Reciprocal recurrent selection applied to Coffea canephora Pierre. I. Characterization and evaluation of breeding populations and value of intergroup hybrids

Two breeding populations have been identified with Coffea canephora , based on geographical and genetic differences: the Guinean group from West Africa and the Congolese group from central Africa. A reciprocal recurrent selection programme based on these groups was initiated in Cote d'Ivoire in 1984. Genotypes of both groups available in field collections are either of cultivated or wild origin. Genotypic and phenotypic variability was evaluated within and between the groups for the following characteristics: isozyme patterns, architecture, drought tolerance and vigour, technological and organoleptic traits, pest and disease resistance. Variation between and within groups was found to be large. Based on isozyme analysis and phenotypic observations, two subgroups were identified within the Congolese group. Phenotypic values of parents and testers used in the first cycle of reciprocal recurrent selection are presented. Results of two intergroup hybrid trials indicate high yield and vigour for these hybrids compared to intragroup hybrids, justifying the reciprocal selection approach. Furthermore, the variation observed indicates that recurrent selection would allow progress for selection traits for both populations and intergroup hybrids.