**2. Collection and conservation of Nigeria root vegetable genetic resources**

With high rate of population growth, demand for agricultural crops worldwide is expected to increase with a higher purchasing power per person which implies higher consumption and use of agricultural produce [2–5]. Genetic materials of horticultural crops and their wild types are of great importance for food and nutrition security, and also serve as good sources of fodder, fuel, shelter, as well as sources of high-value industrial products to meet the high demand of an increasing global population. Genetic materials also provide useful sources of genetic variation required by plant breeders for crop improvement, and a broad genetic base within the gene pool is necessary to expand the scope of identifying and introgessing desirable genes underlying agronomically-important traits [6]. Genetic diversity has huge value for present and future generations, and more efforts must be made for its conservation and sustainable utilization [7]. Despite the usefulness of genetic resources, available genetic variability including landraces is getting eroded at an alarming rate, causing an

*Nigeria Root Vegetables: Production, Utilization, Breeding, Biotechnology and Constraints DOI: http://dx.doi.org/10.5772/intechopen.106861*

enormous reduction of variability. This situation thus requires fast action to conserve germplasm [6]. The conservation, likewise sustainable use of germplasm is necessary in the promotion of food and nutrition security and gives room for securing diversity to respond to future challenges including the increasing climate change [8].

The Genebank of the National Centre for Genetic Resources and Biotechnology (NACGRAB) holds one of the most extensive collections in Nigeria, with a total record of over 10,500 accessions of 40 different crops, comprising of wild relatives, landraces, as well as old and more recent cultivars of crops, with germplasms of various vegetables being well represented. Vegetables include various genera and species; and are a vital element for a balanced diet which supplies vitamins, antioxidants, minerals, fiber, amino acids, as well as other compounds that improves health, and contribute to nutrition security [9]. Roughly a million accessions of crops that are entirely or partly used as vegetables are conserved ex-situ [9]. However, only 7% of the total global ex-situ conservation are fully used as vegetables which are mostly leafy or fruit vegetables. Root vegetables are not well represented in genebanks as they are mostly conserved in the fields; thus, are potentially exposed to pest and diseases and environmental variation. To avoid the risk of losing available germplasm, such crops are however amenable to in vitro conservation which is cost and labour intensive and requires consistent material transfer to fresh growth media. Root vegetables like ginger are conserved in vitro at the NACGRAB's genebank in Nigeria.

Of the ca. 7.4 million accessions of Plant Genetic Resources for Food and Agriculture (PGRFA) that are ex-situ conserved globally, only 7% (i.e. ca. 518,000 accessions) are vegetables [10]. Of these global vegetable collections, only alliums are well-represented root vegetables in ex-situ collections [9]. As a result, the level of representation of root vegetables in both National and global collections, calls for the need to explore, collect and conserve more of the variabilities in root vegetables. Though we still have the benefit of a vast agrobiodiversity, there is the need to be conscious that two out of five plant species are endangered with losses occuring on a regular basis [11] due to the increasing climate change, extension of human settlements, and substitution of landraces with hybrid cultivars. Thus, the need for additional exploration for collection and conservation of root vegetable genetic materials in areas of vegetable diversity to maintain valuable germplasm for the present and future.
