Discrepancies between observed and predicted growth stages in wheat

1997 ◽  
Vol 129 (4) ◽  
pp. 379-384 ◽  
Author(s):  
E. J. M. KIRBY ◽  
R. M. WEIGHTMAN
Keyword(s):  
Stem Elongation ◽  
Daily Maximum ◽  
Growth Stages ◽  
Main Shoot ◽  
Wheat Growth ◽  
Growing Seasons ◽  
Leaf Emergence ◽  
Prediction Scheme ◽  
Number Of Leaves ◽  
Input Variables

A model to predict wheat growth stage is briefly described. It is based on prediction of the number of emerged leaves and the final number of leaves on the main shoot, and the co-ordination between leaf emergence and apex development, including stem elongation. The input variables are daily maximum and minimum temperatures, date of sowing and site latitude, from which thermal time, vernalization and daylength are calculated.Selected growth stages were predicted for six sites in each of three growing seasons. The differences between observations made by independent observers and predictions were mostly 7 days or less but in three site–season combinations the average difference was >10 days. Observer errors were implicated and examined, but it is concluded that the prediction scheme must also have been partly responsible for the discrepancies.

Co-ordination of stem elongation and Zadoks growth stages with leaf emergence in wheat and barley

1994 ◽  
Vol 122 (1) ◽  
pp. 21-29 ◽  
Author(s):  
E. J. M. Kirby ◽  
M. Appleyard ◽  
N. A. Simpson
Keyword(s):  
Growth Stage ◽  
Stem Elongation ◽  
Sowing Date ◽  
Development Stage ◽  
Growth Stages ◽  
Final Number ◽  
Leaf Emergence ◽  
Basal Internode ◽  
Final Length ◽  
Number Of Leaves

SUMMARYLeaf emergence, apex development stage, internode length and Zadoks principal growth stage 3 were measured over 3 years at several sites.Internode elongation and Zadoks score were strongly related to the number of emerged culm leaves. The final length of the most basal internode was very variable and contributed to variation in the relationship between Zadoks stage 30 and the number of emerged culm leaves. Variation in the length of the basal internode was related to the final number of culm leaves. Most plants had six culm leaves but the number of leaves was affected by sowing date. In an experiment where sowings were made from September to March, stem elongation and Zadoks stage 30 started at a later stage of apex development in later sowings.Recognition and prediction of culm elongation and number of emerged culm leaves is important for the application of growth regulator and fungicides. Combined with functions to predict the rate of leaf emergence and final number of leaves, the relationships described in this paper may enable Zadoks principal growth stage 3 and number of emerged culm leaves to be predicted.

scholarly journals Are early foliar fungicide applications on durum wheat grown in southeast Saskatchewan beneficial in increasing grain productivity?

2014 ◽  
Vol 94 (5) ◽  
pp. 891-903 ◽  
Author(s):  
M. R. Fernandez ◽  
W. E. May ◽  
S. Chalmers ◽  
M. E. Savard ◽  
A. K. Singh
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Stem Elongation ◽  
Flag Leaf ◽  
Kernel Weight ◽  
Growth Stages ◽  
Head Blight ◽  
Leaf Emergence ◽  
Grain Productivity ◽  
Foliar Fungicide

Fernandez, M. R., May, W. E., Chalmers, S., Savard, M. E. and Singh, A. K. 2014. Are early foliar fungicide applications on durum wheat grown in southeast Saskatchewan beneficial in increasing grain productivity? Can. J. Plant. Sci. 94: 891–903. Producers have expressed interest in applying fungicides early in the development of durum wheat to reduce disease severity and increase grain yield. To address this issue, a field trial was conducted in southeast Saskatchewan (2004–2006) to determine the impacts of single and double foliar fungicide (tebuconazole) applications at various growth stages on leaf spotting, Fusarium head blight/Fusarium-damaged kernels, deoxynivalenol concentration, dark kernel discolouration, and grain traits of durum wheat. In most cases, application at stem elongation was not effective in reducing Fusarium diseases, or improving yield and grain characteristics. Application at flag leaf emergence was more effective, but for the most part, application at anthesis resulted in the most consistent reduction in disease levels, and improvement in test weight. Double fungicide applications (stem elongation or flag leaf emergence, and anthesis) were not more effective in disease control than a single application at anthesis. Grain yield did not differ significantly among any of the treatments. In contrast to Fusarium diseases and leaf spotting, fungicide applications at stem elongation and/or flag leaf emergence resulted in increased kernel weight and percentage dark kernel discolouration, which was significant in 2005 (10.53–10.60% total kernel discolouration in the stem and flag leaf treatments vs. 6.13% for the untreated control). In one or more years, kernel weight was negatively associated with Fusarium disease variables and leaf spotting, but positively associated with kernel discolouration. We conclude that under variable environmental conditions in Saskatchewan, early preventative fungicide use on durum wheat should not be recommended as a strategy to improve productivity, and might even result in increases in dark kernel discolouration and grain downgrading.

