Abstract
Exploration of local citrus genetic resources grown in the Kingdom of Bhutan was conducted in September 2007, Mongar and Trashigang in the east region, Wangdue Phodrang and Thimphu in the west region, and Tsirang in the south region. Among 14 accessions investigated, all accessions belonged to genus Citrus except one Bael (Aegle marmelos). Among them, eleven accessions were native and/or local Citrus genetic resources; one Ichang papeda relative, four Lime relatives, two Acidless limes, two Citron relatives, one Rough lemon relative, and one unidentified accession. Ichang papeda relative was found at elevations of around 2,000 m. In Bhutan, places at that altitude are normally too cold for any citrus tree to survive especially in winter where the temperature drops to below freezing, occasionally with snowfalls. Analysis of matK sequences revealed that chloroplast DNA of Bhutanese Ichang papeda relative and a preserved tree of Ichang papeda in Faculty of Agriculture, Saga University was different. MatK sequence of Bhutanese Ichang papeda relative was identical with that of a preserved tree of Khasi papeda in Saga University. Diversity was found in matK sequence among lime relatives. Precise accession identification could be conducted from the results of matK sequences in conjunction with morphological traits.
