scholarly journals Effects of Paclobutrazol on Production and Landscape Performance of Texas Maroon Bluebonnet

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 884E-885
Author(s):  
Kyle R. Bading* ◽  
Garry V. McDonald ◽  
Michael A. Arnold ◽  
Wayne A. Mackay ◽  
Jerry M. Parsons

Texas maroon bluebonnets (Lupinus texensis Hook. `Texas Maroon') grown for fall planting may be germinated as early as September. Plant growth regulators are commonly applied to control excessive stem elongation during production, but may potentially result in adverse responses in the landscape due to residual effects. In October 2003, an experiment was initiated to observe potential landscape residual effects of paclobutrazol (formulated as Bonzi) applied during the production phase to retard internode elongation. Seedlings were received in six-pack cell units. On 30 Oct. 2003, while still in six-packs, bluebon-nets were sprayed with paclobutrazol. Paclobutrazol was applied at concentrations of 0, 5, 10, and 15 mg·L-1 a.i. at a coverage rate of 10 mL per 0.93 m2. After treatment, half of the plants were transplanted from six-packs to 0.73 L pots and the other half remained in six-packs. Plants were grown in a nursery until they reached a marketable stage (13 Nov. 2003 for six-packs, 20 Nov. 2003 for 0.73-L pots). At the end of nursery production, one half of the plants (both container sizes) were then planted to landscape plots (0.3 m centers) at either College Station, Texas or Dallas, Texas. During the production phase, bluebonnets grown in 0.73-L pots had slightly larger growth indices than those produced in six-packs. As application rates of paclobutrazol increased, growth indices decreased. Possible residual effects on growth and flowering will also be discussed.

1964 ◽  
Vol 15 (5) ◽  
pp. 729 ◽  
Author(s):  
D Aspinall ◽  
PB Nicholls ◽  
LH May

The effects of soil moisture stress on tillering, stem elongation, and grain yield of barley (cv. Prior) have been studied by subjecting the plants to periods of stress at different stages of development. Soil moisture stress treatments consisted of repeated short cycles of stress, single short cycles (both in large pots), or single long cycles (in large lysimeters). The data collected support the contention that the organ which is growing most rapidly at the time of a stress is the one most affected. Grain numbers per ear were seriously affected by stress occurring prior to anthesis, an effect probably associated with the process of spikelet initiation and, later, with the formation of the gametes. Grain size, on the other hand, was reduced more by stress at anthesis and shortly after. Elongation of the internodes was reduced mostly by stress at or just before earing, and was less seriously affected by earlier or later stress. Tillering, although being suppressed during a drought cycle, was actually stimulated upon rewatering. The effect was greater the earlier the period of stress, and was probably related to nutrient uptake and distribution within the plant.


2001 ◽  
Vol 49 (4) ◽  
pp. 443 ◽  
Author(s):  
Nurussaba Khanam ◽  
Cheang Khoo ◽  
Abdul G. Khan

In non-rooted shoots regenerated from calluses induced with nine different cyokinin–auxin combinations, basal stem elongation and the cell arrangement in the basal stem sections depended on the cytokinin–auxin combinations used at the callus-induction stage. Elongated basal stems like seedling and large cells in the secondary xylem were found in the non-rooted shoots regenerated from calluses induced with benzyladenine (BA) 10 µM + naphthaleneacetic acid (NAA) 1 µM and BA 10 µM + indole-3-butyric acid (IBA) 0.1 µM. Tropane alkaloids were detected in these shoots. The peak hyoscyamine and scopolamine contents were 38.5 × 10 –4 and 6.5 × 10 –4 % dry weight, respectively. Various patterns of vascular regions without large cells in the secondary xylem were found in the basal stem sections of the non-rooted shoots regenerated from calluses induced with the other cytokinin–auxin combinations. No tropane alkaloids were detected in these shoots.


