Foliar Sprays Of Paclobutrazol Research Articles

Effects of Pinching, Number of Cuttings per Pot, and Plant Growth Regulators on Height Control of Purple Firespike

Purple firespike (Odontonema callistachyum), native to Central America, has potential for use as a new flowering potted plant. The effects of number of pinches (zero, one, or two) and number of cuttings (one, two, or three) per 6-inch pot were evaluated on the control of plant height. Plant height was suppressed as the pinch number increased. The greatest reduction was recorded with one cutting per pot and two pinches. The maximum number of branches per pot was recorded with two pinches and three cuttings per pot. In a second experiment, plant growth regulators (PGR) were also tested for efficacy of height control; 2 weeks after pinching, foliar sprays of paclobutrazol, flurprimidol, daminozide, chlormequat, and a tank-mix of daminozide + chlormequat or media drenches of paclobutrazol, uniconazole, or flurprimidol were applied. Plant height, leaf area, and leaf dry weight were recorded at 3, 6, and 9 weeks after PGR application. Maximum height control was obtained with uniconazole drench at 8 ppm, resulting in plants 22 cm tall, 61% shorter than the untreated control (56 cm); however, it resulted in severe leaf distortion. Plant height was 56% and 46% shorter than the control using drenches of paclobutrazol at 30 ppm and flurprimidol at 15 ppm, respectively. Daminozide spray at 2000 ppm and tank-mix of daminozide + chlormequat at 4500/1500 ppm suppressed stem elongation by 20.3% and 19%, respectively. Plants treated with paclobutrazol drench at 30 ppm reduced leaf area and leaf dry weight compared with other PGRs. Chlormequat spray at tested concentrations was ineffective for controlling firespike plant growth. The most attractive potted plants were produced using a drench application of paclobutrazol at 10 or 15 ppm.

ウンシュウミカンの着花に及ぼすジベレリン生合成阻害物質の効果

Foliar applications of gibberellin inhibitors and GA3 on satsuma mandarin (Citrus unshin Marc.) were investigated with respect to flower induction.1. Paclobutrazol, uniconazole-P, prohexadione-Ca, and CCC were applied 3 times during autumn. The number of flowers on vegetative shoots were increased in the following spring by paclobutrazol and uniconazole-P treatments.2. Foliar sprays of paclobutrazol, uniconazole-P, prohexadione-Ca and GA3 were made in winter. There was a significant increase in the number of flowers by paclobutrazol treatments made on 10 and 30 Jan., uniconazole-P at 30 Jan., and prohexadione-Ca at 20 Dec., 10 and 30 Jan. GA3 application reduced the number of flowers and inhibited bud sprout break in the spring.3. Foliar applications of the above three GA inhibitors at 100, 300, 1, 000 and 3, 000 ppm were made on 30 Jan. Paclobutrazol at 100 to 1, 000 ppm, uniconazole-P at 100 ppm and prohexadione-Ca at 300 and 1, 000 ppm were effective for the flower induction. Treatments with 100 ppm paclobutrazol and 3, 000 ppm prohexadione-Ca induced the dropping of flowers and fruitlets.4. To determine the optimum time (s) of application, trees were sprayed with paclobutrazol, uniconazole-P, and prohexadione-Ca on 10 Jan., 30 Jan. and 20 Feb., repeatedly. With any agent, thrice treatments were most effective in promoting flowering, but once and twice applications were sufficient for a significant increase in flower bud formation with any chemicals. Chemical names used (2 RS, 3 RS) -1- (4-chlorophenyl) -4, 4-dimethy1-2- (1 H-1, 2, 4-triazol-1-yl) pentan-3-ol, (paclobutrazol) ; (E) -1- (4-chlorophenyl) -4, 4-dimethy1-2- (1, 2, 4-triazol-1-yl) -1-penten-3-ol, (uniconazole-P) ; Calcium-3, 5-dioxo-4-propionyl cyclohexanecarboxylate, (prohexadione-Ca).

