Geographical distribution of landrace robusta coffee due to its adaptability to different climatic conditions, necessitate the study of relative diversity of available cultivars among Nigeria farmers. Morphological markers proved basic information on observable traits. Six landrace accessions and one accession from germplasm were collected for this study. Ate-kekere (ATK), Shekoni (SEK), Iyamuye (IY1), Kabba bunu (KB3), Omu-Alagbede (OMA), Oranre (ORA1) and C105 collected from coffee germplasm. Coordinate of collection areas were obtained, with the use of GPS. All accessions were subjected to proper nursery managements until they were ready for field establishment. Experiments were conducted at two locations for two years 2018 to 2019, in a randomized complete block design, with three replicates. Data collected on morphological characters were: plant height, stem diameter, numbers of branches, numbers of leafs, inter node length, leaf length and leaf width. All the observations were recorded and subjected to ANOVA using SAS package (9.1) and Minitab package (17). There were variations in all morphological characters, with ATK (67.25) being the tallest among all the accessions. OMA (48.22) was observed to be the shortest among other accessions. ATK had significant highest mean number of branches (15.83) and of leaves (38.67) when compared to other accessions. Locations tend have significant effect on the performance of accessions. Plants at Ibadan show significant better performance in morphological traits than plants at Owena. Year 2019 revealed significant improvement in morphological traits as compared to 2018 except on number of branches that were not different significantly. Dendrogram grouping of accessions according to geographical area of collection (North Central and Southwest), revealed that morphological traits could be used to classify cultivars for characterization of core collection and for establishment of germplasm bank for breeding purposes.
Keywords: landrace robusta coffee, accessions, morphological markers, diversity studies and locations.