1977 ◽  
Vol 28 (2) ◽  
pp. 287 ◽  
Author(s):  
JF Ayres ◽  
JD McFarlane ◽  
GJ Osborne ◽  
EJ Corbin

The residual effects of topdressing the grazed clover-ley were evaluated at four sites in southern New South Wales. The significance (for the initial crop) of changes in soil fertility induced by topdressing were studied in crop experiments (five superphosphate drill rates x three nitrogen rates) immediately following the ley phase. Topdressing influenced the level of available phosphate at all sites: heavy applications induced a large increase in available phosphate, light applications induced a moderate increase, and omission of topdressing led to a slight decline. The rate of soil nitrogen accretion was affected by topdressing only at sites that were initially of medium soil phosphate status. Topdressing exerted residual effects on crop growth, grain yield, and grain composition; crops following topdressed leys showed little response to superphosphate drilled with the crop at sowing. By contrast, crops following untopdressed leys showed a consistent but low requirement for superphosphate; grain production was maximized at low application rates (< 100 kg superphosphate ha-1) and the (economic) optimal rate was usually in the range 30-60 kg superphosphate ha-1. For the initial crop, low drill application rates were apparently equivalent to large amounts of superphosphate applied by topdressing the ley. ___________________ *Part I, Aust. J. Agric. Res., 28: 269 (1977).


1997 ◽  
Vol 15 (3) ◽  
pp. 126-130
Author(s):  
Larry J. Shoemake ◽  
Michael A. Arnold

Abstract Seven groups of seedlings from each of seven single parent (half-sib) families of sycamore, Platanus occidentalis L., were grown to a marketable size in 9.1 liter (#3) containers to test responses to container nursery production in south Texas. Seedlings were then transplanted to a field site (Brazos County, TX) in the fall, spring, and summer to assess seasonal effects on landscape establishment. Regional selections grew larger, both during container production and following subsequent transplant to the field. Growth of nonimproved local half-sib families equaled or exceeded that of genetically improved families from a distant region. Differential responses among genetically improved and non-improved sources were less pronounced when genotypes were grown in a region from which they did not originate. Fall and spring transplanted seedlings had substantially greater growth and survival than did summer transplants regardless of genotype. This study demonstrates a potential for regional market segregation of seed-propagated landscape trees.


2013 ◽  
Vol 31 (3) ◽  
pp. 177-182
Author(s):  
Lucy E. Edwards ◽  
Charles H. Gilliam ◽  
Glenn B. Fain ◽  
Jeff L. Sibley

Pine bark has been the standard container nursery substrate for nearly forty years. However, due to the decline in the timber industry and fluctuations in fuel prices, alternative substrates and amendments are being sought by growers and researchers. This study evaluated locally grown eastern red cedar (Juniperus virginiana L.) as a potential alternative to pine bark in nursery production of 10 ornamental species. For seven of the species evaluated, growth indices for plants in 100% cedar were similar to those in 100% pine bark. ‘August Beauty’ gardenia grown in up to 80% cedar was comparable to plants grown in pine bark. Species that have lower pH requirements did not perform as well in substrates amended with high cedar percentages. ‘Premier’ blueberry did not grow well in cedar above 20%. Root growth for seven of the species in cedar was similar to or greater than those grown in 100% pine bark. ‘Formosa’ azalea and ‘Burgundy’ loropetalum showed slight variations in root growth above 10% cedar. These data conclude that cedar has potential as an amendment to pine bark in nursery production.


2009 ◽  
Vol 19 (2) ◽  
pp. 267-285 ◽  
Author(s):  
Mack Thetford ◽  
Jeffrey G. Norcini ◽  
Barry Ballard ◽  
James H. Aldrich

