Genetic Variation, Population Structure and the Possibility of Association Mapping of Biochemical and Agronomic Traits Using Dominant Molecular Markers in Iranian Tea Accessions

One of the important methods for the study of quantitative traits is the association mapping through the use of phenotypic information and molecular markers. This study was carried out to examine the contrastive relationship between the biochemical and agronomic traits in tea accessions at the molecular level via association mapping and genetic diversity. In this study, 22 tea accessions were studied in an RCBD with two replications in 2017. Analysis of variance showed a significant difference between the accessions for the studied traits. Cluster analysis classified tea accessions into three groups based on the quantitative traits as well as DNA markers (SCoT and ISSR). Based on the Bayesian model, the tea accessions were classified into four subpopulations. In order to identify the molecular markers associated with the genes controlling traits variation, association mapping was carried out via two mixed linear models (MLM). Based on (G + P+K) and (G + P+Q + K) MLM models, 47 and 71 QTLs were identified for the studied traits, respectively. The SCoT4-1 locus was common between the four traits of chlorophyll a (CA), chlorophyll b (CB), total chlorophyll (CT) and leaf yield (LY) in both models. Also, the results showed that the development of STS and CAPS markers based on the identified markers can be used in breeding programs.