Implementation of association mapping for identification of ISSR markers linked with morphological characteristics of Ajowan (Trachyspermum copticum)

Ajowan (Trachyspermum copticum) is a medicinal species that is very useful and is used to treat stomach problems and some other diseases. This study was aimed to fingerprint Ajowan accessions which collected from different geographical regions of Iran by using ISSR markers and identify markers linked with agro-morphological traits through association mapping approach.

In this study, number of 40 Ajowan genotypes related to 10 different populations from different regions of Iran were collected and then their morphological characteristics were recorded in greenhouse condition. Leaf samples were taken from each genotypes and ISSR fingerprinting was done after DNA extraction.

The results of descriptive statistics indicate the existence of genetic diversity in the germplasm of the studied Ajowan in terms of morphological characteristics and the highest and lowest coefficients of phenotypic variation were obtained for the number of seeds formed and the number of flowers per umbrella, respectively. Results of DNA fingerprinting using 12 ISSR primers lead to amplification of 153 loci which 93 out of them was polymorph and the rest was monomorphic. Analysis of molecular variance depicted that 37% and 63% of total variation are belonged to between and within population. In this research private markers were detected for accessions collected from Hamedan and Rafsanjan. The study of population structure related to 40 Ajowan genotypes using ISSR data and STRUCTURE software placed them in two different subpopulations. Using association mapping approach, significant positive markers for biological yield, shoot dry weight, harvest index, number of lateral branches, number of seeds formed, 100-seed weight, mean internode length, umbrella per flower, stem diameter and Single plant yield, number of umbrellas, number of leaves, number of flowers in an inflorescence and leaf length were identified.

In this research, the UBC807-2, UBC812-10, UBC818-8, UBC840-5, UBC848-4, UBC857-11, and UBC857-6 markers control more than one trait simultaneously and can thus be bred in breeding programs of Ajowan in order to simultaneous selection of multiple traits.