Full sun trial gardens (full sun) were established at Leon County (LC) and Santa Rosa County (SRC), Florida, to evaluate the effect of site on horticultural performance traits pertinent to landscape use (long-term growth, flowering, vigor, overall quality, and survival) of native and nonnative warm season grasses when grown under low-input landscape conditions over a 3-year period. The gardens contained landscape fabric- (LC) or plastic (SRC)-covered rows, with the synthetic mulch at each site covered by 4 inches of hardwood chip mulch. Fifteen native and eight nonnative grass species, and cultivars were evaluated as were the two grass-like species black flowering sedge (Carex nigra) and narrowleaf silkgrass (Pityopsis graminifolia), a native dicot with grass-like foliage. Many of the native species were derived from seeds or plants collected from naturally occurring populations in Florida, and other species or cultivars were obtained from commercial sources. Based on quality ratings and survival, a majority of the species and cultivars were rated as at least being marginally acceptable for 2 years or more, but only six species and cultivars were rated as excellent or good over all 3 years. Four of these six species were native, with 100% survival at both sites occurring only for purpletop tridens (Tridens flavus). The other three native species, gulf hairawn muhly, (Muhlenbergia capillaris var. filipes), ‘Alamo’ switchgrass (Panicum virgatum), and indian woodoats (Chasmanthium latifolium) had high rates of survival. Porcupine grass (Miscanthus sinensis ‘Strictus’) and ‘Cabaret’ silver grass (M. sinensis ssp. condensatus) were the only two nonnative species demonstrating potential for long-term performance in a low-input landscape at both sites. Three of the four cultivars of miscanthus (Miscanthus spp.) survived the entire evaluation period in SRC, while two cultivars suffered losses only in LC, demonstrating the importance of site effects on the long-term performance of individual species or cultivars of grasses. Chalky bluestem (Andropogon capillipes) (Orange County, FL), sand lovegrass (Eragrostis trichoides), giant silver grass (Miscanthus ×giganteus), and bamboo muhly (Muhlenbergia dumosa) each survived 3 years at one site but only 1 year at the other site. Pineland threeawn (wiregrass) (Aristida stricta), ‘Red Baron’ cogon grass (japanese blood grass) (Imperata cylindrical), ‘Hameln’ fountain grass (Pennisetum alopecuroides), black flowering fountain grass (P. alopecuroides ‘Moudry’), and ‘Feesey Form’ ribbon grass (Phalaris arundinaceae) were categorized as marginal for low-input landscapes and could only be considered short-term perennials under the conditions of this test. ‘Morning Light’ silver grass (M. sinensis), coastal bluestem (Schizachyrium maritimum), and ‘Lometa’ indiangrass (Sorghastrum nutans) had good 2-year landscape performance and survived at least 2 years at both sites. Bigtop lovegrass (Eragrostis hirsuta), silver plumegrass (Saccharum alopecuroides), and lopsided indiangrass (Sorghastrum secundum) were categorized as having excellent 1-year landscape performance and have potential for short-term performance under low-input conditions. Chalky bluestem (Andropogon capillipes) (SRC), black flowering sedge, ‘Heavy Metal’ switchgrass (Panicum virgatum), and narrowleaf silkgrass were categorized as having good 1-year landscape performance.


2016 ◽  
Vol 37 (5) ◽  
pp. 3231 ◽  
Author(s):  
Rafael Mendonça de Carvalho ◽  
Manoel Eduardo Rozalino Santos ◽  
Bruno Humberto Rezende Carvalho ◽  
Camilla Rodrigues de Almeida Carvalho ◽  
João Paulo Franco da Silveira ◽  
...  

The objective of this study was to evaluate the morphogenic and structural characteristics of the Brachiaria brizantha cv. Marandu Syn. Urochloa brizantha cv. Marandu during the different seasons of the year, in locations closer to or farther from feces deposited by cattle in pastures. The experimental design was in randomized blocks, with four replicates. The following response-variables were calculated: phyllochron (PHYL), leaf appearance rate (LAR), leaf elongation rate (LER), stem elongation rate (SER), leaf senescence rate (LSR), life span of the leaf (LSL), stem length (SL), leaf blade length (LBL), number of dead leaves per tiller (NDLT), and number of living leaves per tiller (NLLT). Farther from the feces, a larger phyllochron period was observed in all seasons. The LSL was greater in winter, especially farther from feces. Closer to feces, higher values were observed for LAR, LER and LBL compared with the sites farther from feces. The SL, SER, and NLLT were lower in the winter compared with the other seasons. In the summer, a greater NDLT value was observed than in the other seasons. The deposition of feces by cattle and the seasons of the year both affect the morphogenesis of B. brizantha cv. Marandu, generating the observed spatial and temporal variability in pasture grass.


