Forging ahead with finger millet
Tasty, durable and nutritious, finger millet (Eleusine coracana) is an important grain in the lives of some of the world's poorest inhabitants. Although little research has been previously conducted on finger millet, new initiatives* to preserve and develop its genetic diversity will allow researchers worldwide to develop new higher yielding varieties and those resistant to pests, diseases (particularly blast), and environmental stresses (including drought).
Grown in arid regions of Eastern and Southern Africa, India, and Nepal, the small millet seeds can be stored safely for many years without insect damage, which is invaluable in farmers' risk avoidance strategies in drought-prone areas. Millet straw is also an important livestock feed, building material, and fuel. Although labour-intensive to grow, finger millet grown on marginal land provides a valuable resource in times of famine. Furthermore, its grain tastes good and is nutritionally rich (compared to cassava, plantain, polished rice and maize meal) as it contains high levels of calcium, iron, and manganese. Finger millet also contains methionine, an essential amino acid lacking in the diets of hundred of millions of the poor who rely mostly on starchy staples.
At the Plant Genetic Resources Conservation Unit in Griffin, Georgia, Dr Melanie Newman, an agronomist and curator for warm season grasses is creating an on-line catalogue of finger millet genetic marker data. Her work has involved drawing on genetic information already discovered by other researchers working on finger millet collected from India and Africa. As a first step, Newman has selected a 'core collection' of 80 samples, or accessions, which represent the range of genetic diversity of over 700 samples collected from various regions around the world.
Traditionally, scientists could access phenotypical descriptors (height and width) of collected plants, but resistance and other such traits "are very much environmentally related," says Newman, "so molecular markers are important." To identify genetic markers for resistance to drought, and to neck and finger blast (Pyricularia grisea), scientists from the Universities of Wisconsin and Georgia in the USA are working with the University of Agricultural Sciences in Bangalore, India to currently assess the core collection. Comparative genetics with rice, which is also affected by fungal blast, will help to identify blast resistance genes. Katrien Devos of the University of Georgia says it can take 5-6 years to establish a genetic marker with any certainly. "There has been very little improvement through breeding of finger millet," she notes, "except in Uganda where yields are routinely as high as 1.8 ton per hectare with over 3 tons per hectare being achieved in experimental plots. In Kenya, yields are much lower, typically around 0.6 ton per hectare."
Providing genetic data to other researchers through the online catalogue will, hopes Newman, greatly improve the usefulness of the germplasm collection. She also hopes that partnerships will be created and strengthened between germplasm collection sites throughout the US, India and other parts of the world to better facilitate the sharing of plant samples. With this in mind, Newman is looking into how institutions can work together to both make individual collections more diverse and act as a "back-up" for each other, particularly as developing countries may not have the resources to keep many samples.
A model for other grains
The project to make genetic information available online will serve as a model for other grains. Data on the core collection should be available to researchers anywhere in the world by the end of 2005; more genetic information on nutritional content will be added over time. Scientists with access to the data can then make decisions on which seeds to order and conduct further studies, using genetic markers to accelerate future improvements in finger millet growth and yield. Their research could involve mapping of other traits, or nutritional experiments on, for example, factors that increase amino acid availability. Breeding programs will allow for the introduction of favourable disease and drought resistant traits into locally adapted plants. Farmers will eventually participate in the effort to produce hardier varieties that suit their preferences.
Newman believes that finger millet has great potential, noting an increase in requests for germplasm, mostly due to its value as a weaning food. The increased attention of researchers is helping finger millet to shift its reputation in India as a poor man's grain, also known there as ragi, to a highly valued food source; in Africa it is already considered as such. Katrien Devos of the University of Georgia agrees. While she notes that it is very hard to get funding for developing country research, finger millet is gaining attention in first world countries which may mean more money for research; its low glycemic index and absence of gluten make it suitable for diabetics and people with digestive problems.
Written by Treena Hein