Phenotypic Classification of Coffee (<i>Coffea arabica</i> L.) Germplasm in Southern Ethiopia

Abstract

Ethiopia is the homeland and center of genetic diversity of arabica coffee (<i>Coffea arabica</i> L., Rubiaceae). Although Ethiopia is known as a primary center for <i>Coffea arabica</i> diversity. Identification and characterization of coffee accessions in the base population is important in order to a successful conservation and utilization of genetic resources. Getting more information on genetic variability is a prerequisite for further improvement of coffee (<i>Coffea arabica</i> L.). A field experiment was conducted at Awada Agricultural Research Sub-Center, Ethiopia, to study the magnitude of phenotypic diversity among southern coffee (<i>Coffea arabica</i> L.) germplasm accessions based on qualitative traits. A total of 104 entries consisting of 100 accessions from southern parts of Ethiopia and four standard cultivars were evaluated using augmented design with five blocks. The main objective of the study was to assess morphological variation among germplasm based on phenotypic qualitative characters. Estimates of frequency distribution and Shannon Index based on 13 qualitative traits revealed the existence of genetic variability among 104 coffee germplasm. The highest diversity index (H’) was found for the growth habit followed by the angle of insertion of the primary branches, leaf shape, stipule shape, fruit shape, fruit ribs, fruit color, leaf apex shape, leaf tip color and stem habit. The phenotypic similarities of 104 coffee genotypes were assessed by average linkage methods of cluster analysis using 13 qualitative traits with proc cluster of SAS. Based on the result of this analysis the coffee accessions were classified into five clusters with cluster-I was the largest and consisted of 66 accessions (63.46%) followed by cluster-II consisted of 12 accessions (11.54%), cluster-III consisted of 24 accessions (23.08%), cluster-IV and cluster V consisted of 01 accessions for each (0.96% for each). Thus, there is a chance to develop hybrid vigor through crossing diverged parents found in a different cluster. Generally, the present study revealed the existence of immense genetic variability among coffee germplasm for various important morphological qualitative traits. Hence, there is an opportunity to exploit these traits to improve genotypes that perform better than the existing varieties for the upcoming coffee improvement program.