Genetic Diversity Analysis of Myanmar Royal Orchid, Thazin (Bulbophyllum auricomum) Cultivars

Abstract

Bulbophyllum auricomum, a fragrant orchid recognized as a royal flower in Myanmar, faces significant threats from habitat loss, illegal trade, and over collection across its limited wild distribution. This study analyzed morphological variation among 59 samples collected from six regions (Dawei/Tanintharyi, Rakhine, Kayin, Putao/Kachin, and Shan States) using 31 quantitative and qualitative traits, alongside SSR marker validation. UPGMA cluster analysis delineated three main groups: Cluster I (29 samples from Dawei (Htawei), Rakhine, Kayin, Putao) showed high genetic similarity and superior commercial traits like flower count and fragrance; Cluster II (Shan Yellow) and Shan (White) formed distinct out groups possibly due to selective breeding for pigmentation and form, despite geographic proximity. Qualitative traits were largely uniform (e.g., 100% linear leaves, fragrant flowers) while polymorphisms in sepal shape and color highlighted cultivar diversity. SSR analysis with 10 Cymbidium markers yielded limited polymorphism, confirming two (KNU-CC-40, KNU-CC-71) with region-specific patterns, underscoring genomic uniformity but subtle differentiation. These patterns reveal local adaptation, gene flow, and anthropogenic influences shaping diversity, informing targeted conservation of wild genetic resources and ex situ propagation of elite cultivars to bolster Myanmar’s orchid bioeconomy. Multivariate approach was found effective despite  resource constraints, advocating integration with molecular tool for breeding and taxonomic refinement.