Changing of Vegetative to Reproductive Ratio as a Response to Different Sowing Dates in Sunflower

Helia ◽  
2018 ◽  
Vol 41 (69) ◽  
pp. 253-266
Author(s):  
Ali Asghar Aliloo
Keyword(s):  
Edible Oils ◽  
Sowing Date ◽  
Biodiesel Production ◽  
Growing Degree Days ◽  
Comprehensive Model ◽  
Yield Losses ◽  
Degree Days ◽  
North West ◽  
Long Period ◽  
Sowing Dates

AbstractSunflower is an important source for edible oils and biodiesel production. Its productivity is limited by many agronomical practices one of which is the sowing date. In this study, the effects of different sowing dates from early April to late June on phenology and yield of sunflower cultivars were investigated. The results showed that sunflower has a relatively long period of possible sowing dates, stretching from early April to late June in North West of Iran. However, delayed sowing dates significantly decreased the number of days needed for phenophases. For every day of delay, the model predicted (R2=0.97) a losing rate in achene yield by 22.2 kg h−1 from the first sowing date. For relationships between growing degree days (GDD) and yield, almost the same results were obtained. About 22 kg h−1 reduction (R2=0.79) in yield per day was estimated by GDD index when the average GDDs per day was 14.2. However, helio-thermal units (HTU) did not predict this reduction accurately. A suggested comprehensive model, that used the percent of yield losses and changes in vegetative to reproductive ratio, found a significant and positive relationship between the indices and yield losses. For all indices, an increase in vegetative to reproductive ratio resulted in increased grain yield losses.

A comparative analysis of the growth of sweet and forage sorghum crops. II. Accumulation of soluble carbohydrates and nitrogen

1986 ◽  
Vol 37 (5) ◽  
pp. 513 ◽  
Author(s):  
R Ferraris ◽  
DA Charles-Edwards
Keyword(s):  
Dry Matter ◽  
Plant Density ◽  
Nitrogen Concentration ◽  
Sowing Date ◽  
Soluble Carbohydrates ◽  
Growth Stages ◽  
Degree Days ◽  
Forage Sorghum ◽  
Density Effects ◽  
Sowing Dates

Well-watered crops of sweet sorghum (cv. Wray) and forage sorghum (cv. Silk) were grown in south-eastern Queensland. Treatments consisted of four sowing dates, two intra-row spacings and harvests taken at six physiological growth stages from the third ligule to 3 weeks after grain maturity. Plant density effects on the concentration of sugars and nitrogen were slight, and changes in yields of these components were a function of density effects on dry matter yields. At any growth stage, the concentration of sugars in both cultivars was decreased with delay in sowing date. The delay in sowing date led to an increased nitrogen concentration in cv. Wray, but in cv. Silk the nitrogen concentration was highest in early and late sowings. At maturity, the concentration of sugars in cv. Wray averaged 40'70, 10 times the level in cv. Silk. In both cultivars, accumulation was a near linear function of either time or radiation sum. The partitioning of carbohydrate differed little between cultivars but altered with their ontogeny. The efficiency of light use for sugars production was greater in cv. Wray and altered with ontogeny. In contrast, concentration of nitrogen was similar for both cultivars and decreased curvilinearly with time or degree days. The partitioning of nitrogen altered with ontogeny and the amount partitioned to leaf material was greater in cv. Silk pre-anthesis but was less post-anthesis. Yield of stem sugars in cv. Wray exceeded 10 t ha-1 when the crops were sown early in the season, but was only 3 t ha-1 with late-sown crops.

scholarly journals Production and Commercialization of Helianthus annuus L. for Cut Flowers in Texcoco, Mexico

2021 ◽  
Vol 14 (05) ◽  
Author(s):  
V. García-Reyes ◽  
J. Silvano-Sánchez ◽  
J. Zavala-Ruiz ◽  
L. Meraz-Huescas ◽  
Obdulia Baltazar-Bernal
Keyword(s):  
Helianthus Annuus ◽  
Cost Benefit ◽  
Sowing Date ◽  
Added Value ◽  
Growing Degree Days ◽  
Cut Flowers ◽  
Degree Days ◽  
Helianthus Annuus L ◽  
Flower Diameter ◽  
Cutting Point

