scholarly journals Sunflower seed germination and storability response to chemical desiccation

2020 ◽  
Vol 26 (2) ◽  
pp. 53-60
Author(s):  
Petar Čanak ◽  
Milan Jocković ◽  
Bojana Vujošević ◽  
Milosav Babić ◽  
Bojan Mitrović ◽  
...  
Keyword(s):  
Seed Germination ◽  
Significant Loss ◽  
Growing Degree Days ◽  
Degree Days ◽  
Performance Time ◽  
Seed Moisture ◽  
Negative Effect ◽  
High Level ◽  
Harvest Maturity ◽  
And Control

The objective was to assess the effect of chemical desiccation on seed germination and storability in three sunflower female inbred lines and to point at possible indicators for optimal performance time. Desiccation was performed with Diquat (2 l ha-1) applied at 7-day intervals from the end of flowering to harvest maturity. There were 6 treatments and control (untreated). Germination was tested 2 and 21 months after harvest. The highest germination was recorded when the desiccation was performed 35 days after flowering. Results showed that optimal moment for applying chemical desiccation when there is no negative effect on the seed germination is specific for each sunflower genotype. Seeds with a high level of germination (>90%) can be stored for 19 months without significant loss in germination, namely, it was not negatively affected by chemical desiccation. Seed moisture and growing degree-days can be used as reliable indicators for optimal desiccation time.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

scholarly journals GROWTH STUDIES WITH SNAP BEANS TO PREDICT HARVEST

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1140e-1140
Author(s):  
Entin Daningsih ◽  
D. L. Coffey ◽  
J. Logan ◽  
C. A. Mullins
Keyword(s):  
Developmental Stages ◽  
Radiant Energy ◽  
Planting Date ◽  
Growth Stages ◽  
Growing Degree Days ◽  
Phaseolus Vulgaris L ◽  
Degree Days ◽  
Snap Beans ◽  
Growing Degree Hours ◽  
Harvest Maturity

Studies were initiated in 1989 to characterize phonological events with corresponding growth and development phenomena of `Eagle' and `Provider' snap beans (Phaseolus vulgaris L.) Ten plantings at approximately 15 day intervals were made at Knoxville, TN from April 17 through July 27. Days to reach growth stages V0 thru R7 were recorded for each cultivar for each planting date. Air temperature, total radiant energy, wind speed and relative humidity were recorded hourly throughout the 171 day test period. Growing degree days (GDD) computed by 8 methods and growing degree hours (GDH) computed by 2 methods were regressed against plant developmental stages. GDD and GDH, along with pod size and pod fiber content, will be discussed as possible indices for predicting harvest maturity. With the methods used to calculate heat summation in this study, GDD and GDH from planting to pod maturity ranged from approximately 550 to 975 and 9,700 to 20,000, respectively.

Effect of climate change and use of improved varieties on barley and canola yield in Manitoba

2015 ◽  
Vol 95 (1) ◽  
pp. 127-139 ◽  
Author(s):  
Henry An ◽  
Richard Carew
Keyword(s):  
Climate Change ◽  
Weather Conditions ◽  
Yield Variability ◽  
Growing Degree Days ◽  
Degree Days ◽  
Improved Varieties ◽  
Negative Effect ◽  
Stochastic Production ◽  
Effect On Yield ◽  
Positive Effect

An, H. and Carew, R. 2015. Effect of climate change and use of improved varieties on barley and canola yield in Manitoba. Can. J. Plant Sci. 95: 127–139. A stochastic production function was estimated to investigate the effect of fertilizer inputs, changes in weather conditions and the use of improved varieties on barley and canola yields and its variability in Manitoba. Adoption of improved barley varieties did not have a significant effect on yield, while the adoption of herbicide-tolerant hybrid canola varieties was positively correlated with yield. An increasingly warmer climate in Manitoba is expected to have a slightly negative effect on mean barley yield and yield variance. In contrast, a warmer climate is expected to have a negligible effect on mean canola yield, but a positive effect on yield variability. Our results showed that a projected 50% increase in growing degree days would lead to a decrease of less than 1% in barley and canola yields.

scholarly journals Evaluation of Variation in Time of Harvest Maturity of Flowering Shoots in Three Cultivars of Gentian

