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Summary: Roots, tubers, and bananas (RTB) are vital staples for food security in the world's poorest nations. A major constraint to current RTB breeding programmes is limited knowledge on the available diversity due to lack of efficient germplasm characterization and structure. In recent years large‐scale efforts have begun to elucidate the genetic and phenotypic diversity of germplasm collections and populations and, yet, biochemical measurements have often been overlooked despite metabolite composition being directly associated with agronomic and consumer traits. Here we present a compound database and concentration range for metabolites detected in the major RTB crops: banana (Musa spp.), cassava (Manihot esculenta), potato (Solanum tuberosum), sweet potato (Ipomoea batatas), and yam (Dioscorea spp.), following metabolomics‐based diversity screening of global collections held within the CGIAR institutes. The dataset including 711 chemical features provides a valuable resource regarding the comparative biochemical composition of each RTB crop and highlights the potential diversity available for incorporation into crop improvement programmes. Particularly, the tropical crops cassava, sweet potato and banana displayed more complex compositional metabolite profiles with representations of up to 22 chemical classes (unknowns excluded) than that of potato, for which only metabolites from 10 chemical classes were detected. Additionally, over 20% of biochemical signatures remained unidentified for every crop analyzed. Integration of metabolomics with the on‐going genomic and phenotypic studies will enhance 'omics‐wide associations of molecular signatures with agronomic and consumer traits via easily quantifiable biochemical markers to aid gene discovery and functional characterization. Significance Statement: A metabolite‐specific database cataloguing the biochemical diversity within and between root, tuber, and banana (RTB) crops has been compiled from profiling thousands of accessions. The database records the extent of metabolite concentrations available in screened germplasm of each RTB crop and therefore can be used to set breeding targets. This information aids in crop breeding programmes to improve the livelihoods for more than two billion people reliant on RTB crops. [ABSTRACT FROM AUTHOR]

• Wild, landrace and bred potato varieties show distinct metabolite profiles. • Group specific metabolite compositions are maintained upon cooking. • Bred native hybrids showed no significant change of Vitamin A precursors. • Accessions with distinct traits were identified for breeding purposes. Elucidating and improving the nutritional value of staple crops is an important focus in breeding programs. Hence, wild and cultivated potatoes have been metabolite profiled to assess metabolic plasticity present in potato tubers and changes that occur in these after cooking. The present data highlighted metabolic similarities of certain wild species to breeding lines, indicating preference during domestication. In the case of potato, the cooking process has to be taken into consideration for the assessment of nutritional quality. The degree of nutritional change during cooking depends on several factors including cooking method, stability of metabolites with nutritional properties and chemotype of the varietal matrix. The differences between raw and boiled tubers were similar within each germplasm group. No notable distinctions of total phenolic levels could be observed within germplasm groups, whereas total carotenoids and glycoalkaloids were significantly decreased. Genotypes/cultivars with notable changes upon cooking distinguished them within their genotype group. [ABSTRACT FROM AUTHOR]

Vitamin A deficiency (VAD) is a global health problem, which despite significant financial investments and initiatives has not been eradicated. Biofortification of staple crops with β-carotene (provitamin A) in Low Medium Income Countries (LMICs) is the approach advocated and adopted by the WHO and HarvestPlus programme. The accurate determination of β-carotene is key to the assessment of outputs from these activities. In the present study, HPLC-PDA analysis displayed superior resolving power, separating and identifying 23 carotenoids in the orange sweet potato (Ipomoea batatas) variety used, including only eight carotenoids with provitamin A properties. Additionally, the results evidently displayed that the use of lyophilised material facilitated the extraction of twice the amount of pigments compared to fresh material, which impacts the precise calculation of the provitamin A content. These results highlight that yellow to orange starchy edible crops produce a wide array of carotenoids in addition to β-carotene. Biosynthetically it is clear from the intermediates and products accumulating that the β-branch of the carotenoid pathway persists in sweet potato tuber material. Collectively, the data also have implications with respect to the determination and biosynthesis of provitamin A among staple crops for developing countries. Image 1 • β-carotene quantification by LC is far more accurate than by spectrophotometer. • 23 different carotenoids are detected by HPLC in orange sweet potato. • Only 9 of 23 carotenoids have provitamin A activity. • Sweet potatoes express a wide range of carotenoid epoxides/furanoids. [ABSTRACT FROM AUTHOR]