Assessment of Taxonomic Affinity of Indonesian Pummelo (Citrus maxima (Burm.) Merr.) Based on Morphological Characters

Citrus maxima is a tropical fruit species with high morphological variability on fruit characters, including shape, size, thickness of peel, flesh color and taste. This variability has been used by breeders and common people to practically distinguish different pummelo cultivars. Despite such well known variation, so far there is no published study specifically addressed the extent of phenotypic variability and taxonomy of pummelo in Indonesia. This study was, therefore, aiming at assessing phenotypic variability and taxonomic affinity of Indonesian pummelo cultivars and landraces using multivariate analysis methods. A total of 60 accessions from six provinces were collected, including some representatives of registered cultivars. Twenty one morphological characters were subjected to cluster analysis and principal component analysis. Results showed that two major clusters were formed, in which each group was characterized by combination of distinctive morphological features leading to recognition of two cultivar groups. Based on the fact that the morphology of individuals from intensively cultivated orchards showed similar level of variability to those from sporadically distributed areas, there was strong indication that the morphological variation has genetic background.