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.

Effects of irrigation and nitrogen on the yield components of fennel (Foeniculum vulgare Mill.)

1994 ◽  
Vol 34 (6) ◽  
pp. 845 ◽  
Author(s):  
M Buntain ◽  
B Chung
Keyword(s):  
Yield Components ◽  
Stem Elongation ◽  
Growth Stages ◽  
Full Irrigation ◽  
Flowering Stage ◽  
Foeniculum Vulgare ◽  
Late Flowering ◽  
Whole Plant ◽  
Dry Conditions ◽  
Different Growth Stages

A field experiment was conducted to study the effects of irrigation and nitrogen applied at different growth stages on the oil and anethole yields of fennel (Foeniculum vulgare Mill.), and its yield components. Irrigation increased the yield of whole plant dry matter, with the stem elongation stage being the most sensitive. Full irrigation and irrigation applied during the flowering and late flowering growth stages increased umbel and oil yields. Irrigation during the late flowering stage made the greatest contribution to oil yield, accounting for >80% of the yield due to full irrigation. This was attributed to the concurrent timing of irrigation during the late flowering stage with dry conditions and the development of the main oil-bearing structures, the secondary and tertiary umbels. Irrigation had no significant effect on the anethole concentration of the oil. The best economic return was achieved by irrigating during the late flowering stage. There was no significant effect of nitrogen on any of the yield components measured in this study.

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.

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.

scholarly journals Water and heat unit requirement in different growth stages of Soybean (Glycine max L. Merrill) at Bhopal

MAUSAM ◽  
2021 ◽  
Vol 58 (4) ◽  
pp. 537-542
Author(s):  
I. J. VERMA ◽  
H. P. DAS ◽  
V. N. JADHAV
Keyword(s):  
Crop Coefficient ◽  
Growth Stages ◽  
Maturity Stage ◽  
Degree Days ◽  
Flowering Stage ◽  
Heat Unit ◽  
Soybean Crop ◽  
Pod Development ◽  
Use Efficiency ◽  
Different Growth Stages

In this study, ET data available on Soybean crop for Bhopal during 1991-95 have been utilized.  With regard to water need of the crop, the life span of soybean has been divided into five important growth stages viz., seedling up to 2 weeks after sowing (WAS), vegetative (3-8 WAS), flowering (9-10 WAS), pod development (11-13 WAS), and maturity (14-15 WAS). In this paper, consumptive use of water (ET), Water Use Efficiency (WUE), Heat Units (HU), Heat Use Efficiency (HUE) and crop coefficient (Kc) for different growth stages of the crop have been computed and discussed.                The study revealed that on an average, Soybean crop consumed about 450 mm of water. The average WUE was found to be 3.23 kg /ha/mm. It was also observed that WUE does not depend only on the total amount of water consumed by the crop but also indicates the importance of its distribution during various growth stages. On an average, the crop consumed nearly 7%, 36%, 24%, 25% and 8% of water during seedling, vegetative, flowering, pod development and maturity stage respectively. The crop consumed maximum amount of water during vegetative stage. However, the average weekly ET rate was found to be highest during flowering stage (nearly 52 mm). Average heat unit requirement of soybean was found to be 1694 degree-days. Maximum heat units were required during vegetative stage (638 degree days) followed by pod development stage (358 degree days). The average HUE was found to be 0.86 kg/ha/degree days. Crop coefficient (Kc) values varied in the range 0.30 – 0.45, 0.55 – 0.90, 1.00 – 1.15, 0.85 – 0.70 and 0.55 – 0.40 during seedling, vegetative, flowering, pod development and maturity stage respectively. The crop coefficient values attained the peak during the flowering stage.  

scholarly journals Characteristics of Benthos communities in Laoting area of Hebei Province

2020 ◽  
Vol 206 ◽  
pp. 02024
Author(s):  
Li Guanglou ◽  
Cao Hongmei ◽  
Ye wei
Keyword(s):  
Community Structure ◽  
Benthic Community ◽  
Dominant Species ◽  
Diversity Index ◽  
Hebei Province ◽  
Benthic Community Structure ◽  
Number Of Species ◽  
Evenness Index ◽  
Sea Area ◽  
Richness Index

According to a survey of benthos in the Laoting sea area of Hebei Province on May 24th 2019, a total of 40 benthos species were obtained, of which mollusks have the largest number, followed by annelids and arthropods. The dominant species are Sternaspis sculata and Ringicula doliaris. The number of species obtained in this survey is much lower than the historical average. The diversity index is significantly lower than that in the April 2008 survey, and the evenness index and richness index have declined slightly, indicating that the benthic community structure in this sea area tends to be simplistic, stability tends to deteriorate.

