Ramakrishna Hegde , Mohan Varghese , S. Padmini , R. S. C. Jayaraj

Abstract

Acacia mangium and A. auriculiformis are two species of Australian Acacias widely planted as exotics in humid tropical climates. Early introductions of A. auriculiformis to India resulted a land race of poor form. New seedlots of both the species were obtained from native collections of Australia and Papua New Guinea as well as from established Seedling Seed Orchards. These collections were compared with earlier introductions for seed and seedling characteristics and early performance in the field A. auriculiformis had larger and heavier seed and more seedling biomass than A. mangium but the species did not differ in the shape of seed. The Oriomo seedlots ofPNG are reported to perform well in moist areas and the same trend was seen in early growth performance in the present location which receives an annual rainfall of 1500mm. The study has to be continued to identify suitable seedlots for the region.

Full Text

     

S. Varadharajan , C. Buvaneswaran , Rekha R. Warrier , R. S. C. Jayaraj

Abstract

Global warming plays a major role in climate change which is caused mainly due to increase in CO₂ level in the atmosphere. Present study attempted to evaluate four important tropical tree-species, Tectona grandis, Ailanthus excelsa, Casuanna equisetifolia and Casuarina ,Jungkuhniana for adaptation to elevated levels of CO₂ at nursery stage. The study was conducted inside the poly tunnels and CO₂ enrichment was done to double the concentration. Seedlings in poly tunnel without CO₂ enrichment served as control The short term experiments revealed that of the four species studied, casuarinas performed well under elevated CO₂ conditions in terms of all growth parameters studied. The performance of teak alone was poor indicating adverse effect of CO₂ enrichment on morphological traits of tbiB species as seen by reduced leaf area, lesser dry' matter accumulation both in shoot and ischolar_main system and poor Seedling Quality Index at elevated CO, levels. Thus, in the present study, all the species except teak showed a positive response to CO₂ enrichment in terms of morphological traits while Cuuarina equisetifolia and C. junghuhniana showed better growth and seedling quality indicating their better adaptability to elevated CO₂level.

Full Text

     

R. S. C. Jayaraj

Abstract

No Abstract

Full Text

     

R. S. C. Jayaraj

Abstract

No Abstract

Full Text