Isozyme variation in five provenances of Santalum album in India

Abstract

Santalum album L., the 'East Indian sandalwood', is among the oldest known perfumery material, highly acclaimed worldwide. Genetic diversity within and between five Indian sandal provenances, namely Marayoor (Kerala state), Bangalore, Mandagadde and Thangli (Karnataka state) and Javadis (Tamil Nadu state), was investigated by using metabolic enzymes, viz. peroxidase (PRX), shikimate dehydrogenase (SKDH), glucophosphate isomerase (GPI), malate dehydrogenase (MDH) and esterase (EST). Ten of the eleven resolved loci (90.9%) were found to be polymorphic at least in one of the individuals analysed. Observed heterozygosity, both at the locus and provenance level, was higher than the expected heterozygosity in Hardy–Weinberg expectations. The average rate of gene flow between the provenances was found to be very low (0.069). An examination of the partitioning of genetic diversity within and between provenances indicated that 78.3% of the observed variation occurred between provenances and the rest of the variation within provenances. The genetic relatedness of the five provenances was revealed by the UPGMA dendrogram, which comprised of mainly two clusters. Bangalore and Thangli were the most genetically similar and Marayoor and Mandagadde were the most diverse provenances. The low degree of genetic variability within Santalum album provenances might be due to the fragmentation of a previously large original population, resulting in loss of genetic variation, least amount of gene flow between provenances and differentiation of population due to random drift.