Abstract
Naphthaleneacetic acid (NAA) was applied in the spring to pruned apple (Malus domestica Borkh.) and pear (Pyrus communis L.) trees for control of sprouting on trunks and scaffold limbs. After one growing season, sprouting was completely controlled on trunks and scaffold limbs of ‘Delicious’ apple and ‘Bartlett’ and ‘d’Anjou’ pear trees. After two growing seasons, about 80 to 90% of the sprouts were inhibited on the scaffold limbs of ‘Delicious’ and ‘Winesap’ apple trees. NAA controlled sprouting at 1% with no added benefit at 2%; 0.5% NAA was least effective.
Abstract
Naphthaleneacetic acid (NAA) ethyl ester formulation at 0.25% plus 20% flat white latex paint applied to nonbearing peach [Prunus persica (L.) Batsch] tree trunks reduce sprouting, had no effect on tree growth, and did not induce gummosis.
The effect of NAA [16.5 mg/L or 500 mg/L sprayed once at end-of-production from two different sources: wettable powder (Fruitone) and sodium hydroxide solution (Sigma)], STS (0.5 mM sprayed once at end-of-production and 0.4 mM sprayed every 15 days after bracts started to be apparent) and ethanol 50% (v/v) solution, sprayed twice: at end-of-production and immediately after simulated transport) were tested using two types of completely randomized experiments. At the end-of-production plants were placed for 3 days under simulated transport conditions (171°C, no light) and then placed under interior conditions (211°C and 11 mol·s–1·m–2 of cool-white fluorescent light 12 h/day). Every other day during post-production the number of bracts not completely developed (ED), as well as the number of completely (CD) developed, bracts remaining in the plants were assessed. Among the post-production treatments tested, NAA (500 mg/L) and STS (applications every 15 days during production) + NAA (16.5 mg/L) were the most-efficient treatments. Ethanol and STS (one single application) did not control bract abscission efficiently and did not increase plant longevity. Plants treated with NAA abscise more not completely develop bracts than completely developed bracts. Use of NAA in potted bougainvillea requires fully developed bracts at end-of-production.
Butternut squash is a newly introduced crop in Saudi Arabia and is gaining very much popularity.
An experiment to evaluate the productivity of butternut squash using different plant spacings and trailed vs untrailed plants was conducted in tunnel greenhouse.
Results showed that trailed plants produced 100% more yield than the untrailed plants with better quality and uniformity in size. Among spacings, the plants in 120 cm produced 82% higher yield/plant than the plants in 40 and 80 cm. NAA increased yield by 14%. NAA treated or untreated trailed fruits had no seeds as compared to the untrailed fruits which did produce small amount of seeds.
NAA was applied to pecan nuts at concentrations of 0, 20, 50, 100, 200, and 500 μg·g-1 on May 19, June 16, and July 20. The 500 μg·g-1 concentration induced nut drop at all dates but was phytotoxic to leaves when applied on May 19. Concentrations of 50-100 μg·g reduced preharvest drop of nuts.
Abstract
In an attempt to solve the problems of nonuniform and delayed shuck dehiscense of pecan [Carya illinoensis (Wangenh.) C. Koch], ethephon and NAA were evaluated for their efficacy as harvest-aid treatments. A 3-year study under commercial-like orchard conditions using 75-year-old ‘Stuart’ trees resulted in a spray mixture of 9 mm ethephon and 1.5 or 3.0 mm NAA, or just 9 mm ethephon alone, accelerating shuck dehiscence by 1 to 2 weeks relative to that of the nontreated control. While all three treatments induced some degree of leaflet abscission, the two treatments employing the NAA and ethephon combination induced only about one-fourth (21% vs. 75%) as much leaflet abscission as when ethephon was used alone. However, this level of leaflet abscission (21%), plus an associated 50% drop in net photosynthesis for several days post-treatment, was sufficient to reduce in-shell nut yields in subsequent years. This appears to preclude commercial acceptability of such treatments for pecan. Chemical names used: (2-chloroethyl)phosphonic acid (ethephon), 1-napthaleneacetic acid (NAA).
Osha (Ligusticum porteri) is a Rocky Mountain native frequently used as a medicinal herb. It is currently harvested largely from the wild. Studies have been under way since 2001 to find ways to propagate and produce the plant. To potentially increase rooting success of crown cuttings of osha, two different rooting hormones were used, each at two concentrations. Treatments were controls, 2500 ppm, and 5000 ppm solutions each of indole-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA). Cuttings were soaked in deionized water or treatment solutions for 2 min. After soaking cuttings were stuck in sterilized sand in 725-mL2 containers, one cutting per container. Containers were placed on a mist propagation bench at 21 °C in a completely randomized design under natural light and day lengths. Data taken were days to visible root and shoot, and presence or absence of root formation after 50 days. Results indicated only one of 70 cuttings (<1%) produced a shoot. Roots formed on 14% of control cuttings, 64% in 2500 ppm IBA, 86% in 5000 ppm IBA, 36% in 2500 ppm NAA, and 14% in 5000 ppm NAA. Days to rooting ranged from 14.9 (2500 ppm IBA) to 29.0 (5000 ppm NAA). Due to considerable variation in days to rooting, and the number of cuttings that did not root, analysis of variance showed no differences among treatments. Frequency analysis indicated differences among treatments in root presence or absence. The 2500 and 5000 ppm IBA treatments showed more root formation than the controls or either NAA treatment. This indicates IBA may enhance rooting of osha crown cuttings.
Abstract
Naphthaleneacetic acid ethyl ester (NAA-ethyl ester) sprays applied to the base of apple (Malus domestica Borkh.) nursery stock for sprout control suppressed sprout development. Rates of 0.25, 0.50, and 1% resulted in significantly less sprout development than the 0.125% rate. Sprout length was suppressed only by the second applications of the 0.25, 0.50, and 1% rates. A second application of the 0.50 and 1% rates killed the existing sprouts at time of application. Trees treated with 1% NAA-ethyl ester were shorter and smaller in diameter. The 0.25 and 0.50% rates were equally as effective in sprout control as the 1% rate, without adversely affecting tree height and diameter.
Abstract
Spray applications of naphthaleneacetic acid (NAA) at concentrations of 0.25 to 1.5% delayed bud break of sweet orange (Citrus sinensis (L.) Osbeck) seedlings for up to 177 days. Untreated buds on the same plants exhibited delayed growth initiation of up to 150 days due to translocated NAA. Length of time of bud break inhibition was dependent on NAA concentration, and the Na salt of NAA produced a more pronounced inhibitory effect than the ethyl ester formulation.
Abstract
Five apple (Malus domestica) cultivars were treated with NAA at 10 mg·liter–1 and dichlorprop at 5, 10, and 15 mg·liter–1 during 2 years. Although the response varied with cultivar, NAA generally delayed fruit abscission compared to the control. Preharvest drop was usually reduced by dichlorprop at 5 mg·liter–1 more effectively than by NAA. Preharvest drop of ‘Stayman’, ‘Rome Beauty’, and ‘Winesap’, but not ‘Delicious’, was inversely related to concentration of dichlorprop. Fruit redness, flesh firmness, soluble solids content, and starch ratings were not affected consistently at harvest or during storage by any treatment for any cultivar. Residue levels of dichlorprop in the fruit were related to treatment concentration and persisted until harvest. Chemical names used: naphthalene acetic acid (NAA); 2-(2,4-dichlorophenoxy) propanoic acid (dichlorprop).