Abstract

Millets, comprising the small-seeded group of the Poaceae family, represent one of the major food- and feed-crops in the semi-arid tropical regions of Africa and Asia. Compared to major crops of the world, these indigenous crops possess a number of beneficial characteristics including tolerance to extreme climatic and soil conditions; hence, adapts to poor soil fertility and moisture deficient areas. Moreover, millets are also nutritionally rich especially in vitamins and minerals, and most of them are gluten-free. Despite all these benefits, millets are encountered with several production constraints. The major bottleneck affecting millets are their extremely low yield since they are mostly cultivated in marginal areas with poor moisture and fertility conditions. Inherent characteristics, such as susceptibility to lodging, also significantly affect the productivity of millets. Millets are also commonly known as orphan- or neglected-crops due to too little attention given to them by the world scientific community. Genetic improvement in millets could be achieved not only by conventional approaches but also through modern techniques such as genetic modification or transgenics. The main benefits of regeneration and transformation in millet improvement are: i) the multiplication of identical copies of plants that are free of diseases and pests, and ii) the regeneration of the whole plant from transformed tissues with desirable traits. Success in plant transformation is largely dependent on the efficiency of regeneration. Establishing optimum regeneration method for each plant species and ecotype is therefore, a pre-requisite before embarking on plant transformation. In this review, we present various studies made to identify optimum regeneration and transformation methods for major millets. The prospects of applying advanced regeneration and transformation techniques to these vital but under-studied crops of the developing world are also discussed.

Key words: Millets, under-researched crops, orphan crops, in vitro regeneration, transformation.