Mary, K GeorgeMarkose, V CKAU2020-06-122020-06-121984http://krishikosh.egranth.ac.in/handle/1/5810147561PhDThe para rubber tree, Hevea brasiliensis, is the commercial source of natural rubber. Introduced into the Far East in 1876, from Brazil, commercial cultivation started in India during 1902. The tree has a gestation period of six to seven years. A large number of clones have been evolved through ortet selection and through hybridisation, which show variability for different characters. The present study was undertaken to estimate (1) productivity (2) yield pattern (3) variability (4) correlations (5) effect of yield attributes (6) genetic diversity of twenty clones, and (7) early growth vigour of open pollinated seedlings of selected clones.ennullThesis