Morphological descriptors for the characterisation of teak clones cuttings (Tectona grandis l.f.)

Abstract

Teak (Tectona grandis) is a forest species cultivated in tropical regions worldwide, due to the traits of its wood and its great economic value on the market. In Brazil, original plantations are being replaced by selected clonal forests, which generate the need and interest to protect this genetic material based on the current legislation. The legal requirements for cultivar protection are that the genotype must result from genetic improvement and provide distinguishability, homogeneity, and stability (DHS). This work identifi es morphological descriptors in teak cuttings to assist the clone protection process of the species. The study was conducted in a completely randomized design with the evaluation of 7 clones and 15 cuttings per clone, at 30, 60, 90, and 120 days old. The information was also organized based on the arrays of presence and absence of variations for each clone, for 21 morphological traits. Subsequently, genetic similarity measures were estimated using the Jaccard index and the UPGMA clustering method. The clones with the 12, 7, 9, and 11 morphological traits formed the morphological descriptors for the 30, 60, 90, and 120 days old cuttings, respectively. The traits of the leaf blade: Length, width, length/width ratio, green intensity, and the brightness of the leaf, were common for all the evaluated ages, but their respective levels of expression were diff erent.