COCOYAM GENOMICS: PRESENT STATUS AND FUTURE PERSPECTIVES

Abstract

Cocoyams (Colocasia esculenta and Xanthosoma sagittifolium) are functional food crops grown in many agroecological
zones around the world. The crop is mostly cultivated by subsistence farmers and serves as food and
source of income for millions of people. Based on importance, it ranks third among the root and tuber crops
grown in sub-Sahara Africa. Despite its cultural importance, world production and yield continue to dwindle. In
addition to the several physiological and biological constraints contributing to production decline, cocoyam
research is underfunded to the point of neglect. There is very little understanding of the complexities of cocoyam
genetics and its genome which has severely hampered conventional efforts at improving the crop. Compared to
crops like yam and cassava, cocoyam genomic research is limited. Despite this, over the years, molecular
technologies have been applied in cocoyam research to develop molecular markers, genetic linkage maps,
conduct functional genomic analysis and develop molecular diagnostic tools. Cocoyam transformation and
tissue culture protocols have been developed for certain cocoyam varieties. These tools have provided a better
understanding of the crops origins, genetic diversity within available germplasm and the pathogens that affect it,
rapid detection of major diseases, conservation and genetic improvement of complex traits including disease
resistance and improved yields. With reducing costs in next-generation sequencing, further efforts need to be
directed towards funding genomic research that allows for novel gene discovery, molecular pathway analysis,
genetic engineering and molecular breeding in non-model organisms like cocoyam.