THE POTENTIAL GENOTYPES WITH HIGH TIMBER VOLUME FROM SIX SPECIES IN THE 1995 RRIM HEVEA GERMPLASM COLLECTION

Abstract

The Hevea germplasm expedition by Rubber Research Institute of Malaysia in 1995 collected six Hevea species ( H. brasiliensis, H. spruceana, H. guainensis, H. nitida, H. benthamiana and H. pauciflora ) from the state of Amazonas of Brazil which are being conserved ex-situ in Rantau Panjang Reserve Forest, Batu Arang, Selangor. This expedition was a worthwhile scientific activity to safeguard valuable genetic resources for the future crop improvement of the Hevea species. However, after twenty years of establishment in the field, the evaluation of these materials is still rather limited and needs to be continued in order to explore the genetic potential of this germplasm. This paper highlights the evaluation of these genotypes for their potential as timber cultivars. A total of 5,789 individuals of the six Hevea species were evaluated in terms of girth, girth increment, bark thickness, annual bark increment, clear bole volume and total wood volume. At the age of 20 years, the highest clear bole volume observed for H. brasiliensis was 1.84 m 3 with straight, smooth and rounded trunk. As for the other Hevea species, the highest clear bole volume for H. spruceana was 1.19 m 3 , followed by H. guainensis with 1.10 m 3 , H. nitida with 0.98 m 3 , H. pauciflora with 0.90 m 3 and H. benthamiana with 0.89 m 3 . The identified genotypes have the potential to be used as a resource for timber to fulfil the demand of the rubber wood industry. However, further evaluation of these genotypes in high-density planting and under different environment is essential to verify their performance before a recommendation for wide scale planting could be made. Keywords: Genetic resources, Hevea species, the 1995 RRIM Hevea germplasm