2019 ASHS Annual Conference

Kalmia latifoliaL. (mountain laurel), an attractive flowering shrub, is considered to be a great ornamental plant for the eastern U.S. Wild plant resources have been historically involved in breeding programs to develop elite cultivars, however limited information on genetic diversity and relationship of wild mountain laurel would be an obstacle. Genetic diversity among and within eight mountain laurel populations and genetic relationship among 48 wild accessions sampled from eight populations were assessed. All accessions were analyzed using eight Inter Simple Sequence Repeat (ISSR) markers. A total of 116 bands were amplified, 90.52% of which (105) were polymorphic. The relatively low proportion of total genetic diversity among populations (G_ST=0.38) corresponding with the low percentage of variation among populations from AMOVA (30%) indicated that individual plants within populations were likely to be genetically different, but each population contained a similar complement of alleles in similar frequencies. A relatively large proportion of diversity was attributed to within-population variation, yet the low actual diversity within populations (H_S=0.19) was observed due to the small geographic size of populations and the ability of self of mountain laurel. Nei’s unbiased genetic identity indicated the higher genetic similarity between geographically closed populations (0.8994-0.9169) compared with that between geographically isolated populations (0.8024-0.8913). Correspondingly, UPGMA dendrogram exhibited the clustering of nearby populations and four clusters correlated with geographic regions. The overall results would benefit breeding of mountain laurel on collecting wild resources, selecting parents, and increasing genetic diversity.