Genetic Diversity of Some Tomato Lycopersicon esculentum Mill Varieties in Iraq Using Random Amplified Polymorphic DNA (RAPD) Markers


This study was conducted to evaluate the genetic diversity among 19 tomato varieties (determinate and indeterminate) cultivated in Iraq using polymerase chain reaction based DNA markers (PCR based DNA markers) ; Random Amplified Polymorphic DNA (RAPDs) .To achieve PCR reactions ,total genomic DNA was isolated from fresh leaves (2 weeks old).The average yields of DNA were in the range of 100-295 ng/μl with a purity ranging between 1.8-1.9.RAPDs amplifications were performed for varieties fingerprinting by testing 27 Operon primers. DNA polymorphisms among varieties were scored within detectable amplified fragments (their numbers and molecular weight) after agarose gel electrophoresis and staining by ethidium bromide. These 27 primers produced 442 of main bands,out of which 312 were polymorphic bands (70.5%) and 70 were monomorphic (15.8%) across all tested varieties. Each selected primer produced between 60 bands (OPA-14) to 290 bands (OPD-13). DNA amplification products ranged in their size from 250 bp ( OPA-01, OPU-14, OPX-15,OPX-19,OPT-08( to 2755 bp (OPX-18). The highest number of polymorphic bands (21 bands) was produced by primer OPU-03 while, the lowest number of polymorphic bands (3 band) was produced by both primers OPA-14 and OPB-17. The primers varied in their capacity in producing polymorphic amplified profiles among studied tomato varieties which individually reflected variety specific DNA profiles (fingerprints). The most important primers for this purpose were primers that produced more variety specific DNA profiles, such as OPD-13, OPT-08, OPW-04, OPA-04, OPA-15, OPB-18, OPU-03, OPC-09.The highest value of discrimination among varieties in this study was obtained by primer OPU-03 while the lowest discrimination value was produced by both primers OPA-14 and OPB-17.The primer efficiency ranged from 0.13 in (primer OPC-09) to 0.02 in (primer OPB-17). The lowest genetic distance was (0.2294) between varieties Oula and Shadylady, while, the highest genetic distance was (0.9459) between varieties Fotton and Special pack. Cluster analysis (phylogenetic tree) by unweighted pair-group method of arithmetic means (UPGMA) based dendrogram revealed that they were two main genetic groups (major clusters). The first small major clusters included four (4 varieties) while the second large major cluster included (15 varieties ). The overall analysis of the results show that RAPDs markers are powerful tool in fingerprinting and revealing the genetic relationships among tomato varieties.The relationship among varieties was not concern to their morphological characters and geographical origins