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Tony H.H. Chen, S.D.K. Yamamoto, L.V. Gusta, and A.E. Slinkard

Abstract

Either imbibition at low temperatures or fast water uptake reduced germination of chickpea (Cicer arietinum L.) by 15%. The combination of imbibition at low temperatures and fast water uptake reduced germination by 65%. The most chilling-sensitive period for chickpea germination is the first 30 minutes of imbibition. Slow imbibition at 20°C for 24 hours prior to seeding of mechanically damaged chickpea seeds significantly improved percentage of germination, and uniform, vigorous seedlings resulted. Such prehydrated seeds also showed better emergence under field conditions, especially in early spring when the soil was still cold. The results suggest that mechanically damaged seeds sown in cold, wet soil undergo imbibitional chilling injury and fast water uptake, leading to poor field emergence. Prehydration of seeds by slow imbibition at warm temperature and/or fungicide application increased the germination and emergence of chickpeas sown into cold, wet soils.

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Michael T. Tesfaendrias, Mary Ruth McDonald, and Jon Warland

patterns. The most important weather factor for cool-season vegetable crops in Ontario was the number of days during the growing season with temperatures that exceeded 30 °C. Yields decreased as the number of hot days increased ( Warland et al., 2006

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Yin-Tune Wane

51 ORAL SESSION 14 (Abstr. 095-101) Floriculture: Light/Temperature

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Robert Berghage

Temperature management has emerged as an important tool for plant height control in greenhouse production systems. This is particularly important in vegetable transplant production where chemical controls for plant height are limited or not legal. Plant height is a function of the number of nodes and the length of each internode, and both are strongly influenced by greenhouse temperatures. Node number, or formation rate, is primarily a function of the average greenhouse temperature, increasing as the average temperature increases. Internode length is strongly influenced by the relationship between the day and night temperature, commonly referred to as DIF (day temperature - night temperature). As DIF increases, so does internode length in most plant species studied. Although the nature and magnitude of temperature effects vary with species, cultivar, and environmental conditions, these two basic responses can be used to modify transplant growth. Although data are limited, controlling transplant height with temperature does not appear to adversely influence plant establishment or subsequent yield.

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Sacha J. Johnson and Carol A. Miles

High-value vegetable crops such as eggplant, tomato, and watermelon are grafted to increase vigor, yield, tolerance to salinity and temperature extremes, and disease resistance ( Lee, 1994 , 2003, 2007; Paroussi et al., 2007 ; Rivard and Louws

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Robert D. Berghage and Royal D. Heins

Abbreviations: ADT, average daily temperature; DIF, DT - NT; DIBE, days from pinching to day internode started to elongate; DT, day temperature; N, total number of internodes below inflorescence; NT, night temperature; VB, date of first visible bud

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James E. Faust, Jeffrey W. Adelberg, Kelly P. Lewis, and Genhua Niu

The effects of storage temperature and shoot preparation of elephant ears (Colocasia antiquorum `Illustris') were examined to determine how to successfully store plants prior to greenhouse forcing. A series of experiments were conducted that provided storage temperatures of 4, 7, 10, 13, or 16 °C (39.2, 44.6, 50.0, 55.4, or 60.8 °F), and plants were placed into storage with the shoots uncut or cut to 3.0 cm (1.18 inches) above the surface of the growing medium. The storage duration ranged from 40 to 49 days. All plants stored at 4 or 7 °C died. Plant survival was 89% to 100% at 10 °C, while plant survival was 100% at 13 or 16 °C. Shoot emergence and plant growth was faster following storage at 13 and 16 °C, than storage at 10 °C. Storage at 16 °C resulted in leaf growth occurring during storage, which was undesirable. Removing shoots prior to storage had no effect on plant survival and performance during forcing. A fungicide drench with iprodione immediately prior to storage did not improve plant survival. This study suggests that 13 °C is near the base temperature for leaf development of elephant ears, thus the plants survive at this temperature with no growth occurring. Shoot removal prior to storage is recommended in order to optimize storage room space.

Open access

Sean M. Campbell, Brian J. Pearson, and S. Christopher Marble

temperatures required to manufacture rockwool render it biologically inert and, therefore, free from potential weeds, pests, and diseases that might normally hinder germination. This manufacturing process also renders a very consistent substrate that possesses

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John E. Erwin, Royal D. Heins, and Roar Moe

Abbreviations: ADT, average daily temperature; DIF, difference; DT/NT, day/night temperature; FR, far red; LD, long day; NI, night interruption; R, red; SD, short day. 1 Current address: Dept. of Horticultural Science, Univ. of Minnesota, 1970

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Martin P.N. Gent

was 24% higher in winter. This result suggests oxalate will be high when nitrate is high. There is little effect on yield or quality of hydroponic spinach produced at root-zone temperatures of 20, 24, or 28 °C in summer or 15, 20, or 25 °C in winter