The application of next-generation sequencing (NGS) technologies for the development of simple sequence repeat (SSR) or microsatellite loci for genetic research in the botanical sciences is described. Microsatellite markers are one of the most informative and versatile DNA-based markers used in plant genetic research, but their development has traditionally been a difficult and costly process. NGS technologies allow the efficient identification of large numbers of microsatellites at a fraction of the cost and effort of traditional approaches. The major advantage of NGS methods is their ability to produce large amounts of sequence data from which to isolate and develop numerous genome-wide and gene-based microsatellite loci. The two major NGS technologies with emergent application in SSR isolation are 454 and Illumina. A review is provided of several recent studies demonstrating the efficient use of 454 and Illumina technologies for the discovery of microsatellites in plants. Additionally, important aspects during NGS isolation and development of microsatellites are discussed, including the use of computational tools and high-throughput genotyping methods. A data set of microsatellite loci in the plastome and mitochondriome of cranberry (Vaccinium macrocarpon Ait.) is provided to illustrate a successful application of 454 sequencing for SSR discovery. In the future, NGS technologies will massively increase the number of SSRs and other genetic markers available to conduct genetic research in understudied but economically important crops such as cranberry.

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Recent cultivar releases of cranberry (Vaccinium macrocarpon) have been reported to differ in terminal bud development, biennial bearing tendencies, and external bud appearance. However, verification of these claims and cultivar comparisons with respect to these characteristics are lacking. The objectives of this project were to 1) evaluate flower initiation, bud development, and potential return bloom across several cultivars of cranberry, including recent introductions; and 2) determine the relationship between external appearance of buds and the presence/absence of flower initials. Samples of upright shoots representing the cultivars Searles, Stevens, HyRed, and Crimson Queen were collected from a commercial cranberry marsh located in central Wisconsin during the 2011 and 2012 growing seasons. Collected uprights were separated based on reproductive status (i.e., reproductive or vegetative). Buds were then dissected and analyzed for presence/absence of flower initials using light and scanning electron microscopy. Growing degree days (GDD) were calculated and related to the progression of bud development. Flower initials were first observed on 29 July 2011 and 10 July 2012, or 290 and 322 GDD, respectively. Excluding ‘Searles’, dates of initiation were the same across all cultivars and did not differ based on reproductive status. Descriptive bud data demonstrated that wider buds are more likely to contain flower initials and overall bud width tended to be greater among recent cultivar releases. Biennial bearing tendencies were also lower among recently released cultivars, as exhibited by greater occurrences of potential return bloom. Results from the study provide evidence that recently released cultivars differ in bud development, have an increased potential for return bloom, and overall wider buds. These findings suggest newer cultivars may have different mechanisms regulating mixed bud development and other yield-contributing factors.

. 2009. Early generation performance of Fragaria species hybrids in crosses with cultivated strawberry. Can. J. Plant Sci. 89: 1117Á1126. Yield (i.e., fruit number and size) and yield component measurements were collected and destructive growth analysis carried out on lower-ploidy Fragaria species, synthetic octoploids (SO), F 1 (SO ) cultivar), OC 1 (F 1 ) cultivar) hybrids and cultivars. Plants were grown in two field trials, at the Elora Research Station, Ontario, and at the Wye Research and Education Centre, Queenstown, Maryland, and in one greenhouse trial in Guelph, Ontario. Total plant dry weight (PDW) was highly variable for the species, but the higher vegetative vigour of the SOs compared with mid-parent values suggested a heterotic effect. The shade adapted species (e.g., F. moschata Duch. and F. nubicola) had greater PDWs than the sun adapted species. Yields of the species, SOs and F 1 hybrids were low; however, flower number was higher compared with cultivars. The first outcross with F 1 s and cultivars resulted in a sixfold increase in yield attributed to both increased fruit size and fruit number. Three of the four OC 1 hybrids had yields that were comparable with cultivars. Through breeding and intensive selection, genotypes introgressed with SO germplasm can be restored to the pre-cultivar yield levels with only a few outcrosses to the cultivated strawberry.Key words: Growth analysis, heterosis, interspecific hybridization, strawberry, yield, synthetic octoploid Harbut, R. H., Sullivan, J. A., Proctor, J. T. A. et Swartz, H. J. 2009. Performance des premie`res ge´ne´rations des hybrides d'espe`ces du genre Fragaria croise´es avec le fraisier cultive´. Can. J. Plant Sci. 89: 1117Á1126. Les auteurs ont mesure´le rendement (nombre et calibre des fruits) et les composantes du rendement, puis proce´de´a`une analyse destructive de la croissance des octoploı¨des synthe´tiques (OS), des membres de la F 1 (cultivars )SO), des hybrides OC 1 (F 1 ) cultivar) et des cultivars des espe`ces du genre Fragaria a`faible ploı¨die. Les plants ont e´te´cultive´s lors de deux expe´riences sur le terrain a`la station de recherche d'Elora (Ontario) et au Wye Research and Education Centre, de Queenstown (Maryland), ainsi que lors d'un essai en serre a`Guelph (Ontario). Le poids sec total des plantes (PST) varie conside´rablement avec l'espe`ce, mais la plus forte vigueur ve´ge´tative des OS, comparativement a`la valeur me´diane des parents, laisse croire a`l'he´te´rosis. Les espe`ces acclimate´es a`l'ombre (par ex., F. moschata Duch. et F. nubicola) ont un PST plus e´leve´que les celles adapte´es au soleil. Les espe`ces, les OS et les hybrides de la F 1 ont un faible rendement; cependant ils portent plus de fleurs que les cultivars. Le premier croisement exte´rieur avec des membres de la F 1 et des cultivars multiplie le rendement par six en raison du plus gros calibre des fruits, e´galement plus nombreux. Trois des quatre hybrides OC 1 pre´sentaient un rendement comparable a`celui des cultivars. On pourrait restaurer l...