Study of the Molecular Diversity of Internal Transcribed Spacer Region (ITS1.4) in Some Lettuce Genotypes

Lettuce is belong to the Cichorium family with leaf consumption, Annual cold weather plants and rich in minerals, vitamins and nutrients. The aim of the present study was to evaluate the genetic diversity of 15 varieties and lettuce populations using the ITS area. Sequence quality was evaluated using Chromas 2.1.1 software, aligned by MegAlign 5 software and then similarity matrix and dendrogram of phylogenic relationships of Lettuce sequences were conducted using Mega 6 software. Also, a comparison was conducted among the lettuce were used in this research and other plants of the Asteraceae genus family (presented on NCBI site). The numerical value of the ratio (dN/dS) was 0.015, which indicates a pure selection in the examined gene and has not caused any key changes. Cluster analysis split the different genotypes of lettuce into 3 groups and could not differentiate by geographical location but it could separate the lettuce of this research and other plants from different species of the Asteraceae family related by NCBI. Therefore, it can be concluded that ITS can be a suitable tool for genetic evaluations among genus and among species. The inability of ITS marker to separate the intra-species of populations it could be because dN/dS was less than and a small number of deletion and insertion sites (376 out of 1551 positions) indicating low variation between different genotypes and populations. Considering that the Initial origin of the plants is belong to the centers that are most diverse and because varzaneh Lettuce populations of Isfahan have the most varieties, as a result, it is necessary to pay more attention to the Varzaneh region of Isfahan to collection of lettuce germplasms for breeding programs.