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Cultivar fingerprinting with RAPD markers has been achieved in a number of plant species (Demeke et al. 1997). Wang et al. (1994) successfully identified inbred parents and their hybrids in rice using RAPD markers. Two random primers were sufficient to distinguish 14 cultivars of broccoli, whereas three primers distinguished 12 cultivars of cauliflower (Hu and Quiros 1991). In this study, a RAPD marker, RC37700 specific for the cultivar AC Domain (Fig. 2), was found after screening the 31 primers against 29 cultivars. In order to confirm if this marker was unique to AC Domain, a further 45 registered Canadian and American wheat cultivars (Table 3) were screened with the primer RC37. With the exception of AC Domain, the RAPD marker RC37700 was not produced when the DNA of the 45 additional common wheat cultivars listed in Table 3 was amplified in the presence of the primer RC37 (Fig. 3), confirming that RAPD marker RC37700 was specific to the cultivar AC Domain.

In the current study, the cultivar pedigree relationships (Table 1) were in agreement with cultivar relationships obtained using cluster analysis based on RAPD polymorphism data (Fig.4). In the dendrogram, subgroup 1 consisted of the cultivars which share CIMMYT-based (Mexico) pedigrees. The cultivars sharing "North Dakota" germplasm in their pedigrees were clustered into subgroup 2. All cultivars in subgroup 3 had a Neepawa-involved pedigree. In this. subgroup, the cultivars Columbus and AC Minto were very close to the cultivars Crocus and AC Cora, respectively, with a genetic similarity coefficient of 0.97. The results are in agreement with the fact that Columbus and Crocus are near-isogenic for two crossability alleles (Zale 1993), and that AC Minto and AC Cora share more than 94% of their pedigrees with Neepawa. In subgroup 4, both cultivars are winter wheats of Russian origin. Bezostaya 1 is a Russian cultivar while Norstar, a Canadian cultivar, is partly of Russian origin since its parent cultivar Alabaskaya is a Russian land race. The apparent lack of divergence between spring and winter wheats is somewhat surprising since winter and spring wheats probably represent different gene pools. Three cultivars (Wildcat, Laura and Leader ) did not fall within the five sub-groups and the pedigrees of these three cultivars were different from each other and from the cultivars in the five sub-groups. There was a significant correlation between coefficients based on Jaccard genetic similarity and the coefficients of parentage (r = 0.69, data not shown), indicating that the genetic similarity values appear to correctly reflect the genetic background of the samples analyzed. Hallden et al. (1994) compared RFLP and RAPD markers for their ability to determine genetic relationships in B. napus breeding lines. They confirmed that RAPD markers could estimate the relationship between closely related B. Napus genotypes. RAPD markers have also been used successfully to determine cultivar relationship in broccoli and cauliflower (Hu and Quiros 1991), barley (Tinker et al. 1993) and celery (Yang and Quiros 1993). Previous studies and the present study indicate that RAPD analysis can be used to assess common wheat cultivar genetic relationships.

In conclusion, cultivar- specific markers were found to be stable and might he used to fingerprint spring wheat cultivars. A significant correlation between genetic coefficients based on RAPD markers and cultivar pedigrees was detected, indicating that the RAPD data provide a good indication of genetic relatedness. These results suggest that if such an analysis is extended to additional wheat cultivars with unknown pedigree, it would be possible to obtain information on their genetic relationships. The utilization of RAPD has been confirmed by Cao et al. (1999) for the reclassification of Triticum accessions, Qian et al. (2001) for the detection of genetic diversity in wild rice (Oryza granulata L.) and Fernandez et al. (2002) for genotype identification among barley cultivars. Sharma et al. (1996) reported that AFLP technique can detect much higher levels of polymorphisms than the RAPD analysis. Recently, this technique has been used to analyze genetic similarity among genotypes of sugar cane (Saccharum spp.) (Lima et al. 2002) and to estimate genetic diversity in modern cultivars of durum wheat (Triticum turgidum L. subsp. durum Husn.) (Soleimani et al. 2002). AFLP technique maybe more efficient than RAPD for study of genetic diversity and cultivar genetic relationships.

Acknowledgments

The authors are grateful to the financial support provided by Winisky Trust and the Agriculture Research Trust of the University of Saskatchewan, College of Agriculture.

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