Coffee Improvement by Interspecific Hybridization

Abstract

Considerable studies on creation of the interspecific hybrids using induced tetraploid Gaffea canephara P. and Gaffea arabica L. varieties for improvement of resistance to Coffee Berry Disease (CBD) and Goffee Leaf Rust (CLR), growth habits, fertility, yield performance, genetic diversity, biochemical attributes and beverage quality as well as similar information on their backcrosses to Arabica coffee genotypes are reviewed in this paper. Whereas the F 1 hybrids obtained by crossing induced tetraploid Robusta and Arabica coffee exhibited low fertility, backcrossing the hybrids to G. arabica parents restored the fertility to near normal levels. The yields and beverage quality of backcrosses improved to the levels of the best parents and in some cases they were even better. Of major significance was the resistance to C BD and CLR that the tetraploid Robusta was able to impart into the backcross progenies. These progenies were therefore potential substitutes for the susceptible Arabica coffee varieties in addition to taking the place of Robusta which has Inferior beverage quality.