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Xingbin Xie, Todd Einhorn, and Yan Wang

‘Starkrimson’, a red-skinned sport of the cultivar Clapp’s Favorite, is a highly profitable european pear produced in the Pacific Northwest region of the United States due to its early maturation and attractive, bright red skin ( Sugar and Lombard

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Achala N. KC, Ann L. Rasmussen, and Joseph B. DeShields

In the United States, Washington and Oregon are the primary European pear ( Pyrus communis L.) producers. Approximately 80% of the nation’s pear production comes from these states ( USDA NASS, 2020 ; USDA NASS Northwest Regional Field Office

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Richard L. Bell and Tom van der Zwet

Pear leaf spot, caused by the fungus Fabraea maculata Atk. (anamorph: Entomosporium mespili (DC.) Sacc.) occurs in most areas of the world where pears are grown. Most major cultivars of the european pear, P. communis L., for which data are available are susceptible. Ratings appearing in the literature are sometimes contradictory. This study evaluated resistance/susceptibility within a diverse collection of Pyrus cultivars and other germplasm in a randomized and replicated nursery plot using quantitative measures of disease incidence and severity. The least susceptible genotypes were the P. communis cultivars `Beurre Fouqueray' and `Bartlett', the P. pyrifolia cultivars `Imamura Aki', and the P. communis × P. ussuriensis hybrid NJ 477643275.

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Masanori Kadota, Dong-Sheng Han, and Yoshiji Niimi

Anthers of six apple [Malus ×domestica (L.) Borkh.], three Japanese pear (Pyrus pyrifolia N.) and two European pear (Pyrus communis L.) scion cultivars were cultured. Callus formation occurred from anthers of all cultivars and androgenic embryogenesis was observed from all except P. pyrifolia `Kosui' and P. communis `La France'. Regeneration of adventitious shoots from anther-derived embryos was shown from all apple cultivars and P. pyrifolia `Shinko'. Many of these shoots did not grow or died on half-strength Murashige and Skoog medium (1962) with 4.4 μm BA and 0.5 μm IBA, whereas several shoots of apple `Starking Delicious' grew to plantlets. Chromosome counts of shoot apical cells of four clones derived from embryos of `Starking Delicious' showed that three clones were diploids and one clone comprised diploid and haploid shoots, suggesting that at least one clone originated from a microspore. Chemical names used: 3-indolyl-butyric acid (IBA); N6-benzyladenine (BA).

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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.

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Fenton E Larsen and Stewart S. Higgins

The influence of five Old Home × Farmingdale (OHF) rootstocks on tree size with 10 Asian pear scion cultivars was examined after 10 years in an experimental orchard in central Washington state. The effect of rootstock on tree size varied among scion cultivars. Within `Chojuro', `Hosui', `Niitaka', and `Seigyoku', trunk cross-sectional areas were similar regardless of rootstock. Within `Li', OHF 333 produced larger trees than OHF 282 and OHF 217. `Okusankichi' trees, which were generally the same size as `Hosui', were significantly larger on OHF 217 and OHF 97 than on OHF 333. `Kikusui' trees, which were generally similar in size to `Niitaka' and `Seigyoku', were larger on OHF 217, OHF 97, and OHF 282 than on OHF 333. `20th Century', which was similar in size to `Chojuro' and `Shinseiki', appeared to be the cultivar most sensitive to rootstock. `20th Century'/OHF 217 were significantly larger than trees on OHF 97 and OHF 282, which were larger than trees on OHF 51. `Shinseiki'/OHF 97 were larger than trees on OHF 333. The smallest trees were `Shinko', with trees on OHF 217, OHF 97, OHF 333, and OHF 51 all being larger than trees on OHF 282. Contrary to research with some European pear scions, consistent trends did not emerge from this research that would allow a general prediction of the relative influence of these five OHF clonal rootstocks on Asian pear tree size.

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Gayle Volk, Christopher Richards, Adam Henk, Ann Reilley, Nahla Bassil, and Joseph Postman

Edible European pears (Pyrus communis sp. communis L.) are thought to be derived from wild relatives native to the Caucasus Mountain region and eastern Europe. We collected genotype, phenotype, and geographic origin data for 145 P. communis individuals derived from seeds collected from wild relatives. These individuals are currently maintained in the USDA–ARS National Plant Germplasm System (NPGS) in Corvallis, Ore. Pear genotypes were obtained using 13 microsatellite markers. A Bayesian clustering method grouped the individual pear genotypes into 12 clusters. The subspecies of pears native to the Caucasus Mountains of Russia, Crimea, and Armenia could be genetically differentiated from the subspecies native to eastern European countries. Pears with large fruit clustered closely together and are most closely related to a group of genotypes that are intermediate to the other groups. Based on the high number of unique alleles and heterozygosity in each of the 12 clusters, we conclude that the genetic diversity of wild P. communis is not fully represented in the NPGS

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Richard L. Bell*, Tom van der Zwet, and Diane D. Miller

`Shenandoah' is a new European pear (Pyrus communis L.) cultivar which combines resistance to fire blight with fruit of excellent quality. The original seedling tree was selected in 1985 from a cross of `Max Red Bartlett'× US 56112-146, and was tested under the original seedling number, US 78304-057. The fruit of `Shenandoah' is pyriform in shape, and moderately large in size, averaging 72 mm in diameter and 92 mm in height. Skin color at harvest is light green, turning yellow-green when ripe. The skin finish is glossy, and 10% to 20% of the fruit surface is blushed red. There is light tan russet at the calyx. Lenticles are slightly conspicuous, and are surrounded by small, light brown russet. The stem is medium to long (≈25 mm), of medium thickness, and slightly curved. Harvest maturity occurs about four weeks after `Bartlett', and the fruit will store in refrigerated (-1 °C) air storage for at least four months without core breakdown or superficial scald. The flesh texture is moderately fine, juicy, and buttery. Grit cells are moderately small and occur primarily around the core and in a thin layer under the skin. The flavor is aromatic, similar to `Bartlett', and is moderately acidic during the first two months of storage, becoming subacid after longer storage. The tree is moderate in vigor on `Bartlett' seedling and `OHxF 97' rootstocks, and upright-spreading in habit. Shenandoah' blooms in mid-season, similar to `Bartlett'. Yield has been moderately high and precocious, and with no pronounced biennial pattern. Fire blight resistance is similar to `Seckel', with infections extending no further than 1-year-old branches. Artificial blossom inoculations indicate a moderate degree of blossom resistance to fire blight infection.

Open access

Fuad Gasi, Naris Pojskić, Mirsad Kurtovic, Clive Kaiser, Stein Harald Hjeltnes, Milica Fotiric-Aksic, and Mekjell Meland

results in lower fruit weight and decreased yields. Self-fertilization in European pears ( Pyrus communis L.), similar to other fruit species of the Rosaceae family, is prevented by gametophytic self-incompatibility ( Crane and Lewis, 1942 ). Consequently

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Akihiro Itai and Naoko Fujita

In Pyrus , there are three major species, P. communis L. (pear or European pear), P. bretschneideri Rehd. or P. uusuriensis Maxim. (Chinese pear), and P. pyrifolia Nakai (Japanese pear: Nashi), which are commercially cultivated in