An, D., Bykova, N. V. and Debnath, S. C. 2015. EST-PCR, EST-SSR and ISSR markers to identify a set of wild cranberries and evaluate their relationships. Can. J. Plant Sci. 95: 1155Á1165. The cranberry (Vaccinium marcrocarpon Ait.) is a woody, evergreen, perennial vine with great potential for economic and health benefits. Selection and use of genetically diverse genotypes are key factors in any crop breeding program to develop cultivars with a broad genetic base. Molecular markers play a major role in selecting diverse genotypes. One hundred and two wild cranberry clones collected from four Canadian provinces and five cultivars were screened with inter simple sequence repeat (ISSR), expressed sequence tagÁ simple sequence repeat (EST-SSR) and ESTÁpolymerase chain reaction (PCR) markers to validate the genetic diversity and relationships among them. EST-PCRs (0.54) and EST-SSRs (0.35) generated higher frequency of major alleles than ISSRs (0.08), but ISSRs presented a higher level of polymorphism and greater polymorphic information content and expected heterozygosity than EST-SSRs and EST-PCRs. Combined cluster analysis by the unweighted pair-group method with arithmetic averages (UPGMA) separated the wild clones and cultivars into four main clusters, which was in agreement with the principal coordinate (PCo) analysis. Analysis of molecular variation detected sufficient variations among genotypes within communities and among communities within provinces with ISSR (66 and 36%, respectively), EST-PCR (72 and 34%, respectively) and EST-SSR (72 and 34%, respectively) markers. These values were 71 and 35%, respectively, for combined analysis. Combined use of three types of molecular markers, for the first time in Vaccinium species, detected a sufficient degree of variation among cranberry genotypes, allowing for differentiation and rendering these technologies valuable for genotype identification in a diverse cranberry germplasm and for more efficient parental choice in the current cranberry breeding program. Abbreviations: AFLP, amplified fragment length polymorphism; AMOVA, analysis of molecular variance; CCC, cophenetic correlation coefficient; EST, expressed sequence tag; ISSR, inter simple sequence repeat; PCo, principal coordinate; PCR, polymerase chain reaction; PIC, polymorphism information content; RAPD, randomly amplified polymorphic DNA; SSR, simple (short) sequence repeat; UPGMA, unweighted pair group method with arithmetic means Can.

Wild germplasm with elevated antioxidants are a useful resource for using directly and in a breeding program. In a study with 136 wild clones and two cranberry cultivars, phenolic, flavonoid and anthocyanin contents varied 2.79, 2.70 and 17.46 times, respectively. The antioxidant activity ranged from 1.17 ± 0.01 to 2.53 ± 0.05 mg/g and varied 2.16 times. Seventy-five of wild clones and the cultivar Franklin were grouped into five distinct classes by molecular structure analysis using inter simple sequence repeat (ISSR), expressed sequence tag-simple sequence repeat (EST-SSR) and EST-polymerase chain reaction (PCR) markers. Grouping with DNA markers did not coincide with that of based on antioxidant properties. Present study indicates that genetic diversity analysis combined with antioxidant properties of wild germplasm play a significant role for conservation and in selecting diverse genotypes for future berry crop improvement.

Debnath, S. C., Siow, Y. L., Petkau, J., An, D. and Bykova, N. V. 2012. Molecular markers and antioxidant activity in berry crops: Genetic diversity analysis. Can. J. Plant Sci. 92: 1121–1133. An improved understanding of important roles of dietary fruits in maintaining human health has led to a dramatic increase of global berry crop production. Berry fruits contain relatively high levels of vitamin C, cellulose and pectin, and produce anthocyanins, which have important therapeutic values, including antitumor, antiulcer, antioxidant and anti-inflammatory activities. There is a need to develop reliable methods to identify berry germplasm and assess genetic diversity/relatedness for dietary properties in berry genotypes for practical breeding purposes through genotype selection in a breeding program for cultivar development, and proprietary-rights protection. The introduction of molecular biology techniques, such as DNA-based markers, allows direct comparison of different genetic materials independent of environmental influences. Significant progress has been made in diversity analysis of wild cranberry, lowbush blueberry, lingonberry and cloudberry germplasm, and in strawberry and raspberry cultivars and advanced breeding lines developed in Canada. Inter simple sequence repeat (ISSR) markers detected an adequate degree of polymorphism to differentiate among berry genotypes, making this technology valuable for cultivar identification and for the more efficient choice of parents in the current berry improvement programs. Although multiple factors affect antioxidant activity, a wide range of genetic diversity has been reported in wild and cultivated berry crops. Diversity analysis based on molecular markers did not agree with those from antioxidant activity. The paper also discusses the issues that still need to be addressed to utilize the full potential of molecular techniques including expressed sequence tag-polymerase chain reaction (EST-PCR) analysis to develop improved environment-friendly berry cultivars suited to the changing needs of growers and consumers.