About biodiversity and GM crops

by Avice Hall.

The Women Workers’ Training Centre in the flat arid plain of Tamil Nadu works with about 100 villages in the surrounding area. Many years there is hardly any rainfall and there is widespread poverty. Most farmers are subsistence farmers and lack money to own the oxen needed for ploughing the land.

Under the motto ‘God loves villages’, the centre runs many different development programmes in the villages, including day-care centres for the under fives, medical programmes and after-school tuition. With the encouragement of the centre, many villages now have Women’s Clubs and Farmers’ Clubs. Each month, the leaders of the Farmers’ Clubs meet at the centre, when outside speakers are often invited. These meetings cover a wide range of topics.

Information from these leaders’ meetings is then passed on to farmers in the villages.

The day I visited, there were three speakers at the meeting; two government advisors on seeds and cultivation, one of whom had been involved in the development of a variety of GM rice for the government, and myself, a plant pathologist. After the talks there was an open question and answer session. Some typical questions and answers are shown on these pages.

Much later that evening after everyone had returned to their villages, we arrived in one village and joined an open-air classroom. Here a small group of men and women was gathered round a blackboard and one of the farmers’ leaders was faithfully reporting all that he had learnt earlier in the day. Chalk was used to reproduce the diagrams from the morning, children were hanging round the area and there was much lively discussion about the information passed on.

Then an elderly gentleman stood up and explained that he was the ‘tree officer’ for the area, and was there to see that they all planted trees, and did not cut them down. He was rather elderly and the school children giggled at his talk, but their parents told them off, order was restored and the lesson continued. As we walked away, I thought that the old man was making a very important contribution to the biodiversity of the area, and that we should all wait to see how GM crops develop and not rush to plant them now.

Dr Avice M Hall is a lecturer in plant pathology at the University of Hertfordshire with an interest in agricultural extension.

Her address is CP Snow Building, University of Hertfordshire, College Lane, Hatfield, Hertfordshire, AL10 9AB, UK.
E-mail: a.m.hall@herts.ac.uk

Questions

Who has developed GM varieties and why?

The majority of GM crops have been developed by large global companies for use as cash crops. Their aim is to increase the profit margin for their shareholders and large landowners. At present very few GM varieties have been developed by organisations concerned to share the benefits with low-income farmers.

Does farming affect biodiversity?

Growing just one crop over large areas (monoculture) will reduce biodiversity at several levels – at regional level, at field level and also within the crop. The use of fertilisers and pesticides also reduces the numbers of beneficial or useful organisms. However, intercropping or small, traditional growing systems will help to preserve biodiversity.

What has biodiversity got to do with agriculture?

There are three levels in which biodiversity operates within agriculture. Firstly there is the general biodiversity of different species of plants, animals and micro-organisms in the environment of the farmed land. Some of these species are helpful to agriculture, such as the micro-organisms that break down organic material so recycling nutrients and improving soil structure, or the beneficial insects that eat crop pests. Other species, such as weeds, pests and those that cause disease, are not beneficial to the farmer.

Secondly there is the diversity of habitat when a mixture of crops is grown together (intercropping). This is useful as the varying sizes of the different crop plants as well as their differing susceptibility to pests and diseases, gives some control of pests and so tends to reduce the likelihood of epidemics on any one species.

Finally there is the diversity within the crop grown which has a mixed genetic makeup. Just one variety of rice may be grown, but the seed may be local, self-saved seed often selected and saved over many generations. These ‘local varieties’ are known as landraces, and are often well adapted to the local environment. Landraces contain vital genetic variation, and we need to preserve them. This is why landraces are saved in seed banks to provide sources of variation for plant breeders.

Are there any advantages to growing GM crops?

Potentially some GM crops offer very real benefits, which may well outweigh any impact on biodiversity that they might have. The growing of ‘golden rice’, high in vitamin A, which will help to reduce blindness due to vitamin A deficiency, is a good example of this.

All farming has an impact on biodiversity, and some of this is negative. When you try to evaluate the impact of GM crops on biodiversity, you not only have to look at the direct impact (will one particular rare insect species be killed?), you also have to look at the farming system that will be used to grow that GM crop and compare that with other farming systems. A monoculture of cotton or tobacco is going to have a negative impact on biodiversity whether it is conventional or GM.

How might GM crops affect biodiversity?

It is possible for GM varieties to have a more positive impact on biodiversity than some conventionally bred crops. For example, a variety resistant to insect attack would reduce the need for insecticide use, which kills beneficial as well as harmful insects.

However, that is not the whole story. Most of the GM seed available is for cash crops (rape, soya, cotton), not of subsistence food crops (cassava, sorghum, millets). Most of the GM seed available is expensive, and farmers are not allowed to save the seed, because of the patents on it, so expensive seed has to be bought every year. In some cases (such as Bt cotton) the management system for the crop is very different from that for conventional cotton. There may also be further effects if a gene from the GM variety ‘escaped’ into a wild relative, or if the gene in the GM variety made the crop toxic to a rare butterfly.

Why do plant breeders want to produce GM crops?

GM offers the opportunity to develop new varieties to meet specific needs. It may help to introduce a range of pest and disease resistance into varieties, so reducing the need for insecticide and fungicide use.

Should we buy GM seed?

At present, GM crops have not been properly evaluated. Few varieties have been produced which bring clear benefits for subsistence farmers. There are many things that can be done to improve yields without spending extra money on GM seed. Farmers should continue to learn and understand more about the concerns and the benefits of GM crops as this is a rapidly changing situation.