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  • Author or Editor: D.C. Ferree x
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Abstract

Traditionally, the size control achieved in summer-pruned apple (Malus domestica Borkh.) trees has been attributed to the removal of shoot leaf area before it could replace the storage carbohydrate depleted during its initial growth. Therefore, tissues of young Top Red ‘Delicious’/M 9 trees grown in pots, and mature, field-grown ‘Jonathan’/M 26 trees were summer-pruned and subsequently analyzed for carbohydrate and nutrient element content. Increasing the severity of summer pruning (the length of shoot removed) did not affect the concentration of water-soluble reducing sugars (SRS) or insoluble hydrolyzable carbohydrates (IHC) in the basal shoot section of the Top Red ‘Delicious’/M 9 trees 11 weeks after pruning. Summer pruning 1) increased leaf SRS, N, K, B and stem IHC and 2) decreased leaf Ca and Mg in shoot regrowth. Levels of Fe, Ca, Zn, Al, and Na in the leaves of regrowth were not affected by summer pruning. There was no significant effect of pruning on SRS or IHC levels in the roots. A separation of the carbohydrates by gas chromatography revealed increasing glucose and fructose concentrations in the roots as pruning severity increased, but sorbitol, sucrose, and phloridzin concentrations in roots were not significantly affected. Neither previous season’s summer pruning nor fruit cropping of ‘Jonathan’/M 26 trees affected SRS or IHC of spur shoots in March or June, except that presence of fruit reduced IHC of spur leaves in June. SRS levels in roots in June were reduced by the previous year’s cropping, but not influenced by summer pruning. Root IHC was not influenced by either pruning or cropping treatments. Spur leaf N, Ca, Mg, Mn, and Al were reduced on defruited trees, with K, Ca, Mn, and Al generally being increased by summer pruning. Pruning and cropping treatments generally did not affect levels of P, Fe, B, Cu, Zn, or Na in spur leaves in June; but summer pruning increased K concentration in harvested fruit.

Open Access

Vines of container grown `DeChaunac', `Vidal blanc', `Seyval blanc' and `Chambourcin' grapes were subjected to 5 days of 80% shade at prebloom, bloom or 2 and 4 weeks after bloom. Fruit set, cluster weight, berries per cluster and juice components [soluble solids concentration (SSC), pH and titratable acidity] of `DeChaunac' and `Vidal blanc' were not affected by a short period of intensive shade. `Chambourcin' was sensitive to a shade period near the time of bloom for most of the aforementioned factors, while `Seyval blanc' was intermediate in sensitivity. Shot (green, hard, and undersized) berries of `Chambourcin' and `Seyval blanc' were increased by a 5-day period of shade 2 or 4 weeks after bloom. In a second study, container-grown `Chambourcin' on 3309C (V. riparia × V. rupestris) with one or two clusters and `Vidal blanc' with one cluster were subjected to the following light regimes beginning at bloom for 5 weeks: supplemental light, ambient greenhouse light and 30%, 50% or 80% shade. Yield, fruit set, specific leaf weight (leaf dry weight/leaf area), saturation index, and total leaf chlorophyll increased linearly with increasing irradiance. `Chambourcin' juice pH, SSC, leaf chlorophyll a/b ratio, cluster color development and hue angle decreased as irradiance increased, likely related to crop reduction. Responses in `Vidal blanc' followed similar trends, but differences were not as great. Results demonstrate that light is an important determining factor in fruit set of French-American hybrid grapes and fruit set of some cultivars are sensitive to short periods of intense shade.

Free access

Rootstock recommendation is complicated by performance-site interactions. The N C140 Regional Project recently completed a lo-year evaluation of 9 rootstocks in locations across North America. Based on this data, we developed stability analysis models and demonstrated significant rootstock-site interactions for cumulative yield (CY) and trunk cross-sectional-area (CSA). The models require a site index (SI) estimated from mean performance over rootstocks within site. Prediction of rootstock performance in untested sites would be possible with an independent estimate of SI. We tested prediction of SI from mean maximum temperature (T) and total moisture received (M) and divided T and M into 5 phenological periods: Dee-Jan (Dormant), Feb-Apr (Prebloom), May-Jun (fruit Set), July-Sept (fruit Growth), and Oct-Nov (Postharvest). SICSA was not predicted by any T or M variable. SICY was predicted by TSet. TGrow, and MSet, but TSet and MSet were codependent. SICY was best predicted from a linear relationship with TSet.

Free access

Survival of replicated rootstock plantings of apple trees (Malus ×domestica) to fire blight (Erwinia amylovora) infection shows that a wide range of rootstock susceptibility exists. Trees on `Malling 26' (M.26), `Malling 9' (M.9), and `Mark' consistently had significant losses. Of the dwarfing rootstocks widely available commercially, `Budagovsky 9' (B.9) survived well with productive trees, but was not resistant to fire blight infection. The following experimental rootstocks had good survivability with many live productive trees in one or more trials: `Poland 2' (P.2), `Vineland 1' (V.1), `Malling 27 EMLA' (M.27 EMLA), `Budagovsky 491' (B.491), `Budagovsky 409' (B.409), `Vineland 7' (V.7), `Vineland 4' (V.4), and `Oregon Rootstock 1' (OAR1).

Full access

Abstract

Spray adjuvants alone and combined with benomyl in single and multiple applications were tested for their influence on net photosynthesis (Pn) and development of apple scab caused by Venturia inaequalis (Cke.) Wint. on trees of apple (Malus domestica Borkh.) grown in the greenhouse. Triton CS-7 increased and ×-100 and 70 second oil deceeased Pn. Nu Film 17, Triton B-1956, Regulaid and ×-77 when combined with benomyl had no influence on Pn. Addition of Biofilm, Nu Film 17 or 70 second oil to benomyl did not improve apple scab control. Three sprays of benomyl plus oil decreased Pn of fully expanded leaves, and 5 sprays decreased Pn of both expanded and newly expanding leaves with the latter showing the greatest reduction.

