Effects of pollen competition on the reproductive performance in cucurbit hybrids (Cucurbitaceae): F1 and backcross generations

1996 ◽  
Vol 74 (7) ◽  
pp. 1113-1118 ◽  
Author(s):  
Mauricio Quesada ◽  
Andrew G. Stephenson ◽  
James A. Winsor
Keyword(s):  
Reproductive Performance ◽  
Reproductive Output ◽  
Backcross Progeny ◽  
Field Studies ◽  
Field Conditions ◽  
Pollen Competition ◽  
Plant Fitness ◽  
Pollen Loads ◽  
Pollen Performance ◽  
Small Pollen

We examined the effect of pollen competition on the reproductive performance of Cucurbita F1 and backcross progeny while attempting to control for nongenetic maternal effects and nonrandom seed abortion as possible explanations for the data. We compared the vigor of F1 and backcross progeny produced from large and small pollen loads under field conditions. The results from both field studies indicated that the progeny produced from large pollen loads outperformed the progeny produced from small pollen loads for several measures of vigor. The F1 progeny produced from large pollen loads germinated faster, and produced 12% more staminate flowers and 9% more pistillate flowers than the progeny from the small pollen loads. Similarly, the backcross progeny produced from large pollen loads germinated faster, and produced 8% more pistillate flowers and 20% more fruits than the progeny from the small pollen loads. This study demonstrates a positive correlation between the size of the pollen load and the vigor of the resulting progeny under field conditions. Keywords: pollen competition, pollen performance, nonrandom fertilization, plant fitness, reproductive output.

scholarly journals Laboratory field studies of mini potato planter

2020 ◽  
Vol 17 ◽  
pp. 00150
Author(s):  
Nikolai P. Laryushin ◽  
Oleg N. Kukharev ◽  
Anton S. Bochkarev ◽  
Vladimir S. Bochkarev
Keyword(s):  
Field Studies ◽  
Field Conditions ◽  
Design Parameters ◽  
Small Scale ◽  
Potato Tubers ◽  
Motion Speed ◽  
Potato Planter

The paper considers the design and operation of the experimental mini potato planter for small-scale farms (private subsidiary farms – PSF). It presents the results of field studies of experimental potato planter in field conditions. The paper also describes probabilistic curves of potato tubers distribution in a furrow depending on motion speed and design parameters of tubers speed damper.

APPLICATION OF CONTROLLED REPRODUCTION TO SHEEP FLOCKS IN NEWFOUNDLAND

1982 ◽  
Vol 62 (3) ◽  
pp. 679-687 ◽  
Author(s):  
J. N. B. SHRESTHA ◽  
L. AINSWORTH ◽  
D. P. HEANEY ◽  
A. N. SMITH
Keyword(s):  
Key Words ◽  
Reproductive Performance ◽  
Field Conditions ◽  
Spring Season ◽  
Fall Season ◽  
Controlled Reproduction

A 3-yr study demonstrates that commercially acceptable reproductive performance can be achieved in breeding sheep following the application of a fluorogestone-acetate- (FGA-) impregnated intravaginal sponge and pregnant mare's serum gonadotrophin (PMSG) treatment to induce a synchronized estrus under field conditions. Overall fertility, prolificacy and fecundity levels of 76%, 1.92 and 148%, respectively, resulted from breeding at the synchronized estrus, and 94%, 1.86 and 175%, respectively, due to breeding at the synchronized and subsequent estruses in the breeding (fall) season. In the nonbreeding (spring) season, these responses were 51%, 1.73 and 88%, respectively, at the synchronized estrus, and 63%, 1.61 and 109%, respectively, due to breeding at the synchronized and subsequent estruses. Significant farm-to-farm variation was observed with reproductive performance ranging from 77 to 100% for fertility, 1.45 to 2.74 for prolificacy, and 134 to 274% for fecundity in the estrous season. There were no significant differences among farms after synchronization and breeding during the anestrous season. Key words: Sheep, synchronization, fluorogestone acetate, pregnant mare's serum gonadotrophin, season, farm flocks.

