Abstract

The genus Gossypium to which the cultivated cottons belong comprises of twentytwo different species and offers considerable scope for the synthesis and study of interspecific hybrids for crop improvement as the cultivated species viz., G. hirsutum L. and G. barbadense L. in the American group and G. herbaceum L. and G. arboreum L. in the Asiatic group are interfertile within themselves, while the application of polyploidy and backeross techniques has contributed to the exploitation of sterile or partially sterile hybrids also derived from other combinations of interspecific crosses in this genus. There are instances like the development of the American - Egyptian varieties in the U. S. A., and Madras-Cambodia Uganda varieties in Madras resulting from hirsutum-barbadense hybridisation and the release of Indo-American crosses in Bombay which are the results of practical significance in cotton improvement through interspecific hybridisa- tion involving cultivated species. Besides, considerable work has also been initiated in the recent past to transfer desirable attributes from the wild species to the cultivated cottons as several of the former have been found to possess useful and rare genes not available within the cultivated biotypes. The useful results achieved so far and the immense potentialities for transferring known and unexpected desirable characters are briefly reviewed and presented below.

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