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Abstract

Movement of ¹⁴C-photosynthates in bearing and nonbearing branches of pistachio (Pistacia vera L.) was examined during the period of inflorescence bud abscission. Most of the ¹⁴C transported from leaves accumulated in developing nuts. Inflorescence buds on defruited trees accumulated twice as much ¹⁴C-photosynthate as those on fruiting trees. Inflorescence buds competed poorly against the developing fruit for photosynthate and this might be responsible for inflorescence bud abscission and resultant alternate bearing.

Abstract

In the paper entitled “Effect of Growth Regulators in Branching, Flowering, and Fruit Development of Ornamental Pepper (Capsicum annum L.)” by M. Khademi and M. Khosh-Khui (J. Amer. Soc. Hort. Sci. 102(6).796-798. 1977) the description for Figure 1 should read “C₁ is control and C₂ to C₄ represent 300,600, 900 ppm ethephon, 400, 800, 1200 BA, and 50,100, 150 ppm IAA, respectively.”

Abstract

In the paper, Effect of growth regulators on branching, flowering, and fruit development of ornamental pepper (Capsicum annuum L.), by M. Khademi and M. Khosh-Khui (J. Amer. Soc. Hort. Sci. 102(6):796-798. 1977), the description for Figure 1 should read … C₁ is control and C₂ to C₄ represent 300, 600, 900 ppm ethephon, 400, 800, 1200 ppm BA, and 50, 100, 150 ppm IAA, respectively.

Recently, the acreages Japanese apricot have been increased for being known of the medical functions. However, the increase of tree height, overgrowing trees and light deficiency at the bottom of canopy induced the poor fruit quality and higher labor charges. This study was conducted to assess the effects of training time, angle and length of water sprout on tree growth, the shoot-curbing, and the occurrence of new shoot for 2 years. Water sprouts were trained on 5, and 25 June, and 15 July with three varying angles of 30°, 45° and 60°, and cut at three lengths (50, 80, 110_) after harvest. Compared to control, the treatment on June 25 showed the highest values of 76%, 82% of internode and shoot length respectiely. In the treatment of training angle, shoot length was 71% in both 30° and 45° but heavily limited to 36% in 60° with comparing to control. The occurrence of shoots showed 18.1, 24.6, and 36.3 in treatment of 50, 80 and 110 cm, respectively, and in 80 cm, the number of shoot with diameter more than 0.5 mm, which is suitable for bearing mother branch, was higher. The best result was obtained in method of branch training with 45° and heading-back 80 cm at height on 15 June for the renewal of lateral branch.

A system for the rapid production of Ottawa-3 (0.3) rootstock (Malus domestica Borkh.) and branched apple nursery stock in the greenhouse is described. The time required for production of a finished' tree, ≈1 year, compared favorably with traditional methods. Cuttings derived from tissue-cultured 0.3 rootstocks rooted well (up to 94% success rate), and the rooting effect persisted in cuttings from tissuecultured rootstocks grown for 1 year in the field. All combinations of two levels of N and P in a Long Ashton nutrient solution were applied weekly to pots containing either tissue-cultured rootstocks or cuttings. The growth rate of tissue-cultured rootstocks exceeded that of cuttings. The growth rate of both sources of rootstocks increased in response to added P and N. Growth of scion shoots (`Royal Gala') increased in response to N. Branch production of `Royal Gala' was greater for trees with the higher P and N rates. Trees on tissue-cultured rootstocks had more branches than those on cuttingderived roostocks at the higher level of N.

Abstract

A block of 2-year-old ‘Starkrimson Delicious’ apple (Malus domestica Borkh.) trees growing in Somerville, Victoria, Australia were treated with 0 to 500 ppm BA when terminal growth was 2 cm. BA application initially increased the rate of lateral shoot growth. However, the growth rate rapidly slowed and extension growth on the lateral shoots stopped earlier than on untreated trees. There was a linear increase in the number of lateral shoots and a linear reduction in the length of these lateral shoots as the concentration of BA was increased. BA forced more lateral shoots to grow at the tip of the branch than at the base, although shoots at the base of the limbs grew longer. A reduced concentration of BA was required to stimulate spurs to grow out into lateral shoots on the vigorous, more upright central leader. Lateral shoots were longer on the central leader than on the scaffold branches, indicating tree and/or branch vigor may be a major factor in producing good scaffold limb development following BA application. Notching forced more spurs to form lateral shoots on the central leader, and these shoots grew longer than those on the scaffold limbs. Notching increased the number of buds developing into lateral shoots following BA application. May and Baker 25-105 increased the number of lateral shoots on a tree. This result occurred both on untreated trees and on those that previously received 400 ppm BA. Reducing the number of lateral shoots by pinching apices of shoots soon after BA application was the most effective method to increase the length of BA-induced lateral shoots. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine (BA) (2-chloroethyl)phosphonic acid (ethephon), butanedioic acid mono(2,2-diemthylhydrazide) (daminozide), propyl 3-t-butylphenoxyacetate (May and Baker 25-105).