Atrazine Dissipation as Affected by Surface pH and Tillage

Weed Science ◽  
1980 ◽  
Vol 28 (1) ◽  
pp. 101-104 ◽  
Author(s):  
J. J. Kells ◽  
C. E. Rieck ◽  
R. L. Blevins ◽  
W. M. Muir
Keyword(s):  
Weed Control ◽  
Soil Ph ◽  
Field Studies ◽  
Conventional Tillage ◽  
Field Conditions ◽  
No Tillage ◽  
Tillage Systems ◽  
Surface Ph ◽  
Factors Affecting ◽  
Decreasing Ph

Field studies and laboratory analyses were conducted to examine factors affecting degradation of14C-atrazine [2-chloro-4-(ethylamine)-6-(isopropylamino)-s-triazine] under field conditions. The effects of these factors on weed control under no-tillage and conventional tillage systems were also examined. The amount of radioactivity which was unextractable in 90% methanol increased with time following treatment with14C-atrazine. The rate of formation of unextractable14C compounds was greater under no-tillage and increased with decreasing pH. After 14 to 18 days, a greater amount of extractable atrazine was present in areas receiving lime. The degradation of atrazine occurred more rapidly when surface pH was less than 5.0 compared with a pH greater than 6.5. The effect of lime on the amount of parent atrazine present in the soil was directly correlated to its effect on soil pH. Extractable atrazine in the soil 45 days after treatment was significantly correlated with weed control with the greatest effect under no-tillage.

Interactions of Four Herbicides with Rhizoctonia solani on Seedling Cotton

Weed Science ◽  
1968 ◽  
Vol 16 (4) ◽  
pp. 453-456 ◽  
Author(s):  
James M. Chandler ◽  
P. W. Santelmann
Keyword(s):  
Gossypium Hirsutum ◽  
Rhizoctonia Solani ◽  
Field Studies ◽  
Antagonistic Effect ◽  
Field Conditions ◽  
Growth Chamber ◽  
Seedling Disease ◽  
Low Level ◽  
High Level

Growth chamber and field studies were conducted to investigate the possibility of an interaction between the herbicides 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin), a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), 3- (m-tri-fluromethylphenyl)-1,1-dimethylurea (fluometuron), and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne), and the seedling disease organism Rhizoctonia solani Kuehn in cotton (Gossypium hirsutum L.). When high levels of trifluralin or prometryne were used in the growth chamber, an interaction with the pathogen that was injurious to the cotton occurred. Prometryne and fluometuron produced an antagonistic effect on R. solani.Under field conditions, R. solani usually caused cotton injury. Interactions injurious to the cotton occurred between trifluralin and a low level of R. solani and between nitralin and a high level R. solani infestation. No interactions occurred with fluometuron or prometryne. In all instances, the effect occurred only when the herbicides were being used at high rates.

Performance of Genetically Modified Soybean Expressing the Cry1A.105, Cry2Ab2, and Cry1Ac Proteins Against Key Lepidopteran Pests in Brazil

2020 ◽  
Vol 113 (6) ◽  
pp. 2883-2889
Author(s):  
Fabiana B Bacalhau ◽  
Patrick M Dourado ◽  
Renato J Horikoshi ◽  
Renato A Carvalho ◽  
Altair Semeão ◽  
...  
Keyword(s):  
Genetically Modified ◽  
Leaf Disc ◽  
Field Studies ◽  
Field Conditions ◽  
Anticarsia Gemmatalis ◽  
Genetically Modified Soybean ◽  
Lepidopteran Pests ◽  
Highly Effective ◽  
The Individual ◽  
Gm Soybean

