'Smart' cereals for management of stemborer pests in staple cereals in Africa

点击翻译按钮获取中文摘要

Stemborers are devastating insect pests of important food crops, maize and sorghum, in sub-Saharan Africa. They damage these crops by burrowing inside the stem causing the plants to collapse and die. Stemborer pests undermine smallholder cereal cultivation and threaten food security of the very high crop losses they cause. In previous research, we demonstrated that these losses can be prevented by changing the plant odours surrounding the crop. We used companion plants to release smells that repel the pest and attract natural enemy insects that attack the pest. The companion cropping system known as "push-pull" or "Sukuma-Vuta" in Swahili is very popular with smallholder farmers but this would be improved if the crop itself could release the appropriate odours when infested with pest insects. Recently we have found that certain farmer selected varieties of maize have a valuable defence trait not present in commercial hybrid maize. The trait involves release of odours, called semiochemicals, which are attractive to natural enemies of the pest after the stemborer lays her eggs on the plant. The semiochemicals released are the same ones released by companion plants in the push-pull system. The crop varieties with this trait, however, are lacking in other important agronomic traits, particularly yield and quality. To deliver this natural pest resistance to the farmer, breeding programmes are needed to move the trait from into improved crop varieties. This is a difficult process but would be greatly facilitated if genetic markers linked closely to the stemborer resistance trait could be identified. The goal of this project is to define genetic markers associated with the semiochemical production trait. We will achieve this by a comprehensive programme of experiments in which the semiochemicals emitted by different crop varieties after insect egg laying will be identified, insect responses to them measured and the underpinning genes associated with induced semiochemical emission mapped. We will use a state-of-the-art semiochemical identification platform available at Rothamsted Research (UK) and resources for genetic analyses at the Biosciences Eastern and Central Africa hub (BECA, Kenya) with a link to the Cornell University sequencing facility. Crops will be grown and trialled at the International Centre for Insect Physiology and Ecology (icipe, Kenya) which has a proven track record of doing research that is relevant to the needs of smallholder farmers in Africa and makes a difference to their livelihoods.