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  • Author or Editor: D.C. Ferree x
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In 1984 trees of `Starkspur Supreme Delicious' apple on 15 rootstocks were planted at 28 locations in North America according to guidelines established by The North Central Regional Cooperative Project (NC-140). The largest trees were on P.18, ANT.313, B.490 and seedling. Producing trees approximately 70% the size of seedling were rootstocks P.1 and M.7 EMLA while M.26 EMLA and C.6 were 50% the size of seedling. A group of rootstocks 30% the size of seedling or smaller were B.9, MAC.39, P.22, P.2, P.16. Rootstocks with high production efficiency were P.16, 8.9, P.22, P.2 and C.6. Rootstocks with low production efficiency similar to apple seedling were MAC.1, M.4., B.490, P.18 and ANT.313.

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The impact of environmental factors on the photosynthetic potential of tree fruits is largely uncontrollable, but one can affect photo synthetic efficiency through the manipulation of various cultural practices. Application of pesticides and other chemicals; tree size and shape; mineral nutrition; and pest damage are all important factors and should be carefully considered in maximizing net photosynthesis (Pn) and ultimate tree performance.

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Greenhouse and field-grown `Seyval blanc' grapevines (Vitis sp.) were grown with low-growing, shallow-rooted, mat-forming, ornamental perennial groundcovers, and the effect of the groundcovers on the vegetative and fruiting growth of the grapevines was evaluated. The groundcovers used in this experiment were `Kentucky-31' tall fescue (Festuca arundinacea); white mazus (Mazus japoonicus albus); english pennyroyal (Mentha pulegium); dwarf creeping thyme (Thymus serpyllum minus); strawberry clover (Trifolium fragiferum); `Heavenly Blue' veronica (Veronica prostrata `Heavenly Blue'); and a companion grass mixture of 75% perennial ryegrass (Lolium perenne) and 25% red fescue (Festuca rubra). A control treatment grown without any groundcover was also used in both the greenhouse and field experiments. All of the groundcovers reduced `Seyval blanc' total shoot length from 22% to 85% in the vineyard. Cluster size was reduced in the field from 7% to 68% by the groundcovers compared to the herbicide control treatment, and from 9% to 66% in the greenhouse experiment, but none of the groundcovers in either the greenhouse or field experiments affected the pH, total acidity, or soluble solids concentrations of the `Seyval blanc' juice. English pennyroyal was the only groundcover that reduced in the leaf area of the grapevine. Single-leaf photosynthesis of the `Seyval blanc' grapevines in the field experiment was reduced by all groundcovers except mazus and creeping thyme. Water infiltration rates were 10 to 50 times higher in the groundcovers compared to the bare soil of the herbicide control treatment. Weed growth in the field caused reduction in shoot length similar to the most competitive groundcovers. Weed growth was reduced in the early season by the english pennyroyal and companion grass, and in the late season by all groundcovers. The reduction in growth of the grapevines caused by groundcovers in the greenhouse was a reasonable screen for the affect of groundcovers in the field. The mazus treatment was the only groundcover in our experiments that coupled fast growth with low competitive ability.

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Dormant, 2-year-old, own-rooted `Chambourcin' grapevines (Vitis sp.) were subjected to two levels of root pruning (none, two-thirds roots removed) and were subsequently trained with either one or two canes. Vines were destructively harvested at bloom and after harvest when dormant to determine the effect of stored reserves in the root and competition between shoots for these reserves on vine growth and berry development. Removing 78% of the root system reduced shoot elongation and leaf area more effectively than did increasing the number of shoots per vine from one to two. Root pruning reduced the elongation rate of shoots for 45 days after budbreak, whereas increasing the shoot number reduced the shoot elongation rate for only 20 days after budbreak. A positive linear relationship was observed between leaf area per shoot at bloom and the number of berries per single cluster. These results demonstrate the importance of 1) the roots as a source of reserves for the initial development of vegetative tissues in spring, and 2) the rapid development of leaf area on an individual shoot for high set of grape berries on that shoot.

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`Smoothee Golden Delicious' apple trees on nine rootstocks or interstems were mechanically root pruned annually for 9 years beginning the year after planting. Root pruning reduced trunk cross-sectional area (TCA) by 14% over the first 5 years and 22% in the last 4 years of the trial. Yield and fruit size were reduced by root pruning in most years with the fruit size effect obvious in June at the end of cell division. Interstem trees of MAC.9/MM.106 were larger than trees on M.9 and the following interstems: M.9/MM.106, M.9/MM.111, M.27/MM.111. Trees on seedling (SDL) rootstock were the largest and had the lowest yield per unit TCA and lower cumulative yield/tree than trees on M.7, MM.106, and MM.1ll. There was no interaction for any measure of growth or yield between root pruning and rootstock or interstem.

