Abstract

Rattans are economically one of the most important group of forest species after timber trees. The rampant cane harvesting in the natural forest is threatening the stability of the wild rattan population. Hence conservation of the genetic resources of rattans require urgent action which necessitates an understanding of the genetic variation. A basic knowledge in the genetic diversity, reproductive biology and cytology is essential for formulating the conservation measures. Phenotypic variations werestudied in Calamus andamanicus, C.thwaitesii and C.palustris. In C.thwaitesii variations were noticed in stem diameter, leaflet arrangement, characteristics of leaf sheath characteristics and the length of inflorescence. In C.palustris no prominent phenotypic variation was noted. Genetic diversity studies show that provenances significantly differ with regard to seedling height. The phenotypic and genotypic coefficients of variation for seedling height were found to be high. Heritability was also found to be high. Highly significant correlation between height at different ages indicates the possibility of early selection. The species studied are dioecious and flowering is annual. The time of initiation of flowering varies slightly depending on the locality from year to year. Generally the flowering starts during July-August and the fruits mature in April-May. Three to four inflorescences are produced in a single plant during one season. In each inflorescence there will be 3-4 partial inflorescences. The order of emergence of partial inflorescence emits a sweet scent. The pistillate flowers do not produce nectar. The adjacent sterile staminate flower exudes nectar. Even though the morphology of Calamus inflorescence suggests wind pollination. Insects are the main pollinating agents. Bees are probably the important pollinators. Karyological studies in C.andamanicus and C.palustris revealed 26 chromosomes in the former and 28 in the latter. Chromosome size ranged from 0.89 to 2.46 um in C.palustris. InC.andamanicus size ranged from 0.44 to 2.22 um