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William B. Evans and Margaret McMahon

There is significant interest in using non-chemical methods to control seedling height in vegetable transplant production. One method being evaluated is the use of greenhouse films that filter signifcant amounts of far-red light from ambient light, resulting in shorter tranplants. This study was undertaken to evaluate fruit yield and quality of field-grown tomatoes produced from seedlings grown under light-filtering plastics. Tomato seedlings were grown under clear polyethylene tents or light-filtering laminate tents in a polyethylene-covered Quonset greenhouse in northern Ohio. Standard 288 deep plug trays, filled with MetroMix 360, were used. Seedlings were placed under the tents at the cotyledon stage and transplanted 28 days later. Once in the field, they were grown as staked plants under open conditions using locally accepted horticultural practices. Differences in seedling height were detected within a few days after being placed under the tents. Compared to those grown under clear polyethylene tents, seedlings grown under the light-filtering plastic increased in height more slowly and were shorter at transplanting. At harvest, within each of the three cultivars tested, no significant differences in fruit number, yield, or mean fruit size were found between treatments. It is inferred that this non-chemical method for reducing vegetable transplant height may be a viable production option in the future.

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Juan P. Brigard, Richard L. Harkess, and Brian S. Baldwin

Tomato seedling hypocotyls elongate rapidly after germination resulting in weak seedlings. The effects of 0, 250, 500, 750, or 1000 mg paclobutrazol (PB)/L seed soak and soaking times from 1 to 12 hours on tomato (Solanum lycopersicum L.) seed germination, seedling growth, and plant growth were tested. Adequate height control was obtained with 250 mg PB/L while soaking time did not affect seedling growth. In a second experiment, PB was tested at 0, 50, 100, 150, 200, or 250 mg PB/L soaking the seed for 1 hour. A concentration of PB at 100 mg·L–1 provided optimum control of hypocotyl elongation with minimal residual effect on subsequent plant growth. In a third experiment, seed soaked at the different PB concentrations were germinated and grown under light intensities of 0.09, 50, 70, or 120 μmol·m–2·s–1. Seedlings grown under 0.09 μmol·m–2·s–1 were not affected by PB treatment and did not develop an epicotyl. PB seed soak treatment gave greater growth suppression under 50 μmol·m-2·s-1 than under the two higher light levels. Soaking tomato seeds in 100 mg PB/L for 1 hour prevented early hypocotyl stretch of tomato seedlings with no long term effects on plant growth. This treatment effectively prevented excessive hypocotyl elongation when seeds were germinated under low PAR while not over controlling elongation under high PAR conditions.

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Stanislav V. Magnitskiy, Claudio C. Pasian, Mark A. Bennett, and James D. Metzger

Shoot stretching in plug production reduces quality and makes mechanized transplanting difficult. The objectives of this study were to measure seedling emergence and shoot height of plugs as affected by paclobutrazol application during seed soaking, priming, or coating on seedling emergence and height. Verbena (Verbena ×hybrida Voss. `Quartz White'), pansy (Viola wittrockiana L. `Bingo Yellow Blotch'), and celosia (Celosia cristata L. `New Look') seeds were soaked in water solutions of paclobutrazol and subsequently dried on filter paper at 20 °C for 24 h. Soaking seeds in paclobutrazol solutions before sowing reduced growth and percentage seedling emergence of verbena and pansy but had little effect on those of celosia. Verbena seeds soaked in 50, 200, or 500 mg paclobutrazol/L for 5, 45, or 180 min produced fewer and shorter seedlings than controls. Osmopriming verbena seeds with 10 to 500 mg paclobutrazol/L reduced seedling emergence. Seedling height and emergence percentage of pansy decreased with increasing paclobutrazol concentrations from 2 to 30 mg·L–1 and with soaking time from 1 to 5 min. The elongation of celosia seedlings was reduced by soaking seeds in 10, 50, 200, or 500 mg paclobutrazol/L solutions for 5, 180, or 360 min. However, these reductions were negligible and without any practical application.

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Kunkun Li, Weiqi Dong, Yun Zhao, Hongxia Xu, Junwei Chen, and Changjie Xu

artificial climate chambers at 25 °C under long-day conditions (16 h light: 8 h darkness), with illumination at 250 μmol·m −2 ·s −1 . The germination rate and seedling height were recorded every 10 d from the beginning of sowing. Ungerminated seeds were not

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Inmaculada Moreno-Alías, Hava F. Rapoport, Rafael López, Lorenzo León, and Raúl de la Rosa

as the beginning of the adult phase) was evaluated during the three first spring blooms (years 2004, 2005, and 2006). Test of pre-selection. The data regarding seedling height at transplant and the final adult (flowering during the

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Patrick Conner

replications per treatment. Each replication consisted of nine seedlings with all measurement and leaf analysis coming from the five seedlings in the center of replication. Stem caliper at soil level and seedling height were measured on 20 May 2005 and then at

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Ajay Nair and Brandon Carpenter

indicate mean separation among biochar concentration within a particular tray cell number, whereas uppercase letters indicate mean separation among cell numbers within a particular biochar concentration. Seedling height. An analysis of variance showed a

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Daniel Struve, Francesco Ferrini, Chandra Bellasio, and Alessio Fini

as either water use per seedling (g/seedling) or as height-adjusted water use (g/cm seedling height). On 24 June, cuttings were taken from the each seedling by severing the shoot within 0.5 cm of the substrate surface. One to five cuttings per

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Joanne E. MacDonald and John N. Owens

an absence of mitotic activity in the shoot apical meristem within the terminal bud ( Arora et al., 2003 ; Owens and Molder, 1973 ). On 6 Oct., 24 seedlings were sampled from each duration of SDs. Seedling height, shoot diameter, shoot dry weight

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Hassan Hajnajari, Bahaeddin Chashnidel, Kourosh Vahdati, Mohsen Ebrahimi, Alireza Nabipour, and Esmaeil Fallahi

morphological traits such as leaf length, seedling height, trunk diameter, leaf chlorophyll concentration, and number of branches ( Kazlovskaya, 2005 ). Tancred et al. (1995) investigated the inheritance of ripening date in apples and obtained high