scholarly journals Developmental sequences for simulating crop phenology for water-limiting conditions

2005 ◽  
Vol 56 (11) ◽  
pp. 1277 ◽  
Author(s):  
Gregory S. McMaster ◽  
W. W. Wilhelm ◽  
A. B. Frank
Keyword(s):  
Soil Water ◽  
Shoot Apex ◽  
Management Practices ◽  
Triticum Aestivum L ◽  
Growth Stages ◽  
Plant Responses ◽  
Environment Interaction ◽  
Developmental Sequence ◽  
Hordeum Vulgare L ◽  
Crop Phenology

The timing, duration, and pace of developmental events, or phenology, are among the many responses of plants to limited soil water. Understanding and predicting plant responses to availability of soil water are important in improving the efficacy of management practices. However, the first steps towards gaining this understanding, summarising the complete developmental sequence of the shoot apex and correlating the timing of these events, have rarely been reported. Also, the effect of water-limiting conditions on crop phenology and shoot apex development is variable. The objective of this paper is to present the developmental sequence of the wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and corn (Zea mays L.) shoot apices and correlate events in these sequences with growth stages for both well-watered and water-limiting conditions. We note that phenological responses to water availability occur at 3 different scales: among crops, among cultivars of a crop, and among growth stages within a cultivar or crop. Clearly, genotype × environment interaction affects the accuracy of predicting phenology. However, the fact that plants develop in an orderly, predictable pattern allows a general foundation for synthesising the complete sequence of developmental events of the shoot apex and correlate these with growth stages when water is not limiting. These patterns and relationships are the foundation to build upon in quantifying our understanding of crop phenology under water-limiting environments.

GENOTYPE-ENVIRONMENT INTERACTION OF YIELD IN CEREAL CROPS IN NORTHWESTERN CANADA

1981 ◽  
Vol 61 (2) ◽  
pp. 255-263 ◽  
Author(s):  
R. M. De PAUW ◽  
D. G. FARIS ◽  
C. J. WILLIAMS
Keyword(s):  
Triticum Aestivum L ◽  
Regression Coefficients ◽  
Cereal Crops ◽  
Environment Interaction ◽  
Ge Interaction ◽  
Hordeum Vulgare L ◽  
Genotype Environment Interaction ◽  
Early Maturing ◽  
Frost Free Period ◽  
Main Effects

Three cultivars of each crop, wheat (Triticum aestivum L.), oats (Avena sativa L.), and barley (Hordeum vulgare L.), were grown for 4 yr at five locations north of the 55th parallel in northwestern Canada. There were highly significant differences among all main effects and interactions. Galt barley produced the highest seed yield followed by Centennial barley, Random oats and Harmon oats. Victory oats, Olli barley, Neepawa wheat and Pitic 62 wheat yielded similarly to each other while Thatcher wheat was significantly lower yielding. Mean environment yields ranged from 2080 to 5610 kg/ha. The genotype-environment (GE) interaction of species and cultivars was sufficiently complicated that it could not be characterized by one or two statistics (e.g., stability variances or regression coefficients). However, variability in frost-free period among years and locations contributed to the GE interaction because, for example, some cultivars yielded well (e.g., Pitic 62) only in those year-location environments with a relatively long frost-free period while other early maturing cultivars (e.g., Olli) performed well even in a short frost-free period environment.

HOE 23408, A NEW SELECTIVE HERBICIDE FOR WILD OATS AND GREEN FOXTAIL IN WHEAT AND BARLEY

1976 ◽  
Vol 56 (3) ◽  
pp. 567-578 ◽  
Author(s):  
H. A. FRIESEN ◽  
P. A. O’SULLIVAN ◽  
W. H. VANDEN BORN
Keyword(s):  
Foliar Application ◽  
Acid Methyl Ester ◽  
Growth Period ◽  
Triticum Aestivum L ◽  
Yield Reduction ◽  
Growth Stages ◽  
Weed Species ◽  
Hordeum Vulgare L ◽  
Wild Oats ◽  
Green Foxtail

