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

茎螟虫是撒哈拉以南非洲重要粮食作物玉米和高粱的毁灭性害虫。它们通过钻入茎内破坏这些作物，导致植物倒塌和死亡。蒸腾害虫破坏小农的谷物种植，并因其造成的巨大作物损失而威胁粮食安全。在之前的研究中，我们证明可以通过改变作物周围的植物气味来防止这些损失。我们用伴生植物释放气味来驱赶害虫，并吸引攻击害虫的天敌昆虫。在斯瓦希里语中被称为“推拉”或“Sukuma-Vuta”的伴生种植系统在小农中非常受欢迎，但如果作物本身能够在害虫侵袭时释放出适当的气味，这种系统将得到改进。最近，我们发现某些农民选择的玉米品种具有一种在商业杂交玉米中不存在的有价值的防御性状。这种特性包括释放一种称为“半化学物质”的气味，这种气味在蒸煮虫在植物上产卵后，会吸引害虫的天敌。所释放的半化学物质与同类植物在推挽系统中释放的半化学物质相同。然而，具有这种特性的作物品种缺乏其他重要的农艺性状，特别是产量和质量。为了向农民提供这种天然的害虫抗性，需要育种计划将这种特性从改良作物品种中转移出来。这是一个困难的过程，但如果能够确定与抗蒸煮性状密切相关的遗传标记，将大大促进这一过程。本项目的目标是定义与符号化生产性状相关的遗传标记。我们将通过一项全面的实验计划来实现这一目标，其中将鉴定不同作物品种在昆虫产卵后释放的半化学物质，测量昆虫对它们的反应，并绘制与诱导半化学物质释放相关的基础基因。我们将利用英国洛桑研究所（Rothamsted Research）提供的最先进的符号化学鉴定平台，以及肯尼亚生物科学东非和中非中心（BECA, Kenya）的遗传分析资源，并与康奈尔大学测序设施相连。这些作物将在国际昆虫生理学和生态学中心（icipe，肯尼亚）种植和试验，该中心在开展与非洲小农的需求相关的研究并对他们的生计产生影响方面有着良好的记录。

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.