Umbrella fern [Sticherus flabellatus (R. Br.) St John] is a successful Australian native foliage product. Currently, all umbrella fern sold on the market is bush-harvested. To meet the growing demand for this product on local and international markets, a commercially viable method for its production must be developed, with effective management of the germplasm resource in terms of conservation and exploitation. To manage this resource, breeders require a detailed knowledge of the amount and distribution of genetic variability within the species. Traditionally, plant breeders focus on a combination of agronomic and morphological traits (phenotype) to measure genetic diversity. In umbrella fern there are a limited number of morphological traits, and these are influenced by environmental factors and therefore do not reflect true genetic diversity. To overcome these problems, molecular techniques such as PCR-based DNA markers are used to complement traditional strategies for genotype assessment. DNA markers have the advantages of being independent of environmental effects, as well as being fast, cost-effective, reproducible, and largely accessible to the nonmolecular geneticist. Amplified fragment length polymorphisms (AFLPs) fulfil many of the desirable features of molecular markers, as well as requiring little knowledge of the genome to be investigated. AFLPs have been used widely in the analysis of breeding systems, ecogeographical variation, and genetic variation within and between natural populations. To date there are no published accounts of DNA molecular marker research on umbrella fern. A DNA extraction protocol has been developed for this species, and AFLP markers have been used to analyse genetic diversity within and between natural populations sampled in the Sydney Basin. A large number of polymorphic loci were revealed using 11 primer combinations. The genetic variation detected was partitioned between rather than within populations, suggesting that the mating system in Sticherus is primarily inbreeding. Data will be presented illustrating AFLPs as useful molecular markers for assessing genetic diversity within and between populations of umbrella fern and providing insight on the breeding system used by the species.
F.J. Keiper and R. McConchie
David Jesús Gil-Ariza, Iraida Amaya, José Manuel López-Aranda, José Federico Sánchez-Sevilla, Miguel Ángel Botella and Victoriano Valpuesta
the analysis of population structure in polyploids. Only very recently was information on genetic diversity in F. virginiana and F. chiloensis populations provided ( Carrasco et al., 2007 ; Hokanson et al., 2006 ). This is most likely the result
Amnon Levi, Alvin M. Simmons, Laura Massey, John Coffey, W. Patrick Wechter, Robert L. Jarret, Yaakov Tadmor, Padma Nimmakayala and Umesh K. Reddy
watermelon cultivars ( Si et al., 2009 ; Wang et al., 2014 ). A previous study using randomly amplified polymorphic DNA markers ( Levi et al., 2001a , 2001b ) indicated that high levels of genetic diversity exist among CC PIs. In a later study, we developed
Lyn A. Gettys and Dennis J. Werner
Stokes aster is a herbaceous perennial native to the southeastern United States. Stokesia is a monotypic genus belonging to the tribe Vernonieae Cass. (family Asteraceae Dumont). The level of genetic diversity within the genus is unknown. The goal of this study was to determine the level of genetic diversity and relatedness among cultivars of stokes aster. The genetic relatedness among 10 cultivars of stokes aster, one accession of Vernonia crinita Raf. (syn. V. arkansana DC.), and one accession of Rudbeckia fulgida Ait. var. sullivantii (Beadle et Boynton) Cronq. `Goldsturm' was estimated using 74 randomly amplified polymorphic DNA (RAPD) primers. Similarity indices suggest that cultivars of stokes aster are very closely related, with values for all pairwise comparisons of cultivars of stokes aster ranging from 0.92 to 0.68. One cultivar, `Omega Skyrocket', had markedly lower similarity indices from the other cultivars, ranging from 0.72 to 0.68. Similarity indices between stokes aster and Vernonia and between stokes aster and Rudbeckia were 0.44 and 0.50, respectively.
Lack of variation among black raspberry cultivars is thought to be a limiting factor in fruit production and in breeding improved cultivars. An assessment of the available diversity in black raspberry is needed to effectively develop improved cultivars. Such an assessment was done to estimate the genetic similarities for RAPD markers in 16 black raspberry genotypes and to determine the genetic diversity among these genotypes based on these markers. In addition, the ability to distinguish between the black raspberry genotypes, two red raspberry cultivars (Rubus idaeus L.), and a blackberry cultivar (Rubus hybrid) was determined. A similarity matrix from 379 RAPD markers was calculated, and a phylogenetic tree was constructed using the PHYLIP suite of phylogeny software, which revealed the relationship among the genotypes. An average of 81% similarity was calculated among 16 black raspberry genotypes with a maximum similarity of 98% and a minimum of 70%. The average similarity between black raspberry and red raspberry was 41% and was 26% between black raspberry and blackberry. Combined marker profiles from six RAPD primers could be used to distinguish between the 16 black raspberry genotypes. Red raspberry and blackberry could be distinguished from black raspberry by 27 and 29 of 30 RAPD primers tested, respectively. Genetic diversity was most prominent in genotypes from the extremes of the black raspberry indigenous range. Diversifying the germplasm pool for black raspberry cultivar improvement can be achieved through utilizing genotypes from the extremes of the black raspberry range and through interspecific hybridization.
