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AFLP-based genetic diversity among the populations of Rosa laxa in Tianshan Mountains of Xinjiang, China

Yang, S.H., Guo, N., Ge, W.Y., Ge, H.
Acta horticulturae 2013 no.977 pp. 307-312
Rosa laxa, amplified fragment length polymorphism, cold, environmental factors, gene flow, genes, genetic variation, genotype-environment interaction, introgression, loci, mountains, Central Asia, China
Rosa laxa Retz. has been used for introgression of cold resistant traits into modern roses for many years. It is widely distributed in the regions of Central Asia. In this study, six populations of R. laxa in Tianshan Mountains of Xinjiang, China, were investigated for their genetic diversity with AFLP markers. Results showed that the number of polymorphic loci (NPL) and the percentage of polymorphic loci (PPL) varied from 142 to 168 and from 52.40 to 61.99% among five out of the six populations except the extremely lower NPL (97) and PPL (35.79%) for population 6 (P6), indicating an abundant molecular polymorphism in the first five populations while there were a much lower genetic diversity in P6. Likewise, both Nei’s genetic diversity index (h) and Shannon information index (I) exhibited slight fluctuation within the first five populations of R. laxa except the lowest h (0.1192) and I (0.1793) in P6, confirming the lowest genetic differentiation in P6 among the six populations studied. Gene differentiation (G(st)) of 0.3236 showed that there was relatively lower genetic diversity among populations than within populations of R. laxa. Moreover, estimated value of gene flow (N(m)) of 1.0451, quite lower than the N(m) threshold, further indicated the moderate gene flow among populations of R. laxa. In comparison to previous study that the clustering of morphological polymorphism is mainly due to environmental factors, clustering analysis on molecular polymorphism showed six populations were grouped mainly according to geographic distances, indicating the interaction between genotype and environments.