**6. Conclusion**

Cassava (*Manihot esculenta* Crantz) is produced globally and a food security crop for many households in sub-Saharan Africa. Commonly available white cassava can provide most of the body's daily energy needs, but it is deficient in vitamin A and some essential micronutrients such as iron and zinc. Vitamin A deficiency makes the body susceptible to infection. Most widely consumed cultivars of cassava are white

*Carotenoids in Cassava (*Manihot esculenta *Crantz) DOI: http://dx.doi.org/10.5772/intechopen.105210*

or off-white, and the roots are generally low in carotenoids [10]. Although recently, some yellow pulp-colored varieties associated with the presence of carotenoids are being propagated, and it is gradually gaining public acceptance. The nutritive importance of carotenoids is attributed to its conversion to vitamin A when consumed. Numerous genes have been identified in the carotenoids biosynthesis pathway of plants, but studies show that phytoene synthase 2 (*PSY2*), lycopene epsilon cyclase, and β-carotene hydroxylase genes have higher expression levels in yellow cassava roots. So far, the *PSY2* gene has been identified as the key gene associated with increased carotenoids in cassava and has also been tested for its efficiency in breeding [12, 41].

One bottleneck associated with the breeding for increased carotenoids in cassava storage roots is the phenotyping as large populations need to be subjected to selection. The most highly reproducible tool in predicting carotenoids is the high-performance liquid chromatography (HPLC), but its analysis is expensive, costing 50–70 US dollars per sample with very low throughput [57]. Thus, other easy-to-use devices have been accessed for use in phenotyping carotenoids in cassava such as the near-infrared spectroscopy, Chromameter, iCheck Carotene device. These devices have been observed to have high correlation with HPLC, for instance, total β-carotene as quantified by HPLC had high correlation (r = 0.75) with total carotenoids quantified using the iCheck device [12].

Also, molecular markers tools such as simple sequence repeats, single-nucleotide polymorphisms and even genomic selection [12, 64, 68] have been employed to speed up the breeding for increased carotenoids in cassava roots.

## **Acknowledgements**

We acknowledge the support of Mr. A. I. Udoh.

## **Conflict of interest**

No conflict of interest.

## **Notes/thanks/other declarations**

Thanks to all coauthors for contributing to the success of this work.

## **Appendices and Nomenclature**


*Carotenoids - New Perspectives and Application*
