Comparative Analysis of Rapd and Issr Markers For Assessing Genetic Diversity Among Pigeonpea (Cajanus Cajan) Genotypes.

Abstract

Development and use of molecular markers for the detection and exploitations on DNA polymorphism is one of the most significant development in the field of molecular genetics. Currently only a few studies have been performed on Caianus Cajan at a molecular level. Therefore a, range of pigeonpea Accessions was used in this. study to demonstrate the Applicability of RAPD & ISSR analysis for assessing the genetic diversity between and within accessions of Cajanus cajan germplasm. Forty two pigeonpea varieties/ genotypes were evaluated for biodiversity analysis under in vitro, condition at Molecular Biology Laboratory (MBL), SVP University of Agriculture and Technology, Meerut. In the RAPD results all the chosen primers amplified fragments across the 42 genotypes studied, with the number of amplified fragments ranging from I (OPJ-08F) to 7 (OPF-14F). The total number of bands generated by 10 primers was 43 with an average of 4.3 bands per primer. Of the 43 amplified bands, 39 were polymorphic, with an average number of bands per primer and average number of polymorphic bands per primer was 4.3 and 3.9, respectively. Percentage polymorphism ranged from 66% (OPF-17F, OPJ-13F) to a maximum of 100% (6 primers), with an average of90.6% polymorphism. Only 2 ou~ of 10 primers showed less than 75% polymorphism. Genotypes ICP- 14968and ICP-15018 and ICP-14760 and ICP-13207 were 100% similar. The value ofP1C ancl ' Resolving power ranged from 0.489 (OPJ 08F) to 0.951 (OPC 15F) and 0.714 (OPC 15F) to 6.5(0PC 7F) for primer of RAPD patterns respectively. A dendrogram based on UPGMA analysis grouped the 42 genotypes into two main clusters I and clusters II with Jaccard's similarity coefficient ranging from 0.65 to 0.95. In the ISSR results the number of polymorphic bands ranged from 2 to 8 with a range of polymorph isms 86.5percent in all primers. The size or the amp !icons generated varied from 300 bp to 1300 bp. The total number of bands generated by 10 primers was 52 with an average of5.2 bands per primer. Ofthe 52 amplified bands, 45 were polymorphic, with an average number of bands per primer and average number of polymorphic bands per primer was 5.2 and 4.9, respectively. Percentage polymorphism ranged from SO% (ISSR-2F) to a maximum of 100% (5 primers), with an average of 86.5% polymorphism. Only 2 out of 10 primers showed less than 75% polymorphism. The value of PIC and Resolving pwer ranged from 0.4726 (ISSR-2F) to 0.9822 (ISSR-7F) and 0.666 (ISSR-7F) to 6 (ISSR-9F) for primer of ISSR patterns respectively. PIC was the highest for the ISSR primer 0.9822 (ISSR-7F) ·and was the lowest for the primer 0.4726 (ISSR-2F) with an average value of 0.7673. The Jaccard 's pair wise similarity coefficient values for pigeon pea ISSR ranged from 0.70 to 0.98 for single primer based ISSR patterns. All the 10 amplifying arbitrary primers produced polymorphic bands. None of the single primers produced unique patterns for all the genotypes collectively. Genotypes ICP 1090 and, ICP8258 were I 00% similar. It is, therefore, not surprising to find significant levels of polymorphism among the 42 genotypes of Cajanus cajan with RAPD and ISSR markers. RAPD markers were more efficient than the ISSR assay with regards to polymorphism detection, as they detected 90.6% as compared to 86.5% for ISSR markers. Whereas the average number of polymorphic bands per primer and total number of polymorphic bands are more for ISSR (4.5 and 45 respectively) than for RAPD (3.9 and 39 respectively). Resolving power (Rp), PIC value, average number of bands per primer, were more for JSSR (6.0, 0.982, and 5.3, respectively) than RAPD markers (6.5, 0.950 and 4.3 respectively). Based on ISSR marker system, the similarity index values ranged from 0.70 to 0.98 while that on the basis of RAPD markers ranged from 0.6;5 to 0.95. Similarity indices values based on both the marker systems together ranged from 0.71 to 0.93 indicating more diversity in case ofRAPD. In comparative analysis of RAPD and ISSR primers only ICP-14968 and ICP-15018 show max similarity. The UPGMA dendrogram obtained from the cluster analysis of RAPD and ISSR combined data gave near similar clustering pattern, with Jaccard's similarity coefficient ranging from 0.71 to 0.93.The close correspondence between the genetic similarity matrices ofRAPD and ISSR revealed that all the two marker systems could be effectively used individually or in combinations for detet:glination of genetic relationships among pigeonpea genotypes.