Genetic diversity in sewan grass (Lasiurus sindicus Henr.) in the hot arid ecosystem of Thar Desert of Rajasthan, India

Abstract

Aim : Sewan grass (Lasiurus sindicus Henr.), considered as the “King of Desert Grasses”, is a dominant grass species of hot arid ecosystem of Great Indian Desert, covering Western Rajasthan and parts of Pakistan. This grass is extremely drought resistant and thrives even in areas receiving very low rainfall (100 to 150 mm) annually under extreme temperatures ranging from -3 to 50 ºC. The present study was undertaken to analyze the extent of genetic variability existing among the L. sindicus germplasm collected from Bikaner, Barmer and Jaisalmer, the diversity rich districts of hyper-arid Rajasthan, using ISSR and RAPD markers. Methodology : Twenty seven genotypes of L. sindicus were collected from Jaisalmer (10 accessions), Barmer (9 accessions) and Bikaner (7 accessions) and 1 old collection maintained at CAZRI, Jodhpur, Rajasthan was used in this study. A total of 18 RAPD and 14 ISSR markers were screened of which 12 RAPD and 10 ISSR primers amplified distinct and scorable fragments. Data analysis was performed using NTSYS-pc, SIMQUAL, Genalex 6.5 and POPGENE version 1.32 programs, and dendrograms were generated using unweighted pair group method for arithmetic mean (UPGMA). Results : The comparative analysis of data showed that RAPD markers were better than ISSR with regard to polymorphism detection, as they detected 90% polymorphism in comparison to 74% for ISSR markers. The values of average number of polymorphic fragments per assay, polymorphism information content (PIC) and discriminatory power (Dj) were more for RAPD (5.83, 0.222 and 0.78 respectively) than for ISSR (5.7, 0.138 and 0.605 respectively) markers. The UPGMA clustering was not conspicuous under the influence of high within region diversity, however, accessions collected from same region tended to cluster together. Genetic similarity values obtained from Jaccard's coefficient using combined data of both the marker systems were between 0.58 and 0.74. Interpretation : The results indicated the existence of wide genetic variability within and among regions in this species which can be used for germplasm conservation and improvement.