scholarly journals Morfogeneza pędów krzewiącej się pszenicy oraz dynamika ich elongacyjnego wzrostu [Morphogenesis of shoots of tillering plants of winter wheat and the dynamics of their elongation growth]

2015 ◽  
Vol 28 (1) ◽  
pp. 5-28
Author(s):  
Witold Drezner
Keyword(s):  
Winter Wheat ◽  
Elongation Growth ◽  
Growth Stages ◽  
Main Shoot ◽  
Wheat Growth

The morphogenesis of vegetative shoots of tillering plants of the winter wheat, the mode of identification and the description of the sequence of formation of individual shoots are presented. The average elongation growth of plants (e) in the successive growth stages are described as the sum of the increase of the main shoot (a) and of the side (secondary) shoots (Σ b) divided by the number of measured tillers (1) and by the time unit (t) according to the equation. By this method the correlation between the dynamics of winter wheat growth and the grade of tillering are described for three varieties.

scholarly journals Sulu Şartlar İçin Geliştirilen Ekmeklik Buğday Çeşitlerine Optik Sensor ile Azotlu Gübre Tavsiyesi

2020 ◽  
Vol 8 (9) ◽  
pp. 1882-1891
Author(s):  
Erdinc Savasli
Keyword(s):  
Agricultural Research ◽  
Stem Elongation ◽  
Block Design ◽  
Vegetation Indices ◽  
Transitional Zone ◽  
Growth Stages ◽  
Growing Seasons ◽  
Randomized Complete Block Design ◽  
Winter Wheat Cultivars ◽  
Nitrogen Rates

This study was conducted at Transitional Zone Agricultural Research Institute in Eskisehir, in 2017-2019 growing seasons. In the study, responses of four winter wheat cultivars (Atay85, Hat 31, Yunus and Nacibey) to nitrogen fertilization under irrigation conditions were compared with vegetation indices based on spectral reflection and In- Season Estimates of Yield calculated from these indices. GreenSeekerTM (NTech Industries, Inc., Ukiah,CA) hand-held sensor was used for this purpose. The experimental layout were used 0, 4, 8, 12, 16 and 20 kg N/da nitrogen rates 2 factor factorial in randomized complete block design in the experiment. Vegetation indices (NDVI) were obtained at growth stages Zadoks2,4, Zadoks3,0, Zadoks3,1 and Zadoks3,2. Zadoks3,0 (stem elongation) was found to be the most realistic reading time. A comparison of the system with traditional farmer applications, based on the average of 3 experiment fields, the new system was shown to give similar yields with 2,8 kg/da less N in the spring (ZD3,0), showing its economically promising value. The sensor application is determined to be 2% more economically effective than farmer application. Economic nitrogen dose respectively Atay85, Hat 31, Yunus and Nacibey was determined as the nitrogen dose 12,6 kgN/da, 14,1 kgN/ da, 14,4 kg N/da and 17,9 kgN/da.

