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  • Author or Editor: M. N. Westwood x
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Abstract

Roots of most of the primitive Pynus species were infested with pear root aphid Eriosoma pyricola Bak. and David., and increase or decrease in number noted 30 days later. Although seedling populations varied somewhat, P. amygdaliformis, P. elaeagrifolia, P. syriaca, P. betulaefolia, P. calleryana, P. koehnei, P. ussuriensis, and P. nivalis can be considered resistant. P. communis, P. cordata, P. gharbiana, P. pashia, P. Fauriei, and P. pyrifolia were either susceptible or very variable in resistance. Only P. bucharica, P. dimorphophylla, and P. mamorensis had no resistant seedlings in the lots tested. Interspecific hybrid populations were predictable though variable in resistance.

Open Access

Abstract

Growth and performance of ‘Anjou’ pear, Pyrus communis L., were reduced by infection with severe vein yellows virus (VYV) tested in 2 plots for 10 years. Bloom density and yield with some selections were reduced by the virus. Overall performance was affected by scion source as well as by VYV content. Inconsistencies resulted apparently from either undetected viruses, different strains of VYV, or from differences in genetic strains of the pear cultivar.

Open Access

Abstract

The nutrient content of rootstock and scion leaves from trees of ‘Napoleon’ and ‘Corum’ sweet cherry (Prunus avium L.) growing on Stockton Morello (Prunus cerasus L.) and East Mailing Mazzard F12-1 (Prunus avium L.) was analyzed. The concentration of Ca was greater in ‘Corum’ on F12-1 than on Stockton Morello. Rootstocks interacted with scions for K, P, Mg, Fe, Cu, B, and Zn.

Open Access

Abstract

Growth and yield of ‘Montmorency’ cherry varied greatly both within and between species of rootstock clones. Trees on FI2/1 mazzard (Prunus avium L.) were very vigorous and less productive than those on other stocks. Some growth control was found within each species or hybrid group but was most pronounced with P. mahaleb L. clones PI 193688, PI 163091 and PI 193693. Yield efficiency was not necessarily related to tree size but tended to be better with smaller trees. The 3 P. mahaleb clones listed above and the vigorous clones OCR-3 (P. mahaleb × P. avium) and PI 194098 (P. mahaleb) had high yield efficiencies. Trees on F12/1 and P. mahaleb PI 193703 had the lowest yield efficiencies. Based upon ideal orchard spacing for tree size, calculated annual yields exceeded 10 metric tons per ha for 6 of the clonal stocks.

Open Access

Abstract

‘Golden Delicious’ and ‘Starking Delicious’ apple (Malus domestica Borkh.) on Mailing 9 (M 9) rootstock were planted in 1956 in alternate rows 4.57 m (15 ft) apart, with in-row spacings of 1.22, 1.83 and 2.44 m (4, 6, and 8 ft). Average annual yield was higher at the closest spacing (1794 trees/ha) during the entire 18 years of the test. The pattern of yield was similar for the 2 cultivars but was higher for ‘Golden Delicious’ because of the lower fruit set of ‘Starking’ in some years due to adverse weather. Pruning during the last 6 years of the test was done by mechanical shearing of tops and sides, with no detailed pruning within the fruiting wall. This type of pruning on dwarf trees resulted in adequate fruit size, color, and quality with normal fruit thinning practices.

Open Access

Abstract

Boron sprays applied in the fall to ‘Italian’ prune trees (Prunus domestica L.) not deficient in boron resulted in a significant increase in fruit set and yield the following year. Analysis of midshoot leaf tissue the August following treatment showed no differences in boron content. These data indicate a possible transitory need for boron during the floral development and fruit set processes in ‘Italian’ prune which cannot be diagnosed by traditional leaf analysis.

Open Access

Abstract

Deep supercooling was found in the stem tissues of all the Pyrus species studied. There was more than 1 low temperature exotherm resulting from the freezing of supercooled water in stem tissue, and these exotherms were associated with the tissue injury. The supercooled water in the stems of P. nivalis Jacq., P. cordata (Desv.) Schneider and P. elaeagrifolia Pall, was found in both xylem and bark tissues. The supercooling characteristics of vegetative and flower buds are also described. The hardiest and least hardy species found were P. caucasica Fed. and P. pashia D. Don., respectively.

Open Access

Abstract

Conflicting opinions have been expressed for a number of years about the use, effectiveness, and cost of HortScience and the Journal. Because of the importance of these publications, the Publications Committee decided to conduct a survey of the membership to get a more complete picture of member views and to obtain some solid facts regarding the publishing behavior of different classes of members.

Open Access

Abstract

Tree survival beyond 2 years of intergeneric pear/apple graft combinations depended on the scion cultivar, the use of ‘Winter Banana’ apple interstock, and the specific rootstock. Trees with ‘Cornice’ scion and ‘Winter Banana’ interstem (on all six stocks) had higher survival (27%) after 11 years than those with ‘Bartlett’ scion (12%). No ‘Cornice’ tree on apple rootstock survived without the ‘Winter Banana’ interstem. Tree survival with ‘Winter Banana’ interstem after 11 years was 73% on M.26, 14% on M.7 and M.9 EMLA, 7% on MM.106 and MM.111, and 0% on M.9. Only trees of ‘Bartlett’ and ‘Cornice’ on M.26 and ‘Cornice’ on M.7 with ‘Winter Banana’ interstems produced fruit through the 11th year. Tree size ranged from 10% of standard for ‘Bartlett’ on M.26 to 25% for ‘Cornice’ on M.7 with the ‘Winter Banana’ interstem. Incompatability suppressed mainly foliar N and Zn but, to a degree, also P, Ca, and B.

Open Access

Abstract

The west coast of North America has long been a major production area of pears (Pyrus communis L.), because the relatively mild winters and dry summers reduce disease incidence and encourage high yield and quality. Depending on the year of planting, the site, variety, and cultural considerations, orchards have been planted on several different rootstocks.

Open Access