A series of field, growth chamber, and laboratory experiments showed that HOE 23408 [4-(2,4-dichlorophenoxy)-phenoxy propionic acid methyl ester] as a post-emergence herbicide provided selective control of wild oats (Avena fatua L.) and green foxtail (Seteria viridis L. Beauv.) in wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) equal to or better than barban (4-chloro-2-butynyl m-chlorocarbanilate) over a growth period extending from the 2- to 5-leaf stages in both weed species. Wheat was highly tolerant to HOE 23408 at all growth stages, while with barley there was some leaf mottling and suppression of both shoot and root development. The 6-row cultivars Gait, Bonanza and Conquest largely recovered from the effects, but the 2-row cultivar Betzes suffered significant yield reduction. HOE 23408 moved mainly in an acropetal direction when applied to different parts of the wild oats plant. Application made on or below the meristematic area of the stem apex caused necrosis and eventual death of the entire plant. Phytotoxicity following soil application was markedly less than with foliar application. Indications were that it was also more phytotoxic to the emerging weeds via shoot than via root contact. Although HOE 23408 is relatively insoluble in water, it leached to a limited extent in soils.

scholarly journals The intensity of competitive interactions between spring wheat (Triticum aestivum L. emend. Fiori et. Paol) and spring barley (Hordeum vulgare L.) under different fertilisation conditions

2012 ◽  
Vol 61 (2) ◽  
pp. 195-203
Author(s):  
Kinga Treder ◽  
Maria Wanic ◽  
Janusz Nowicki
Keyword(s):  
Spring Wheat ◽  
Spring Barley ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Competitive Interactions ◽  
Growth Stages ◽  
Hordeum Vulgare L ◽  
Spring Cereals ◽  
Set Up ◽  
Better Than

Competitive interactions between spring wheat and spring barley were traced based on a pot experiment. In the years 2003-2004, three cycles of the experiment were carried out in a greenhouse. Two spring cereals - wheat and barley, sown in a mixture and in a monoculture, with different mineral fertilisation levels, were the object of evaluation and comparison. The experiment was set up according to the additive scheme, determining dry weight values for both species in 5 growth stages (emergence, tillering, shooting, heading and ripening). Results were used to determine relative yields and competition ratios. It was demonstrated that competition between the cereals started already from the emergence stage and lasted till the end of vegetation, manifesting itself with the greatest strength at the heading stage, but thereafter it weakened in the NPK poorer environment. Access to a larger pool of macroelements resulted in the intensification of competitive interactions. Spring barley used the limited growth factors better than wheat from shooting till the ripening period, and a reverse relation was exhibited only at the tillering stage.

Can increased nutrition raise cereal yields to the rainfall-limited potential in the high rainfall cropping zone of south Western Australia?

2007 ◽  
Vol 47 (1) ◽  
pp. 39 ◽  
Author(s):  
N. L. Simpson (née Hill) ◽  
R. McTaggart ◽  
W. K. Anderson ◽  
L. Anderton
Keyword(s):  
Western Australia ◽  
Management Practices ◽  
Growing Season ◽  
Triticum Aestivum L ◽  
Seasonal Rainfall ◽  
Hordeum Vulgare L ◽  
Potential Yield ◽  
Water Losses ◽  
Grain Yields ◽  
High Rainfall

Average yield of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) in the high rainfall cropping zone (>750 mm) of south Western Australia from 1996 to 2001 was 2.5 t/ha. This is far below the water-limited potential yield (water losses of 110 mm, transpiration efficiency of 20 kg/ha.mm) of 6–8 t/ha. Nutrition of the cereal crops has been regarded as one constraint to reaching the potential yield, although grain yield increases (responses) under conventional management practices (a series of full cultivation operations) have been inconsistent. Three experiments, with a total of five trial sites conducted over two seasons, were carried out to test the response of wheat and barley to fertiliser applications of nitrogen (N), phosphorus (P), potassium (K), sulfur (S) and trace elements (TE). Various combinations of nutrients were applied. These ranged from no fertiliser (nil), to farmer practice (N at rates at 34–82 kg/ha, P at 3–17 kg/ha, K at 0–50 kg/ha and S at 4–11 kg/ha), to nutrients calculated to supply the needs of a 6–8 t/ha cereal crop (N, P, K, S, TE). The aim was to determine whether the supply of non-limiting levels of crop nutrients could raise yields to the potential yield as determined by seasonal rainfall. In the drier seasons experienced in 2001 and 2002 at Arthur River and Cranbrook, with growing season rainfall (May–November) up to about 350 mm, it was possible to raise grain yields to levels at or above the calculated rainfall-limited potential with increased nutrition (4.2 t/ha for barley and 4.5 t/ha for wheat). However, in the wetter environment of Boyup Brook in 2002, where seasonal rainfall was greater than 500 mm, extra nutrition by itself was not sufficient to reach the water-limited potential, even where the yields were increased from 3.5 to 5.2 t/ha for wheat and from 3.9 to 4.5 t/ha for barley. Further experimentation is required to clarify the factors limiting responses to nutrition when the growing season rainfall is greater than 500 mm and thus allow greater confidence in extrapolating these results in the high rainfall cropping zone of Western Australia. In wheat, the highest profits were obtained from the complete fertiliser strategy (N, P, K, S, TE). However, for barley, the greatest profits were not obtained with the highest grain yields and fertiliser strategies due to decreased grain quality.

