Genetic diversity in 'Xianlajiao' pepper (Capsicum annuum var. annuum) in China

Z.L. Zhao, G.P. Wu, N.L. Xu
'Xianlajiao' is a unique type of pepper (Capsicum annuum var. annuum) that has been cultivated on a large scale for many years in China. There is a high degree of phenotypic diversity present in 'Xianlajiao' germplasm in China. The genetic diversity of 20 Capsicum germplasm accessions (including 13 'Xianlajiao' and seven other Capsicum accessions) was analyzed by means of RAPD and SSR markers. Molecular marker analyses were compared with an analysis based on morphological characters. The results showed that both types of molecular markers can uncover genetic diversity within the 20 Capsicum accessions, and that genetic diversity estimates obtained with SSRs was higher than with RAPDs. With RAPDs, three to ten fragments were amplified with each primer, with an average of 5.7 per primer. Using 38 random primers, 218 bands were amplified in the 20 accessions, and 168 of these were polymorphic (the polymorphism ratio was 77.1%). The genetic similarity (GS) of the 20 Capsicum accessions ranged from 0.615 to 0.905. In the SSRs, between two and eight fragments were amplified per primer pair (average, 4.4). Based on 33 pairs of SSR primers, 153 fragments were amplified in the 20 accessions, 128 of which showed polymorphisms (the polymorphism ratio was 82.3%). The GS of the 20 Capsicum accessions ranged from 0.632 to 0.886. Correlation analysis showed that the correlation coefficient between RAPD markers and morphological traits was 0.743, the correlation coefficient between SSR markers and morphological traits was 0.710, and the correlation coefficient between the combined RAPD+SSR data and morphological traits was 0.65; all of these correlation coefficients were statistically significant. Cluster analysis showed that accessions with higher GS and similar morphological characteristics tended to cluster together. There was a good agreement between the results obtained using molecular markers and morphological characters.
Zhao, Z.L., Wu, G.P. and Xu, N.L. (2016). Genetic diversity in 'Xianlajiao' pepper (Capsicum annuum var. annuum) in China. Acta Hortic. 1127, 521-526
DOI: 10.17660/ActaHortic.2016.1127.83
pepper, random amplified polymorphic DNA, simple sequence repeats, morphology, genetic diversity

Acta Horticulturae