Search Results
You are looking at 1 - 10 of 18 items for :
- Author or Editor: Wallace G. Pill x
- HortScience x
Seeds of `Champion' collard (Brassica oleracea L. var. acephala) were hydrated in water or a fluid-drilling gel (N-gel, hydroxyethyl cellulose) for 1 or 2 days at 20C (50 seeds/ml) before they were fluid-drilled into peat-lite in a greenhouse. Time to 50% seedling emergence from these seeds was more than 2 days earlier than from dry-sown untreated seeds, although emergence synchrony and percentage were unaffected. A second greenhouse study revealed more rapid seedling emergence from hydrated seeds that then were fluid-drilled than from dry-sown untreated seeds even when the delivery gel contained up to 25 g 9N-19.8P-12.5K/liter. Increasing fertilizer from 5 to 25 g·liter-1 led to increased shoot fresh weight 6 weeks after planting. When sown on two dates into field plots, hydrated seeds (1 day in either water or gel at 20C, 50 seeds/ml) that were fluid-drilled in 1.5% (w/v) N-gel containing 5 or 15 g 9N-19.8P-12.5K/liter yielded 42% greater final shoot fresh weights than untreated seeds sown dry.
Kenaf core (xylem) particles (2 to 4 mm in diameter) were submersed in ammonium nitrate solutions (0 to 5000 mg N/liter) for 5 days. The kenaf was incorporated into complementary components as 30% kenaf: 70%. sphagnum moss or 10% kenaf: 10% vermiculite: 10% calcined clay: 70% sphagnum moss. These media received standard preplant fertilizer additions. Tomato and impatiens bedding plant shoot dry weights increased with up to 5000 mg N/liter in media containing 10% kenaf and with up to 3000 mg N/liter in media containing 30% kenaf. By selecting the N concentration of the kenaf soak solution, shoot growth could be matched to that achieved with commercial peat-lites after any post-transplanting period (2 to 9 weeks). A further study revealed that kenaf was an effective carrier for Bonzi and Sumagic growth regulators. By combining N-soaked kenaf with growth-regulator-soaked kenaf in the growth medium, bedding plant shoot growth was healthy but restricted.
Abstract
The granulated, insoluble acrylamide-based hydrophilic polymers, Terrasorb HB and Alcosorb AB3C, hydrated initially with all the essential nutrients (15 g gel solids/liter of 1-fold Hoagland solution), were effective media for the production of 3-week seedlings of tomato (Lycopersicon esculentum Mil.) in plug (modular) trays. Higher concentrations of the nutrient solution used to hydrate gels or incorporation of resin-encapsulated, slow-release fertilizer (Osmocote, 17N–3.9P–10.8K, 1.5 or 3.0 g·liter–1) in the hydrated gels decreased seedling growth. Daily application of fertilizer solution (100 mg N/liter) or water resulted in similar seedling growth. Seedlings were healthy, with roots permeating the voids between the hydrated granules of the entire gel mass. The gel mass adhering to the root system could be extracted readily and intact from the plug tray cell.
Abstract
Parsley (Petroselinum crispum L.) seeds osmoconditioned in −1.2 MPa polyethylene glycol 6000 (PEG) for 3 weeks at 15°C emerged earlier and gave higher seedling shoot fresh weights 24 days after planting than raw seeds. Further improvement in earliness of emergence was achieved by fluid-drilling the nongerminated, imbibed seeds in hydroxy ethyl cellulose gel. Germinating the osmoconditioned seeds (42% germination after 4 days at 15° in aerated water) before fluid-drilling decreased the time to 50% emergence by 52% and increased shoot fresh weight by 192% relative to raw seed performance. As emergence rate increased due to treatment, shoot fresh weight increased but emergence synchrony decreased. Neither grading seeds into density classes nor daily PEG replacement during osmoconditioning influenced seedling performance to a practical extent.
Seeds of `Ace 55VF' tomato were soaked in solutions of -1.0 MPa Instant Ocean™ (inorganic salt mixture) or -0.6 MPa polyethylene glycol 8000 (P.E.G.) at 25 C for 1 week. `Mary Washington' asparagus seeds were soaked in the same solutions for 2 weeks. In solutions of decreasing matric or osmotic potentials, primed seeds germinated faster than untreated seeds. Germination percentages of primed seeds generally were greater than those of untreated seeds when water stress exceeded -0.5 MPa. All primed seeds, whether dried to a low moisture content or not, germinated faster than untreated seeds after storage for up to 3 months at 4 C or 20 C. Primed asparagus seeds germinated most rapidly and synchronously after storage at 4 C and high moisture content. Storage temperature and seed moisture content had no effect on subsequent germination of primed tomato seeds.
Following dry storage for 5 or 11 months (new and old seeds, respectively) at 5 °C, less than 10% of the seeds of Indiangrass germinated as determined by a standard germination test. We attempted to increase germination by subjecting seeds to dormancy-breaking treatments, including sodium hypochlorite soak (5.25% v/v NaOCl; 20 or 60 min), prechilling (5 °C for 2 weeks), gibberellic acid during germination (GA3, 1000 mg·L-1), and combinations thereof. Treatment with NaOCl increased the germination of non-prechilled seeds only when they were germinated in GA3; a 60-min soak in NaOCl increased germination to 53% and 65% in new and old seeds, respectively. Prechilling increased germination to 65% and 47% in new and old seeds, respectively. Germination of new, prechilled seeds was increased further to 86% by either a 20-min soak in NaOCl or germination in GA3. Germination of old, prechilled seeds was not promoted further by treatment with NaOCl, but was increased to 67% by germination in GA3. Since NaOCl treatment alone failed to promote germination, we examined the effects on seedling emergence and growth of providing GA3 at 1000 mg·L-1 during the 2-week prechilling period. While prechilling alone increased emergence to an average 34% for new and old seeds, prechilling with GA3 increased emergence to 75% and 50% for new and old seeds, respectively. These treatments did not influence seedling shoot dry mass. Seed exposure to GA3 during rather than after prechilling was more effective in promoting Indiangrass establishment.