An appraisal of cereal crop phenology modelling

1995 ◽  
Vol 75 (2) ◽  
pp. 329-341 ◽  
Author(s):  
C. F. Shaykewich
Keyword(s):  
Zea Mays L ◽  
Triticum Aestivum L ◽  
Weather Data ◽  
Cereal Crops ◽  
Cereal Crop ◽  
Degree Days ◽  
Hordeum Vulgare L ◽  
Crop Phenology ◽  
Climatological Station ◽  
Phenological Modelling

A review of responses of phenological development of cereal crops, primarily corn (Zea mays L.), wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), to environmental conditions was conducted. Examples of how these studies have been used to model phenological development on the basis of weather data were given.It was concluded that the development rate of most species is a sigmoidal rather than a linear function of temperature. Consequently, phenological models assuming a linear relationship (e.g., degree–days) are inappropriate. Another consequence of the way plants respond to temperature is that the most precise phenological models will require use of temperature data over relatively short periods (e.g., 3 h), rather than just a daily mean temperature. Several suggestions regarding the ways standard climatological station data may be used in such phenological modelling are made.Phenological response to photoperiod was also reviewed, and methods of modelling this response were proposed. Key words: Phenology, temperature, photoperiod, modelling

scholarly journals Simulating winter wheat shoot apex phenology

1992 ◽  
Vol 119 (1) ◽  
pp. 1-12 ◽  
Author(s):  
G. S. McMaster ◽  
W. W. Wilhelm ◽  
J. A. Morgan
Keyword(s):  
Winter Wheat ◽  
Great Plains ◽  
Shoot Apex ◽  
Cultural Practices ◽  
Seedling Emergence ◽  
Simulation Models ◽  
Climatic Conditions ◽  
Growth Stages ◽  
Developmental Sequence ◽  
Wheat Shoot

SummarySimulation models are heuristic tools for integrating diverse processes and help to increase our understanding of complex processes and systems. Models that predict crop development can serve as decision-support tools in crop management. This paper describes a phenology simulation model for the winter wheat shoot apex and reports validation and sensitivity analysis results.The complete developmental sequence of the winter wheat shoot apex is quantitatively outlined and correlated with commonly recognised phenological growth stages. The phyllochron is used to measure the thermal time between most phenological growth stages, thereby increasing the flexibility over the growing degree-day (GDD) and photothermal approaches. Nineteen site-years covering a range of climatic conditions, cultural practices and cultivars across the Central Great Plains, USA, are used to validate the model.Validation results show that the predicted phyllochron (108 GDD) agrees well with the observed phyllochron (107 GDD) for ten cultivars. Mean seedling emergence is predicted to within 2 days in almost all of the 19 site-years. The ability of the model to predict growth stages accurately increased successively from jointing to heading to maturity. Maturity is generally predicted to within 5 days of the observed day.After validation, recalibration of the phyllochron estimates between growth stages are provided, and corrections for mesic and xeric conditions are suggested. Further validation of the entire developmental sequence of the shoot apex is recommended.

EFFECTS OF CHLORMEQUAT ON PLANT HEIGHT, DISEASE DEVELOPMENT AND CHEMICAL CONSTITUENTS OF CULTIVARS OF BARLEY, OATS, AND WHEAT

1977 ◽  
Vol 57 (1) ◽  
pp. 31-36 ◽  
Author(s):  
R. V. CLARK ◽  
G. FEDAK
Keyword(s):  
Leaf Growth ◽  
Chemical Constituents ◽  
Genetic Relationships ◽  
Disease Incidence ◽  
Triticum Aestivum L ◽  
Growth Stages ◽  
Cellulose Content ◽  
Trimethylammonium Chloride ◽  
Hordeum Vulgare L ◽  
Barley Cultivars

Applications of chlormequat ((2-chloroethyl) trimethylammonium chloride) to field plots of cereals at the 3- to 5-leaf growth stages reduced the height of wheat (Triticum aestivum L.) the most, followed by barley (Hordeum vulgare L.), and oats (Avena sativa L.). Height reductions were cultivar-specific in the three crops. Lodging was temporarily delayed by the use of chlormequat, while disease incidence, seed yields, protein, lignin, and cellulose content of the straw were unchanged. Of 53 barley cultivars treated with chlormequat, 35 showed variable degrees of height reduction with 5 reduced significantly to a maximum of 13.2%; 6 showed no response, while 12 grew taller following treatment. In general, reaction of barley cultivars to chlormequat followed genetic relationships similar to those determined by isozyme patterns.

