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  • Author or Editor: J. R. Manalo x
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Abstract

Garden bean seeds stored under high temperature (32.2°C) and relative humidity (90%) for periods up to 15 weeks showed a drop in germination after 9 weeks with the standard laboratory germination test while a recently developed vigor test for beans (Epicotyl wt measurement) showed a loss in vigor after only 3 weeks of storage. We conclude that this new testing procedure can be used to measure loss of vigor in bean seed stored under unfavorable conditions before a loss of viability is detected by the standard germination test.

Open Access

Abstract

Germination of some lots of lettuce seeds is strongly inhibited by slight moisture stress at 25°C but not at 20°. Under soil conditions, this sensitivity to moisture stress could be a factor in plant establishment.

Open Access
Authors: and

Abstract

The moisture content of snap bean (Phaseolus vulgaris L.) seeds used in commercial plantings ranged from 7.7 to 13.7% on a fresh-weight basis. Bean seeds having initial seed moisture contents above 12% had higher field emergence than lower moisture seeds particularly at soil temperatures below 10°C. The high-moisture seeds quickly lost moisture when planted in very dry soil. Laboratory germination was improved a lesser amount by raising initial seed moisture content.

Open Access

Abstract

Seeds otherwise free from mechanical breakage may be subjected to stress during a germination test to give symptoms of mechanical damage typical of those resulting from harvesting and cleaning machinery. This physiological breakage occurs when seeds at low moisture levels are imbibed in a wet germination medium, and is an artifact of the testing procedure. It is not clear whether the potential susceptibility to such damage should be considered as a factor in planting quality.

Open Access

Abstract

Germination of samples of 12 commercial seed lots from among several commercial varieties of garden beans, Phaseolus vulgaris L., was tested against stresses applied during a 24 hr imbibition period. The variables studied were temperature (15° vs. 25°C), substrate moisture-oxygen supply (fine sand with high moisture and low oxygen vs. coarse sand with lower moisture and higher oxygen), and initial seed moisture (8% vs. 10% vs. 12%). The effect of stress was evaluated by determining germination percentage, seedling size, decay, mechanical damage, and rate of emergence. All lots were adversely affected by the stresses, but the stress response varied greatly between lots and between varieties. The lots of the newer varieties, ‘Tendercrop’ and ‘White Seeded Tendercrop’, were especially sensitive, with a germination percentage of one lot decreasing from 72% to 7% under stress. By contrast, the lots of older varieties were relatively insensitive, with one lot decreasing only from 92% to 81%. The stress conditions increased the number of decaying seeds and decreased seedling size and number of normal seedlings. Transverse cotyledonary cracking, in crack-sensitive varieties, increased when seeds were imbibed at a low seed moisture, especially if imbibition occurred in a fine, moist sand. The potential application of these results to seed testing, vigor testing, and stand establishment is discussed.

Open Access