scholarly journals Resistance to Puccinia triticina at different stages of wheat

2009 ◽  
pp. 183-190
Author(s):  
Marina Putnik-Delic
Keyword(s):  
Leaf Senescence ◽  
Latency Period ◽  
Infection Intensity ◽  
Puccinia Triticina ◽  
Growth Stages ◽  
Infection Frequency ◽  
Strongly Correlated ◽  
Wheat Growth ◽  
Reaction Type ◽  
Different Growth Stages

Ten wheat genotypes were tested for resistance characteristics to Puccinia triticina. Infection intensity in the field was evaluated at different growth stages, and time of spike appearance and leaf senescence were recorded. At seedling stage, under the controlled conditions of greenhouse, latency period, infection frequency and reaction type were determined. Resistance characteristics at different wheat growth stages were strongly correlated. Correlation coefficient between LP x RT x IF and AUDPC values, was 0.828. The highest coefficients of correlation between particular resistance characteristics and maximal intensity in the field were determined with the last evaluation in the field (0.665, 0.476 and 0.834). Time of spike appearance was very variable for different genotypes, whereas leaf senescence was recorded concomitantly for near all genotypes. The exception was Rusalka, as the most resistant in the field. All genotypes included in this three-year long experiment expressed stability with respect to infection intensity at different growth stages. Genotype Timson showed the highest level of resistance according to all tested characteristics, while genotype Pkb krupna showed the lowest.

Response of wheat to single short-term waterlogging during and after stem elongation

1988 ◽  
Vol 39 (1) ◽  
pp. 11 ◽  
Author(s):  
WS Meyer ◽  
HD Barrs
Keyword(s):  
Grain Yield ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Root Length ◽  
Stem Elongation ◽  
Stem Growth ◽  
Yield Reduction ◽  
Growth Stages ◽  
Short Term

Transient waterlogging associated with spring irrigations on slowly draining soils causes yield reduction in irrigated wheat. Physiological responses to short-term flooding are not well understood. The aim of this experiment was to monitor above- and below-ground responses of wheat to single waterlogging events during and after stem elongation and to assess the sensitivity of the crop at these growth stages to flooding. Wheat (cv. Bindawarra) was grown in drainage lysimeters of undisturbed cores of Marah clay loam soil. A control treatment (F0) was well-watered throughout the season without surface flooding, while three others were flooded for 96 h at stem elongation (Fl), flag leaf emergence (F2) and anthesis (F3), respectively. Soil water content, soil O2, root length density, leaf and stem growth, apparent photosynthesis (APS), plant nutrient status and grain yield were measured. Soil water content increased and soil O2 levels decreased following flooding; the rate of soil O2 depletion increasing with crop age and root length. Leaf and stem growth and APS increased immediately following flooding, the magnitude of the increases was in the order F1 >F2>F3. A similar order existed in the effect of flooding which decreased the number of roots. Subsequently, leaf and stem growth decreased below that of F0 plants in F1, and briefly in F2. Decreases in APS of treated plants compared to F0 plants appeared to be due to their greater sensitivity to soil water deficit. There was no effect of flooding on grain yield. It is suggested that, while plant sensitivity to flooding decreased with age, flooding at stem elongation had no lasting detrimental effect on yield when post-flood watering was well controlled.

Recovery of field-grown canola from sulfur deficiency

1996 ◽  
Vol 36 (1) ◽  
pp. 79 ◽  
Author(s):  
PJ Hocking ◽  
A Pinkerton ◽  
A Good
Keyword(s):  
Seed Yield ◽  
Seed Oil ◽  
No Reduction ◽  
Stem Elongation ◽  
Potassium Sulfate ◽  
Growth Stages ◽  
Flower Buds ◽  
S Deficiency ◽  
Oil Concentration ◽  
Seed Yields

Sulfate-sulfur was applied to sulfur (S)-deficient canola at several growth stages in a field experiment at Cargo near Orange, New South Wales. Applications of 0, 10 or 40 kg S/ha (S0, S10 and S40) as mixtures of potassium sulfate and potassium chloride were made at sowing, the 5-6 leaf rosette stage, flower buds visible, stem elongation and first flowering. The plots received either 80 or 160 kg nitrogen (N)/ha at sowing. Plants from the S0 plots showed symptoms of severe S deficiency during rapid stem elongation, and had a 52% reduction in seed yield and a 21% reduction in seed oil concentration compared with the S40 plants. Application of S10 at sowing, or topdressing S-deficient plants with this rate of S, was inadequate because, although seed oil concentrations were normal (39-42%), seed yields were 25% lower than those from plots that received S40. Topdressing S-deficient plants with S40 at either the 5-6 leaf rosette stage, flower buds visible or stem elongation resulted in the same seed yields and seed oil concentrations as obtained when S40 was applied at sowing. However, there was a 15% reduction in seed yield but no reduction in seed oil concentration when the S40 topdressing was delayed until flowering. Although S10 was inadequate to correct the S deficiency, there was no reduction in either seed yield or seed oil concentration when S10 was topdressed as late as flowering, when compared with this rate of S applied at sowing. Seed meal protein levels were increased by the S40 topdressings. Concentrations of S in seed from the S0 and S10 plants were below the critical value of 0.36% for canola. Seed N:S concentration ratios of S-deficient plants were greater than 10, but 7.5 for plants which received adequate S. Total glucosinolates in seed were increased by the application of S, but the levels were still well below the limit set for the canola standard.

