Genetic diversity and population structure of Haloxylon salicornicum moq. in Kuwait by ISSR markers.

Haloxylon salicornicum moq. Bunge ex Boiss (Rimth) is one of the native plants of Kuwait, extensively depleting through the anthropogenic activities. It is important to conserve Haloxylon community in Kuwait as it can tolerate extreme adverse conditions of drought and salinity to be potentially used in the desert and urban revegetation and greenery national programs. Therefore, a set of 16 inter simple sequence repeat (ISSR) markers were used to assess genetic diversity and population structure of 108 genotypes from six locations in Kuwait. The ISSR primers produced 195 unambiguous and reproducible bands out of which 167 bands were polymorphic (86.5%) with a mean PIC value of 0.31. The overall average values of Nei's gene diversity (h') and Shannon's diversity index (I) were 0.254 and 0.375, respectively. Results of AMOVA revealed high genetic variations within populations (77.8%) and low among populations (22%). The values of Fixation index (FST = 0.22; P = 0.0), Genetic differentiation (GST = 0.262; G'ST = 0.327; D = 0.335 and Gene flow (NM = 0.880) were indicative of heterozygous populations. The results of STRUCTURE and split decomposition analysis suggested that the Rimth accessions of Kuwait can be grouped into five and six subpopulations, respectively. Principal coordinate analysis (PCoA) grouped them into three clusters. The pairwise Nei's genetic distances (DS) among populations demonstrated a narrow range from 0.047 to 0.187 (Scale-0.0 to 1.0). The Mantel's test revealed a weak correlation (r2- 0.188; P-0.013) between the genetic distance and geographic distances. Our results suggest that the narrowly distributed Haloxylon community in Kuwait demonstrated a high genetic diversity within the populations however the overall population structure was weak.