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ISSR markers were analyzed to study phylogenetic relationships among 46 Citrus L. accessions representing 35 species. A dendrogram based on the unweighted pair-group method, arithmetic average cluster analysis was constructed using a similarity matrix derived from 642 polymorphic ISSR fragments generated by 10 primers. These 46 accessions could be classified into five major groups: 1) C. indica Tan.; 2) C. maxima (Burm.) Merrill; 3) lemon [C. limon (L.) Burm.] or lime [C. aurantifolia (Christm.) Swingle] type accessions; 4) C. halimii B. C. Stone; and 5) sour orange (C. aurantium L.), mandarins and their hybrids. Group 5 was further divided into three subgroups. Although some previous work had grouped it with mandarins, C. indica appeared to be a distinct genotype or species that was not close to mandarins. C. tachibana Tan. grouped closely to mandarins. C. vulgaris Risso was not related to sour orange but was similar to accessions usually classified in the lime or lemon group. Sour orange and its hybrids, C. nippokoreana Tan., C. hanayu Hort. ex Shirai, C. sudachi Hort. ex Shirai, and C. yuko Hort. ex Tan. had close phylogenetic relationships with mandarins. Although the mandarin accessions studied were divergent in morphology, the genetic distances among them were relatively small. Relationships among these Citrus accessions revealed by ISSR markers were generally in agreement with previous taxonomic classifications.

The genetic relationships among 96 peach and nectarine [Prunus persica (L.) Batsch.] genotypes and botanical varieties originating from different ecogeographical regions of China, Japan, North America, and South Korea were evaluated with 33 SSR markers screened from 108 published SSR markers developed for peach or sweet cherry (P. avium L.). The 33 SSRs detected polymorphisms among 96 genotypes and revealed a total of 283 alleles with an average of 8.6 alleles per locus. The polymorphism information content (PIC) value ranged from 0.40 (BPPCT041) to 0.98 (BPPCT009) with an average of 0.80. Unweighted pair group method average (UPGMA) cluster analysis based on Nei's genetic distances classified genotypes into six groups, corresponding to their ecogeographical origin. Group I consisted of northern Chinese and northwestern Chinese local cultivars, and was divided into two subgroups, white and yellow peaches. Group II contained mainly southern Chinese local, Japanese, and North American cultivars and can be divided into four subgroups: Japanese white, Chinese flat, North American yellow, and some Chinese local ornamental peach cultivars. Groups III, IV, and V were comprised of Chinese local ancient cultivars, and contained `Xinjiangdatianren' and `Renmiantao', Chinese dwarf cultivars, and `Fenshouxing', respectively. Group VI had only `Baishanbitao', a Chinese ornamental cultivar. Northern and northwestern Chinese local cultivars clustered together with a greater diversity than southern Chinese local cultivars, indicating that the northern and northwestern Chinese local cultivars are similar ecotypes, and southern Chinese local cultivars are a subset of the northern Chinese group. Moreover, the Japanese and North American genotypes had a close phylogenetic relationship with southern Chinese local cultivars. The taxonomic placement of P. ferganensis (Kost. et Kiab) Kov. et Kost. and the phylogenetic relationship of `Baishanbitao' with peaches are discussed.

Fifteen highbush (or highbush hybrid) blueberry cultivars (Vaccinium corymbosum Linnaeus), two rabbiteye blueberry cultivars (V. ashei Reade), and one southern lowbush (V. darrowi Camp) selection from the wild were examined using seventeen 10-base RAPD and seven 15- to 18-base SSR-anchored primers (primers comprised of SSR motifs) in polymerase chain reactions (PCRs). Fifteen RAPD and three SSR markers resulting from these reactions were chosen to construct a DNA fingerprinting table to distinguish among the genotypes included in this study. Similarity values were calculated based on 132 RAPD and 51 SSR bands, and a dendrogram was constructed based on the similarity matrix. The V. ashei cultivars and V. darrowi selection grouped out separately from the V. corymbosum cultivars as expected. However, estimates of relative genetic similarity between genotypes within the V. corymbosum group did not agree well with known pedigree data and, thus, indicated that RAPD and SSR data did not accurately assess the genetic relationships of cultivars within this species.