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Twenty-six (26) morphological descriptor traits were used to characterize six (6) genotypes of natural rubber at the immature stage using the natural rubber descriptor manual and the traits characterized included petiole, leaf storey and stems. The experiment was set up at the experimental ﬁeld of Rubber Research Institute of Nigeria (RRIN) Iyanomo, Benin City. The objective of the study was to characterize the juvenile characteristics of natural rubber and to determine the extent of genetic variability that exists among the half-sibs. Data on characterization and agronomic traits were collected and subjected to analysis of variance (ANOVA) using the Generalized Mixed Model to determine the variability that existed among the half-sib genotypes for various traits. Treatment means of the offspring genotypes were separated using Fisher's least signiﬁcant difference (F-LSD) at a 5% level of probability. The result of the combined analysis of variance (ANOVA) indicated highly signiﬁcant genotypic differences among the genotypes for all the agronomic characters measured except stem girth, bark thickness and vigour index. The mean square result from ANOVA showed signiﬁcant variations among the genotypes evaluated in each year as well as the periods and genotype x period interactions for most of the traits measured. In conclusion, the information obtained from this research work showed that considerable genetic variability exists in agro-morphological attributes of natural rubber genotypes. Genotypes with highly similar traits and high- yielding potentials have been identiﬁed and characterized.