Apple (Malus domestica Borkh.) cultivars Spur Galagored (#42) (`Gala'), Jonagored (`Morren's'), and Red Fuji (B.C. #2) (`Fuji') on Mark rootstock and `Gala' on Malling 26 EMLA (M.26) and Malling 9 EMLA (M.9) were planted in the four major apple-production regions of western North Carolina. Three leader management techniques, weak leader renewal, snaked leader, and heading with partial terminal leaf removal (H + PTLR), were applied to five-tree plots beginning the spring after planting. Leader management techniques, weak leader renewal or H + PTLR, which involved dormant pruning or vegetation removal and an interruption in vegetative vigor, reduced total branching and yield during the third year. Fumigation with methyl bromide increased lateral branching and yield in the third year. No significant yield differences were detected for `Gala' grown on M.9, M.26, or Mark rootstocks. Trees grown in the most western region of the state, Haywood County, had smaller trees and reduced yields compared to the other three regions due to a shorter growing season.

The partitioning of photosynthates labeled by ¹⁴CO₂ in exposed and shaded `Empire' apple (Malus domestica Borkh.) branches was examined at 1, 3, 5, and 10 weeks after bloom. Extension shoots, nonfruiting spurs, or fruiting spurs were labeled separately to examine which shoot types exported to the fruit at each time. The general partitioning patterns were observed with autoradiography, while label accumulation in fruit was determined by oxidation and scintillation counting. At each treatment time, half of the branches was preconditioned with artificial shade (to 35% full light) for 48 hours before labeling and returned to the shade for a 2-day translocation period. One and 3 weeks after bloom, extension shoots showed little export to fruit; nonfruiting and vigorous fruiting spurs exported label to weak spurs and extension shoot tips. Shade had no major effect on partitioning patterns at 1 and 10 weeks, but essentially eliminated export from extension shoots at 3 weeks and greatly reduced export to fruit 5 weeks after bloom, as observed on the autoradiograms. At 5 weeks after bloom, the shading effect was equal to a 2-week delay in export. By 10 weeks after bloom, all shoot types were exporting most of the ¹⁴C fixed to fruit. The photosynthate support of the fruit before fruit set seemed to strongly depend on the spur canopy, especially when the extension shoots were exposed to low light.

Five Wave™ petunias, i.e., `Purple Wave™', `Pink Wave™', `Misty Lilac Wave™', and `Rose Wave™', and two hedgaflora petunias, i.e., `Dramatica Cherry™', and `Dramatica Hot Pink™', were investigated to determine the effects of plant growth regulators on plant size, branching, and flowering. Plant regulator treatments consisted of daminozide (B-Nine) spray two times at 7500 ppm, Paclobutrazol (Bonzi) spray two times at 30 ppm, paclobutrazol drench at 5 ppm, paclobutrazol drench at 5 ppm plus spray at 30 ppm, and ethephone (Florel) spray two times at 500 ppm. Plant diameter and central stem height were controlled effectively through daminozide spray and paclobutrazol drench. Plant branching was promoted by ethephone and daminozide. However, time to flowering was delayed significantly in the ethephone treatment. The size of the first flower responded to plant growth regulators negatively. The different responses to growth regulators among different types of petunias and different varieties in the same petunia type will be discussed based on the current trial and other separated experiments.

Abstract

Applications of 6-benzylamino purine (BA) and gibberellin A_{4 + 7} (GA_{4 + 7}) over a period of 3 years significantly increased primary and secondary branching and total shoot growth of 6 apple cultivars (Malus domestica Borkh.) from the first through the fourth growing seasons in the field. In spur-type ‘Delicious’ and ‘McIntosh’, BA + GA_{4 + 7} was more effective than deblossoming, pruning, or branch spreading in inducing lateral branching.