Drought, Paclobutrazol, Abscisic Acid, and Gibberellic Acid as Alternatives to Daminozide in Tomato Transplant Production

`Floradade' tomato (Lycopersicon esculentum Mill.) transplants treated with foliar sprays of paclobutrazol at 0, 14, 30, 60, or 90 ppm exhibited reductions in stem length, leaf area, and plant dry weight in a cubic response pattern. Gibberellic acid (GA) drenches, at 10, 100, or 250 ppm, increased stem length, leaf area, and plant dry weight. Daminozide (2500 or 5000 ppm) sprays reduced leaf area and dry weight, but 5000 ppm had no effect on stem length. Abscisic acid drenches, at 275, 660, or 1320 ppm, did not affect final plant size. In subsequent experiments to produce transplants for field evaluation, plants treated with paclobutrazol sprays at 90 (1987) and 14 or 60 ppm (1988) had smaller leaf area, stem length, and shoot dry weight than untreated plants. In 1987,90 ppm paclobutrazol reduced stem shear strength, while 2500 ppm daminozide increased stem strength relative to controls. In 1988, 2500 ppm daminozide increased transplant growth while 660 ppm abscisic acid had no effect. Paclobutrazol (14 ppm) and drought improved field establishment of transplants as measured by shoot dry weight gain after field planting. In 1988, total fruit yield was reduced by 60 ppm paclobutrazol and GA. Although fruit size was unaffected by treatments, fruit number was reduced by GA. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); B-[(4-chlorophenyl)methyl]-α -(1,1-dimethylethyl) -N-1,2,4-triazole-1-ethanol (paclobutrazol).

Use of paclobutrazol sprays at mid-anthesis for increasing fruit size and yield of avocado (Persea americanaMill. cv. Hass)

SummaryMid-anthesis foliar sprays of paclobutrazol (PB) at 2.5, 1.25 and 0.62 g a.i. I-1 reduced spring growth and altered dry-matter distribution in fruiting spring shoots of ‘Hass’ avocado.(Persea americana Mill.) trees. There was a decrease in dry matter allocation to vegetative components and an increase in allocation to fruit. The starch concentration in the wood of spring shoots on trees treated with 2.5 g a.i. I-1 foliar PB was increased by ca. 70% compared with spring shoots from trees of other treatments. The mid-anthesis foliar treatments also reduced summer growth by ca. 20%. Trunk injection of PB at 0.2 g a.i. m~2 of canopy silhouette area when the spring growth matured, in addition to a mid- anthesis foliar spray of 1.25 g a.i. I-1, reduced the length of summer shoots by 36% when compared with untreated trees. The spray treatments of 2.5 and 1.25 g a.i. T1 PB at mid- anthesis increased the mean fruit size at harvest by 16 and 11% respectively. Fruit yield was not significantly affected by PB ...

Growth and Development of Young ‘Loring’ Peach Trees after Foliar Sprays of Paclobutrazol and GA3

Abstract Container-grown ‘Loring’/Lovell seedling peach trees [Prunus persica (L.) Batsch] trained to four current-season extension shoots (ES) were treated with 60, 240, or 960 mg of foliar-applied paclobutrazol (PBZ)/liter 8 weeks after shoot growth began, followed 2 weeks later by a 50-mg spray of gibberellic acid (GA3)/liter. PBZ reduced both the post-treatment increment in trunk cross-sectional area (𝚫TCA) and current-season shoot length (𝚫ES) by up to 26% and 43%, respectively, as compared to control. GA3 increased 𝚫TCA by 45% and stimulated an increase in 𝚫ES, especially on the trees treated with PBZ at 0 and 60 mg·liter-1. PBZ had reduced the total length of lateral shoots (LS) developing on the ES by up to 48% and 38% as compared to control by 2 and 14 weeks, respectively, after PBZ application. However, the GA3 application increased the total LS length by 38%. The ES positioned at the two most basal locations on the tree trunk produced a 31% increase in LS length per ES, but there was no interaction between ES location and PBZ or GA3 influence on the final growth parameters. Total plant dry weight and root: shoot ratio were not affected by PBZ, but GA3 increased plant dry weight 38% and decreased the root: shoot ratio. Chemical name used: β -[(4-chlorophenyl) methyl]- α-(1,1-dimethylethyl)-l-H-l,2,4-triazole-1-ethanol (paclobutrazol).

