Breeding for drought tolerance has so far been difficult given the ‘low heritability of tolerance’, the variety of effects of drought dependent on timing, and the limited understanding of drought physiology. Recently, however, a suite of genes that regulate drought adaptation and tolerance have been identified. Their combination with transgenic approaches has led to rapid progress in improving drought tolerance. One such gene is a so-called ‘chaperone’ gene.
Chaperone genes can confer tolerance to stress of various kinds, including cold, heat and lack of moisture. They act on the physiology of the plant and allow it to recover rapidly from stress. The product of the gene helps to repair mis-folded proteins caused by stress and so the plant recovers more quickly. Found in bacterial RNA, chaperone genes have been transferred to maize with excellent results in field trials. Plants with the gene show 12%-24% increase in growth in high drought situations compared with plants without the gene. Field trials are now being carried out in Africa through the African Agricultural Technology Foundation’s (AATF) Water Efficient Maize for Africa (WEMA) programme.
WEMA was initiated in 2008 as a public private partnership between the AATF, a Nairobi based non-profit, the International Wheat and Maize Improvement Center (CIMMYT), Monsanto and the national agricultural research organizations (NAROs) in participating countries: Kenya, Mozambique, Tanzania, Uganda and South Africa. The project aims to deliver maize varieties that will increase yields around 20% to 35% compared to current varieties under moderate drought conditions. An estimated 2 million tonnes of additional food, benefitting 14 to 21 million people could be produced. The project aims to release the varieties royalty-free to smallholders through African seed companies and their benefits and safety will be assessed by national authorities according to the regulatory requirements of individual participating countries.