Prediction of leaf and internode development in wheat

1997 ◽  
Vol 129 (4) ◽  
pp. 385-396 ◽  
Author(s):  
R. M. WEIGHTMAN ◽  
E. J. M. KIRBY ◽  
R. SYLVESTER-BRADLEY ◽  
R. K. SCOTT ◽  
R. W. CLARE ◽  
...  
Keyword(s):  
Flag Leaf ◽  
Sowing Date ◽  
Leaf Length ◽  
Growth Stages ◽  
Factors Affecting ◽  
Final Number ◽  
Leaf Emergence ◽  
Basal Internode ◽  
Number Of Leaves ◽  
The Difference

Functions which predict rate of leaf emergence and final number of leaves, used in a model to predict the date at which growth stages occur, were tested in an experiment on winter wheat cv. Mercia grown with standardized husbandry at six sites in 1992/93, 1993/94 and 1994/95. A study of the number of detectable nodes on the culm and leaf length was also made.The predicted rate of leaf emergence was mostly within 5% of the observed value. The difference between observed and predicted final number of leaves was mostly less than half a leaf but suspected errors in leaf counts resulted in some differences of more than two leaves.Variable extension of the basal internode impaired confidence in the detection of nodes. The mean number of detectable nodes differed significantly among sites and between seasons from 3·7 to 4·8 but could not be related to sowing date or final number of leaves. Further information on factors affecting extension of the basal internode is desirable to standardize node detection and improve prediction of culm leaf appearance.Culm leaves showed successively longer laminae up to the penultimate leaf. There was a significant relationship between length of the flag leaf and the final number of leaves, but it was positive in 1993/94 and negative in 1994/95. This may have been due to greater water stress in 1994/95.

Performance of spring cereal genotypes under defoliation on the Eyre Peninsula, South Australia

2015 ◽  
Vol 66 (4) ◽  
pp. 301 ◽  
Author(s):  
R. A. Latta
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Stem Elongation ◽  
South Australia ◽  
Farming Systems ◽  
Growth Stages ◽  
Grain Yields ◽  
Growing Seasons ◽  
Spring Cereals ◽  
The Impact

In mixed cropping and livestock dryland farming systems in southern Australia, grazing of cereals during their vegetative growth stages (typically during winter) can provide a valuable contribution of high-quality feed during a period of low pasture growth. This paper reports results from a series of experiments investigating the impact of defoliation on the grain production of cereals in the Eyre Peninsula region of South Australia. The comparative dry matter production and grain yield of wheat, barley and oats cultivars, with and without defoliation, at a range of growth stages were measured in four experiments over three growing seasons, two of which were water-deficient. The barley varieties evaluated produced up to twice the dry matter of the wheat or oats cultivars to the time of defoliation. Mowing following stem elongation more than halved grain yield (1.9 to 0.9 t ha–1) relative to no defoliation in an early-maturing variety, but with less reduction in later maturing varieties. Defoliation before stem elongation in two seasons of very low growing-season rainfall (<100 mm) caused no or very little loss in grain yields, which were generally <1 t ha–1. A long-season winter wheat produced similar grain yields irrespective of defoliation and timing, but with no yield advantage over the defoliated spring cereals. The results suggest opportunities to incorporate the grazing of cereals to fill a winter feed-gap in the low-rainfall zone of southern Australia.

scholarly journals Effect of sowing date and variety on main shoot leaf emergence and number of leaves of barley and wheat

Agronomie ◽  
1985 ◽  
Vol 5 (2) ◽  
pp. 117-126 ◽  
Author(s):  
E. J. M. KIRBY ◽  
Margaret APPLEYARD ◽  
Gwynneth FELLOWES
Keyword(s):  
Sowing Date ◽  
Main Shoot ◽  
Leaf Emergence ◽  
Number Of Leaves

scholarly journals On collection of predatory thrips (Insecta: Thysanoptera) in wheat fields

2020 ◽  
pp. 83-88
Author(s):  
Behzad Miri ◽  
Naser Moeini-Naghadeh
Keyword(s):  
Dominant Species ◽  
Stem Elongation ◽  
Population Fluctuation ◽  
Growth Stages ◽  
Ripening Stage ◽  
Flowering Stage ◽  
Wheat Growth ◽  
Thrips Species ◽  
Evenness Index ◽  
Rainfed Wheat

