Divergent selection for flowering in annual bluegrass and its impact on plant development and turfgrass utility

2003 ◽  
Vol 83 (1) ◽  
pp. 157-162 ◽  
Author(s):  
D. J. Cattani
Keyword(s):  
Population Distribution ◽  
Divergent Selection ◽  
Main Stem ◽  
Poa Annua ◽  
Low Light ◽  
Annual Bluegrass ◽  
Light Levels ◽  
Turfgrass Quality ◽  
Selection For ◽  
Made In

Annual bluegrass (Poa annua L.) is a widely occurring turfgrass component. Recent efforts to develop cultivars of this species have led to increased interest in selection methods. The objectives of this study were to evaluate the utility of controlled growth studies for divergent selection for flowering and to evaluate the resultant selections for development and turfgrass quality. Two growth cabinet selection runs (1997 and 1998) were made at a constant 20°C and a 16-h photoperiod at low light levels. Selection was based upon the earliest and latest plants to produce a seedhead on the main stem. In the second selection run, mid-flowering selection was made to characterize the population distribution. Selections were grown out in the greenhouse in 1998 and 1999. Selections made in 1998 were seeded into a field study in August 1999 and maintained as golf green turf. Late selections flowered later than early or mid selections and produced more leaves on the main stem prior to inflorescence appearance. Seedhead ripening showed greater uniformity in late selections. Some late selections produced few seedheads under the greenhouse conditions. Selection for divergent flowering types was successful using the method employed. Turf performance was not related to flowering type, indicating that screening for turf performance will be required after initial selection for plant type. Key words: Poa annua L., selection, life history, tillering, seed production, turf performance

Dates of Herbicide Application for Weed Control in Bermudagrass

Weed Science ◽  
1975 ◽  
Vol 23 (2) ◽  
pp. 110-115 ◽  
Author(s):  
B. J. Johnson
Keyword(s):  
Weed Control ◽  
Cynodon Dactylon ◽  
Field Studies ◽  
Poa Annua ◽  
Herbicide Application ◽  
Annual Bluegrass ◽  
Made In

In field studies, herbicides were applied at various times to different plots during the summer and fall at two locations over a 3-year period to control winter weeds in nonoverseeded bermudagrass [Cynodon dactylon (L.) Pers.] turf. Annual bluegrass (Poa annua L.) control was higher at Griffin for all herbicide applications made in October when compared with herbicide applications made at the same rate in July, August, or September. At Lawrenceville, optimum annual bluegrass control was obtained when bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl) benzenesulfonamide] was applied in August, terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate) applied in either August or September, benefin (N-butyl-N-ethyl-α,α,α-trifluoro −2,6 dinitro-p-toluidine) applied in September, pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl) benzamide] applied in either September or October, and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] applied in October. DCPA (dimethyl tetrachloroterephthalate) did not control annual bluegrass satisfactorily at either location, regardless of dates of application. The control of several broadleaf weeds was generally higher when herbicides were applied in October at Griffin and when applied in September or October at Lawrenceville when compared with earlier treatments. Bensulide applied in October was the only herbicide that satisfactorily controlled parsley-piert (Alchemilla microcarpa Boissie Reuter).

scholarly journals Hybrid tea-roses under controlled light conditions. 3. Flower and blind shoot production in the glasshouse of seedlings selected for flowering or flower bud abortion at low irradiances in a growth room.

1978 ◽  
Vol 26 (4) ◽  
pp. 399-404
Author(s):  
D.P. de Vries ◽  
L.A.M. Dubois ◽  
L. Smeets
Keyword(s):  
Lower Percentage ◽  
Light Conditions ◽  
Flower Bud ◽  
Low Light ◽  
Light Intensities ◽  
Shoot Production ◽  
Growth Room ◽  
Selection For ◽  
Flower Bud Abortion ◽  
Made In

Seedlings of hybrid tea roses, previously selected in a growth room for flowering or flower bud abortion at low light intensities were grown in a greenhouse for periods of at least 14 months. Previously flowering seedlings whether grown on their own roots or on a rootstock yielded more flowers, particularly in winter, than previously aborting ones. This was due to a lower percentage of blind shoots and a tendency to produce more shoots. It was shown that selection for better winter performance under glass could be made in young seedlings. [For part 2 see HcA 48, 7528.] (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Effects of Light, N and Defoliation on Biomass Allocation in Poa annua

