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Abstract
Sweet potato (Ipomoea batatas L.) blister is primarily a superficial disease that develops in stored roots. The cultivar ‘Nugget’ is particularly susceptible and was used to investigate the role of mineral nutrition of the growing plant on the development of the disease. Results from greenhouse and field experiments demonstrated that the disease developed in roots that received excesses of N, K, and Mg during growth and the disease was prevented by including B in the fertilizer program.
Abstract
The effect of 2-chloroethanepliosphonic acid (ethrel) on the sex expression of pickling cucumbers was studied. Tests to determine concentrations, effect on sex expression, and yield potential were conducted in greenhouse and field situations.
As many as 19 successive pistillate nodes were observed for the treated monoecious cultivar ‘SC 23’. The most effective concentrations of ethrel were 120, 180 and 240 ppm for these studies. These rates in single or multiple application resulted in the greatest number of continuous female nodes with the least shortening of internodes. A much lower concentration of 24 ppm had little effect as to stunting and only limited effect on sex conversion. Significant yield increases, as measured by value per acre, were obtained for 3 monoecious cultivars, ‘Model’, ‘SC 23’ and ‘Chipper’, treated with ethrel.
Abstract
Fruit of cucumbei plants (Cucumis sativus L.) of a gynoecious and 2 monoecious cultivars treated at the 2-3 leaf stage with 0 or 240 ppm (2-chloroethyl)phosphonic acid (ethephon) were harvested at 3 weekly intervals, and processed as either fresh-pack pickles or brine stock. Experienced judges detected differences in shape and degree of seed development attributable to ethephon treatment. There were no significant differences in texture, flavor, external or internal color, firmness or internal defects. Differences caused by ethephon treatment were less apparent in fruit of the gynoecious than monoecious cultivars.
Methods for detecting and mathematically regressing daily tall fescue (Festuca arundinacea Schreb.) leaf appearance on environmental variables are presented. Morphological stages of leaf development were quantified and the rate of leaf appearance was linearly regressed on environmental variables. The following model was developed to predict daily tall fescue leaf appearance and was successfully tested on unrelated data: Daily leaf appearance rate = 0.016 – (2.48 × 10-4 × solar radiation) + (0.015 × precipitation 2-day lag) + (0.117 × soil moisture 3-day lag) + (8.79 × 1 0-6 × maximum air temperature × solar radiation) - (3.61 × 10-' × maximum air temperature × age) + (0.00307 × minimum air temperature × precipitation) – (4.39 × 10-4 × precipitation × age), (R2 = 0.78). Growers of tall fescue and researchers will benefit in the identification of environmental characteristics and cultural practices that significantly influence leaf appearance rate.
Abstract
Twenty-one cultivars of vegetables were treated in the greenhouse with Ethrel (2-chloroethanephosphonic acid) at concentrations of 240, 480 or 960 ppm. The stages of growth at treatment varied from 1 to 4 true leaves for the various cultivars.
The earliest observable response was stunting. With some cultivars, the stunting was permannent; but with others it appeared to be temporary. The degree and duration of stunting varied with cultivar and ethrel concentration.
Ethrel caused a strong tendency toward pistillate flowers on most of the monoecious cucurbits tested and in some cases almost complete absence of staminate flowers. The chemical greatly reduced the number of staminate flowers but had no observable effect on the number of perfect flowers of the muskmelon. The chemical also altered fruit shape of ‘Butternut’ squash.
Abstract
Aqueous solutions of 2-chloroethylphosphonic acid (Ethrel) at concn of 120 ppm were applied twice at 48 hr intervals to monoecious cucumber plants having either 1, 2, 3, 4, 6, 8, 10, or 12 true leaves. Slight checks in plant growth were noted at treatments through the 6th leaf. Plants treated at either the 8th, 10th, or 12th leaf were severely checked in growth and pistillate flowers open at time of treatment and developing floral primordia aborted within a week; however, all treated plants recovered and flowering resumed 15-18 days after treatment. Ethrel treatment, regardless of time of application, resulted in increased no. of pistillate flowers, concentrated pistillate flower production, and a significant reduction in the no. of staminate flowers.
Science is a challenging subject to teach at the middle school level. The state of Louisiana requires public school teachers to plan their curriculum around Grade-Level Expectations or state mandated educational benchmarks. A program titled Horticulture in a Can has been designed to teach horticulture lessons to middle school students while targeting the state regulated grade-level expectations. All lessons use a hands-on approach as it has been proven more effective than traditional classroom teaching. Horticulture in a Can was developed by a cooperative effort between the Louisiana Sea Grant College Program and the LSU AgCenter's Department of Horticulture within the Coastal Roots Nursery Program. Eight lesson plans have been created to meet twenty-six Grade-Level Expectations for 463 students in 4 schools. Pre- and PostHorticulture tests were given to each class in addition to pre- and postChildren's Attitude Towards the Environment Scale (CATES). All tests were given to both treatment and control classes within each school. The evaluations tested both short and long-term memory on material contained in the lesson plans. The data was analyzed by school, treatment, sex, and grade-level.
Abstract
Two gynoecious pickling cucumber inbred lines, GY 14-2 and GY 2, and 4 hybrids derived from crosses of these gynoecious lines by a monoecious determinate (M 20-2), and a monoecious indeterminate line (M 11) were grown at densities of 1, 2, and 4 plants per hill, all at populations of 84,000 plants/ha. Increasing numbers of plants/hill reduced the percentage of pistillate nodes/plant in all hybrids, the number of flowering nodes in both gynoecious inbred lines and their hybrids, and the percentage of gynoecious plants in both gynoecious inbred lines, and in their hybrids with the determinate M 20-2 line.