Open Access

Abstract

Shoots of newly planted ‘Oregon Spur Delicious’ (Malus domestica Borkh.) apple trees were trained at angles of 30°, 60°, or 90° from vertical and compared to an untrained control in 1973. Lateral shoots of some trees with the 30° orientation in 1973 were bent to 60° in 1974. Generally, during the first growing season shoot growth was reduced proportional to the degree of bending toward the horizontal. Shoots trained at an angle of 30° the first season and 60° the second season had the greatest reduction in shoot growth in 1974 and had more flowering on the upper and middle scaffold shoots than other treatments. Unpruned trees with shoots developing naturally produced more total shoot and new root growth and produced more spurs and flower clusters than other treatments. Trees with shoots trained to the horizontal (90°) produced the greatest number of watersprouts and the least flowering.

Open Access

Abstract

Overtree misting for bloom delay reduced fruit set of ‘Golden Delicious’ apple (Malus domestica Borkh.) flowers hand-pollinated with ‘Jonathan’ or ‘Golden Delicious’ pollen in 1978, or open-pollinated or hand cross-pollinated with ‘Jonathan’ pollen in 1979. Misting did not affect fruit set of flowers that were open-pollinated in 1978 or self-pollinated in 1979. The number of seeds per fruit was not reduced. Soil Ca, Mg, pH and base saturation of Ca and Mg were increased, and flower and spur leaves contained lower concentrations of N, P, K, B, Mn, Fe, Zn, and Cu at either full bloom or petal fall as a result of misting. Foliar sprays of B increased B concentrations but did not influence fruit set on either misted or nonmisted trees.

Open Access

Abstract

Fifty-nine flowering crab apple cultivars (Malus spp.) were evaluated in 1977 and 1978 to determine time and pattern of bloom period relative to that of 5 commercial cultivars. The crab apple cultivars ‘David’, ‘Simpson 10-35’, and ‘Ellen Gerhart’ had similar bloom patterns with the commercial cultivars, ‘Delicious’, ‘Jonathan’, ‘Golden Delicious’ and ‘Gallia Beauty’. Bloom patterns of ‘Donald Wyman’ and ‘Indian Magic’ were similar to the bloom patterns of ‘Jonathan’, ‘Golden Delicious’, and ‘Delicious’. ‘E.H. Wilson’, M. robusta ‘Erecta’, ‘Ormiston Roy’, ‘Sentinel’, and ‘Turesi’ had bloom patterns that were similar with ‘McIntosh’. Hand pollination with pollen from 10 crab apple cultivars resulted in fruit set on ‘Delicious’ equal to open pollination or hand pollination with ‘Jonathan’ pollen.

Open Access

The 1980 NC-140 uniform apple rootstock trial plantings located in Michigan and Ohio were used to determine root distribution patterns of the nine rootstooks involved in the trial. The scion for the trial was Starkspur Supreme (Malus domestica Borkh.) on Ottawa 3, M.7 EMLA, M.9 EMLA, M.26 EMLA, M.27 EMLA, M.9, MAC 9, MAC 24 and OAR 1 rootstock. Trenches were established parrallel with the tree rows 0.8 m from the center of the trunks on both sides. The trenches were 1.5 to 2 m deep. Grids were constructed 1.2 m deep × 1.8 m wide with 30 cm × 30 cm grid squares. Soil was washed from the profile and the grid was placed over the profile. Roots were classified into 3 size categories; less than 2 mm, 2 to 5 mm and greater than 5 mm. Soil physical properties were also characterized. Differences were found between rootstock root distribution patterns and will be discussed in relation to rootstock and location/soil properties.

Free access

Container-grown apple (Malus ×domestica Borkh.) trees were exposed to soil compaction created by changing soil bulk density (SBD) to determine the effect of compaction levels, rootstock, and moisture stress on mineral nutrition, leaf gas exchange, and foliar carbohydrate levels. With SBD of 1.0, 1.2, and 1.4 g·cm-3, there was no interaction of rootstock and soil compaction for growth of `Melrose' trees on nine rootstocks. Trees grown in a SBD of 1.2 g·cm-3 had a greater dry weight than trees at 1.4 g·cm-3 bulk density. Increasing SBD to 1.5 g·cm-3 reduced shoot length, total leaf area, leaf size, and dry weight of leaves, shoots, and roots. The interaction between rootstock and SBD was significant and total dry weight of `B.9', `G.16', `G.30', and `M.7 EMLA' was less influenced by 1.5 g·cm-3 soil than trees on `M.26 EMLA' and `MM.106 EMLA'. Withholding moisture for 10 days at the end of a 70-day experiment caused 8% to 25% reduction in growth in a non-compacted (1.0 g·cm-3) soil with much less effect in a compacted soil. Prior to imposing the moisture stress by withholding water, net photosynthesis (Pn) was reduced 13% and transpiration (E) 19% by increasing bulk density to 1.5 g·cm-3. Following 7 days of moisture stress in non-compacted soil, Pn and E were reduced 49% and 36%, respectively, with no such reductions in the compacted soil. Increasing SBD to 1.5 g·cm-3 caused a decrease in the leaf concentration of quinic acid, myoinositol, and sucrose and an increase in fructose and glucose. Trees growing in 1.5 g·cm-3 had reduced concentrations of N, Ca, Mg, Mn, Na, and Zn, and increased P, K, B, and Fe in leaves.

Free access