The pear tree ( Pyrus spp.) is a temperate-climate fruit species, and its cultivation in subtropical regions was made possible by hybrid cultivars obtained from the cross Pyrus communis × Pyrus pyrifolia ( Curi et al., 2017 ). This cross
Rayane Barcelos Bisi, Rafael Pio, Daniela da Hora Farias, Guilherme Locatelli, Caio Morais de Alcântara Barbosa, and Welison Andrade Pereira
David R. Coyle, Brayden M. Williams, and Donald L. Hagan
objective was largely accomplished, one particular callery pear individual was marketed as the bradford pear tree and was once commonly planted. It is now nearly ubiquitous in lawns and other managed landscapes across much of the eastern (and parts of the
Karen Mesa, Sara Serra, Andrea Masia, Federico Gagliardi, Daniele Bucci, and Stefano Musacchi
. Loescher et al. (1990) noted that treatments like defoliation or pruning performed in the orchard affect mainly roots in terms of depletion of stored carbohydrates. In one of the first studies on carbohydrate reserve dynamics in pear trees, Cameron (1923
Zhenxu Liang, Mingde Sun, Yang Wu, Jun Liu, Yanyan Zhao, Haiqing Tian, Ruirui Du, and Songzhong Liu
. During their annual growth cycle, pear trees need to consume many nutrients. Therefore, different fertilizers should be added according to the different growth periods and the type of fertilizer needed by pear trees to meet their needs ( Mitcham and
Delmer O. Ketchie and Eugene D. Fairchild
Five different pruning techniques were begun in 1990 on Anjou pear trees to determine their effect on fruit set: (1) unpruned; (2) central leader, (3) central leader modified to Verner method; (4) stubbed into 2- to 4-year-old wood first year and then developed to central leader; and (5) mold-and-hold. Half of each treatment was spread, the other half not spread. Half of each of the combination training and spreading were tipped back to the first fruit bud at cluster bud time. The trees were 9 years old and on OHXF97 rootstock. The unpruned trees had the highest yield, 81 Kgm/tree. The other treatments ranged between 52 and 58 Kgm/tree. Regardless of pruning treatment, the spread trees out yielded the non-spread trees by 16 Kgm/uee.. There was essentially no difference between trees tipped in the spring and those that were not tipped.
A. Richard Renquist, Horst W. Caspari, M. Hossein Behboudian, and David J. Chalmers
Stomatal conductance (g s) of `Hosui' Asian pear (Pyrus serotina Rehder) trees growing in lysimeters was characterized for trees in well-watered soil and after brief water deficit. The measures of water status used to interpret g s data were soil-water content, leaf water potential (ψl), and instantaneous water use (trunk sap flow by the compensation heat-pulse technique). The diurnal course and range of g s values of well-irrigated Asian pear trees were similar to those reported for other tree fruit crops. Soil moisture at the end of a midsummer deficit period was 60% of lysimeter pot capacity, and diurnal ψl reflected this deficit predawn and in the late afternoon compared to well-irrigated trees. The g s was sensitive to deficit irrigation during more of the day than ψl, with g s values <3 mm·s-1 for most of the day; these were less than half the conductances of well-irrigated trees. The reduction of g s in response to a given soil-water deficit was not as great on days with lower evaporative demand. After a water deficit, g s recovered to predeficit values only gradually over 2 to 3 days. The low g s of trees in dry soil was the apparent cause of reduced transpiration, measured by trunk sap flow, and reduced responsiveness of sap flow to fluctuations in net radiation.
Hsin-Shan Lin and Jia-Shing Lin
Taiwan, located in subtropic regions, naturally is not an ideal region for temperate-zone fruit trees' production due to the supra-optimum temperature, heavy rainfall, and higher relative humidity in summer and insufficient chilling in winter. Higher relative humidity and temperature in summer and autumn months cause excessive vegetative growth, resulting in poor flowerbud initiation and formation. Typhoon invasions result in the severe damage of twigs as well as the loss of quality and yield of fruits. In order to overcome these natural barriers, Hengshan (Pyrus serotina Rehd.) pear has been selected as a major cultivar for lowlands in Taiwan. It has low-chilling requirement and higher temperature tolerance. Branches of Hengshan are pulled and tied to a horizontal wire net to adapt to the environmental status. This trellis system enhances flowerbud initiation through the retardation of vegetative growth. It also induces numerous water shoots. Scions from high-chilling cultivars grown at a high altitude on mountains are grafted onto water shoots of Hengshan pear trees. The system has been successful in the production of both high-chilling pears in June and the Hengshan pears in August, and has made production of both pears an important industry in Taiwan. Heavy load and trellis systems, however, result in hastening the senescence of Hengshan trees. Vitality of trees could be restored by grafting scions from a vigorous cultivar, P. koehnei, onto the terminal position of the branches. The practice resulted in several advantages including: 1) uniform growth of branches, 2) redistribution of water shoots, 3) inducing formation of calluses on old damaged trunks, 4) quick recovery of mealybug-damaged branches, 5) rejuvenation of branches, and 6) termination of dormancy.
Todd C. Einhorn, Janet Turner, and Debra Laraway
/box) equating to 248,600 tons ( Ing, 2002 ). ‘Anjou’ pear trees are inherently vigorous and non-precocious but have a long productive life; consequently, a large percentage of ‘Anjou’ acreage has not undergone renovation and exists at low tree densities (less
Jerome Hull Jr.
Chenggang Wang, Rolf Färe, and Clark F. Seavert
In this paper we analyze the sources of variation in revenue per unit of trunk cross-sectional area (TCA) across a 0.87-ha block of 272 pear (Pyrus communis L.) trees in 2003. Revenue capacity efficiency associated with TCA provides an overall measure of nutrient deficiency and revenue inefficiency caused by environmental constraints in the fruit production process. Data envelopment analysis (DEA) is adopted to estimate revenue capacity efficiency and its components. The deficiencies of macro- and micronutrients are measured and optimal nutrient levels computed for each individual tree. These measures are aggregated for comparing between grids and between rootstocks.