Denise Morrison said the Bolthouse deal will help Campbells court the generation known as Millennials more aggressively. Millennials are particularly drawn to healthy and on-the-go foods, but have largely eluded Campbells.

Two-thirds now support GM crop testing
Public opinion appears to be shifting in favour of the development of genetically-modified crops, according to a ComRes survey for The Independent. Asked whether the Government should encourage experiments on GM crops so that farmers can reduce the amount of pesticides they use, 64% of the public agreed and 27% disagreed, with 9% 'don't knows'. There was a significant gender gap, with women more cautious about the trials than men. While 70% of men believe that such experiments should be encouraged, only 58% of women agree. More

No risk with GMO food, says EU chief scientific advisor
Genetically modified organisms (GMOs) are no riskier than their conventionally farmed equivalents, the European Commission's Chief Scientific Advisor Anne Glover has said and called for countries impeding GMO use to be put to proof. 'There is no substantiated case of any adverse impact on human health, animal health or environmental health, so that's pretty robust evidence, and I would be confident in saying that there is no more risk in eating GMO food than eating conventionally-farmed food.' More

Biorenewables Development Centre set to study non-food plant use
A new Biorenewables Development Centre was officially opened by the Rt Hon Dr Vince Cable MP, Secretary of State for Business, Industry and Skills at the University of York. This will provide a world-class scale-up facility that allows York researchers to test the most promising processes for converting renewables into chemicals and materials. In this way they can prove a new process and/or produce enough product for detailed commercial analysis and assessment for example, by an interested company. More

An new idea for affordable therapeutic drugs
Queensland scientists are unlocking the benefits of a protein found in seeds of a spiky red-fruited cucurbit that could lead to the development of more affordable medicines made from plants. The odd-looking seeds of the gac fruit (Momordica cochinchinensis) contain a small protein called MCoTI-2 whose circular shape and resulting stability make it ideal as a basis for drugs. However, producing such protein-based drugs with traditional synthetic methods is prohibitively expensive on a large scale.

Researchers from the Australia and USA discovered the genes that produce MCoTI-2. 'Knowing how these genes, which we named TIPTOP, manufacture MCoTI-2 naturally in gac could allow us to co-opt this process and use it to grow protein-based drugs in plants,' Dr Mylne from the University of Queensland said. 'We've already moved the system to seeds of the model plant Arabidopsis, where it worked remarkably well.'

Researchers find tobacco protein enhances crop immune systems
A Japanese study has found a component in tobacco that makes crop immune systems more resistant to viral attacks. Although crops have a general defence mechanism in order to fight against viruses, their invaders counteract this defence by suppressing the plant immune response. Evidence from recent studies implies that plants have developed an additional set of countermeasures to combat the virus's immune suppression tactics. In order to examine how plants do this, the researchers set out to find the mechanisms involved.

They found rgs-CaM, otherwise known as 'tobacco calmodulin-like protein', a calcium-binding messenger protein. In tobacco this protein binds to the viral (RNA interference) suppressors (molecules produced by the virus that chemically counteract the plants' own defences) and inhibits the virus from impeding the plant's defences. These findings have the potential to enhance the immune systems for crops that are vulnerable to pesticide-resistant viruses.

Are organic tomatoes better for your health?
A Spanish study has shown that the organic tomatoes contained higher levels of polyphenols than the non-organic tomatoes. Reporting these findings the NHS notes 'this study suggests that some organic tomatoes contain higher levels of polyphenols than 'conventionally grown' tomatoes. It does not, however, tell us whether eating organic tomatoes will provide any additional health benefits over eating conventional tomatoes. Nobody ate the tomatoes, so no health outcomes could be measured.'

UV enhances vitamin-D in mushrooms
A new commercial processing technology is suitable for boosting the vitamin D content of mushrooms and has no adverse effects on other nutrients, the first study on the topic has concluded. The technology, which involves exposing mushrooms to ultraviolet light, can greatly boost mushrooms' vitamin D content.

Although few people realise it, mushrooms are an excellent natural source of vitamin D. Scientist set out to answer several questions about commercial-scale UV light processing of mushrooms. They compared button mushrooms exposed to UVB light, those exposed to natural sunlight and those kept in the dark. The UVB-exposed mushrooms got a dramatic boost in vitamin D (700% more of the vitamin than mushrooms not exposed to light) and the UVB processing had no effect on levels of vitamin C, folate, riboflavin, niacin and a host of other essential nutrients.

Bayer purchases of AgraQuest
Bayer CropScience announced today that it has signed an agreement to purchase California-based AgraQuest, Inc. for a purchase price of $425m (approximately €340 million) plus milestone payments. AgraQuest is a global supplier of innovative biological pest management solutions based on natural microorganisms. Bayer CropScience hopes this acquisition will help it build a leading technology platform for green products and strengthen its strategically important fruits and vegetables business, while also opening new opportunities in other crops and markets.

Glyphosate-Resistant plants may be less susceptible to diseases
Most laboratory tests done to understand glyphosate resistance are done in sterile soil, void of any soil microbes. Research now shows that those microbes may play a significant role in how glyphosate affects plants. Giant ragweed (Ambrosia trifida), horseweed (Conyza canadensis) and common lambsquarter (Chenopodium album) in both sterile soil and field soil and subjected them to glyphosate.

In each soil, strains of weeds both susceptible and resistant to glyphosate were tested. Both versions of giant ragweed were damaged more from the glyphosate in field soil. The susceptible version of common lambsquarter was also more heavily damaged in field soil.