Abstract The pyramided genetically modified (GM) soybean [Glycine max L. (Merr.)] MON87751 × MON87708 × MON87701 × MON89788, expressing Cry1A.105, Cry2Ab2, and Cry1Ac from Bacillus thuringiensis Berliner, was approved for commercial use in Brazil. We conducted laboratory, greenhouse, and field studies to assess the efficacy of this Bt soybean against key soybean lepidopteran pests. Neonates of Anticarsia gemmatalis (Hübner) (Lepidoptera: Erebidae), Chrysodeixis includens (Walker), and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) were exposed to Bt proteins in diet-overlay bioassays. MON87751 × MON87708 × MON87701 × MON89788 soybean and individual components were evaluated in laboratory (leaf disc), greenhouse (high artificial infestations), and in field conditions (natural infestations). Neonates of A. gemmatalis, C. includens, and H. armigera were highly susceptible to Cry1A.105 (LC50 from 0.79 to 48.22 ng/cm2), Cry2Ab2 (LC50 from 1.24 to 8.36 ng/cm2), and Cry1Ac (LC50 from 0.15 to 5.07 ng/cm2) in diet-overlay bioassays. In laboratory leaf disc bioassays and greenhouse trials, MON87751 × MON87708 × MON87701 × MON89788 soybean as well as the individual components were highly effective in controlling A. gemmatalis, C. includens, and H. armigera. Similarly, under field conditions, the pyramided genotypes expressing Cry1A.105, Cry2Ab2, and Cry1Ac were highly effective at protecting soybean against C. includens. We concluded that the individual Bt proteins expressed by GM soybean MON87751 × MON87708 × MON87701 × MON89788 killed all or nearly all the susceptible A. gemmatalis, C. includens, and H. armigera, fulfilling one important criterion for successfully delaying resistance to pyramided Bt crops.

Field Dissipation of Atrazine and Metribuzin in Organic Soils in Florida

2014 ◽  
Vol 28 (4) ◽  
pp. 578-586 ◽  
Author(s):  
Dennis C. Odero ◽  
Dale L. Shaner
Keyword(s):  
Weed Control ◽  
Residual Activity ◽  
Field Studies ◽  
South Florida ◽  
Field Conditions ◽  
Agricultural Area ◽  
Organic Soils ◽  
Bioavailable Fraction ◽  
Rate Of Dissipation ◽  
Atrazine Degradation

Sugarcane growers have observed reduced residual activity of atrazine on organic soils in the Everglades Agricultural Area (EAA) of south Florida. Field studies were conducted between 2011 and 2012 to determine the rate of dissipation of atrazine at 2.24, 4.48, and 8.96 kg ha−1and metribuzin at 0.56, 1.12, and 2.24 kg ha−1in the top 10 cm of soil in sugarcane fields in the EAA. The bioavailable fraction of atrazine dissipated more rapidly than the total amount of atrazine in the soil. Half-lives of the total and bioavailable fraction of atrazine ranged between 3.9 to 12.1 d and 1.0 to 7.5 d, respectively. Metribuzin dissipated much more slowly than atrazine on organic soils. Similarly, dissipation of the bioavailable fraction of metribuzin was more rapid than was the dissipation of the total amount of metribuzin in the soil. Half-lives of the total and bioavailable fraction of metribuzin ranged between 16.2 and 24.8 d and 6.0 and 14.3 d, respectively. These results indicate that enhanced atrazine degradation occurs on organic soils under field conditions in the EAA, resulting in shorter residual atrazine activity. This implies that metribuzin is a better option for weed control in sugarcane grown on organic soils of the EAA exhibiting enhanced atrazine degradation.

