Towards sustainable conservation and domestication of Balanites aegyptiaca L. (Zygophyllaceae) in Africa: progress and challenges

Balanites aegyptiaca is a key agroforestry tree species widely distributed across the African drylands, and with a high socioeconomic potential for rural communities. Previous research studies have revealed the importance of this multipurpose fruit tree species from an ecological perspective, however, there is still little documentation of the current state of knowledge and research perspectives required for setting further sustainable management policies for the species. Here, we conducted a global systematic review covering the last three decades (1989-2021), to understand the patterns and insights from publications on various aspects related to both the conservation ecology and the domestication of B. aegyptiaca. Published materials were identified using four online search engines including Science Direct, Google Scholar, African Journals Online and Scopus. A total of 4538 publications were initially identified, of which 346 publications were finally retained, on the basis of broad cross-disciplinary perspectives. These 346 publications covered 24 African countries and the five African sub-regions. The majority of the publications was recorded in both West Africa (n = 170) and East Africa (n = 106), while the North Africa (n = 34), Central Africa (n = 21) and Southern Africa (n = 15) had the lowest number of publications on B. aegyptiaca along its distribution range in Africa. About 70% of the studies undertaken in West Africa were from Nigeria, Senegal and Burkina Faso. In-depth analyses of these publications showed critical research gaps on B. aegyptiaca, in terms of its distributional ecology, socioeconomic importance, reproductive biology, ecophysiological performance, genetic diversity and propagation initiatives. This review provides crucial information that would guide the development of research agenda and sustainable strategies for conservation and domestication of the desert date in Africa.