2013 ◽  
Vol 23 (5) ◽  
pp. 595-601 ◽  
Author(s):  
Uttara C. Samarakoon ◽  
Keith A. Funnell ◽  
David J. Woolley ◽  
Edward R. Morgan
Keyword(s):  
Growing Season ◽  
Growing Degree Days ◽  
Cut Flower ◽  
Degree Days ◽  
Significant Control ◽  
Factors Influencing ◽  
Before And After ◽  
Harvest Maturity ◽  
Shoot Emergence ◽  
Time Of Harvest

The time to harvest maturity of flowering shoots and the extent and source of variability in maturity dates differed among cultivars of gentian (Gentiana sp.), with a wider spread in time to harvest maturity in Showtime Starlet (41 days) than Showtime Diva (35 days) and Showtime Spotlight (29 days). Cultivars also differed by more than twice in their plant-to-plant variability in time to harvest. Although later-emerging shoots reached harvest maturity more quickly than earlier-emerging shoots, the use of growing degree-days (GDD) for this field-grown cut flower did not account for differences. For ‘Showtime Diva’, 77% of outliers reached harvest maturity at the beginning of the season (i.e., before the 10th percentile). For ‘Showtime Spotlight’, only 20% of shoots classified as outliers flowered early with the remaining 80% emerging late (i.e., after the 90th percentile). Strategies to control the spread in time to harvest maturity in late-maturing cultivars such as Showtime Starlet should focus on uniform shoot emergence and controlling temperature during growth. Although strategies to achieve uniform shoot emergence should also be targeted for ‘Showtime Diva’, controlling temperature during the growing season would not appear to offer significant control of the spread in time of harvesting floral shoots. However, in earlier-maturing cultivars such as Showtime Spotlight, strategies will primarily require a greater understanding of the factors influencing the variability in maturation of shoots within individual plants before, and after, emergence.

scholarly journals Diffuse Flesh Browning in ‘Honeycrisp’ Apple Fruit is Associated with Low Temperatures during Fruit Growth

HortScience ◽  
2016 ◽  
Vol 51 (10) ◽  
pp. 1256-1264 ◽  
Author(s):  
Cindy B.S. Tong ◽  
Hsueh-Yuan Chang ◽  
Jennifer K. Boldt ◽  
Yizhou B. Ma ◽  
Jennifer R. DeEll ◽  
...  
Keyword(s):  
Detailed Comparison ◽  
Apple Fruit ◽  
Fruit Growth ◽  
Growing Degree Days ◽  
Climate Data ◽  
Degree Days ◽  
Full Bloom ◽  
Flesh Browning ◽  
Harvest Maturity ◽  
Storage Disorders

Multiple types of flesh browning can occur as storage disorders in ‘Honeycrisp’ apple (Malus ×domestica Borkh.) fruit. Predicting its occurrence is hindered by differing definitions of the types of browning, incomplete understanding of their etiologies, and difficulty in assessing harvest maturity of ‘Honeycrisp’ fruit. In 2013, of ‘Honeycrisp’ fruit grown, harvested over multiple weeks, and stored in Maine, Minnesota, Ontario, and Quebec, only the Quebec fruit developed diffuse flesh browning. A detailed comparison showed that the Quebec fruit differed in size, but not in other quality attributes, from fruit of the other locations. The Quebec fruit experienced lower temperatures during active fruit growth and were increasing in cell size up to harvest. Analyses of climate data from 2009 to 2015 indicated that accumulated growing degree-days (GDD) 50–60 day after full bloom (DAFB) could account for 31% of the variation in diffuse flesh browning, and seasonal GDD <500 are associated with a greater likelihood of injury. Fruit that exhibited diffuse flesh browning had higher magnesium and lower fructose levels than unaffected fruit. As these measurements were made after browning was assessed, the timing of the onset of these characteristics in relation to browning cannot be determined.