Objective: To evaluate the process of sunflower production (Helianthus annuus L.) for fresh cutting flowers, considering two sowing dates, growing degree-days, and commercialization. Design/Methodology/Approach: A completely randomized experimental design with subsampling was used, with five repetitions per treatment (sowing date), in order to analyze the variables: number of leaves, height, and flower diameter. Vincent Choice Dark Eye Ball™ sunflowers were sown in black plastic boxes with 8 cm of soil on January 31 and February 11, 2020, at 153 plants per m-2 in a greenhouse. Later, the seedlings were grown in the open field until harvesting, after which they were given added value and then locally traded. In addition, the growing degree-days (GDD) were calculated. Results: The sunflowers registered a height of 55 cm, 13 leaves per stalk, and a flower diameter of 6.88 cm. Late sowing favored the height and diameter of the flower. The sunflower hybrid required more GDD to reach commercial flower maturity in the first sowing date. The cost-benefit ratio was 1.38. Study Limitations/Implications: Seeds were sown on only two dates. Findings/Conclusions: The production process involved planning, management, and commercialization. The sunflower hybrid required on average 499 GDD to reach the cutting point. The added value increased the price fivefold.

scholarly journals Sowing date reduces the incidence of wheat blast disease

2016 ◽  
Vol 51 (5) ◽  
pp. 631-637 ◽  
Author(s):  
Maurício Antônio de Oliveira Coelho ◽  
Gisele Abigail Montan Torres ◽  
Paulo Roberto Cecon ◽  
Flávio Martins Santana
Keyword(s):  
Grain Yield ◽  
Sowing Date ◽  
Minas Gerais ◽  
Blast Disease ◽  
Yield Losses ◽  
Potential Yield ◽  
Wheat Blast ◽  
Sowing Dates ◽  
Severity Of The Disease ◽  
Disease Pressure

Abstract: The objective of this work was to assess the effect of sowing date on the intensity of wheat blast disease, as well as the yield losses caused by this disease in different wheat (Triticum aestivum) genotypes. The experiments were conducted in 2013 at the Sertãozinho experimental station of Empresa de Pesquisa Agropecuária de Minas Gerais (Epamig), in the municipality of Patos de Minas, in the state of Minas Gerais, Brazil. Fourteen wheat genotypes and two sowing dates were evaluated. The experimental design was a randomized complete block with three replicates. The evaluated variables were: incidence, severity, thousand grain weight (TGW), grain yield, and yield losses. A disease index (DI) was calculated, based both on the incidence and the severity of the disease, to measure blast intensity in wheat. The sowing date significantly affected DI, TGW, and grain yield. Significant linear correlations were observed between DI and yield losses (0.89), between losses and TGW (-0.85), and between losses and grain yield (-0.93). For wheat blast, DIs greater than or equal to 0.5 indicate potential yield losses equal to or greater than 70%. The EP063030 line and the MGS Brilhante and BRS 264 cultivars are the most tolerant to blast, when exposed to high disease pressure.

Volunteer Potato Density Influences Critical Time of Weed Removal in Bulb Onion

2007 ◽  
Vol 21 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Martin M. Williams ◽  
Corey V. Ransom ◽  
W. Mack Thompson
Keyword(s):  
Yield Loss ◽  
Critical Time ◽  
Field Trials ◽  
Growing Degree Days ◽  
Crop Loss ◽  
Yield Losses ◽  
Degree Days ◽  
Potato Plants ◽  
Volunteer Potato ◽  
Weed Removal

Volunteer potato is highly competitive with onion and few control tactics are effective for removing this weed from an onion crop. Both volunteer potato density and duration of interference reduce onion yield, but the interaction of these factors is unknown. Field trials were conducted in 2003 in Idaho, Oregon, and Washington to determine the influence of volunteer potato density on the critical time of weed removal (CTWR) in onion. Yield losses of 2.5, 5.0, and 10% were estimated to occur at 534, 654, and 830 growing degree days (GDD) after onion emergence, respectively, with a volunteer potato density of 0.5 plants/m2. At 2.0 volunteer potato plants/m2, yield losses of 2.5, 5.0, and 10% were estimated to occur at 388, 481, and 598 GDD after onion emergence, respectively. Volunteer potato at 2.0 plants/m2had to be removed at least one onion leaf stage sooner, compared to a weed density of 0.5 plants/m2, to avoid yield loss. Yield loss due to volunteer potato density or duration of interference was greatest among jumbo, colossal, and supercolossal market grades (P ≤ 0.1). Lowering potato tuber density in crops preceding onion will extend the critical time for weed removal and reduce the risk of crop loss.

