represent 85 maternal sources of seeds (families) ( Table 1 ). All 496 individuals were analyzed using the seven microsatellite markers and a total of 126 alleles were amplified with an average gene diversity of 0.72 ( Table 2 ). Markers GD12, GD96, GD142
Gayle M. Volk, Christopher M. Richards, Ann A. Reilley, Adam D. Henk, Patrick A. Reeves, Philip L. Forsline and Herb S. Aldwinckle
Marko Maras, Barbara Pipan, Jelka Šuštar-Vozlič, Vida Todorović, Gordana Đurić, Mirjana Vasić, Suzana Kratovalieva, Afrodita Ibusoska, Rukie Agić, Zdravko Matotan, Tihomir Čupić and Vladimir Meglič
( Phaseolus vulgaris L.) Theor. Appl. Genet. 119 955 973 Blair, M.W. Giraldo, M.C. Buendia, H.F. Tovar, E. Duque, M.C. Beebe, S.E. 2006 Microsatellite marker diversity in common bean ( Phaseolus vulgaris L.) Theor. Appl. Genet. 113 100 109 Blair, M
Haiying Zhang, Jianguang Fan, Shaogui Guo, Yi Ren, Guoyi Gong, Jie Zhang, Yiqun Weng, Angela Davis and Yong Xu
assessed using simple sequence repeat markers Sci. Hort. 175 150 155 Kottapalli, K.R. Burow, M.D. Burow, G. Burke, J. Puppala, N. 2007 Molecular characterization of the U.S. peanut mini core collection using microsatellite markers Crop Sci. 47 1718 1727
Timothy Rinehart, Sandra Reed and Brian Scheffler
Hydrangea popularity and use in the landscape has expanded rapidly in recent years with the addition of remontant varieties. Relatively little is known about the genetic background or combinability of these plants. We recently established microsatellite markers for hydrangea and evaluated their utility for estimating species diversity and identifying cultivars. We also verified an interspecific cross using these markers. Future research includes marker assisted breeding, particularly with respect to remontant flowering traits.
Shinichi Masuzaki, Naoyuki Araki, Naoki Yamauchi, Naoko Yamane, Tadayuki Wako, Akio Kojima and Masayoshi Shigyo
Bulb onion (Allium cepa L.) has a very large genome composed of a high proportion of repetitive DNAs. Genetic analyses of repetitive sequences may reveal microsatellites in order to increase the number of genetic markers in onion. Thirty microsatellites were previously isolated from an onion genomic library (Fischer and Bachmann, 2000). A complete set of Japanese bunching onion (A. fistulosum) – shallot (A. cepa Aggregatum group) monosomic addition lines were used to assign these microsatellites to the chromosomes of A. cepa. Simplified PCR conditions for each microsatellite were determined and 28 of the 30 primer pairs amplified DNA fragments, of which 21 microsatellite markers were assigned to chromosomes of A. cepa. Subsequent mapping of these microsatellites will enable us to establish the chromosomal distribution of these markers.
A. Belaj, G. Cipriani, R. Testolin, L. Rallo and I. Trujillo
Nine simple-sequence-repeat (SSR) primer pairs were assayed in 35 Spanish and Italian olive cultivars of commercial interest. All microsatellites were polymorphic, showing 5 to 13 alleles per locus (7.5 alleles per locus on average). The frequency of each alleles was generally low, with most of the alleles present at one or two cultivars. Heterozigosity ranged from 0.15 to 0.95; the discrimination power (PD) ranged from 0.30 to 0.93 (mean 0.79). The set of microsatellites analyzed discriminated all cultivars investigated. The combination of only three SSR primer pairs—UDO99-009+UDO99-043+UDO99-14—made possible the identification of all cultivars included in the study. Cluster analysis did not find differences between Spanish and Italian cultivars, but most of the cultivars from southern and central Spain grouped together. Hence, microsatellites markers are recommended for olive fingerprinting to generate a database for olive cultivar identification.
R.J. Schnell, C.T. Olano, J.S. Brown, A.W. Meerow, C. Cervantes-Martinez, C. Nagai and J.C. Motamayor
Commercial production of cacao in Hawaii is increasing, and this trend is expected to continue over the next several years. The increased acreages are being planted with seedlings from introduced and uncharacterized cacao populations from at least three initial introductions of cacao into the islands. Productive seedlings have been selected from a planting at Waialua, Oahu. The parents of these selections were believed to be the population at the Hawaii Agriculture Research Center (HARC) at Kunia; however, potential parental populations also exist at Univ. of Hawaii research stations at Waimanalo and Malama Ki. Using microsatellite markers, we analyzed the potential parental populations to identify the parents and determine the genetic background for 99 productive and 50 unproductive seedlings from the Waialua site. Based on 19 polymorphic microsatellite loci the parental population was identified as trees from Waimanalo and not trees from Malama Ki or Kunia. The Kunia and Malama Ki populations were very similar with low allelic diversity (A = 1.92) and low unbiased gene diversity (Hnb) of 0.311 and 0.329, respectively, and were determined to be Trinitario in type. The Waimanalo, productive seedling, and unproductive seedling populations had much higher levels of genetic diversity with Hnb of 0.699, 0.686, and 0.686, respectively, and were determined to be upper Amazon Forastero hybridized with Trinitario in type. An additional 46 microsatellite markers were amplified and analyzed in the Waimanalo parents, productive, and unproductive seedlings for a total of 65 loci. Seventeen loci contained alleles that were significantly associated with productive seedlings as determined by Armitage's trend test. Of these, 13 loci (76.4%) co-located with previously reported quantitative trait loci for productivity traits. These markers may prove useful for marker assisted selection and demonstrate the potential of association genetic studies in perennial tree crops such as cacao.
