Delineation of Teak (Tectona grandis Linn.f.) Clones through Leaf Descriptors

Abstract

Documenting variations among Teak populations for morphology, phenology, growth rate, relative immunity to insect/disease attack and timber quality are very essential for its fine-scale genetic improvement. Further, there is a need to develop simple morphological descriptors, to characterize elite genotypes that can be easily and reliably adoptable at the field level. Such descriptors would form the basis for rouging operations and for verifying the clonal identity in seed orchards. Therefore, an attempt was made to characterize fifty Teak clones of Karnataka State based on leaf characters. Seven qualitative leaf traits viz. leaf petiole, leaf texture, leaf shape, leaf tip/leaf base shape, leaf pubescence and leaf colour were adopted to describe each of the fifty genuine Teak clones of Karnataka observing three ramets of each clone. Intra clonal differences were not present for all the seven traits suggesting that there were no admixtures among the ramets. Based on the key developed, majority of the Teak clones of Karnataka could be delineated. Perhaps this is the first ever leaf descriptor-based key to identify Teak clones developed after observing large number of Teak clones. This key can be easily adopted to describe new clones from other regions also. Based on the variations observed, new descriptors can be developed. Hence the key is open-ended, upgradeable and useful.