Genetic diversity, population structure and gene flow pattern among populations of Lasiurus sindicus Henr. - an endemic, C4 grass of Indian Thar desert

Abstract

Lasiurus sindicus Henr. (Sewan grass), an endemic perennial grass species, has a restricted and fragmented population in Indian Thar desert. Four single primer based DNA markers viz., ISJ, DAMD, ISSR and SCoT were used for genetic diversity analysis of 48 accessions of L. sindicus collected from 24 sites. The percentage polymorphic bands (PPB) produced for ISJ, DAMD, ISSR and SCoT were 86.73%, 75.20%, 89.05%, and 96.67% respectively. Highest resolving power (Rp) and marker index (MI) were calculated for ISSR and SCoT markers respectively. Shannon's information index (I) ranged between 0.309 and 0.379 with an average value of 0.415. Nei's gene diversity (h) ranged between 0.209 and 0.257 with overall diversity of 0.268. Gene flow (Nm) and the diversity among populations (Gst) were recorded 2.889 and 0.152, respectively. AMOVA revealed high percentage of variations (88%) within populations whereas variations among populations were 12% only. The clustering pattern of Neighbour Joining (NJ) and sequential, agglomerative, hierarchical, and nested (SAHN) tree did not yield clear and distinct pattern of genetic structure. However, accessions viz. JNVU LS BN- 13, 14, 15 and 16, from Bikaner, were shown to have grouped together as well accession JNVU LS BN-24 from Bikaner and accession JNVU LS JS-39 from Jaisalmer. The Principal co-ordinate analysis (PCoA) also supported these results. Mantel's test showed that there was no correlation between genetic distance and geographical distance (R2 = 0.0072). Nei's (1978) unbiased genetic diversity analysis revealed that population from Jodhpur and Barmer was closely related while population from Jaisalmer and Bikaner were most diverse. A comprehensive analysis of all these genetic diversity parameters enables to devise means and strategies for effective and meaningful conservation and management of L. sindicus.