Genetic diversity and phylogenetic relationship among small cardamom (Elettaria cardamomum Maton.) cultivars and related genera using DNA markers

Elettaria cardamomum Maton is a monotypic genus native to India but a few related tribes like Amomum, Aframomum, Alpinia and Hedychium, coexist with small cardamom. In the present study, about 11 species representing 5 major tribes viz., Amomum, Aframomum, Alpinia, Hedychium and Elettaria and 96 collections of cardamom germplasm representing the range of genetic variability available in different Cardamom Research Centers were studied using RAPD, PCR -RFLP and ISSR polymorphism. The study indicated that all the genotypes are distinct from each other and there are no duplicates in germplasm collections studied. Among the released varieties and promising genotypes, the lines developed by different research centers by selection, clustered together, indicating narrow range of diversity from which these selections are made. But the distinct grouping of hybrids showed that the varieties developed by hybridization have higher divergence. Hence, hybridization rather than selection should be the preferred method of improvement to broaden the genetic base of cultivated cardamom. Among the eleven species representing 5 major tribes studied, Amomum is closer to cultivated cardamom. The present study revealed that the genetic variation expressed by molecular markers is relatively low among the cultivated cardamom though most of them are clear morphological variants and this is expected from a monotypic genus like Elettaria.