Morphological descriptors for the characterization of teak clones (Tectona grandis L.f.) in plantations

Aim of study: The objective of this work was to identify possible morphological descriptors for teak clones, in order to support the cultivars protection process of this species. Area of study: This experiment was carried out in 'Sao Jose dos Quatro Marcos', Mato Grosso, midwest Brazil. Material and methods: A teak clonal test, assessing 18 clones, was evaluated at the ages of 29 and 41 months by means of 41 morphological characteristics, related mainly to the branches, leaves and trunk. The clonal test was established in a randomized block design composed by three blocks, each block containing 18 plots, one for each clone. Each plot had 36 plants, but only the innermost five individuals were selected and evaluated. The information was organized in a presence and absence matrix. Subsequently, genetic similarity measures were estimated, by means of the Jaccard index, and a clustering was performed by the Unweighted Pair Group Method using the Arithmetic averages (UPGMA) method. Main results: A total of 26 and 28 morphological characteristic that exhibited DHS (distinction, homogeneity and stability) were identified at the ages of 29 and 41 months, respectively. Of these, 17 characteristics showed the same behavior at 29 and 41 months of age. However, it is important to emphasize that the evaluation must be performed under the same planting conditions in which these descriptors were developed. Research highlights: These 17 morphological characteristics can compose the list of potential morphological descriptors to be used in the process of teak clones/cultivars protection.