Fachun Guan, Shiping Wang, Rongqin Li, Mu Peng and Fanjuan Meng
rigorous conditions and inaccessibility of the Tibetan Plateau, few studies regarding the genetic diversity in plant populations have been conducted ( Guo et al., 2006 ). Prunus mira Koehne ( Prunus mira Koehne Kov et. Kpst) has been recognized as an
Eric Stafne, Jon Lindstrom and John Clark
Passiflora is an important ornamental genus, mainly within tropical zones. However, two cold-hardy, North American Passiflora species exist. Previous work has been done to incorporate these species into breeding programs with some success. The intent of this study was to evaluate the extent of genetic diversity among five different Passiflora genotypes, including the two native North American species, P. incarnata L. and P. lutea L. Results indicate low genetic similarity among all genotypes with none at 50% or greater. P. incarnata and the ornamental cultivar `Lady Margaret' displayed the highest relationship at 49%. P. incarnata averaged 35.5% similarity with the other genotypes and P. lutea was 29.5%. Average overall similarity among all genotypes was 31.1%. These and other results show that the Passiflora genus has a high degree of genetic variation and breeding efforts could expand interest within North America.
The genus Actinidia contains more than 66 species and 118 taxa. The best-known species is A. deliciosa C.F. Liang et A.R. Ferguson, the commercially developed kiwifruit. The natural range of Actinidia is remarkably wide, extending from the tropics (latitude 0°0′) to cold temperate regions (500°N). However, the original distribution of most taxa of Actinidia is centered around the mountains and hills of south-central and southeast China, with the QinLing mountain as its northern boundary and the HengDuan mountain as its western boundary. Sixty-two species, 114 taxa have been found in China. Genetic variation ranging from morphological traits to DNA is discussed in here. 1) Morphological variation (mainly horticulturally important traits): fruit size varies from 2 to 100 g, fruit skin color ranges from brown to green to white to purple, fruit surface from setose to villose, and flesh color from green to purple. 2) Nutritional value and flavor: vitamin C content varies from 10 mg/100 g to 1000 mg/100 g fresh fruit, soluble solids ranges from 2% to 22%, and flavor includes variation form bitter and astringent to desirable sour-sweet. 3) Gender variation includes six phenotype/genotypes of female, inconstant female, male, fruiting male, neuter and hermaphrodite. 4) Ploidy variation is consist of 2x, 4x, 6x, 8x in both intra- and inter-taxa variation. 5) Isozyme genetic variation: high polymorphisms were detected in commercial cultivated species and 28 wild species. 6) Genetic diversity was evaluated by RAPD, SSR, PCR-RFLP of mtDNA and cpDNA, a high level of genetic diversity was found in both inter-taxa and intra-taxa. Conservation strategy for diverse genetic resources of Actinidia in China is also discussed.
Wenting Wang, Chao Feng, Zehuang Zhang, Liju Yan, Maomao Ding, Changjie Xu and Kunsong Chen
parentage analysis, hybrid identification, cultivar discrimination, and genetic diversity studies in various fruits ( Heidi and Andrew, 2007 ). However, despite the availability of SSR markers from previous studies, the number of high-quality and highly
Roberto F. Vieira, Peter Goldsbrough and James E. Simon
Molecular markers were used to assess genetic diversity in basil (Ocimum L. spp., Lamiaceae). Using randomly amplified polymorphic DNA (RAPD) analysis, 11 primers generated 98 polymorphic bands, ranging from 300 to 2,000 base pairs, that discriminated among 37 accessions across nine Ocimum spp. Means of genetic similarities within Ocimum spp. showed that the domesticated species, O. minimum L. (0.887), O. basilicum L. (0.769), and O. ×citriodorum Vis. (0.711) had highest similarity indices within species, while the nondomesticated, O. americanum L. (0.580), O. gratissimum L. (0.408), and O. kilimandscharicum Guerke (0.559) showed the lowest similarity. RAPD results indicated that O. minimum should not be considered a distinct species but rather a variety of O. basilicum. Consistent clusters among all but one of the O. ×citriodorum spp., all containing citral as the major constituent, were identified using bootstrap analysis. RAPD analysis was useful in discriminating among Ocimum spp., although within species resolution will require a higher number of polymorphic bands.