Southern Seed Exchange
Organic Horticulture Section
Christchurch Polytechnic
What Is Happening To Our Food?
Our food plants are becoming extinct! If that sounds like fantasy, read on.
History Of Our Food Crops
Thousands of years ago, wild plants that were eaten commanded more attention and so were arranged to grow in favourable places. The seed from good plants was saved, then scattered in suitable ground to provide a good crop. The best seed ensured the best quantity and quality of food. This was the start of breeding programmes. Saving seed was an integral part of providing food for the next year.
These ancient crops had a large genetic diversity, and therefore could withstand many conditions and hardships. This meant that at least some of the crop would survive any sort of catastrophe.
Modern mechanized farming does not tolerate such variation. Breeders have tended to concentrate on only a few traits - uniformity, yield, colour, handling ability, etc.
Variety Is The Spice Of Life
We are eating more of the same. Our "primitive" ancestors gathered food from 1,500 species and cultivated wild another 500 species. Today 95% of our food comes from just 30 plants. Older food species have often not been left out because they don't taste good; they may just be a hassle for the commercial grower to produce. For example in the Peruvian Andes - the origin of the potato - the indigenous people cultivated more than 500 varieties.
Older varieties are often well suited to the home gardener who finds satisfacton in growing something different.
Open pollination
This is the natural transfer of pollen from the male to the female sexual parts. Genetic material is "mixed and matched" for the next generation. No genetic information is lost and the "genetic pool" remains the same size. A wide variation is maintained, therefore plants are able to adapt to many different conditions.
Hybridization
A hybrid is the cross between two inbred uniform varieties. The crop is grown and the weak and deformed are weeded out until a uniform crop is achieved. Some growers find hybrids attractive because they boast such characteristics as high productivity, uniform size and ripening, and the ability to withstand handling. Hybrids often show "hybrid vigour", but this often goes hand in hand with inputs of chemical fertilizer.
The natural gene flow is restricted in hybrids to what scientists want in a crop. The seed from hybrids however does not follow "true to type" and so cannot usually be saved. This means growers are forced to buy commercial seed. Often growers are forced to grow higher yielding hybrids because of squeezed profit margins.
Genetic Erosion
This is the loss of genetic material due to extinction of particular vegetable/plant varieties. Virtually everything we eat has its origin in "Vavilov Centres". These are centres of extreme genetic diversity, often in the Third World. The genetic material that is contained in these centres is vital for world food.
The "Green Revolution" replaced many native seeds for hybrid. Peasant farmers were forced to grow higher yielding hybrids in the big push for higher productivity. The farmers gave up saving the old seed and often ate the remaining traditional seed for breakfast.Many of these areas of classic diversity are rapidly becoming areas of seed uniformity. When half of Asia's ricefields are planted with a single high yield variety - IR36 - the crop's vulnerability to disease is immense. The thousands of varieties of rice are disappearing as a result. Genetic erosion is happening in New Zealand too. Many varieties of kumara were lost when Maori farmers dropped traditional crops to grow potatoes for immigrants. Fortunately some were returned from Japan where they were being grown.
Another problem is that older varieties are being dropped from seed catalogues because they are no longer commercially viable. Therefore growers no longer have access to that variety unless they have the seed. The genes of disease resistance, flavour, hardiness, etc, which are contained in older varieties may be needed in the future for breeding modern varieties. The loss of these older varieties is serious - they are irreplaceable and the cost of extinction is unknown.
The Dangers
Genetic uniformity leaves the door wide open to disaster. Diseases and pests can devastate crops, leading to larger input of fungicide and pesticides. The Irish potato blight of the 1840s was due to there being a single variety grown, "Lumper". Since potatoes are propagated from tubers they are genetically very similar. The blight was uncontrollable.
The American corn blight in the Midwest in the 1970s arose because of genetic vulnerability. The corn was unfortunately being bred susceptible to disease.
The average life expectancy of a new wheat variety in the US (before it is hit by a new disease) is only five years, but there has been little heed paid to these ominous warnings. In the US only six varieties of corn account for 71% of the crop. Four varieties of rice make up 65% of the crop.
Moreover, large transnational corporations are busy buying seed companies due to there being "plant breeders rights" (ie patents) on new varieties. This is happening in the US and England at an alarming rate. These big companies are hardly interested in little, old lines that can be sold by other companies as well.
New Zealand's Heritage In Vegetables
Our ancestors brought food crops to our country. These traditional varieties have sometimes been saved by gardeners who pass their seeds on to their sons and daughters.
We are keen to hear from gardeners who have kept rare vegetables or other interesting plants. Old varieties that were on sale in 1888 for example :We are also on the lookout for the more than 50 types of kumara that existed at the turn of the century or any other traditional Maori crop plants.
- Potatoes - Walnut leaved, Early Lapstone Kidney
- Cauliflower - Early London Giant, Asiatic
- Tomatoes - Large Red, Keys Early Prolific
- Broccoli - Knights Protecting, Early Penzance
- Parsnip - Student
Many of these weird and wonderful varieties may still be grown. They represent the same vegetables as those of our ancestors, perhaps they were brought from the UK, Ireland or Polynesia and have disappeared from there. They don't appear in New Zealand seed catalogues because "new and improved" varieties take their place.
The Seed Exchange
Our aims are to provide a source of exchangeable seeds for growers to use. The seed exchange will, on a non-profit basis, operate the storage and facilitate the exchanges of seed. Some vegetables will be grown for seed at the Polytechnic Organic gardens for input into the exchange. In this way we will preserve many old traditional vegetable varieties, maintaining genetic diversity the way people have been doing for thousands of years.
We welcome old "tried and trusted" heirloom vegetables so that the seed may be distributed and the whole community may inherit the vegetable. Growers may become guardians of an interesting variety or two, saving the seed and exchanging it for others through seed exchange.
Information on seed saving techniques is available through the seed exchange.
The seed exchange is a source of "clean" open pollinated vegetable seed. Commercial seed is often treated with fungicide, although the grower may not want treated seed.
Enquiries to:
Southern Seed Exchange
Organic Horiculture Section
Christchurch Polytechnic
PO Box 22 095
CHRISTCHURCH
Ph : (03) 364 9680
Fax : (03) 364 9648