scholarly journals Optimizing irrigation and determining the most sensitive development stage to drought in barley (Hordeum vulgare L.) in a semi-arid environment

2020 ◽  
Vol 79 (1) ◽  
pp. 87-94
Author(s):  
Leila Romdhane ◽  
Nicola Dal Ferro ◽  
Amor Slama ◽  
Leila Radhouane
Keyword(s):  
Water Potential ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Yield Components ◽  
Stem Elongation ◽  
Leaf Water ◽  
Water Deficit Stress ◽  
Growth Stages ◽  
Development Stages ◽  
Three Stages

Rising temperatures and increasing water scarcity, which are already important issues, are expected to intensify in the near future due to global warming. Optimizing irrigation in agriculture is a challenge. Understanding the response of crop development stages to water deficit stress provides an opportunity for optimizing irrigation. Here we studied the response of two barley varieties (Rihane, Martin), to water deficit stress at three development stages (tillering, stem elongation, and heading) by measuring water status and grain yield components in a field experiment in Tunisia. The three stages were selected due to their importance in crop growth and grain development. Water deficit stress was initiated by withholding water for 21 days at the three stages with subsequent re-watering. Water deficit led to a progressive decrease in leaf water potential. In both varieties, heading was the stage most sensitive to water deficit. Leaf water potential measurements indicated that water deficit stress was more severe during heading, which to some extent may have influenced the comparison between growth stages. During heading, the number of ears per plant and weight of a thousand grains were reduced by more than 70% and 50%, respectively compared with stress at tillering. Comparison of yield components showed differences between the two barley varieties only when the water deficit was produced during the tillering stage.

scholarly journals Changes in dry matter, protein percentage and organic matter of soybean-oat and groundnut-oat intercropping in different growth stages in Jilin province, China

2018 ◽  
Vol 111 (1) ◽  
pp. 33
Author(s):  
Yang YONG ◽  
Yue-gao HU ◽  
Mohamad Hesam SHAHRAJABIAN ◽  
Chang-zhong REN ◽  
Lai-chun GUO ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Cropping Systems ◽  
Jilin Province ◽  
Individual Species ◽  
Growth Stages ◽  
Nitrogen Accumulation ◽  
Ripening Stage ◽  
Protein Percentage ◽  
Sole Cropping

<p>One of the most important and sustainable cropping practice is intercropping. The study was conducted under field conditions in the arid Horqine sandy land in Baicheng District, Jilin Province, Northern China in 2011. A randomized complete block design with four replications was used. Treatments comprised different mono cropping and intercropping patterns, TO: sole cropping of oat, TOS-O: oat in the intercropping of oat and soybean, TOG-O: oat in the intercropping of oat and groundnut, TS: sole cropping of soybean, TOS-S: soybean in intercropping of oat and soybean, TG: sole cropping of groundnut, TOG-G: groundnut in the intercropping of oat and groundnut. In mono-cropping systems, oat mono-cropping obtained the highest dry matter and nitrogen accumulation in all growth stages. The maximum protein percentage in all stages except for ripening stage, were for groundnut mono-cropping. Although, the maximum organic matter in ripening stage was achieved in mono-cropping of soybean, the highest one in other stages was related to groundnut mono-cropping. In intercropping patterns, oat in oat-groundnut obtained the highest dry matter in all stages. The highest value of protein percentage and organic matter in heading stage, grain filling stage, and grain dough stage was achieved in groundnut in oat-groundnut intercropping. Furthermore, the maximum value of protein percentage and organic matter in booting stage and ripening stage was related to soybean in oat-soybean intercropping. The results of this study clearly indicate that intercropping oat and groundnut affects the growth rate of the individual species in mixtures as well as the dry matter yield and nitrogen accumulation. This information can help in the adaptation of oat- intercrops for increased forage production in new cropping systems.</p>

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