Horseweed fared the same no matter which soil or strain - susceptible or resistant. The results show that microbes can play an important role in the activity of glyphosate, presumably by invading the glyphosate-weakened plants. The results also suggest that glyphosate-resistant weeds may be more resistant to disease pressure as well. More

Ladybirds thrive on organic aphids
Ladybird larvae that eat prey raised on organically-grown crops are more likely to survive than those eating aphids raised on crops grown with conventional fertiliser, a new experiment shows. Ladybird larvae fed on organically-raised aphids were ten per cent more likely to make it to adulthood - a difference that could end up making a big impact on their populations, if it turns out to hold true on farms. The researchers say 'This is just a preliminary study, but we've shown that a simple change of fertiliser in a single crop plant can produce a significant difference to ladybird mortality,'

Events Calendar

Other Events of Interest

Potatoes in Practice
9 Aug, James Hutton Institute
Dundee, UK

Plantarium
24 - 27 Aug,
Boskoop, The Netherlands

Amenity Arboriculture Conference
2 - 5 Sep, Arboricutural Association
Reading, UK

Ornamental Breeding Worldwide
2 - 5 Sep, International Society for Horticultural Science
Warsaw, Poland

Physics meets Biology
3 - 5 Sep, Society of Biology
Oxford, UK

Four Oaks Trade Show
4 - 5 Sep
Lower Withington, UK

Saltex
4 - 6 Sep, Institute of Groundsmanship
Windsor, UK

International Chestnut Symposium
4 - 8 Sep, International Society for Horticultural Science
Shepherdstown, USA

International People Plant Symposium
6 - 8 Sep, International Society for Horticultural Science
Venlo, The Netherlands

International Humulus Symposium
9 - 14 Sep, International Society for Horticultural Science
Zatec, Czech Republic

European Microscopy Congress
16 - 21 Sep, European Microscopy Society
Manchester, UK

GLEE
17 - 19 Sep, i2i Events Group
Birmingham, UK

Postharvest Research, Education, and Extension
18 - 20 Sep, International Society for Horticultural Science
Bogor, Indonesia

Natural Products and Biocontrol
19 - 21 Sep, International Biocontrol Manufacturers Association
Perpignan, France

Biological Plant Protection as the Basis of Agricultural Ecosystem Stabilization
25 - 27 Sep,
Krasnodar, Russia

Olive Growing
25 - 29 Sep, International Society for Horticultural Science
San Juan, Argentina

Macfruit
26 - 28 Sep, Cesena Fiera
Cesena, Italy

South West Growers Show
3 Oct, South West Growers
Exeter, UK

Precision Farming for Crop Protection
3 Oct, Association of Applied Biologists
Harper Adams, UK

Biopesticide Market Opportunities
5 Oct, University of Greenwich and Natural Resources Institute
Greenwich, UK

Integrated Fruit Production
7 - 12 Oct, International Organisation for Biological and Integrated Control of Noxious Animals and Plants
Kusadasi, Turkey

Acrylamide, furans and other food-borne contaminants
8 - 9 Oct, Association of Applied Biologists
Munich, Germany

Above Ground - Below Ground Interactions
8 - 10 Oct, British Ecological Society, Biochemical Society and Society for Experimental Biology
London, UK

Medicinal and Nutraceutical Plants
14 - 19 Oct, International Society for Horticultural Science
Aracaju, Brazil

Light in Horticultural Systems
15 - 18 Oct, International Society for Horticultural Science
Wageningen, The Netherlands

Advances in Biological Control and IPM
16 - 19 Oct, Association of Applied Biologists
Marston, UK

Postharvest Quality of Ornamental Plants
16 - 19 Oct, International Society for Horticultural Science
Porto de Galinhas, Brazil

Vegetables and Greens
16 - 20 Oct, International Society for Horticultural Science
Yerevan, Armenia

National Fruit Show
17 - 18 Oct, Marden Fruit Show Society
Marden, UK

International Symposium on Persimmon
20 - 26 Oct, International Society for Horticultural Science
Guilin City, China

Annual Biocontrol Industry Meeting
22 - 24 Oct, International Biocontrol Manufacturers Association
Lucerne, Switzerland

Saffron Biology and Technology
22 - 24 Oct, International Biocontrol Manufacturers Association
Srinagar, India

BCPCWeed Review 2012
24 Oct, British Crop Protection Council
Peterborough, UK

Horti Fair
30 Oct - 2 Nov
Amsterdam, The Netherlands

CropWorld Global
6 - 8 Nov, British Crop Protection Council
London, UK

Human Health Effects of Fruits and Vegetables
6 - 10 Nov, International Society for Horticultural Science
Dharwad, India

Brassica 2012
12 - 16 Nov, International Society for Horticultural Science
Catania, Italy

Soil & Water Live
13 Nov, Royal Agricultural Society of England
Stoneleigh, UK

Scientific Horticulture
13 - 14 Nov, Slovak University of Agriculture
Nitra, Slovakia

Interpoma
15 - 17 Nov, Fiera Bolzano
Bolzano, Italy

Biomolecular Thermodynamics
16 - 17 Nov, Institute of Physics Biological Physics Group
London, UK

Citrus Congress
18 - 23 Nov, International Society for Horticultural Science
Valencia, Spain

Biostimulants
26 - 29 Nov, International Society for Horticultural Science
Strasbourg, France

Crop Protection in Southern Britain
27 - 27 Nov, Association of Applied Biologists
Peterborough, UK

If you would like to advertise a forthcoming event please contact charne.green@soci.org

Horticulture Group Contact Details

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

Chairman - Peter Grimbly
Meetings Secretary - Alison Foster
Minutes Secretary - Margaret Waddy
Newsletter co-ordinator - Sue Grimbly scihortigroup@btinternet.com
Group Contact - Charne Green charne.green@soci.org T: +44 (0)20 7598 1594