This year, the world food crisis has been in the headlines, but for millions of farmers in developing countries, food shortages are nothing new. Every year they struggle to grow enough to feed their families and obtain income for basic necessities. An unexpected drought or downpour or sudden crop infestation can mean that after months of hard work they find themselves with nothing.

Climate change and the related movement of pests and plant diseases are making each harvest even more uncertain.

The Wallingford-based not-for-profit inter-government organisation CABI works with vulnerable farmers in Asia and Africa to help them improve their food security. Its projects are based on scientific research into agricultural and environmental issues and aiming to find practical and sustainable solutions to problems.

CABI works closely with African and Asian scientists and development workers who have an in-depth understanding of the problems people in their countries are facing, and know how to work in ways that are culturally-appropriate - acknowledging the different roles that men and women may have in agriculture, for example.

Originally established in 1910, when it was called the Commonwealth Agricultural Bureau, CABI currently has more than 400 staff based in 16 countries (including about 100 at its head office in Wallingford) but its influence is global.

The organisation has recently secured three years' further funding from the Swiss Agency for Development and Co-operation for its Good Seed Initiative (GSI), which for the past three years has been assisting small-scale farmers in Bangladesh, Kenya, Tanzania and Uganda.

CABI Senior Scientific Officer Dr Sam Page, who heads the initiative, explained: "Good quality seed is the basis of food security, but many farmers - for all kinds of reasons - have got out of the habit of selecting their seed."

These reasons include the HIV/AIDS epidemic, which has devastated families and prevented traditional knowledge being passed on as it was previously, and the assertive marketing of new varieties of seed by multinational agricultural companies. This has made many farmers wonder whether traditional, indigenous varieties are really any good.

In fact, they often are the best choice, because they are adapted to local conditions and resistant to diseases and pests, but to perform well they must be grown from quality, selected seed.

In Bangladesh, working with scientists at the Rural Development Academy of Bogra, Dr Page has been helping farming families to increase the quantity and quality of their rice seed.

The scientists researched the techniques that farmers have traditionally used to select and store seed, tested them scientifically, then made short videos about the most effective methods.

These included drying rice seed on bamboo tables which can be moved onto the verandah when it rains, rather than on the ground, where it can be damaged by damp and animals, and a traditional method of making storage jars airtight using a lighted candle to remove the oxygen.

Groups of women - who are generally responsible for saving seed in Bangladesh -watched the videos on DVD, discussed the ideas, and adopted some of the techniques.

"Having videos meant that we could reach a large number of people, and the message didn't deteriorate," said Dr Page.

Research with some of the 100,000 women who watched the videos showed that on average yields increased by 10-15 per cent.

In some countries farmers are prevented by law from selling their seed, and CABI is encouraging governments to address this.

In both Bangladesh and Tanzania the law already enshrines farmers' rights to sell quality-assured seed. When seed is produced locally, profits sustain growing local economies instead of leaving the country.

Rice is a staple food in rural Bangladesh, and often grown for family consumption, but wheat has become an important cash crop.

CABI has also been helping the poorest Bangladeshi farmers to grow quality, climate-change tolerant wheat seed to sell, giving them a cash income for the first time.

In Uganda, far fewer villages have electricity than in Bangladesh, so information about good seed-saving techniques is being shared over the radio and through training courses.

Farmers learn about the benefits of producing seed of a new variety of rice called NERICA (New Rice for Africa), developed by scientists from the Africa Rice Centre (WARDA), which combines the high yields of Asian rice with the drought-tolerance and pest-resistance of African varieties.

The GSI is just one example of CABI's many projects, which also include mobile plant clinics that help farmers to identify and deal promptly with potentially devastating diseases such as banana wilt, and assistance for farmers selling commodities on the international market.

Recently, for example, it has helped to re-establish the coffee industry in Angola, which had been destroyed by war.

Another important area of research investigates the actual and possible impact of invasive species, including biofuel crops.

Summing up its approach, the organisation explains: "We link science directly with rural communities."