Search Results
You are looking at 21 - 30 of 32 items for
- Author or Editor: R. W. Robinson x
Aglaonema is among the most popular tropical ornamental foliage plants used indoors because of its bright foliar variegation, low light and humidity tolerance, and few pests. Aglaonema, however, has been labeled as one of the most chilling-sensitive foliage plants. The dark, greasy-appearing patches on leaves injured by chilling can result in completely unsalable plants. With recent breeding activity, more and more Aglaonema cultivars have been developed and released. How new cultivars respond to chilling temperatures is, however, mostly unclear. This study was undertaken to evaluate cultivar chilling responses to identify chilling-resistant cultivars. Twenty cultivars were chilled at 1.7, 4.4, 7.2, 10, and 12.7 °C for 24 h using a detached single-leaf method and also whole-plant assay. Results indicate that great genetic variation exists among the cultivars, ranging from no injury at 1.7 °C to severe injury at 12.7 °C. A popular cultivar, Silver Queen, is the most sensitive, while the cultivar Stars is the most resistant. There was also a chilling response difference based on leaf maturity. Young leaves showed less injury than did either mature or old leaves. In addition, there was a significant correlation between the single-leaf and whole-plant assay for chilling resistance in Aglaonema'; the single leaf assay could be particularly useful for a quick test.
Abstract
Lycopersicon and Solanum species and an F1 hybrid of L. esculentum × S. lycopersicoides differed in growth and concentration of elements in leaves in response to levels of NaCl in outdoor sand culture. S. lycopersicoides and its hybrid with the tomato were more sensitive to NaCl on the basis of reduction in dry matter accumulation than L. esculentum, L. peruvianum, or S. pennellii. The dry weights of S. lycopersicoides and the F1 grown without NaCl in the rooting medium were 6 times greater than the average of L. esculentum, L. peruvianum, and S. pennellii, but only 2 times greater when the plants were grown with 294 meq NaCl/liter of rooting medium nutrient solution. S. lycopersicoides and the F1 were fruitless. The average tops without fruit of all species had 10.9% dry weight when grown without NaCl while tops of plants grown with 294 meq NaCl/liter nutrient solution had 14.0% dry wight. NaCl in the rooting medium increased the concentration of Na less in the leaves of S. lycopersicoides and the F1 than the other species and increased the Cl concentration in the leaves of all species. S. lycopersicoides and the F1 had higher concentration of K, and lower Ca in the leaves than the other species. S. pennellii had higher concentrations of Fe and Mn in the leaves than other species.
Abstract
‘Horizon’ (Fig. 1) is a high-yielding white wine grape that produces a neutral blending wine. It fulfills the need in the Great Lakes grape growing region for a winter-hardy grape relatively free of cultural and enological defects.
Abstract
Asparagus (Asparagus officialis L.) cv. UC 157 planted in desert coarse sand in the fall of 1979 and harvested in the springs of 1981, 1982, and 1983 was irrigated with geothermal water, with 2240 ± 1290 ppm total dissolved solids and ground water 1430 ± 460 ppm total dissolved solids. Yields of 3.1 MT/ha of large spears were obtained with ground water and 0.03 MT/ha with the geothermal-irrigated asparagus. Na and Li were significantly increased in the spears that received geothermal irrigation, and B and Fe were significantly increased in those irrigated with ground water. Toxic accumulation of elements in the spears did not occur when geothermal water was used for irrigation, but yields were reduced.
Abstract
Genetic variation in foliar symptoms of B deficiency in the seedling stage of red beet was observed among inbred lines and commercial cultivars grown in sand culture in growth chambers. F1, F2 and backcross populations between the most susceptible and tolerant lines, tested at .001 ppm B, indicated that susceptibility was conditioned primarily by a single dominant gene. No linkage was established between this gene and the gene controlling red leaf color.
The most susceptible line was inherently more vigorous than the most tolerant line but this relationship was not evident among the other inbreds and cultivars tested.