Some thrips species are known as predators of eggs, exist as the inactive stages of mites, and can be tiny, especially phytophagous thrips. This study aimed at evaluating the population fluctuation and species diversity of predatory thrips in wheat fields of Eyvan county (Ilam province, Iran) in the year 2016. Thrips specimens were collected and identified by weekly sampling during wheat growth stages (from early April to late June). Wheat bushes were shaken on a white dish. Finally, microscopic slides were prepared and all samples were enumerated. The population fluctuation of predatory thrips was calculated. In this study, six species of predatory thrips belonging to three genera were identified. Amongst them, Aeolothrips intermedius Bagnall (family Aeolothripidae) was the dominant species in both irrigated and rainfed wheat fields accounting for 72.43% and 50.85% of all species, respectively. Biodiversity indices were calculated using the number of species and their relative abundance. Shannon diversity, Simpson’s, Margalef’’s and species richness indices were 1.76, 0.86, 1.25 and 1, respectively. The highest biodiversity was in rainfed fields and during the wheat flowering stage, and the highest Shannon-Wiener evenness index was also in rainfed fields and at the ripening stage. The richness of thrips in rainfed wheat fields during the stem elongation stage was higher than in other wheat stages. Correlation of the density of predatory thrips with temperature and humidity showed a significantly positive correlation with temperature.

scholarly journals Effects of nitrogen on development and growth of the leaves of vegetables. 2. Appearance, expansion growth and life span of leaves of leek plants

1995 ◽  
Vol 43 (2) ◽  
pp. 233-246 ◽  
Author(s):  
H. Biemond
Keyword(s):  
Leaf Area ◽  
Field Trials ◽  
Application Rate ◽  
Leaf Expansion ◽  
Mature Leaf ◽  
Growth Stages ◽  
Leaf Emergence ◽  
N Application Rate ◽  
Number Of Leaves ◽  
Leaf Appearance

In greenhouse pot experiments and field trials, leek cv. Albana plants were supplied with different amounts of N fertilizer at various growth stages. Leaf emergence, expansion, size and senescence were monitored. The rate of leaf appearance was not affected by N treatments and almost constant across experiments at 0.15/day. The rate of leaf expansion and the mature leaf area increased with leaf number, reaching maximum values between leaf numbers 11 and 14 and decreasing with higher leaf numbers. Both variables increased with increasing N application rate. The duration of leaf expansion was more or less constant across leaf numbers and not influenced by N treatments; the leaf expansion rate was the main factor determining mature leaf area. The rate of leaf senescence was not influenced by N treatments. Differences in total green leaf area per plant were caused by differences in the area of individual mature leaves and not by differences in the number of leaves. The specific leaf area of all leaves was more or less constant at 100 cmsuperscript 2/g.

scholarly journals Changes in spring wheat (Triticum aestivum ssp. vulgare L.) and persian clover (Trifolium resupinatum L.) biomass under the influence of plant competition and density

2014 ◽  
Vol 67 (4) ◽  
pp. 125-134
Author(s):  
Maria Aniela ◽  
Monika Myśliwiec
Keyword(s):  
Growth Rate ◽  
Spring Wheat ◽  
Leaf Development ◽  
Plant Density ◽  
Stem Elongation ◽  
Biomass Accumulation ◽  
Growth Stages ◽  
Wheat Growth ◽  
Mixed Crop ◽  
Persian Clover

The influence of sowing method and plant density on the biomass of spring wheat and Persian clover was evaluated. In a pot experiment conducted in three series during the years 2010–2012, plants were cultivated as mixed and pure crop at higher (consistent with agronomic recommendations) and lower density, decreased by 20% compared to it. Dry mass accumulation tests for both species were conducted during the following wheat growth stages (BBCH): leaf development (12–14), tillering (21–23), stem elongation (31–32), inflorescence development (54–56), and ripening (87–89). Based on the results obtained, the biomass growth rate for both species in question was also determined. It was shown that the mass of shoots of spring wheat cultivated as mixed crop was lower than that of wheat shoots grown as pure crop during the stem elongation and ripening stages. Mixed sowing limited aboveground accumulation in the heads and grain the most and in the stems the least. During the leaf development and stem elongation stages, the wheat presented a more pronounced response to the presence of clover expressed by biomass decrease in case of the treatment with lower plant density and during ripening in the treatment with recommended plant density. In case of both sowing methods and plant densities, the mass of wheat roots was similar. Biomass accumulation in Persian clover shoots and roots in mixed sowing was lower than in pure crop during the entire growing period. The wheat limited biomass accumulation of Persian clover in inflorescences the strongest and in the roots the least. The spring wheat growth rate in both sowing methods was similar as opposed to Persian clover in the case of which a decrease in the growth rate was observed in the mixed crop during the generative development period.

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