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  • Author or Editor: B. M. Pollock x
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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

The discovery of cytoplasmic male sterility in onions, and its application to commercial seed production, was a major breakthrough in vegetable breeding. Initial use of this new technique was moderately successful and seedsmen assumed that experience would lead to higher seed yields. Instead, yields have been disappointing; many fields have not even been harvested. The resulting economic problem has become serious for both seedsmen and onion producers. Many suggestions have been made as to the cause of low yields but there is no agreement on the biological nature of the problem. Therefore, during the 1966 growing season we began to analyze the problem by following the development of the seed crops in commercial fields in southwestern Idaho. We believe our methods and preliminary data may be useful in stimulating other workers to also examine this problem.

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