Isozyme, ISSR and RAPD profiling of genotypes in marvel grass (Dichanthium annulatum)

 

Raghvendra Saxena¹ and Amaresh Chandra*²

¹Institute of Allied Science and Computer Application (IASCA), Institute of Technology and Management (ITM), University, Gwalior - 474 001, India

²Crop Improvement Division, Indian Grassland and Fodder Research Institute, Jhansi - 284 003, India

 

(Received: April 04, 2009; Revised received: March 08, 2010; Accepted: March 25, 2010)

 

Abstract: Genetic analysis of 30 accessions of marvel grass (Dichanthium annulatum Forsk.), a tropical range grass collected from grasslands and open fields of drier regions, was carried out with the objectives of identifying unique materials that could be used in developing the core germplasm for such regions as well as to explore gene (s) for drought tolerance. Five inter-simple sequence repeat (ISSR) primers [(CA)₄, (AGAC)_4, (GACA)₄]; 27 random amplified polymorphic DNA (RAPD)? and four enzyme systems were employed in the present study.? In total, ISSR yielded 61 (52 polymorphic), RAPD 269 (253 polymorphic) and enzyme 55 isozymes (44 polymorphic) bands. The average polymorphic information content (PIC) and marker index (MI) across all polymorphic bands of 3 markers systems ranged from 0.419 to 0.480 and 4.34 to 5.25 respectively. Dendrogram analysis revealed three main clusters with all three markers. Four enzymes namely esterase (EST), polyphenol oxidase (PPO), peroxidase (PRX) and superoxide dismutase (SOD) revealed 55 alleles from a total of 16 enzyme-coding loci. Of these, 14 loci and 44 alleles were polymorphic. The mean number of alleles per locus was 3.43. Mean heterozygosity observed among the polymorphic loci ranged from 0.406 (SOD) to 0.836 (EST) and accession wise from 0.679 (IG3108) to 0.743 (IGKMD-10). Though there was intermixing of few accessions of one agro-climatic region to another, largely groupings of accessions were with their regions of collections. Bootstrap analysis at 1000 iterations also showed large numbers of nodes (11 to 17) having strong clustering (>50 bootstrap values) in all three marker systems. The accessions of the arid and drier regions forming one cluster are assigned as distinct core collection of Dichanthium and can be targeted for isolation of gene (s) for drought tolerance. Variations in isozyme allele numbers and high PIC (0.48) and MI (4.98) as observed with ISSR markers indicated their usefulness for germplasm characterization.

Key words: Cluster analysis, Dichanthium annulatum, Genetic resources, Genetic similarity, Marvel grass, Polymorphism?

Copyright ? 2010 Triveni Enterprises. All rights reserved. No part of the Journal can be reproduced in any form without prior permission. Responsibility regarding the authenticity of the data, and the acceptability of the conclusions enforced or derived, rest completely with the author(s).