scholarly journals Improving performance of index insurance using crop models and phenological monitoring

2020 ◽  
Author(s):  
Mehdi H. Afshar ◽  
Timothy Foster ◽  
Ben Parkes ◽  
Koen Hufkens ◽  
Francisco Ceballos ◽  
...  
Keyword(s):  
Management Practices ◽  
Growing Season ◽  
Multivariate Adaptive Regression Splines ◽  
Extreme Weather Events ◽  
Index Insurance ◽  
Growth Stages ◽  
Crop Phenology ◽  
Weather Index ◽  
Basis Risk ◽  
Insurance Contracts

<p>Extreme weather events pose significant risks to the livelihoods of smallholder farmers across Asia and Africa. Weather index-based insurance provides a potential solution to mitigate risks caused by crop failures, providing farmers with a payout in the event of a poor harvest. It also reduces costs relative to traditional indemnity insurance by eliminating the need for resource-intensive, in-situ assessment of losses. However, one challenge associated with weather index-based insurance is basis risk – where the payouts triggered by the index do not match actual crop losses. High levels of basis risk are observed across many existing weather index-based insurance products, and represent a key constraint to successful upscaling.  </p><p>A common feature of existing weather index-based insurance contracts is that payouts are triggered based on weather indices defined over fixed calendar periods, specified to capture the typical duration of the crop growing season or key phenological stages in a given agricultural system. In reality, however, the timing of a crop’s sensitivity to weather often varies significantly between individual plots or farmers due to differences in management practices (e.g., sowing date, variety choice) and meteorological conditions (e.g., temperature and precipitation) that affect rates of crop development. Failure to consider this heterogeneity is potentially a significant driver of basis risk, and suggests that opportunities may exist to improve the quality of index insurance by designing phenology-specific insurance contracts. </p><p>In this study, we evaluate the impacts of improved monitoring of crop phenology on the performance of index-based crop yield models through a range of synthetic model-based simulated experiments for wheat and rice production in Haryana and Odisha states in India. We use a calibrated process-based crop simulation model (APSIM) to evaluate yields for a range of potential weather realizations and agricultural management practices typically observed in our case study regions. Subsequently, we develop non-linear statistical (i.e. index-based) models using non-parametric regression techniques (Multivariate adaptive regression splines; MARS) to reproduce APSIM-simulated yields as a function of rainfall and temperature conditions during key sensitive crop growth stages. </p><p>Our results show that by considering field-level heterogeneity in crop phenology and development, it is possible to reliably estimate (>0.8 r-squared) wheat and rice yields. In contrast, model performance deteriorates significantly when variability in growth stage between individual simulated fields is not considered or when weather predictors are aggregated over the entire growing season as opposed to specific growth stages. These findings show that considering crop phenology can dramatically improve the performance of statistical yield models and, in turn, the accuracy of an index-based insurance product. Nevertheless, reductions in basis risk must also be balanced against the increasing complexity and implementation costs of these potential products in smallholder environments.</p>

Using AMMI approach to delineate genotype by environment interaction and stability of barley (Hordeum vulgare L.) genotypes under northern Indian shivalik hill conditions

2020 ◽  
Vol 80 (03) ◽  
Author(s):  
Om Prakash Yadav ◽  
A. K. Razdan ◽  
Bupesh Kumar ◽  
Praveen Singh ◽  
Anjani K. Singh
Keyword(s):  
Hordeum Vulgare ◽  
Grain Yield ◽  
Principal Component ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Hordeum Vulgare L ◽  
Genotype By Environment ◽  
Biplot Analysis ◽  
Principal Component Axis ◽  
Ammi Analysis

Genotype by environment interaction (GEI) of 18 barley varieties was assessed during two successive rabi crop seasons so as to identify high yielding and stable barley varieties. AMMI analysis showed that genotypes (G), environment (E) and GEI accounted for 1672.35, 78.25 and 20.51 of total variance, respectively. Partitioning of sum of squares due to GEI revealed significance of interaction principal component axis IPCA1 only On the basis of AMMI biplot analysis DWRB 137 (41.03qha–1), RD 2715 (32.54qha–1), BH 902 (37.53qha–1) and RD 2907 (33.29qha–1) exhibited grain yield superiority of 64.45, 30.42, 50.42 and 33.42 per cent, respectively over farmers’ recycled variety (24.43qha–1).

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