Early generation performance of Fragaria species hybrids in crosses with cultivated strawberry

Abstract

. 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...

Temperature affects dry matter production and net carbon exchange rate of lower-ploidy Fragaria species and species hybrids

“…Subsequent refinements to the system created many synthetic octoploids (Bors 2000;Bors and Sullivan 1997) with breeding potential. The performance of SO germplasm introgressed into the cultivated strawberry has been documented in previous studies (Harbut et al 2009;Sangiacomo and Sullivan 1994;Sullivan et al 2003).…”

“…In a related study, three Fragaria species (moschata, nilgerrensis and nubicola) and two SOs (8183 and 8212) were grown in a field trial at Elora, ON. The mean PDW after fruit harvest (i.e., early July) for the species and SOs was 33.2 and 34.0 g plant (1 , respectively (Harbut et al 2009). These field results are comparable with the 23/108C and 30/258C treatments of this experiment.…”

“…In earlier work with these genotypes on dry matter partitioning and yield components of SOs and early generation SO )cultivar hybrids (Harbut et al 2009), we reported that Fragaria species had a wide range of dry matter accumulation and four SOs had very high plant dry weight. Yield potential of F 1 hybrids, based on flower number, was high, but fruit set was low; additional outcrossing increased yield.…”

Net Carbon Exchange Rate of Fragaria Species, Synthetic Octoploids, and Derived Germplasm

“…In a study that compared NCER of F. chiloensis with the cultivar Totem, F. chiloensis had rates that were 20% to 70% higher (Cameron and Hartley, 1990). In addition to the octoploid species, several lower-ploidy Fragaria species (2·, 4·, and 6·) have desirable characteristics such as extreme vigor (Harbut et al, 2009), unique flavors, disease resistance (Xue et al, 2005), and temperature adaptability (Harbut et al, 2010) that hold great potential as breeding germplasm (Harbut and Sullivan, 2004;Xue et al, 2005). The lower-ploidy species are found in a wide range of habitats including temperate, Mediterranean, grassland, and subtropical environments (Darrow, 1966;Hancock, 1990Hancock, , 1999, which may influence photosynthetic capacity.…”

“…Each SO is a complex interspecific hybrid composed of at least two Fragaria species and can be easily crossed with the cultivated strawberry. The yield and vegetative growth of three lower-ploidy Fragaria species, SOs, F 1 hybrids with the cultivated strawberry, were evaluated in field trials in Ontario, Canada (Harbut et al, 2009). SOs had high vegetative vigor and the F 1 hybrids were also vigorous with a high flower number.…”