Growth and Development of Young Peach Trees as Influenced by Foliar Sprays of Paclobutrazol or XE-1019

Abstract A single or four sequential foliar sprays of paclobutrazol (PBZ) and XE-1019 (Valent Corp., Walnut Creek, Calif.) to peach [Prunus persica (L.) Batsch.] supplied, respectively, 7.5 to 480 mg a.i. and 0.75 to 48 mg a.i. doses per tree. These treatments reduced the net change in total shoot length (current-season extension shoots plus lateral shoots) occurring over the 15-week period after the sprays were applied by up to 80% and 69%, compared to the control, for each compound, respectively. The average number of lateral shoots was decreased 85% and 81% by the highest dose of each material. The shoot and whole plant dry weight at the end of the growing season (15 weeks after treatment) were ≍22% and 27% lower than the control for PBZ and XE-1019, respectively. Trunk cross-sectional area, leaf area, and dry weight of leaves and roots were also smaller on the trees treated by either compound. Root : shoot ratios were not influenced by any treatment. Chemical names used: β-[(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazole-1-ethanol (paclobutrazol); (E)-1-(p-chlorophenyl)-4-,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (Valent XE-1019).

Cranberry growth and yield response to fertilizer and paclobutrazol

In glasshouse studies with cranberry, paclobutrazol (PP333) ((2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pentan-3-ol) applied twice as a foliar spray at 75, 150, 300, 600 or 1200 mg 1 −1 decreased shoot and root growth, and the shoot: root ratio. Paclobutrazol decreased shoot elongation within 3 weeks of application and increased the number of branches on primary shoots. Buds were formed within 7 weeks of treatment and some contained flowers. In a second experiment, flower-bud formation was greater when plants were treated with paclobutrazol at 1.25, 2.50 or 5.00 mg pot −1 as a soil drench and grown for a longer period. Plants grew more with high NPK than with low NPK but growth was diminished still by paclobutrazol. High NPK decreased floral induction. Paclobutrazol was still detected in the soil 50 weeks after application. In a cranberry field study, foliar sprays of paclobutrazol at 75 or 150 mg 1 −1 at full bloom and 2 weeks later decreased fruit set, fruit size and yield, but increassed bud set and flower-bud set on uprights. Shoot growth was decreased the following year but the number of flowers per upright was increased. Fruit set was the most important contributor to yield variation, followed by fruit size and flowers per upright. The effects of paclobutrazol upon adjusted yield components accounted for a substantial amount of yield variation. No effect of cultivar on yield was apparent as the higher proportion of adjusted number of uprights flowering in cultivar ‘McFarlin’ was offset by an increased adjusted number of flowers per upright in cultivar ‘Bergman’. Bud set and flower-bud set were greater in uprights that did not flower in the current season.

Restructuring and cropping large ‘Red Delicious’ apple trees with paclobutrazol and daminozide

SummaryApplications of paclobutrazol to the soil in 1983 did not affect shoot length in either the first year (1983-4), or in the following year. In trials in 1983-4 and 1985-6, foliar sprays of paclobutrazol or daminozide reduced shoot length. Sequential sprays were mostly similar to one high-concentration spray of the same quantity of chemical applied in November. With appropriate concentrations, paclobutrazol and daminozide increased fruit numbers/unit trunk area and increased the number of flower clusters per unit limb area, but did not affect fruit shape. Mean fruit weight was decreased by daminozide. Fruit shape, measured by length-diameter ratios was unaffected by any treatment in these trials. After the 1984 treatments, where vegetative growth was retarded, more flowers were initated.

Effect of Fertilizer, Paclobutrazol, and Chlormequat on Strawberry

Abstract In a greenhouse study with strawberry (Fragaria × ananassa Duchesne), foliar sprays of paclobutrazol (PP333) at 10, 46, 215, or 1000 ppm and chlormequat chloride (CCC) at 215 or 1000 ppm decreased runnering, but PP333 was most effective. PP333 inhibited runnering more for ‘Totem’ than ‘Shuksan’, with the reverse true for CCC. Biweekly fertilization with 20N-4.3P-8.3K at 180 mg/pot increased leaf area and runnering relative to 45 mg/pot. PP333 at equal rates produced larger decreases in leaf area than CCC. Both high fertilizer and PP333 in a rate-dependent manner delayed leaf senescence and berry ripening. CCC increased yield in ‘Shuksan’ only, and while berry fresh weight was increased by PP333, no increase in yield occurred, as it was offset with a decreased number of berries that ripened over the period of our study. PP333 decreased pollen germination. Soil residues of PP333 were evident 11 weeks after application. Chemical names used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H- - 1,2,4-triazole-1-ethanol (paclobutrazol); 2-chloro-N, N, N-trimethylethanaminium chloride (chlormequat chloride).

