Seed of Cucumis sativus and Pelargonium ×hortorum were imbibed for 24 hours in solutions containing 0 (deionized water), 2500, 5000, 10,000, and 20,000 ppm humic acid. Additional treatments included seed which were imbibed in nutrient solutions corresponding to the nutrient content of each humic acid solution as well as an untreated dry control. Percent germination was reduced for geranium seed imbibed in 20,000 ppm humic acid and for cucumber seed imbibed in either 20,000 ppm humic acid or the corresponding nutrient control. Root fresh weights for untreated and water imbibed geranium seed were 0.05 g. Humic acid treatment increased root fresh weights to a maximum of 0.14 g at 5000 and 10,000 ppm. Shoot fresh weights for geranium were 0.12 and 0.10 g for untreated and water imbibed seed, respectively. Humic acid treatment increased shoot fresh weight to a maximum of 0.18 at 2500 ppm. Root fresh weights for cucumber were 0.16 and 0.18 g for untreated and water imbibed seeds, respectively. Humic acid treatment increased root fresh weight to a maximum of 0.33 g at 10,000 ppm. Shoot fresh weights for cucumber were 0.31 and 0.38 g for untreated and water imbibed seed, respectively. Humic acid treatment increased shoot fresh weight to a maximum of 0.43 at 10,000 ppm.
Primed, primed + BA, or nontreated lettuce (Lactuca sativa L.) seeds were sown with several soil amendment covers or a sandy soil cover (control) to assess stand establishment in three field experiments. Seeds covered with amendments Growsorb LVM 24/48, Growsorb 6/30, and plug-mix had a higher percent emergence than soil-covered seeds in warm soil. Primed seeds (with or without BA) had a higher percent emergence than nontreated seeds. Emergence was more rapid with plug-mix, LVM 24/48, and LVM 6/30 covers than with the sandy soil control. Primed seeds with or without BA also emerged more rapidly and produced heavier seedling shoots than nontreated seeds. Using primed lettuce seeds combined with specific soil amendments can improve lettuce stand establishment under various field conditions. Chemical name used: 6-benzyladenine (BA).
Experiments were conducted in the Dominican Republic to determine the effect of physical and chemical treatments on the germination of the ornamental palms Roystonea hispaniolana Bailey (Royal palm), Acrocomia quisqueyana Bailey (Corozo palm), Sabal umbraculifera Mart (Cana palm), Phoenix canariensis (Canary Islands date palm), Veitchia merrillii (Becc) Bailey (Manila palm), Chrysalidocarpus lutescens Wendl (Areca palm), and Caryota urens (Fishtail palm). Treatments were seed immersion in water or gibberellic acid 3 (GA3) solution for 72 hours, immersion in concentrated nitric acid for 5 minutes, or cracking of the seed coat. Rate and percentage of emergence 90 days after treatment were measured. The best results for Roystonea, Phoenix, Veitchia, Caryota, and Chrysalidocarpus were obtained soaking the seeds in water or a 200-ppm gibberellic acid solution. Nitric acid and seed coat cracking significantly reduced the germination percentage in all the species, except Acrocomia guisqueyana and Sabal umbraculifera. Seeds of Acrocomia did not germinate as a response to any of the treatments tested. Sabal seeds germinated only after coat cracking or nitric acid treatment.
Poor peach seed germination can be a problem for commercial tree fruit nurseries. Even standard rootstocks such as Lovell and Nemaguard do not always have high germination rates. New seed-propagated rootstocks under development, such as Guardian peach rootstock, often are selected for their field traits, with nursery characteristics being of secondary importance. Guardian rootstock is derived from bulked open-pollinated seed from a number of F1 seedling selections. Germination of Guardian bulked seed has been poor. Four pre-stratification cold treatments were given to four 100-seed lots each of Lovell, Nemaguard, and 10 Guardian selections prior to planting each year (1994 to 1998) in a Cecil sandy loam at Musser Fruit Research Center near Clemson, S.C. Treatments included taking dry, refrigerated seed that were harvested in August and soaking 100-seed seedlots in 1500 mL perlite and 400 mL distilled water for 0 (no soaking), 2, 4, 6, and 8 weeks at 6 °C before sowing (typically early November). All treatments consisted of 25 seeds per replicate (4 reps/year) per rootstock or selection and were sowed the same day. The experiment was analyzed as a blocked split plot design with duration of stratification the whole-plot and seedlot the sub-plot. Number of emerged seedlings were counted weekly starting in January of each year. There were significant differences between stratification treatments, seedlots and years. The 6-week pre-stratification had the highest germination over 5 years and like the 8-week treatment advanced the average germination date by 20 to 30 days. Nemaguard (65%), Lovell (64%), and Guardian 3-17-7 (60%) had the best germination percent across all treatments and years, with SL2891 (42%) slightly less. All other selections averaged less than 25%. Year-to-year variation was large, indicating strong environmental influences on seed germination despite the pre-stratification treatments.