Purple coneflower seeds following priming (-0.04 MPa, 10 days, 15C, darkness) osmotically in polyethylene glycol 8000 (PEG) or matrically in expanded no. 5 vermiculite had greater germination rate and synchrony at continuous 20C or 30C than untreated seeds, but germination percentage was unaffected. Inclusion of 5.5 × 10-2 M gibberellic acid (GA3 as ProGibb Plus 2X, Abbott Laboratories, N. Chicago, Ill.) further improved germination rate and synchrony at 20C, but not at 30C. In a greenhouse study (30C day/27C night, July-August natural light), seeds primed in PEG or vermiculite containing G A3 compared to untreated seeds had 6 percentage points higher maximum emergence (ME), 3.3 fewer days to 50% ME, 1.9 fewer days between 10% and 90% ME, 116% greater shoot dry weight, and 125% longer leaves at 16 days after planting in peat-lite. Inclusion of ethephon (0.01 m, as Florel) either alone or with GA3 during priming provided no benefit to seed germination or seedling emergence. Moistened vermiculite substituted for PEG solution as a priming medium for purple coneflower seeds, the priming benefit on seedling emergence and growth being enhanced by 5.5 × 10-2 m G A3 inclusion in the priming media.
Seed treatments with paclobutrazol (PB), a triazole growth retardant, were examined for seedling growth suppression without exerting a deleterious effect on germination or emergence. Seeds of `Salmon Picotee impatiens (Impatiens wallerana Hook f.) and `Marglobe tomato (Lycopersicon esculentum Mill.) were soaked for 24 or 48 hours at 22 °C in 0, 50, 500, or 1000 mg·L-1 PB or were primed in polyethylene glycol 8000 or grade 5 exfoliated vermiculite (both at -1.0 MPa for 7 days at 22 °C) containing these PB solutions. Any PB seed treatment of impatiens (including a series of lower concentrations up to 50 mg·L-1 PB) that elicited seedling growth suppression also reduced germination and emergence. For tomato, soaking seeds for 24 hours in up to 1000 mg·L-1 PB had little or no effect on germination or emergence, and yet shoot height or dry weight was not decreased further by exceeding 50 mg·L-1 PB. At any PB concentration, soaking seeds for 48 hours or priming seeds resulted in lower percentage of germination or emergence than soaking seeds for 24 hours. Soaking tomato seeds in 50 mg·L-1 PB for 24 hours resulted in similar shoot growth suppression until at least 31 days after planting as a growth medium drench (1 mg·L-1 PB) or as a shoot spray (10 mg·L-1 PB), both applied at 14 days after planting. Beyond 31 days after planting, however, the latter two treatments gave greater shoot growth suppression than the PB seed soak treatment, which had lost its growth suppressive effect. Chemical name used: (+)-(R *,R *)-[(4-chlorophenyl)methyl]- -(1,1,-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
`Moss Curled' seeds of parsley (Petroselinum crispum L.) were primed osmotically in polyethylene glycol or matrically in fine, exfoliated vermiculite at –0.5 MPa for 4 or 7 days at 20 or 30 °C with 0 or 1 mm GA3. All priming treatments stimulated and hastened germination. Matric priming resulted in greater germination (89%) than osmotic priming (83%) when seeds were primed for 7 days at 30 °C, but priming agent had no effect on germination percentage following priming at 20 °C or for 4 days. In seeds primed for 4 days at 20 or 30 °C, matric priming hastened germination more than did osmotic priming. Germination was generally less synchronous with matric than with osmotic priming. Increasing priming time from 4 to 7 days increased the rate of germination, but increased germination synchrony only when seeds were primed at 20 °C. Inclusion of 1 mm GA3 during priming had little or no effect on germination. All matric priming treatments (other than 4-day priming) were repeated to assess seedling emergence in a greenhouse (25°C day/22 °C night). Priming increased the percentage, rate and synchrony of emergence, and increased hypocotyl length at 3 weeks after planting. Priming at 30 °C with 1 mm GA3 resulted in the greatest emergence percentage, hypocotyl length, and shoot dry weight. We conclude that matric priming is a satisfactory alternative to osmotic priming of parsley seeds. Chemical name used: gibberellic acid (GA3).
Abstract
Metalaxyl, etridiazole, and captan were incorporated at 0, 50, 450, and 850 mg active ingredient per liter of magnesium silicate (Laponite 445) gel to ascertain fungicide efficacy in controlling damping-off [Pythium aphanidermatum (Edson) Fitzp.] in fluid-drilled ‘Heinz 1350’ tomato (Lycopersicon esculentum Mill.). Metalaxyl and etridiazole at 50 and 450 mg a.i./liter, respectively, gave percentage emergence values in infested growth media equal to those in control media. Captan at 850 mg a.i./liter gave lower percentage emergence values in Pythium-infested media than in control media. Thus, damping-off control efficacy was in the order metalaxyl > etridiazole > captan. Seedling growth reflected fungicide efficacy in controlling Pythium, since plant fresh weight and infection index values were inversely related. Fungicides incorporated in gel were nonphy to toxic.