the dry state, with studies showing 5–12 years for plants in the grass family seed viability. A 10-year study in Russia concluded chinese silvergrass had high self-incompatibility, low viability, and extremely poor seed set in cultivated and wild
( Westbrooks, 1998 ). One way that invasive plants displace natives and harm natural ecosystems is by escaping cultivation and germinating at undesirable locations ( Meyer and Tchida, 1999 ). Such viable seeds of invasive plant species may persist in the seed
the rate of seed dormancy loss as well as seed viability loss in a number of species ( Baskin and Baskin, 1979 ; Bazin et al., 2011 ; Commander et al., 2009 ; Foley, 1994 , 2008 ; Leopold et al., 1988 ; Probert, 2000 ; Steadman et al., 2003
is known about the ploidy level, vigor, flowering, and seed viability of cultivars grown in Florida, because they are routinely propagated by vegetative cuttings. The overall objective of this study was to evaluate horticultural attributes and
strategies of desert species include the formation of persistent seed banks and latency mechanisms that allow the seeds to remain viable for long periods until conditions for germination and propagation of the plants become favorable. Considering that Z
temperatures (30 to 35 °C), the viability of seeds can decline within 6 to 24 months ( George, 1985 ). In previous work, we reported that the germination of the majority of pepper seed lots declined to less than the acceptable commercial level (75%) in Turkey
Vermicompost or worm-worked wastes have been reported to enhance seedling germination and growth during plug production. The objective of this project was to examine the effects of vermicompost on germination of a herbaceous perennial having varying viability in coir-based container media. Seeds of Echinacea purpurea (Purple Coneflower) collected from field-grown plants in 1998 and 1999 were considered low- and medium-viability seeds, respectively. A third group of seeds was purchased from a major seed company and was considered to have high viability due to optimal storage conditions. “Ragdoll” germination tests resulted in the following viability ratings: low (1%), 1998; medium (67%), 1999; and high (79%), purchased seed. The three sources of seed were planted into coir-based media. Vermicompost was incorporated into the media at 10% by volume. The control media did not have vermicompost added. Twelve days after project initiation seeds sown into media containing vermicompost had 73% and 90% greater germination than control media for the 1999 and purchased seed. At the project conclusion, 24 days after initiation, seeds sown into media containing vermicompost had 23% and 42% greater germination than the controls for the 1999 and purchased seed. The 1998 seed had 5% germination after 24 days compared to 1% for the control. The addition of vermicompost could be used as a method to increase germination rate and percentage of seeds having lower viability.
Abstract
A study was undertaken to determine the moisture content at which the seed of ‘Sweet Spanish’ onion (Allium cepa L.) expressed maximum yield and viability but at the same time did not shatter. A harvest maturity curve was developed to provide an estimate for optimum time of harvest. Umbels could be harvested with moisture contents as high as 66% without any adverse effect on seed size or viability. The umbels could be left on the plant until umbel moisture was as low as 52% before shattering commenced. The resulting 14% moisture range, within which harvest may proceed without losses to shattering or immature seed, provides an adequate buffer for harvesting onion seed.
Cryopreservation in liquid nitrogen (LN) is relatively routine for many small, desiccation-tolerant (orthodox) seeds. Seeds of Pyrus species are considered orthodox but have not been evaluated for LN storage. Seeds of freshly collected P. communis L. (`Bosc') were evaluated for germinability and by TZ staining after exposure to four LN treatments: 1) direct immersion and direct removal; 2) direct immersion and 1 minute in LN vapor phase before removal; 3) 2 minutes in vapor phase before immersion and direct removal; and 4) 2 minutes in vapor phase before immersion and 1 minute in vapor phase before removal. Fresh `Bosc' seed viability evaluated by TZ and greenhouse germination tests remained high (83% to 100%) following four types of LN treatments, compared to the controls (77% to 87%). Differences in `Bosc' seed viability were small and TZ results showed no significant differences among the LN treatments. Direct LN immersion and removal resulted in significantly more greenhouse-germinated `Bosc' seeds than the other treatments and fewer control seeds germinated than any LN treated seeds. Fresh `Bosc' seed cryopreserved at 7.9% moisture exhibited high germinability by both TZ and germination tests. LN exposure caused no physical damage to the seeds. Chemical name used: 2,3,5-triphenyltetrazolium chloride (TZ).
Miscanthus is one of the most popular ornamental grasses. Reports of self-seeding however, have occurred in the Central Atlantic states, making it a possible weed threat. Ascertaining whether Miscanthus self-seeds or not may determine its continued use as an ornamental, decorative plant. With more than 50 named cultivars of Miscanthus sinensis and several other Miscanthus species available in the trade, wide morphological variation appears to exist within this genus. Because Miscanthus is a warm-season grass requiring a relatively long growing season, self-seeding may vary depending on the USDA Hardiness Zone in which the plant is grown. Mature inflorescences from 35 different cultivars or species of Miscanthus were collected or acquired from nurseries or arboreta in USDA Zones 4, 5, 6, and 7 in the fall or early winter of 1996. Inflorescences were examined for seed set by hand cleaning. The percentage of viability seed and seed germination was determined by germination in laboratory conditions. Results varied by cultivar or species and as well as by source. A comparison of results will presented and the implications of Miscanthus self-seeding or becoming a potential weed threat will be discussed.