Abstract:
The rubber tree (He»ea brasiliensis muell.Arg.) is indigenous to the tropical rain forests in Brazil (Thomas and Panikkar, 2000). It is the only major commercial source of natural rubber (T'J R). In commercial plantations, the economic like span of rubber tree is about 30 years. In Sri Lanka, the rubber industry provides remarkable benefits to increase the living standards of human being as sinii far to other rubber growing countries. Ac the beginning of the commercial plantations, seedlings were used as planting materials (Panikkar e/ at., 1 980). Panikkar e/ at., (1980) and Seneviratne e/ at., ( 1 998) showed high variation among
Individuals in such plantations. However, to avoid * 8I1 variation in plantations Rubber Research Institute of Sri Lanka has introduced about fourty five rubber clones at present,
i.e. RRIC 100 series, RRISL 200 series, ftRlSL 2000 series etc, A long time period is needed to develop, test and release a clone of rubber. Also the growth and yield of the tree vary according to the clone. Photosynthetic and growth parameters are important characters which affect the crop productivity. Carbohydrate is the main product of process of the photosynthesis and subsequently a part of these assirilates are converted into polyisoprene which is the NR o£ rubber latex. The photosynthetic parameters can also be changed due to type of the clone. Correlations can be exist between selected characteristics of the immature plants with the pet formai1ce of mature plants of the same clone. I£ mature tree performance
can be Forecast Iron immature trees, it will l1elp to reducing period spent on the clonal evaluation program. There Fore, the present study was carried out to identification of clonal differences of rubber based on photosynthetic parameters that is very much important to develop early detection criteria for rubber clone.
