Search Results
Abstract
The effect of different amounts of irrigation on vegetative growth and fruit yield of okra (Abelmoschus esculentus Moench) was determined in field experiments. Irrigation increased vegetative growth and fruit yield in okra in comparison to an unirrigated control. Similar increases in vegetative growth were produced at all irrigation amounts, ranging from 40% to 100% of pan evaporation (Epan), but fruit yield differed with the amount of irrigation. Irrigation equal to 60% Epan produced maximum fruit yield, and significant decreases in yield were noted with an increase or decrease in the amount of irrigation.
Two studies were conducted to assess the effects of leaf aging on gas exchange in okra [Abelmoschus esculentus (L.) Moench] leaves. Gas exchange was measured at 6- to 10-day intervals starting 15 days after leaf emergence (DFE) and continuing until senescence at 50 DFE. Rates of transpiration (E), stomatal conductance (gs) and CO2 exchange (CER) increased as leaves matured up to ≈25 DFE, about full leaf expansion. Transpiration rate, gs, and CER declined after 25 DFE and as leaves aged further. Internal leaf CO2 concentration (Ci) was higher in old than young leaves. This study suggests that the most efficient okra canopy would maximize exposure of 25-day-old leaves to sunlight.
Abstract
A technique to induce early fruit maturation would permit staggering the harvest and provide an opportunity to avoid early fall rains which are common to grape growing regions with Mediterranean climates. Dipping trials with ethephon have resulted in advanced maturation in some cultivars of Vitis vinifera in Australia (2). The main effect observed was a decrease in total acidity. Weaver and Pool (4) observed that ethephon induced a significant increase in total soluble solids in ‘Carignane’ a wine cultivar but contrary results have also been reported (3). The present study was designed to determine the effect of ethephon on ‘Delight’, a table cultivar.
A 2-year field study was conducted to determine the effects of within-row spacing (WRS) on CO2 exchange rate (CER), leaf-area index (LAI), and yield of okra [Abelmoschus esculentus (L.) Moench]. Okra cultivar Clemson Spineless was seeded at WRS of 8, 16, 24, 32, 40, and 48 cm in a randomized complete-block design replicated three times. CER and LAI were measured five times at about biweekly intervals between first flowering and final harvest. Fruits were harvested three times weekly for 7 weeks. There was no year-to-year variation in CER or LAI. Plants at 8 cm WRS attained maximum CER by 56 days after planting (DAP), while all other spacings took longer. CER at all WRS declined after 85 DAP. In 8 and 16 cm WRS, maximum LAI developed by 56 DAP, but 69 DAP were required at all other spacing. Depending on the spacing, LAI regressed linearly or cubically on DAP. Fruit number/plant (FNP), fruit fresh and dry weight/plant (FFW and FDW), and fresh and dry fruit yield/ha (FFY and DFY) were greater in 1991 than in 1990 as a result of more favorable weather during 1991. There was a linear increase in FNP, FFW, and FDW as WRS increased. Conversely, FFY and DFY were highest at 8 cm and decreased linearly in 1990 and quadratically in 1991 as WRS increased. Results of this study suggest that okra plants reach maximum CER and LAI earlier and produce higher fruit yield per unit area when spaced close together in the row.
Conventional production of tomatoes (Lycopersicon esculentum Mill.) requires substantial investments, intensive management and high inputs of nitrogen. High N rates invariably leave residual soil NO3-N with the potential of polluting ground water and posing health hazard to humans and animals. The objective of this study was to examine the value of cover crops as a substitute to synthetic N fertilizer in growing of tomatoes. The experimental treatments consisted of control (no N fertilizer or cover crop), Abruzzi rye (Secale cereale L), hairy vetch (Vicia villosa Roth), or crimson clover (Trifolium incarnatum L.) cover crop, and fertilization of N at 90 or 180 kg·ha-1. The treatments were replicated four times over 2 years in a randomized complete block experiment for growing `Mountain Pride' tomato on a Greenville fine sandy loam soil. The parameters used to evaluate the performance of tomato consisted of leaf area index (LAI), gas exchange (GE), above ground plant dry weight, number of fruits, dry weight of fruits, and marketable fruit yield. Tomato LAI was similar under legumes and N fertilizers. Hairy vetch and applied N at 90 kg·ha-1 influenced net photosynthesis (Pn) and transpiration (E) the most in both years at all stages of growth. Highest number of tomatoes were produced in hairy vetch and applied N at 90 kg·ha-1 plots. There was no significant difference in the above ground plant dry weight, fruit yield and dry weight of fruits between legumes and N fertilizers. The results suggested that the legume cover crops compared favorably to N fertilizers in promoting tomato growth and development and may have potential of substituting N fertilizers in fresh-market tomato production.
During the fall of 1993 and 1994, four commonly used growth retardants (B-nine, Cycocel, A-rest, and Bonzi) were compared for their effect on the growth and development of three ornamental flowering cabbage cultivars (white, red, and pink) and two ornamental flowering kale cultivars (frizzy red and red peacock). Two weeks after transplanting, seedlings of each cultivar were sprayed with aqueous solutions of the four growth retardants. Treatments for each cultivar were arranged in a randomized complete block design with 6 replications. Plant height, plant width, and dry weight were the parameters used to measure growth and development. Treatments for each cultivar were rated for head formation and color development. Results showed that all the growth retardants except for Cycocel significantly affected growth and development without any effect on head formation and color development. Bonzi caused the greatest growth suppression.
Abstract
Plants grown in dichloropropene (a soil fumigant) treated soil have significantly higher than usual carotenoid levels. Treatments with dichloropropenes, 3-chloroallyl alcohol, 3-chloropropionic acid, 3-hydroxypropionic acid, 3-chloro-l-propanol and malonic acid decreased the incorporation of β-hydroxy-β-methylglutaric acid and mevalonic acid into carotenoids of etiolated maize. Lipoxidase in tomato was inhibited by much lower concentrations of these compounds than were required to inhibit the incorporation of β-hydroxy-β-methylglutaric acid or mevalonic acid. This difference could account for the eventual increase in the total carotenoids in the plant.
Abstract
The chelating agents, monocalcium disodium salt of ethylenediaminetetraacetic acid (CaNa2EDTA) and sodium hexametaphosphate (Na-HMP), at 800 ppm, were used for canning ‘Honey Sweet’ carrots, ‘Van’ sweet cherries, and ‘Large Early Montgament’ apricots with water containing 0, 20, 40, 80, and 160 ppm of Ca and 20 ppm of magnesium. The control cans did not contain EDTA or Na-HMP.
The canned carrots, cherries, and apricots were stored at 70° or 100°F. Evaluations were made at 60-day intervals for 6 months. All 3 commodities had better organoleptic acceptibility when they were canned with CaNa2 EDTA or Na-HMP than the controls.
Carrots canned with CaNa2EDTA were firmer and retained better color than those canned with Na-HMP or the controls. The rate of loss of firmness and color increased with time of storage. Retention of firmness, volatile reducing substances, pH, and taste quality was improved in sweet cherries and apricots canned with CaNa2EDTA or Na-HMP.
Abstract
Soil fumigations with Telone (1,3-dichloropropene and other chlorinated hydrocarbons) at the rates of 10, 20, and 30 gal/A and Nemagon (1,2-dibromo-3-chloropropane) at the rates of 1, 2, and 3 gal/A, one week before planting carrot and sweet corn seeds brought about significant increases in the content of total carotenes, β-carotene, and total sugars in carrots and the total carotenoids in sweet corn seeds and decreases in respiratory rates of the carrot roots.