Gayle M. Volk, Christopher M. Richards, Adam D. Henk, Ann A. Reilley, Nahla V. Bassil and Joseph D. Postman
Edible european pears (Pyrus communis L. ssp. communis) are derived from wild relatives native to the Caucasus Mountain region and eastern Europe. Microsatellite markers (13 loci) were used to determine the relationships among 145 wild and cultivated individuals of P. communis maintained in the National Plant Germplasm System (NPGS). A Bayesian clustering method grouped the individual pear genotypes into 12 clusters. Pyrus communis ssp. caucasica (Fed.) Browicz, native to the Caucasus Mountains of Russia, Crimea, and Armenia, can be genetically differentiated from P. communis ssp. pyraster L. native to eastern European countries. The domesticated pears cluster closely together and are most closely related to a group of genotypes that are intermediate to the P. communis ssp. pyraster and the P. communis ssp. caucasica groups. Based on the high number of unique alleles and heterozygosity in each of the 12 clusters, we conclude that genetic diversity of wild P. communis is not fully represented at the NPGS. Additional diversity may be present in seed accessions stored in the NPGS and more pear diversity could be captured through supplementary collection trips to eastern Europe, the Caucasus Mountains, and the surrounding countries.
E.J. Parks, J.W. Moyer and J.H. Lyerly
Fluorescent amplified fragment length polymorphism (F-AFLP) and microsatellites (SSRs) were used to evaluate new guinea impatiens (Impatiens hawkeri W. Bull) cultivars. Ninety-five quality-selected polymorphic fragments from 10 F-AFLP+3 primer combinations were used to evaluate 100 cultivars representing a variety of colors, forms, and breeding programs. Jaccard similarities and unweighted pair-group method of the arithmetic average (UPGMA) clustering formed a dendrogram with three cultivar groups, to a large extent clustering the cultivars by breeder with a high cophenetic correlation coefficient. A small insert genomic library was created and 442 kb of new guinea impatiens sequence was screened for repetitive motifs, resulting in 14 microsatellite markers. A subset of 46 cultivars representing five commercial breeding companies and 11 cultivar series was selected for microsatellite analysis. Seven loci were polymorphic, with two to six alleles per locus. Although both methods were equally effective in distinguishing the cultivars from one another, the topologies of the dendrograms for the two methods were different. The topology of the AFLP dendrogram reflected possible relationships based on cultivar series and breeding company, while the SSR dendrogram did not. The objectives of this research were to develop and validate both F-AFLP and SSR methodologies for new guinea impatiens, identify markers that can be reliably used for fingerprinting, and create a database for future cultivar comparisons.
Timothy A. Rinehart, Brian E. Scheffler and Sandra M. Reed
Using 14 codominant microsatellite markers that amplify loci across 14 different Hydrangea L. species, we analyzed gene diversity and genetic similarity within Hydrangea. Samples also included Dichroa Lour., Platycrater Sieb. and Zucc., and Schizophragma Sieb. and Zucc. genera to establish their relatedness to Hydrangea species since previous work suggests they may be closely related. Our results support the close affiliation between Macrophyllae E.M. McClint. and Petalanthe (Maxim.) Rehder subsections and their separation from the other Hydrangea species. Most of the Hydrangea species analyzed cluster within their designated sections and subsections; however, genetic distance between species within each subsection varied considerably. Our data suggest that morphological analyses which labeled H. serrata (Thunb.) Ser. as a subspecies of H. macrophylla (Thunb. Ex J.A. Murr.) Ser. are probably more accurate than recent genome size data suggesting H. macrophylla ssp. macrophylla (Thunb.) Ser. and H. macrophylla ssp. serrata (Thunb.) Makino are separate species. Gene diversity estimates indicate that 64.7% of the total diversity is due to differences between species and 49.7% of the overall variation is due to differences between subsections. Low diversity suggests a lack of gene flow between species and subsections and underscores the difficulty in making wide hybrids. Since only 35.3% of the genetic variation is common to all species, unique alleles were used to develop a molecular key for unambiguous species identification and interspecific hybrid verification. Genetic similarity estimates for all 85 samples suggests a roadmap for introgressing horticulturally important traits from different Hydrangea species.