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Container-grown `Chambourcin' grapevines were exposed to soil compaction created by changing soil bulk density to determine the effect of levels of compaction, rootstocks and moisture stress on mineral nutrition, leaf gas exchange and foliar carbohydrate levels. Shoot growth, leaf area, number of inflorescences and leaf dry weight decreased linearly as soil bulk density increased with the effects being significant above 1.4 g·cm-3. The early season leaf area was reduced 40% in the second season, but later leaves were unaffected by a soil bulk density of 1.5 g·cm-3. Net photosynthesis (Pn) and transpiration (E) increased linearly with increasing soil bulk density the first year, but the second year a nonlinear pattern was observed with highest rates at 1.3 and 1.4 g·cm-3. Soil bulk density of 1.5 g·cm-3 reduced number of leaves, leaf area and shoot length and advanced bloom 16 days on `Chambourcin' vines on six rootstocks with no interaction of rootstock and soil compaction. Withholding water for 8 days reduced Pn and E in all treatments, with no effect on shoot length, leaf, stem and total dry weights. Moisture stress in the noncompacted soil caused a reduction in leaf concentration of fructose, glucose and myo-inositol, but moisture stress had no effect in the compacted soil. Moisture stress caused a reduction in sucrose in both compacted and noncompacted soil. Compacting soil to a bulk density of 1.5 g·cm-3 was associated with an increase in leaf N, Ca, Mg, Al, Fe, Mn, Na, and Zn and a decrease in P, K, B, and Mo.

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Abstract

‘Delicious’/M9 planted in 1974 were unpruned or pruned on 3 July, 3 Aug., or 3 Sept. 1979, and at a comparable time in 1980. In the distal section, total length and dry weight of lateral shoots were greater on vertical than on horizontal limbs. Lateral shoot length and dry weight were decreased in the distal but not affected in the middle and proximal sections by pruning. Pruning and limb orientation had no effect on the distribution of dry weight in the limb sections. Time of pruning had no influence on the distribution of growth in the limb sections.

Open Access

`Seyval blanc' and `Vidal blanc' grapevines (Vitis sp.) grown in large containers were root-pruned at different severities and/or stages of development and the effects on growth of both cultivars and fruiting of `Seyval blanc' were determined. As the severity of root pruning increased, stomatal conductance (g s) and transpiration (E) decreased and the number of wilted leaves increased in both cultivars. In both cultivars, root pruning reduced net photosynthesis (Pn) and E for as long as 18 to 20 days, as well as total leaf area and dry weight of leaves and petioles plus tendrils. The reductions were proportional to the degree of root pruning. A similar pattern existed for cane and root tissue of `Vidal blanc'. As the severity of root pruning increased, berry and cluster weight, and titratable acidity (TA) of `Seyval blanc' decreased. There was no effect of root pruning on berries per cluster, soluble solids content (SSC), or pH of the juice. No interaction was significant for any factor between time of root pruning and fruiting measured on `Seyval blanc' vines. Root pruning at bloom reduced leaf area, number of leaves, and dry weight of petioles, trunks, and canes. Root pruning at veraison had no effect on any vegetative or fruit parameters. Fruiting `Seyval blanc' vines had less leaf area and smaller petiole and cane dry weights than did nonfruiting vines.

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Abstract

Spray treatment a single dormant application of high concentrations of anionic (Triton CS7) and nonionic (Triton N57 and Triton X100) surfactants caused up to 5 days delay in bud break in apple (Malus domestica Borkh.), but had less effect on grape (Vitis spp.) and peach (Prunus persica (L.) Batsch) and none on pear (Pyrus spp.). Surfactants tended to extend the bud break period but were frequently lethal to buds, particularly at concentrations of 3% and 5% active ingredient. In field studies, surfactants delayed the early stages of flower bud development but not bloom of apple or peach and did not control apple scab caused by Venturia inaequalis (Cke.) wint. or powdery mildew caused by Podosphaera leucotricha (Ell & Ev.) Salm.

Open Access
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Abstract

Laboratory and field application methods of (methyl 1-(butylcarbamoyl)-2 benzimidazolecarbamate) (benomyl) and oil were evaluated for their influence on net photosynthesis of leaves of potted apple trees. Superior 70-second viscosity oil applied as a dip caused a significant reduction in net photosynthesis of young leaves at both the 1.26 ml and 2.52 ml/liter levels, with the greater reduction at the higher level. Benomyl alone or in combination with oil had no influence on net photosynthesis. Spray application in the laboratory or by commercial field sprayers had no effect on net photosynthesis of fully expanded leaves.

Open Access