HortScience ◽  
2015 ◽  
Vol 50 (10) ◽  
pp. 1567-1571
Author(s):  
Timothy K. Broschat

Potassium (K) deficiency is a widespread problem in palms growing in sandy or calcareous soils in southeastern United States. Its symptoms are highly conspicuous, reduce palm aesthetic appeal, are difficult to correct, and can be exacerbated by nitrogen (N) fertilization. The objective of this study was to determine the optimum fertilization rates and ratio for N and K in areca palm [Dypsis lutescens (H. Wendl.) Beentje & J. Dransf. and Mexican fan palm (Washingtonia robusta H. Wendl.) growing in a calcareous sandy fill soil. Both species had their highest quality when fertilized with 12.2 g·m−2 N and 12.2 g·m−2 K from controlled-release (2–3 month release) sources every 3 months. Actual N and K application rates were better predictors of palm quality than N:K ratio at the highest fertilization rates that would be recommended for field nursery production. However, at lower application rates more typical of those used for landscape palm maintenance, palm quality improved as the N:K application ratio was decreased.


2019 ◽  
Vol 112 (4) ◽  
pp. 1798-1804 ◽  
Author(s):  
Cléber Antonio Baronio ◽  
Inana Xavier Schutze ◽  
Marcelo Zanelato Nunes ◽  
Daniel Bernardi ◽  
Ruben Machota ◽  
...  

Abstract Ceratitis capitata (Wiedemann, 1824) is the main insect pest of fruits worldwide. The objective of this study was to evaluate the toxicity and residual effects of the ready-to-use toxic baits Success 0.02CB (0.24 g of active ingredient [a.i.] per liter of spinosad) and Gelsura (6 g of a.i./liter of alpha-cypermethrin) and to compare them with other food lures containing spinosad and malathion mixed with hydrolyzed protein (Biofruit 5% and Flyral 1.25%), Anamed without dilution or sugarcane molasses (7%) against adult C. capitata in laboratory and greenhouse trials. Ceratitis capitata adults were highly susceptible to all toxic bait formulations (mortality > 80%) until 96 h after exposure. The lowest LT50 (hours) of toxic baits were 2.32 (Gelsura at 4,000 mg/liter), 4.26 (Gelsura at 2,000 mg/liter), 4.28 (Anamed + malathion) and 4.89 (sugarcane molasses + malathion), while formulations containing spinosad (Biofruit, Flyral, Anamed and Success 0.02CB) showed LT50 of approximately 11 h. Without rain, Gelsura (2,000 mg/liter) and all spinosad formulations provided mortality superior to 80% 14 d after application. Gelsura and Anamed + spinosad showed higher resistance to a 5-mm simulated rain, similar to Anamed + malathion, while the other formulations had its efficacy decreased. All toxic baits were effective on adult C. capitata in residual experiments without rain while Anamed + spinosad caused high adult mortality after 5 to 25 mm rains. Gelsura and Anamed + spinosad can be used to replace toxic baits containing malathion for C. capitata population management.


1977 ◽  
Vol 17 (87) ◽  
pp. 629
Author(s):  
S Tudsri ◽  
PC Whiteman

The re-establishment of four legumes, Stylosanthes guianensis cv. Schofield, Lotononis bainesii cv. Miles, Desmodium intortum cv. Greenleaf and Macroptilium atropurpureum cv. Siratro by oversowing into a Setaria anceps cv. Kazungula stand was studied in plots with different phosphate (P) levels. Half the plots had received different levels of initial P only, seven years previously, the other half received initial and maintenance P plus a further application at oversowing. At 15 weeks after sowing all species had similar seedling densities (10 to 23 plants m-2). The densities of stylo and siratro declined over the 88 week trial, and desmodium also declined except at the highest rate of P. Lotononis density increased except at Nil P where all legumes, except stylo, were almost eliminated. In terms of legume survival and growth, setaria tiller density, and P concentration in plant tops, residual effects of P applied seven years previously were clearly evident, particularly at the higher rates (44 and 88 kg P ha-1). P and N concentrations in tops were linearly related.


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