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.
Abstract
Physical characteristics measured individually for each lettuce (Lactuca sativa L.) seed and its embryo were significantly correlated with seedling and plant growth (vigor) up to a certain stage, possibly heading, after which the correlations diminished. Embryo physical measurements, although slightly better correlated with subsequent vigor than seed (achene) physical measurements, were highly correlated with those of the whole seed.
Of the 5 physical measurements studied, all but length were found to be associated with early vigor. Thorough statistical analyses place seed and embryo physical characteristics in a consistent and significant order in determining vigor: weight > thickness > density (as measured by an air column) > width > length.
A high seed germination percentage is a prerequisite for successful commercial vegetable production. Seed vigor, appropriate temperature, and oxygen and water bioavailability are key factors in high percentages of seed germination ( Bewley and Black
Abstract
The possibility of using seed adenosine triphosphate (ATP) content as an indicator of seed vigor was studied. Seeds of corn (Zea mays L.), cucumber, (Cucumis sativus L.), onion (Allium cepa L.), and radish (Raphanus sativus L.) with seed moisture contents of 5, 10, 15, 20, or 25% were stored at temperatures of −10°, 5°, 15°, 25°, or 35°C for 0, 2.5, 5, and 10 months. Germination and seedling vigor decreased as storage time, temperature, and moisture level increased. Viability was lost in most seeds after 2.5 months at high temperature (25-35°) and high moisture (20-25%) contents. Seed stored at 5° and 5% moisture maintained the highest viability and seedling vigor over the 10-month storage. Low temperature (−10°) and high seed moisture levels (20-25%) reduced germination and vigor of radish seed. Seed ATP content did not correlate with reduced germination or vigor in any species. ATP concentrations consistently decreased over the 10-month storage period in all seeds stored at −10°. However, this trend did not correlate with the other vigor indices.
in olive breeding programs such as the choice of parents, how to improve seed germination procedures, and seedling initial vigor, which is related to the length of the juvenile period. This is particularly interesting for table olive for which
141 POSTER SESSION 21 (Abstr. 833-841) Seeds and Seedlings
Abstract
New hybrids of sweet corn (Zea mays L.) utilize genes which allow the build-up of high levels of sugar but which also lead to problems with seed and seedling vigor. In this study, ATP and various seedling vigor measurements were compared with seed germination and seedling vigor in normal and 3 corn endosperm mutants harvested at 16 to 42 days post-pollination. Germination and seedling vigor measurements (germination rate, radicle length, fresh and dry weight) showed that a shrunken-2 (sh2) corn was significantly lower in both laboratory and field tests than sugary (su), brittle (bt), and normal. The latter 3 genotypes were nearly equal in seedling vigor. Sugar levels of all mutants and normal were similar at 42 days post-pollination. Total polysaccharides in sh2 were 50% or more below the other 3 genotypes. ATP levels in seeds imbibed 4 hours, were generally similar in sh2 as in the other genotypes. In a time course study of 0 to 96 hr imbibition using 42 day-old seeds, the ATP content of sh2 seeds, was generally as high or higher than in the other 3 genotypes. It did not appear that ATP level was related to poor vigor during the early stages of germination of sh2 corn seeds.
Florida is the nation's second leading state in lawn care services with annual $5 billion impact and 84,000 jobs per year ( Hodges and Mulkey, 2003 ). There are several warm-season turfgrasses established from seeds, including bahiagrass
Abstract
In the paper by O. E. Smith, N. C. Welch, and T. M. Little in J. Amer. Soc. Hort Sci. 98(6):529-533, November 1973, the following changes should be made on page 529, column 2, lines 28 and 35:
Line 28: change “transferred to a 1/15 M” to read “transferred to a 20-fold dilution of a 1/15 M”
Line 35: change “of the pH 7.0 phosphate” to read “of the pH 7.0 dilute phosphate”
If the buffer is used at 1/15 molar, the roots of the young plants will be injured due to the high osmotic strength of the buffer.
91 WORKSHOP 8 (Abstr. 1042-1045) Seed Vigor Testing and Utilization