Boron deficiency sumptoms on leaves of both tolerant and susceptible lines were significantly accentuated by reducing the Ca(NO3)2 content of the nutrient solution from 8 to 7 mEq/litre without altering B content. At both Ca levels the B content was greater in the tolerant than in the susceptible line. When supplied with adequate Ca but low B the susceptible line contained higher Ca, Na and P and lower Mg than the tolerant line.
Three experiments were conducted on `Empire' apple (Malus ×domestica Borkh.) to evaluate the effects of hard water, calcium chloride (CaCl2), water conditioners, surfactants, and captan fungicide on the growth reduction and fruit cracking caused by prohexadione-calcium (PC). Two applications of 63 mg·L-1 PC provided season-long growth control in two studies. Adding a water conditioner to PC reduced shoot growth more than an application of PC in hard or soft water in one New York study. Ammonium sulfate (AMS) and Choice were equally effective water conditioners. PC provided no growth control of water sprouts and had no effect on fruit set or yield. PC applied at 250 mg·L-1 reduced fruit size. `Empire' fruit cracking and corking was severe, despite the use of only 63 mg·L-1 PC in two of the three experiments. This damage was exacerbated by the addition of a water conditioner, however AMS applied with a surfactant but without PC had little or no effect on either the severity or extent of fruit injury. In a third experiment, the addition of surfactants, CaCl2, or captan to 250 mg·L-1 PC plus a water conditioner had no effect on the severity of fruit damage. Fruit cracking caused by PC increased preharvest drop in two of three experiments, and increased postharvest rot in the Geneva, N.Y., experiment where fruit were stored prior to grading. Application of PC plus a water conditioner reduced estimated gross return per hectare for `Empire. We conclude that the fruit injury is caused by the formulated PC product itself under certain environmental conditions, and that this product should not be used on `Empire. Chemical name used: calcium 3-oxido-4-proprionyl-5-oxo-3-cyclohexine-carboxylate [prohexadione-calcium (PC)].
Abstract
Internal ethylene concentrations in green tomato fruits rose to a maximum of 30 to 70 ppm within 2 to 5 hours of dipping in a 10,000 ppm solution of Ethrel (2-chloroethylphosphonic acid), then fell to approximately 5 ppm after 24 hours. A second rise in ethylene concentration was associated with fruit ripening, and was observed both in treated fruits and in untreated fruits which ripened as a result of removal from the plant. Incubation of Ethrel with homogenates of green tomato fruits likewise resulted in evolution of ethylene. Autoclaving or boiling the homogenates did not affect activity, indicating that release of ethylene from the chemical was non-enzymatic.
Abstract
‘Melody’ is a late midseason, white wine grape (Fig. 1) which produces a vinifera-type wine with varietal character. In addition, ‘Melody’ does not require cluster thinning and is moderately resistant to powdery mildew [Uncinula necator (Schw.) Burr.]. It is the 3rd wine grape cultivar to be named by the Dept. of Horticultural Sciences, Geneva, N.Y., and follows the release of ‘Cayuga White’ (1) and ‘Horizon’ (2). It is the first in a series of wine grape releases from this station to be given a name with a musical theme.
Effects of three sterol-demethylation inhibiting (DMI) fungicides and a contact fungicide were compared over two years at each of two locations to determine if fungicide treatments had differential effects on productivity, fruit size and shape, or gross returns for `Empire' apples (Malus ×domestica Borkh.). Treatments were applied four to five times per year during the primary apple scab season. Effects of treatments were assessed by comparing fruit set efficiencies, number of fruit per tree, total harvested fruit weight, and fruit length: diameter ratios at harvest. No significant differences were noted among individual treatments in any of the four trials. However, when treatments were contrasted by grouping individual treatments, significantly larger fruit size was noted for triflumizole treatments vs. combined fenarimol and myclobutanil treatments in one of the four trials and for captan or mancozeb compared to fenarimol and myclobutanil treatments in two trials. None of the DMI fungicides compared in these trials had any consistent adverse affect on fruit size, total yield, or estimated gross return per hectare. We conclude that the plant growth regulator effects of DMI fungicides are inconsistent and are unlikely to have significant economic impact on commercial apple production.