Effect of Foliar- and Soil Surface-applied Paclobutrazol on Vegetative Growth and Fruit Quality of Sweet Cherries

Abstract The length of the lag phase following treatment and the persistence of the eventual growth suppression effect of 1.15 g paclobutrazol (PBZ) per tree declined as the area of treated soil surface beneath the tree increased. Treating one side of the tree row was as effective as treating both sides, but immediately adjacent “control” trees were largely unaffected by these soil-surface treatments. In a 2nd experiment, single, or multiple sprays applying the same amount of chemical in total gave equal growth control in the season of application, but residual growth control was slightly superior on trees sprayed four or 10 times. All PBZ treatments advanced anthesis but failed to improve flower number or fruit set. The weight of individual cherries was increased in each of the three years following the soil-surface application of PBZ, but, except for a reduction in soluble solids, fruit quality was unaffected. Foliar sprays of PBZ in 1984 led to larger fruit size in 1985, but fruit coloring was delayed and soluble solids were reduced. A preharvest spray of 20 ppm gibberellic acid (GA3) substantially enhanced the PBZ effect on fruit size and color but also increased fruit firmness, juice acidity, stem length, and fruit removal force and reduced the incidence and severity of pitting following 2 weeks of cold storage. Chemical names used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

The effect of paclobutrazol sprays with or without the addition of surfactants on the shoot growth, yield and fruit quality of the apple cultivars Cox and Suntan

SummaryThe addition of surfactants to single foliar sprays of paclobutrazol, applied 3½ weeks after full bloom, enhanced their effect in suppressing shoot growth of the cv Suntan; the surfactant Ortho X-77 was particularly effective in this respect. Similarly, the addition of the surfactant Sunspray 67E to paclobutrazol sprays applied sequentially three times during the growing season, improved shoot growth control on the cv Cox. Increasing the concentration of paclobutrazol in these three sprays, from 30 to 240 mg l−1, produced only a minimal increase in the level of shoot growth suppression where no Sunspray 67E was included, but the effect was much greater in the presence of the surfactant. Except when applied to Suntan in combinations with Ortho X-77, paclobutrazol sprays had no effect on the numbers of extension shoots formed on either cultivar but increased the proportion of shorter shoots measured at the end of the growing season; the addition of surfactants or increased paclobutrazol concentration...

Comparison of a new triazole retardant paclobutrazol (PP 333) with ancymidol, chlorphonium chloride, daminozide and piproctanyl bromide, on stem extension and inflorescence development in Chrysanthemum morifolium Ramat

Several experiments in glasshouses at different times of the year have demonstrated that a new growth retardant, paclobutrazol (PP 333), applied as a single compost drench or as a foliar spray, is very effective in controlling stem extension in the pot chrysanthemum ( Chrysanthemum morifolium) ‘Bright Golden Anne’, a tall cultivar. Moreover, the concentration required, 30–50 mg a.i. l −1, was much lower than with a drench of chlorphonium chloride (Phosfon/Phosfleur), or with a foliar spray of daminozide (Alar/B-Nine) or piproctanyl bromide (Alden/Stemtrol). In two trials, a comparison of paclobutrazol and ancymidol (A-Rest/Reducymol) drenches indicated that, on a weight basis, the two compounds induced approximately equal dwarfing, whereas foliar sprays of paclobutrazol were more active than those of ancymidol, particularly at the lower concentrations. As before, at least 50–100 times the concentration of daminozide was needed than of paclobutrazol or ancymidol in order to induce an equivalent response. However, the variability in lateral stem length within a pot of 12 flowering shoots was a little higher with foliar sprays of paclobutrazol than with daminozide, possibly indicating that the amount of paclobutrazol transported to its site(s) of action varied more between shoots. Paclobutrazol produced similar delays in flowering (which invariably accompany commercially adequate reductions in plant height) to ancymidol and daminozide, whereas the delays with chlorphonium chloride and piproctanyl bromide were 2–4 days greater. In an experiment with the dark pink ‘Regal Anne’, daminozide caused some loss of flower pigmentation, but paclobutrazol and the other compounds did not.