Influence of sowing dates on the growing degree days and phenology of winter maize (Zea mays L.)

1986 ◽  
Vol 38 (1-3) ◽  
pp. 47-57 ◽  
Author(s):  
S.S. Narwal ◽  
S. Poonia ◽  
G. Singh ◽  
D.S. Malik
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Growing Degree Days ◽  
Degree Days ◽  
Sowing Dates

scholarly journals Heat unit requirement and yield of wheat (Triticum aestivum L.) varieties under different growing environment in mid hill conditions of Himachal Pradesh

2021 ◽  
Vol 21 (3) ◽  
pp. 282-287
Author(s):  
RANU PATHANIA ◽  
RAJENDRA PRASAD ◽  
RANBIR SINGH RANA ◽  
S. K. MISHRA
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Wheat Variety ◽  
Triticum Aestivum L ◽  
Growing Degree Days ◽  
Thermal Unit ◽  
Degree Days ◽  
Sowing Time ◽  
Sowing Dates ◽  
And Performance

A eld experiment was conducted during rabi seasons of 2015-16 and 2016-17 to study the accumulated growing degree days (GDD), helio-thermal unit (HTU), photo-thermal unit (PTU), heat use efciencies (HUE) at different phenological stages and performance of wheat (Triticum aestivum L.) varieties grown under different sowing dates. Results of present study revealed that the crop sown on 20th October required maximum calendar days, growing degree days, photo-thermal unit and helio-thermal unit for tillering, owering, earing and maturity which was signicantly reduced with subsequent delay in sowing time. The grain yield recorded in 20th November (4065 kgha-1) was statistically at par with 5th November yield (3863 kgha-1). The signicant reduction in grain yield on varieties was recorded when sowing was delayed beyond 20th November. Among the varieties 'VL-907' produced highest grain yield(3771 kgha-1) which was statistically on par with 'VL-829' (3726 kgha-1). The early and timely sown wheat  variety like VL-829 and VL-907 took highest calendar days, GDD, HTU and PTU for earing and maturity. The variety 'VL-907' recorded the highest grain yield (4196 and 4168 kgha-1) at 5th and 20th November sowing as compared to all other sowing dates.

Effect of sowing date and soil type on yield, yield components and survival of dry beans (Phaseolus Vulgaris L.)

1974 ◽  
Vol 82 (2) ◽  
pp. 343-347 ◽  
Author(s):  
H. M. Ishag ◽  
Ali T. Ayoub
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Field Experiments ◽  
Sowing Date ◽  
Clay Loam ◽  
Phaseolus Vulgaris L ◽  
Degree Days ◽  
Sowing Dates ◽  
Predominant Factor ◽  
Highly Correlated

SummaryField experiments were conducted on clay and sandy clay-loam soils to investigate the effects of sowing date on the incidence of plant losses. Early sowing dates from 2 to 23 September resulted in very low seed yield (360 kg/ha) mainly because fewer plants survived. High air temperature increased the rate of plant death which was highly correlated with degree days, r = +0·95.Number of plants/m2 was the predominant factor determining seed yield and number of pods/plant could not compensate for loss of plants.

