country, China grows more than 60% of the world pear ( Pyrus sp.) production ( Boyer et al., 1943 ; Wu et al., 2013 ). K is highly mobile in plants and constitutes up to 10% of plant dry weight ( Adams and Shin, 2014 ; Shin, 2014 ; Walker et al., 1996
, Q. Qian, M. Teng, Y. 2015 Effects of exogenous application of GA 4+7 and N-(2-chloro-4-pyridyl)-N′-phenylurea on induced parthenocarpy and fruit quality in Pyrus pyrifolia ‘Cuiguan’ Plant Growth Regulat. 76 251 258 Ohara, H. Sakamoto, D. Ohkawa, K
the soil testing laboratory at Oregon State University Agr. Expt. Sta., Oregon State Univ Corvallis, OR Laywisadkul, S. 2008 Factors affecting the incidence and severity of Phytophthora syringae cankers in pear ( Pyrus communis ) trees PhD Thesis
A study was undertaken to determine if microsprinkler irrigation (MI) can provide sufficient water and produce similar yield and quality of pear (Pyrus communis L.) fruit as flood irrigation (FI) in a cracking (shrinking-swelling) clay soil. Soil water content and fruit quality attributes were measured under MI and FI in 2 years. Water potential of the upper 120 cm (47 inches) of soil was maintained at 0.1 to 0.3 MPa (14.5 to 43.5 lb/inch2) through most of the growing season in both MI and FI treatments. MI and FI treatments did not differ in their effect on fruit size, yield, or firmness decline during cold storage. No consistent effect on fruit susceptibility postharvest fungal decay related to irrigation treatment was observed. MI has the potential to reduce chemical and water movement to groundwater, while providing sufficient water to produce satisfactory yield and fruit quality in a cracking clay soil.
`Comice' pears (Pyrus communis) harvested early in the maturity range needed 25-31 days of storage at 0 °C to develop the capacity to ripen to an average firmness of 5 lbf within 5 days after being moved to 20 °C. After 24 h exposure to 100 ppm ethylene at 20 °C applied immediately after harvest, 17-27 days additional chilling were needed to develop ripening capacity, while ethylene exposure for 48 hours required an additional 7-17 days chilling. After 72 h ethylene exposure, ripeness was achieved within 5 days following 3 days cold storage, the minimum duration tested. Similar results were obtained when the sequence of ethylene treatment followed by cold storage was reversed. This technique may be applied to reduce the amount of time that `Comice' pears must be stored after harvest before marketing fruit with the capacity to ripen.
Immersion of Anjou pears (Pyrus communis L. cv. Beurre d Anjou) in sodium lignin sulfonate (SLS), a flotation agent used in hydraulic handling of pears, did not cause injury leading to skin browning. Immersion of cut pear slices in SLS discolors pear fruit flesh, but the discoloration derived from SLS pigments does not intensify with time. When the fungicide sodium orthophenylphenate (SOPP) was combined with SLS, necrotic skin mottling occurred with increased immersion times and temperatures. A white precipitate in the SLS SOPP solution accompanied phytotoxicity of pear skin tissue. Acidification of alkaline SOPP solutions (pH 11.3) with 0.01 N HCl down to pH 10 produced mild skin necrosis. Both acid (0.01 N HC1) and alkaline (0.01 n KOH) solutions of SOPP and SLS-SOPP combinations caused browning of pear flesh.
Management of pear (Pyrus communis L.) trees for low N and high Ca content in the fruit reduced the severity of postharvest fungal decay. Application of N fertilizer 3 weeks before harvest supplied N for tree reserves and for flowers the following spring without increasing fruit N. Calcium chloride sprays during the growing season increased fruit Ca content. Nitrogen and Ca management appear to be additive factors in decay reduction. Fruit density and position in the tree canopy influenced their response to N fertilization. Nitrogen: Ca ratios were lower in fruit from the east quadrant and bottom third of trees and from the distal portion of branches. High fruit density was associated with low N: Ca ratios. Nutritional manipulations appear to be compatible with other methods of postharvest decay control.
The evidence for several hypotheses regarding the mechanism(s) controlling biennial bearing in apple (Malus×domestica Borkh.) are reviewed, citing relevant evidence from work with citrus (Citrus sp.) species and pear (Pyrus communis L.). The view that flowering is inhibited by withdrawal of nutrients, primarily carbohydrates, by apple fruit is questionable, given the effects of seed development in inhibiting flowering in facultatively parthenocarpic (normally seedless) apple cultivars. The hypothesis that seeds inhibit flowering by exporting hormones, chiefly gibberellins (GAs), is an attractive one, given a) the effects of application of GAs in inhibiting flowering and b) the high concentrations of GAs in seeds. However, an alternative hypothesis, namely that seeds compete with apices for hormones that are required for flowering, is equally tenable.
Pears (Pyrus communis `d'Anjou') were packed in six commercial paper wraps (dry; 3% oil; 3% oil with copper and ethoxyquin; 6% oil; 6% oil with ethoxyquin; 9% oil). After packing, the pears were placed in three different controlled atmosphere (CA) storage conditions in commercial CA rooms: 1) 1.5% oxygen (O) and 1% carbon dioxide (CO2); 2) 1.5% O2 and 3% CO2; 3) 1.5% O2 and 1% CO2 for 60 days, 4% O2 for 60 more days and finally 6% O2 for an additional 90 days. Pears were stored in CA for 120 and 210 days, with or without an additional 30 days in regular atmosphere (RA) storage to simulate shipping and handling. Objective quality evaluations were conducted after each storage period and sensory evaluations after 210 days of storage. Paper type influenced both the peel and flesh color of pears before and after ripening, but did not influence firmness, soluble solids or acid content. Subjective ratings of appearance and disorder incidence were unacceptable for pears stored in a variable atmosphere wrapped in dry or paper containing 3% oil. The disorder black speck was present only in pears wrapped in paper with 6% oil and stored in an atmosphere of 1.5% O2 and 1% CO2. Pears stored in an atmosphere of 1.5% O2 and 3% CO2 received acceptable subjective scores regardless of paper type.
The Auburn University Shade Tree Evaluation is an ongoing trial of a moderately diverse range of species, and varieties of larger-growing trees. The study was initiated in 1980 with the planting of 250 selections in three replications of three trees each, located at the Alabama Agricultural Experiment Station, Piedmont Substation in east-central Alabama. Among the fruit of the investigation have been an evaluation of 10 red maple (Acer rubrum) selections with respect to growth and fall color characteristics; a comparison of growth rate and aesthetic characteristics of 14 oak (Quercus) selections; a comparison of the growth and fireblight (Erwinia amylovora) susceptibility of 10 callery pear (Pyrus calleryana) selections; and a 12-year evaluation of the overall best performing trees. The Shade Tree Evaluation has served as a precedent for six additional landscape tree evaluations in Alabama. It has provided a living laboratory for a wide range of educational audiences including landscape and nursery professionals, county extension agents, urban foresters, Master Gardeners, garden club members, and horticulture students. Knowledge gained from the Shade Tree Evaluation has been shared through presentations at meetings and conferences.