In Africa, agriculture is largely based on low-input and small-holder farming systems that use little inorganic fertilizers and have limited access to irrigation and mechanization. Improving agricultural practices and developing new cultivars adapted to these low-input environments, where production already suffers from climate change, is a major priority for ensuring food security in the future. Root traits improving water and nutrient uptake could represent a solution toward achieving these goals. In this review, we illustrate how breeding for specific root traits could improve crop adaptation and resilience in Africa using three case studies covering very contrasted low-input agroecosystems. First, we review how targeted changes in root system architecture allowed a dramatic increase in common bean yield in low input agroecosystems of South East Africa. We next discuss how root traits could be targeted to improve the productivity and resilience of dryland cereals in the face of climate change and soil degradation. Finally, we evaluate how root traits could be mobilized to develop water-saving rice agroecosystems for West Africa. We conclude with a discussion on how to prioritize target root traits, how they could be validated and made available to breeders and farmers through participatory approaches.

In Africa, agriculture is largely based on low-input and small-holder farming systems that use little inorganic fertilizers and have limited access to irrigation and mechanization in comparison to modern agricultural systems. Improving agricultural practices and developing new cultivars adapted to these low-input environments, where production already suffers from climate change, is a major priority for ensuring food security in the future. Root phenes improving water and nutrient uptake could represent a solution toward achieving these goals. In this review, we illustrate how breeding for specific root phenes could improve crop adaptation and resilience in Africa using three case studies covering very contrasted low-input agro-ecosystems. We conclude with a discussion on how these phenes could be validated and made available to breeders and agronomists.

Amaranthus spinosus L. is a member of family Amaranthaceae is widely distributed throughout the tropics and warm temperate regions of Asia from Japan to Indonesia to India, the Pacific islands and Australia as a weed in cultivated as well as uncultivated lands. In Indian traditional system of medicine and AyurvedaAmaranthus spinosusL.is used as digestible, laxative, diuretic, stomachic, antipyretic, improves the appetite, biliousness, blooddiseases, burning sensation, leprosy, bronchitis, piles andleucorrhoea. Its extract is used for its antiinflammatory properties, effect on hematology, immunomodulatory activity, anthelmintic properties, antidiabetic, antihyperlipidemic and spermatogenic. (Mishra et al, 2012). In Maharashtra it is commonly known as "Kate Math" or "Deth" as it is utilized as leaf vegetable when young and tender stem vegetable at time of flowering. In Satara district it is commonly known as "Dhesa" where whole stem along with roots is used as vegetable. It is most common food throughout Satara district in non irrigated and low rainfall zones. It is also a common vegetable in Narayangaon and other suburban cities of Pune district where Amaranthus spinosusL. is used as stem vegetable on sacred occasions called "Mahal".