The genetic modification of crop plants is the defining feature of the domestication of plants by humans for agriculture. It has been practiced for thousands of years, and in its various forms, has provided us with all the crops humanity depends on for food and fibres.
Traditional Crop Breeding
The ancestors and wild relatives of our crops often look very different, are inedible, and occasionally even poisonous. The repeated selection of seeds from plants with the good crop characteristics over time is the backbone of traditional breeding methods. Traits for selection include better crop quality, taste, higher yield, earlier cropping, and resistance to drought, high salinity, pests and diseases. Traditional plant breeding relies therefore on two basic processes: variation and selection. It is effective, and also relatively cheap, and has provided us with all the most of our food crops, and continues to do so. The main limitation of conventional breeding is that the required trait may not be present in the population nor in plants that can be used for crossing.
Modern Genetics and Crop Improvement
Two discoveries made it possible to understand how plants change through traditional breeding processes. The first of these was the discovery of the basic principles of genetics – the finding that what makes a species distinctive, and also each individual unique among all others, is the information locked in our genetic make-up. Each cell of the millions that compose an organism carries in long, folded strands, thousands of discrete information units, genes. It is genes that are the basis of heredity: we look like our parents because we have inherited our genes from them, and our children look like us because we passed on our genes to them. So, what our ancestors did unknowingly when they settled down to cultivate the land is to start a process of shuffling genes between related plants, and selecting the combinations that made better crops.
The second discovery is that the information encoded in genes is written in a universal language, the genetic code: all living organisms share it. This is the language of life. Modern molecular biology has made it possible to identify genes and to determine their function. It has also made it possible to isolate genes, modify them, and reintroduce them. Modern genetics has therefore provided tools to make conventional breeding more efficient, and also allowed breeders to extend the possible sources of variation for crop improvement beyond populations if the same species and its close relatives.
One Size does not Fit All
Every farmer knows that one good trait does not make a good crop, and that all the traits that make a plant a good crop in one place can make it a bad crop in another place Therefore modern biotechnology should never be seen as a stand-alone solution – these tools need to be combined with conventional breeding techniques and good agricultural practices.
Regardless of the technologies used, access to improved planting material is essential: you reap what you sow. Poor quality planting material will give you a poor harvest, while good quality seed and tubers are one of the things you need for a good harvest. And a good harvest means more food on the table, and the ability to sell surplus, driving economic development for individuals, families and communities.