Abstract
Seeds of gynoecious cucumber (Cucumis sativa L.) were soaked for 2 to 4 hours in a solution of dichloromethane (DCM)+ gibberellic acid (GA4+7). Staminate flowers were produced on the first 6-8 nodes in plants which developed from these seeds, whereas plants developing from seeds soaked in GA4+7 + water produced only pistillate flowers as did control plants from seeds soaked only in water.
Abstract
Seeds of pimiento pepper (Capsicum annuum L.) artificially inoculated with Xanthomonas vesicatoria (Doidge) Dows., were disinfected by a 4.20% calcium hypochlorite solution or a 2.63% sodium hypochlorite solution for 15 minutes followed by a 15 minute water-rinse. Germination after 14 days was not reduced.
Abstract
Pregerminated (PG) chile pepper (Capsicum annuum L.) seed was fluid-drilled in gels on three dates (early to late spring). Plants grown from PG seed emerged earlier than those from dry seed, and plant growth was enhanced (including earlier flowering), but the fruit yields were not affected. In the first planting date in cold soils, PG slowed emergence and the hypocotyls tended to coil within the gel. In a companion test, pre-soaking seed improved emergence, growth, and yield compared to plants from dry seed. Adding P to the soaking solution enhanced emergence, early plant growth, and plant P, but decreased fruit yields. Phosphorus added to the gel water of hydration increased seedling growth, but did not significantly affect fruit yields.
Abstract
Seeds of hairy indigo, a tropical legume cover crop, are dormant due to hard seed coats. Immersion of the seed in concentrated H2SO4 for 20 or 30 minutes or hot water at 70° to 80°C for 2 minutes, significantly increased the germination percentage and rate. H2SO4 was more effective than hot water. Redrying the seed after treatment improved the effectiveness of the treatments slightly.
Abstract
‘Miragreen’ garden pea seeds from individual seed lots were sorted into bleached, partially-bleached, and non-bleached categories. Seeds were either soaked for 48 hours in aerated water at 22°C, coated with thiram fungicide, or received no treatment. Seeds were planted in Conover loam soil where damping-off and seedling rot were primarily caused by Pythium ultimum Trow and Fusarium solani (Mort.) Sacc f. sp. pisi (Jones) Snyd. & Hans. No differences in germination in vitro were found among bleached, partially bleached, and non-bleached seeds. However, seedling emergence in the field was greater from untreated non-bleached seeds (69%) than from untreated bleached seeds (30%); emergence from partially bleached seeds (58%) was intermediate. Regardless of degree of bleaching, all seedlings were a normal green color after emergence, and appeared equal in vigor. Pea yields from untreated bleached seeds were less than from untreated non-bleached seeds, apparently because pea-emergence damping off was so much greater with bleached than with non-bleached seeds. No yield differences occurred with fungicide-treated seeds. Soaking partially bleached seeds for 48 hours in aerated water at 22°C prior to planting in April was as effective in improving emergence in artificially infested soil as coating seeds with thiram. However, when seeds were planted in mid-June, the thiram treatment gave higher seedling emergence than the soaking treatment. In general, high yields were achieved by early planting of seeds and minimum root rot.
Abstract
Table beet (Beta vulgaris L.) ‘Ruby Queen’ seeds were either germinated in aerated water till radicle emergence or osmoconditioned (OC) in –1.2 MPa solutions of polyethylene glycol 6000 or MgSO4 for 7 days at 15°C. Seeds were sown in soil in growth chambers, infested with Pythium spp., and damping-off incidence was evaluated after 14 days. Disease incidence was reduced, compared to dry sown seeds, as a result of presowing treatments. High populations of bacteria (106–108 CFU/ml of solution) developed during the aerated soak, which protected seeds from Pythium damping-off. Seed leaching or osmoconditioning did not decrease susceptibility to damping-off in the absence of high seed bacterial populations. The fluid drilling gel was studied as a delivery system for chemical fungicides. Damping-off in dry-sown seed was reduced by incorporating thiram into a hydroxyethyl cellulose (Natrosol 250 HHW) gel. Gel alone had no effect on damping-off. In field studies, only slight improvements in stand were attributed to the incorporation of thiram in presowing treatments. Fungicide dressing of dry seed resulted in a large improvement in emergence. All presowing treatments had greater field emergence than dry-sown seeds in the absence of thiram, which was attributed to bacterial protection from damping-off.