Hophornbeam Copperleaf (Acalypha ostryifolia) Biology and Control

1998 ◽  
Vol 12 (3) ◽  
pp. 515-521 ◽  
Author(s):  
Michael J. Horak ◽  
Zhuping Gao ◽  
Dallas E. Peterson ◽  
Larry D. Maddux
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Dry Matter ◽  
Growing Degree Days ◽  
Dry Matter Accumulation ◽  
Cold Stratification ◽  
Degree Days ◽  
And Control

Little is known about the biology and control of hophornbeam copperleaf, a weed of increasing importance in the Midwest. More than 2 wk of cold stratification and a 0.2% KNO3solution increased germination of hophornbeam copperleaf. Germination at constant 30 C was 47% and alternating 30/20 C was 65%. Scarification did not increase hophornbeam copperleaf germination. Within the first 600 growing degree days after soybean planting, plant height, leaf area, and dry matter accumulation of hophornbeam copperleaf grown in soybean and alone were similar. Subsequently, leaf area and dry matter accumulation of hophornbeam copperleaf grown alone were greater than of those grown in soybean. In contrast, plant height of hophornbeam copperleaf grown in soybean was greater than when grown alone. Hophornbeam copperleaf grown alone produced up to 12 510 seeds/plant, whereas hophornbeam copperleaf grown with soybean produced 980 seeds/plant. Of 13 postemergent herbicides evaluated on hophornbeam copperleaf in soybean, only lactofen, acifluorfen, and fomesafen controlled 80% or more. Lactofen at 210 g ai/ha consistently controlled more than 95% of the hophornbeam copperleaf.

Effect of pre-sowing treatments on seed germination and seedling vigour index of Abies spectabilis (D.Don) spach

2019 ◽  
Vol 26 (1) ◽  
pp. 23-25
Author(s):  
Pitambar Singh Negi ◽  
◽  
Sandeep Sharma ◽  
Keyword(s):  
Seed Germination ◽  
Seedling Vigour ◽  
The Poor ◽  
Western Himalayan Region ◽  
Vigour Index ◽  
Germination Behaviour ◽  
Abies Spectabilis ◽  
High Level ◽  
And Control ◽  
Empty Seeds

An experiment was conducted to study the effect of pre-sowing treatments on germination of Abies spectabilis commonly called as “Talispatra” - an important high level conifer of Western Himalayan region. The seeds of Abies spectabilis collected from Kalabagh near Churdhar area of Shimla district (H.P.) were given different pre-sowing treatments of cold moist stratification in sand for 1 to 4 weeks and control (untreated seeds) to study their effect on germination behaviour and seedling vigour index. Significant differences were observed in germination per cent and seedling vigour index of seeds subjected to different pre-sowing treatments. The maximum germination per cent (42.00%) was recorded in seeds treated with cold moist stratification treatment in sand for 1 week followed by 36.00 per cent germination recorded for control (untreated seeds). The minimum germination per cent (19.50%) was recorded in seeds treated with cold moist stratification treatment in sand for 4 weeks. The findings of the present investigation revealed that Abies spectabilis seeds do not possess any dormancy and the poor germination is primarily due to presence of large number of empty seeds.

A Collaborative Study to Establish an International Standard for Alpha-Thrombin

1992 ◽  
Vol 67 (04) ◽  
pp. 424-427 ◽  
Author(s):  
P J Gaffney ◽  
A B Heath ◽  
J W Fenton II
Keyword(s):  
Elevated Temperatures ◽  
Collaborative Study ◽  
World Health Organisation ◽  
Significant Loss ◽  
Thrombin Inhibitors ◽  
World Health ◽  
Expert Committee ◽  
International Standard ◽  
Assay Procedure ◽  
And Control

SummarySince 1975 an International Standard for Thrombin of low purity has been used. While this standard was stable and of value for calibrating thrombins of unknown potency the need for a pure a-thrombin standard arose both for accurate calibration and for precise measurement of thrombin inhibitors, notably hirudin. An international collaborative study was undertaken to establish the potency and stability of an ampouled pure a-thrombin preparation. A potency of 97.5 international units (95% confidence limits 86.5-98.5) was established for the new a-thrombin standard (89/ 588) using a clotting-assay procedure. Stability data at various elevated temperatures indicated that the standard could be transported and stored with no significant loss of potency.Ampoules of lyophilised a-thrombin (coded 89/588) have been recommended as an International Standard for a-thrombin with an assigned potency of 100 international units per ampoule by the International Society for Thrombosis and Haemostasis (Thrombin and its Inhibitors Sub-Committee) in Barcelona, Spain in July 1990 while the Expert Committee on Biological Standardisation and Control of the World Health Organisation will consider its status at its next meeting in Geneva in 1991.

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