DNA Markers and Biodiversity

Ann Marie Thro, Coordinator, Cassava Biotechnology Network (c/o CIAT, Cali, Colombia), wrote to say she appreciated the unusual and thought-provoking set of articles in Spore 69 and sent her comments on Spore 66 article The promise of biotechnology in agriculture. 'The article presents the benefits of micro propagation for cloning the best genotypes for top quality and performance - benefits that are extremely important in appropriate situations. I wish, however, that the article had also presented some of the ways that biotechnology may be used to increase diversity in farmers' fields. Biotechnology tools such as DNA markers offer the long-term potential of combining uniform high performance and quality, with a high degree of intra-varietal genetic diversity. By contrast, using their present tools breeders must choose which they will maximize: high yield or quality on one hand, or genetic diversity on the other. It has been difficult to obtain varieties with high levels of both. Realizing biotechnology's potential for increasing diversity in high performing varieties will require increased knowledge of the molecular genetics of such complex traits as drought tolerance, photosynthesis and crop quality characteristics.'