Relationships Among Green Foxtail (Setaria viridis) Seedling Development, Growing Degree Days, and Time of Nicosulfuron Application

1996 ◽  
Vol 10 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Frank Forcella ◽  
Kevin R. Banken
Keyword(s):  
Seedling Growth ◽  
Weed Management ◽  
Corn Yield ◽  
Growing Degree Days ◽  
Yield Losses ◽  
Degree Days ◽  
Predictive Tool ◽  
Application Timing ◽  
Green Foxtail ◽  
The Relationship

Success of postemergence weed management often depends upon application timing and weed seedling size. To develop a predictive tool for estimating green foxtail development and optimizing timing of management operations, seedling growth was monitored in fields for two years, as well as in a single greenhouse experiment, and compared with elapsed thermal time (growing degree days, GDD, base 10 C). The relationship between seedling height (mm) and GDD was similar both years and could be described by the following equation: Height = (-0.27 + 0.033 * GDD)2. A comparable equation described seedling growth in a greenhouse. Leaf number was linearly related to GDD. Green foxtail in corn was controlled with nicosulfuron applied at seven intervals between 100 and 450 GDD after corn planting in 1993 and 1994. In 1993 corn yield losses due to green foxtail interference were least when nicosulfuron was applied 200 to 300 GDD after planting, at which time green foxtail height was 50 to 100 mm. In 1994 corn yield losses were minimized if nicosulfuron was applied any time before 300 GDD.

scholarly journals Crop yield prediction using CERES-Rice vs 4.5 model for the climate variability of different agroclimatic zone of south and north-west plane zone of Bihar (India)

MAUSAM ◽  
2021 ◽  
Vol 65 (4) ◽  
pp. 539-552
Author(s):  
P.K. SINGH ◽  
K.K. SINGH ◽  
A.K. BAXLA ◽  
B. KUMAR ◽  
S.C. BHAN ◽  
...  
Keyword(s):  
Climate Variability ◽  
Growth Models ◽  
Sowing Date ◽  
Rice Cultivar ◽  
Growth And Yield ◽  
Weather Data ◽  
North West ◽  
Agroclimatic Zone ◽  
Sowing Dates ◽  
Crop Growth Models

CERES-rice models are being validated and tested across the world and vigorously used in agrotechnology transfer. Crop growth models have been considered as potential tools for simulating growth and yield of crops. Hence, DSSAT v 4.5/ CERES-Rice (Decision Support System for Agro-technology Transfer / Crop Estimation through Resource and Environment Synthesis) was applied to validate the Rice productivity from Bihar State in India. Long term historical weather data (1980-2011) and (1985-2011) from South and North West Alluvial plane zones of Bihar was used for yield analysis. Genetic coefficients required for running the CERES-Rice vs 4.5 model were derived and the performance of the model was tested under the climate variability conditions experienced by these two agroclimatic zones. Management combinations simulated were three transplanting dates (1st, 15th & 30th July) for rice cultivar Rmansuri under rainfed conditions.The results indicated that both the early and late sowing dates result in lower yields as compared to optimum sowing date of 15th July. The simulated phenology and yield were found to be in agreement with observed data suggesting that the calibrated model may be operationally used with routinely observed soil, crop management and weather parameters for Rice yield estimation from these two regions of Bihar.

Agronomic studies on pigeon pea (Cajanus cajan (L.) Millsp.). I. Field responses to sowing time

1975 ◽  
Vol 26 (1) ◽  
pp. 43 ◽  
Author(s):  
JO Akinola ◽  
PC Whiteman
Keyword(s):  
Cajanus Cajan ◽  
Climatic Factors ◽  
Pigeon Pea ◽  
Day Length ◽  
Growing Degree Days ◽  
Degree Days ◽  
Sowing Time ◽  
Sowing Dates ◽  
Photoperiodic Responses ◽  
Plot Design

A split-plot design was used to investigate the vegetative and reproductive responses of two earlymaturing and two late-maturing Cajanus cajan accessions to eight sowing dates. Pre-flowering to pod-ripening durations varied, depending upon interactions between climatic factors and the photoperiodic responses of the accessions. Quantitative short-day, day-neutral or nearly day-neutral, and intermediate photoperiodic forms were identified. Relationships between day length, radiation, growing degree-days, and seed yield per hectare based on individual monthly harvests and harvest index were established for a sowing density of 2990 plants ha-1. Optimum sowing times were identified as late November-mid January for dry seed production in the latematuring accessions, and not later than December for periodic green pod picking in the earlymaturing accessions.

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