Assessment of certain wood quality parameters of selected genotypes of Melia dubia Cav. grown in a seedling seed orchard
Certain wood quality parameters of about 9-year-old Melia dubia Cav. trees grown in a seedling seed orchard at Yeshwanthpura Research Station of Kolar research range, Karnataka India were studied. Trees were categorized into three classes depending upon their girth at the breast height––small (<40 cm), medium (40–60 cm) and big (>60 cm). Different anatomical (gross structure), physical and mechanical properties of the wood were evaluated using standard testing procedures and Indian Standards. The results of this study showed that there was no significant difference in the heartwood percentage and specific gravity among three girth classes. High shrinkage values from green to oven-dry condition in all the classes indicate that the timber is dimensionally unstable compared to teak. The static bending strength parameters––FS at LP, MOR and MOE, compression strength parallel to grain, compressive strength perpendicular to grain at limit of proportionality and surface hardness (side and end) were evaluated and compared among all the three girth classes. The data on mechanical properties were statistically analysed using ANOVA between three girth classes. The results on wood quality parameters may be utilized in selection of suitable genotypes for raising large scale plantations.
Species delimitation of Melia dubia Cav. from Melia azedarach L. complex based on DNA barcoding
The genus Melia L., which belongs to the ‘Mahogany’ family Meliaceae, is a source of important phytochemicals with marked medicinal properties. Species identification in Melia is complex due to the existence of overlapping morphological features. Though Melia dubia Cav. is listed as a synonym of Melia azedarach L., it is not clear from the available literature whether they are the same species or different, and the species complexity still remains unresolved. In the present study, ten accessions of M. dubia and M. azedarach were analysed by DNA barcoding using three chloroplast DNA markers (rbcL, matK, and trnH-psbA), and one nuclear marker (ITS2). Intra-specific divergence was not found in any of the four markers. However, the inter-specific divergence between M. azedarach and M. dubia ranged between 0.3% (rbcL) and 4.7% (ITS2) for individual markers, and for the combined dataset, it was 8.5%. Among the four markers, ITS2 was found to be the most suitable marker for differentiating M. azedarach and M. du...
Vegetative propagation of Parkia biglobosa (Jacq.) Benth., an undomesticated fruit tree from West Africa
SummaryThe rooting of single node leafy stem cuttings from seedlings of Parkia biglobosa (Jacq.) Benth. was examined with respect to provenance, auxin application, basal wounding, and the nodal position on the shoot. Provenances of P. biglobosa from three West African savanna ecozones: Derived, Guinea and Sudan were used for the study. In the absence of auxins and basal wounding, 40% of the cuttings rooted and 80% survived throughout the observation period of 6–8 weeks. However, the addition of auxins and wounding significantly affected the rooting of the cuttings. 100 ppm of the auxin α-napthalene acetic acid (NAA) was more effective than 100 ppm indole-3-butyric acid (IBA). However, when the concentration of both auxins was increased to 200 ppm, IBA was more effective than NAA. In general, wounding cuttings by making a diagonal cut at the end of the stem enhanced rooting, yet the application of 100 ppm NAA negated the beneficial effect. Bruising the stem was detrimental to rooting, except for cuttings f...