Genetic Resources of Phaseolus Beans Their maintenance, domesticatio
The period following the second world war has witnessed an expanding commitment to incr~ased food production in tropical countries. Public and private initiatives at the national and international levels have led to the creation of programs geared specifi
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CURRENT PLANT SCIENCE AND BIOTECHNOLOGY IN AGRICULTURE Aims and Scope of the Bookseries The bookseries is intended for readers ranging from advanced students to senior research scientists and corporate directors interested in acquiring in-depth, stateof-the-art knowledge about research findings and techniques related to plant science and biotechnology. While the subject matter will relate more particularly to agricultural applications, timely topics in basic plant science and biotechnology will be explored as well. Some volumes will report progress in rapidly advancing disciplines through proceedings of symposia and workshops while others will detail fundamental information of an enduring nature that will be referenced repeatedly. Scientific Editor: F .A. Bliss, University of Wisconsin, Dept. of Horticulture, 1575 Linden Drive, Madison, WI 53706, USA Scientific Advisory Board: P .S. Baenziger, University of Nebraska-Lincoln, Lincoln, Nebr. K. Barton, Agracetus Corp., Middleton, Wisc. F. Cannon, Biotechnica Int., Cambridge, Mass. ( . '
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Weeks in storage
FIGURE 3. Effect of unfavorable storage conditions on seedling vigor as measured by seedling emergence (A), survival (B), and fresh wt of epicotyl (C and D), and total seedling fresh wt (E and F). See text for definition of high and low germination stress. (Data from ROOS and MANALO, 1971)
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major sources of variability in the test is the uneven uptake of moisture by the seeds during the aging period. Seed lots should be adjusted to the same moisture level prior to the test. If hard seeds are present in a lot, which usually occurs when seed moisture content has dropped below 8% (NUTILE and NUTILE, 1947), the accelerated aging test will have limited usefulness in detecting differences in seed vigor due to the lack of or delay in moisture uptake during the test period (72 hours). In these cases seeds could be scarified by cutting a piece of the seed coat with a scalpel before placing them in the accelerated aging chamber. 4.
GENETIC FACTORS Although storage environment plays a major role in seed longevity, genetic factors have also been shown to influence storage life. In the case of germplasm accessions, which in many instances are heterogeneous populations, genetic shifts take place during storage and seed regeneration. 4.1. Genotypic differences in longevity JAMES ET AL. (1967) studied what effect varietal differences have on the longevity of bean seed stored under nine conditions. Seeds of eight bean cultivars representing three successive crop years, along with several other vegetables, were included in the study. Analysis of variance indicated significant differences between the varieties for seed longevity as well as among v