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1783
Author(s):  
Louis John Irving ◽  
Sayuki Mori
Keyword(s):  
Biomass Allocation ◽  
Light Level ◽  
Poa Annua ◽  
Root Mass ◽  
Light Conditions ◽  
Low Light ◽  
Light Levels ◽  
Below Ground ◽  
Shoot Mass

Plants allocate biomass to above- and below-ground organs in response to environmental conditions. While the broad patterns are well-understood, the mechanisms by which plants allocate new growth remain unclear. Modeling approaches to biomass allocation broadly split into functional equilibrium type models and more mechanistically based transport resistance type models. We grew Poa annua plants in split root boxes under high and low light levels, high and low N supplies, with N supplied equally or unequally. Our data suggest that light level had the strongest effect on root mass, with N level being more important in controlling shoot mass. Allocation of growth within the root system was compatible with phloem partitioning models. The root mass fraction was affected by both light and N levels, although within light levels the changes were primarily due to changes in shoot growth, with root mass remaining relatively invariant. Under low light conditions, plants exhibited increased specific leaf area, presumably to compensate for low light levels. In a follow-up experiment, we showed that differential root growth could be suppressed by defoliation under low light conditions. Our data were more compatible with transport resistance type models.

Divergent Selection for In Vitro Dry Matter Digestibility in Smooth Bromegrass 1

Crop Science ◽  
1986 ◽  
Vol 26 (6) ◽  
pp. 1123-1126 ◽  
Author(s):  
N. J. Ehlke ◽  
M. D. Casler ◽  
P. N. Drolsom ◽  
J. S. Shenk
Keyword(s):  
Dry Matter ◽  
Divergent Selection ◽  
Smooth Bromegrass ◽  
Dry Matter Digestibility ◽  
Selection For

Effects of Divergent Selection for Growth on Carcass Traits in Japanese Quails

2014 ◽  
Vol 42 (2) ◽  
pp. 51-56
Author(s):  
Khairy M. El–Bayomi ◽  
Mahmoud S. El-Tarabany ◽  
Mohammed A.F. Nasr ◽  
El-Shimaa M. Roushdy
Keyword(s):  
Carcass Traits ◽  
Divergent Selection ◽  
Japanese Quails ◽  
Selection For

Growth ofPseudotsuga menziesiiandTsuga heterophyllaseedlings along a light gradient: resource allocation and morphological acclimation

1997 ◽  
Vol 75 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
D. Mailly ◽  
J. P. Kimmins
Keyword(s):  
Leaf Morphology ◽  
Biomass Accumulation ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Low Light ◽  
Growing Seasons ◽  
Light Levels ◽  
Light Gradient ◽  
Relative Light Intensity

Silvicultural alternatives that differ in the degree of overstory removal may create shady environments that will be problematic for the regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Gradients of light in the field were used to compare mortality, growth, and leaf morphological acclimation of two conifer species of contrasting shade tolerances: Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Results after two growing seasons indicated that Douglas-fir mortality occurred mainly at relative light intensity (RLI) below 20%, while western hemlock mortality was evenly distributed along the light gradient. Height, diameter, and biomass of the planted seedlings increased with increasing light for both species but at different rates, and maximum biomass accumulation always occurred in the open. Douglas-fir allocated more resources to stem biomass than western hemlock, which accumulated more foliage biomass. Increases in specific leaf area for Douglas-fir seedlings occurred at RLI ≤ 0.4 and red/far red (R/FR) ratio ≤ 0.6, which appear to be the minimal optimum light levels for growth. Conversely, western hemlock seedlings adjusted their leaf morphology in a more regular pattern, and changes were less pronounced at low light levels. These results, along with early mortality results for Douglas-fir, suggest that the most successful way to artificially regenerate this species may be by allowing at least 20% of RLI for ensuring survival and at least 40% RLI for optimum growth. Key words: light, light quality, leaf morphology, acclimation.

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