Assessment of genetic relationships among Spring Dendrobium cultivars and varietal materials using amplified fragment length polymorphism (AFLP) analysis

Abstract

Spring Dendrobiums have been largely produced as one of the top grade ornamental pot plants due to their various flower colors, multitudinous flowers and graceful flower shape as well as their long period of florescence. Genetic relationships among Spring Dendrobium cultivars, however, have not been documented. This study analyzed the genetic relatedness of 30 commonly grown cultivars or varietal materials using amplified fragment length polymorphism (AFLP) markers with near-infrared fluorescence-labeled primers. Eight EcoRI + 3 bases/MseI + 3 bases primer set combinations were used in this investigation. Each selected primer set generated 113 to 158 scorable fragments. A total of 1102 AFLP fragments were detected, of which 778 were polymorphic (70.6%). An unweighted pair-group method of the arithmetic averages (UPGMA), principal coordinate analysis (PCOA), and bootstrap analysis were used to analyze the genetic relationships. The 30 cultivars were separated into five clusters. Cluster I contains 6 cultivars that are either from Senlan No.1 or Senlan No. 6 with Jaccardfs similarity coefficients ranging from 0.70 to 0.80. All of these 6 cultivars came from Taiwan, and were derived from somaclonal variants or sports. Just 3 cultivars were positioned in cluster II ranging from 0.71 to 0.76, and also originated from Taiwan. Cluster III included 13 cultivars, Jaccardfs similarity coefficients varied from 0.69 to 0.84. Seven cultivars from Senlan No. 15 or eSnowboy Romancef were situated in cluster IV with Jaccardfs similarity coefficients ranging from 0.69 to 0.82. Only eSantana Canaryf was positioned in cluster ‡X with Jaccardfs similarity coefficient at 0.62. This study established the genetic relationships of these commonly cultivated Spring Dendrobiums, and raised a concern over genetic vulnerability of cultivars in this study because of their close genetic similarities.

Key words: Spring Dendrobium, amplified fragment length polymorphism (AFLP), genetic relationship, cultivars and varietal materials.