Influence of Postpartum Cloprostenol Treatment in Sows on Subsequent Reproductive Performance under Field Conditions

2008 ◽  
Vol 43 (4) ◽  
pp. 484-489 ◽  
Author(s):  
C Vanderhaeghe ◽  
J Dewulf ◽  
A Daems ◽  
A Van Soom ◽  
A de Kruif ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Field Conditions

MAJOR FIELD TEST EVALUATES A SHORELINE CLEANER TO SAVE OILED MARSH GRASS

1997 ◽  
Vol 1997 (1) ◽  
pp. 397-402 ◽  
Author(s):  
S. R. Pezeshki ◽  
R. D. DeLaune ◽  
A. Jugsujinda ◽  
G. P. Canevari ◽  
R. R. Lessard
Keyword(s):  
Spartina Alterniflora ◽  
Field Test ◽  
Field Tests ◽  
Field Studies ◽  
Test Site ◽  
Field Conditions ◽  
Marsh Vegetation ◽  
Beneficial Effects ◽  
Live Biomass ◽  
South Louisiana

ABSTRACT Extensive greenhouse studies using intact cores of marsh vegetation including Spartina alterniflora demonstrated the potential of a shoreline cleaner (Corexit 9580) to remove oil from plant canopy. Because of these positive results, a permit to conduct a full-scale field test was obtained by Louisiana State from regulatory agencies in June 1995. Field tests were conducted in a Louisiana marsh at a wildlife refuge in August 1995. The test site contained replicated 8 ft X 8 ft test plots that included the following treatments: oiled with South Louisiana crude oil, oiled and chemically cleaned after 2 days using Corexit 9580, and control. Significant initial reductions in plant stomatal conductance, transpiration, and CO2 fixation rates in response to the “oil” and “oil + Corexit 9580” treatments were noted, which were followed by substantial recovery in the “oil + Corexit 9580” treatment. Use of the cleaner improved the survival and regeneration capability of treated plots because of the low initial mortality rates and the rapid restoration of plant gas exchange activities. Plots treated with “oil + Corexit 9580” had a significantly greater number of live shoots throughout the measurement period in 1995. Biomass harvests conducted at the end of the 1995 growing season revealed that live biomass per unit area of marsh was significantly reduced under all treatments. The second harvest in 1996 indicated that live biomass had recovered to levels close to those of control plots. Our field studies demonstrated that oil can be removed using Corexit 9580 in the field without any detectable adverse effects on plants, In addition, the beneficial effects of Corexit 9580 in rapidly restoring plant transpiration pathways under field conditions was evident. However, plants under all treatments recovered, showing that Spartina alterniflora, given adequate time, can recover from oiling with South Louisiana crude. Additional studies using more stressful oil types such as Bunker C are needed to examine the effectiveness of Corexit 9580 in cleaning plant canopies under field conditions.

scholarly journals Fused Vein Trait in Cucurbita pepo L. Associated with Subvitality of the Male Gametophyte

1996 ◽  
Vol 121 (1) ◽  
pp. 18-22 ◽  
Author(s):  
R. Bruce Carle ◽  
J. Brent Loy
Keyword(s):  
Pollen Tube ◽  
Seed Yield ◽  
Microscopic Examination ◽  
Cucurbita Pepo ◽  
Male Gametophyte ◽  
Pollen Competition ◽  
Pollen Load ◽  
Pollen Loads ◽  
Normal Pollen

Two experiments were conducted to test and delineate gametophytic subvitality of the fused vein trait in Cucurbita pepo. Gametophytic subvitality was verified by comparing pollen tube growth for fused vein and normal pollen in situ. Microscopic examination of partitioned, co-pollinated distillate flowers revealed inferior fused vein gametophyte performance. Normal pollen tubes grew faster and were significantly more abundant in the lower portion of the style. The consequences of gametophytic subvitality on seed yield and inheritance were shown by manipulating the severity of pollen competition. Fused vein, normal and F1 lines were pollinated with fused vein, normal, F and a 50:50 pollen mix at three different pollen loads. Fused vein pollen generated significantly fewer seed per fruit in all female genotypes. As a constituent in F, or mixed pollen, it produced significant seed yield reductions at the low pollen load. In F1 and testcross populations, a reduction in pollen load and therefore pollen competition significantly increased the number of fused vein individuals in segregating populations.

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