Effects of simulated rust epidemics on the growth and yield of sunflower

1977 ◽  
Vol 28 (3) ◽  
pp. 389 ◽  
Author(s):  
MQ Siddiqui ◽  
JF Brown
Keyword(s):  
Growth And Yield ◽  
Oil Yield ◽  
Growth Stages ◽  
Yield Losses ◽  
Intensity Of Infection ◽  
Development Stages ◽  
Rust Infection ◽  
Stages Of Growth ◽  
Puccinia Helianthi ◽  
Number Of Seeds

Oil yield losses in sunflower (cv. Peredovic) caused by rust infection (Puccinia helianthi) were greatly influenced by the growth stage of the plant when infection occurred and by the intensity of infection. Simulated epidemics produced under greenhouse conditions, where plants were first inoculated at the vegetative, budding, anthesis or seed development stages of growth and thereafter at 10 day intervals, resulted in reductions in oil yield of 85, 73, 38 and 13% respectively relative to those in uninoculated controls. In contrast, plants inoculated once only at each of these growth stages showed reductions in 011 yield of 13, 42, 35 and 10% respectively. When plants were inoculated at the vegetative stage and thereafter at 10, 20 and 40 day intervals, the reductions in oil yield were 85, 79 and 64% respectively relative to uninoculated controls. The reduction in oil yield of infected plants was caused by a reduction in the number of seeds produced per head, the weight of individual seeds and the percentage oil content of seeds. The effects of rust infection on other parameters showed similar trends to that on oil yield.

scholarly journals Growth and Yield Losses of Roundup Ready Soybean as Influenced by Micro-rates of 2,4-D

2021 ◽  
Vol 10 (4) ◽  
pp. 27
Author(s):  
Ivan Cuvaca ◽  
Stevan Knezevic ◽  
Jon Scott ◽  
O. Adewale Osipitan
Keyword(s):  
Plant Height ◽  
Yield Loss ◽  
Maximum Growth ◽  
Growth And Yield ◽  
Growth Stages ◽  
Spray Drift ◽  
Canopy Closure ◽  
Yield Losses ◽  
Roundup Ready ◽  
Timing Of Exposure

Widespread resistance to glyphosate has made weed control very challenging. In response, new approaches to managing resistant biotypes such as the Enlist E3TM have been developed. This technology allows in-crop use of 2,4-D but there is fear associated with unintentional application of the herbicide (e.g. direct application, tank contamination, or spray drift) to sensitive crops. A study was conducted to evaluate Roundup Ready (RR) soybean growth and yield loss as influenced by 2,4-D [six micro rates of 1/5, 1/10, 1/50, 1/100, 1/500 and 1/1000 of the 1,120 g ae ha-1 label recommended dose, and a check with no herbicide applied] applied at V2, R1 and R2 growth stages. In general, RR soybean was more sensitive to 2,4-D at R1 than V2 and R2. The highest 2,4-D rate, 1/5 of the label recommended rate, caused 51% soybean injury symptom, 13 d canopy closure delay, 41.2% plant height reduction, and 68.9% yield loss at R1. Based on effective dose (ED) estimates, 37.7 g ae ha-1 2,4-D caused 5% yield loss (0.23 Mg ha-1) at R1 compared with a 2.5- and 2.0-fold higher dose at V2 and R2, respectively. With respect to number of days to canopy closure, both reproductive stages (R1 and R2) were equally less sensitive to 2,4-D than the vegetative one (V2) as the plants had already achieved maximum growth recorded. On the other hand, ED estimates for plant height have shown that both V2 and R2 were equally more sensitive to 2,4-D than R1. These results clearly indicated that RR soybean growth and yield loss were significantly influenced by the timing of exposure and amount of 2,4-D.

Regeneration dynamics in an alluvial dense ash (Fraxinus excelsior L.) stand

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Tabari ◽  
N. Lust ◽  
L. Nachtergale
Keyword(s):  
Alluvial Soil ◽  
Single Species ◽  
Fraxinus Excelsior ◽  
Growth Stages ◽  
Acer Pseudoplatanus ◽  
Development Stages ◽  
Regeneration Dynamics ◽  
Broadleaved Tree Species ◽  
Succession Process ◽  
Broadleaved Tree

Broadleaves  regeneration dynamics and the succession mechanism were studied within  a    transect of 14 m x 56 m in a dense 80-year-old ash stand situated on an  alluvial soil. For this    purpose, abundance and height of all naturally regenerated species at  different development    stages were analyzed and their distribution over the juvenile and older  growth stages    determined.    The study reveals that from the main broadleaved tree species, Quercus robur and Fagus    sylvatica regeneration scarcely occur at any  growth stages. No Fraxinus excelsior regeneration,    except 1 unit, taller than sapling (1.5-4 m) can be found on this soil  type. On the contrary, Acer    pseudoplatanus represents different development  stages (seedling, sapling, thicket, small pole    and large pole) and in stand patches where an understorey is practically  lacking, its    regeneration is well developed. Results generally show that at the juvenile  and older growth    stages Acer proceeds Fraxinus and regeneration is largely  dominated by the invasive Acer. It is    expected that this succession process will continue and that Acer will overcome in the    overstorey and even gradually form an almost single-species dominating  stage. Direct    interventions are unavoidable in order to regulate the primary mixture  patterns.

scholarly journals Quantitative Response of Maize Vcmax25 to Persistent Drought Stress at Different Growth Stages

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1971
Author(s):  
Xingyang Song ◽  
Guangsheng Zhou ◽  
Qijin He ◽  
Huailin Zhou
Keyword(s):  
Drought Stress ◽  
Early Warning Systems ◽  
Growth And Yield ◽  
Leaf Water Content ◽  
Growth Stages ◽  
Leaf Stage ◽  
Maximum Value ◽  
Maize Varieties ◽  
Persistent Drought ◽  
Different Growth Stages

Drought stress has adverse effects on crop growth and yield, and its identification and monitoring play vital roles in precision crop water management. Accurately evaluating the effect of drought stress on crop photosynthetic capacity can provide a basis for decisions related to crop drought stress identification and monitoring as well as drought stress resistance and avoidance. In this study, the effects of different degrees of persistent drought in different growth stages (3rd leaf stage, 7th leaf stage and jointing stage) on the maximum carboxylation rate at a reference temperature of 25 °C (Vcmax25) of the first fully expanded leaf and its relationship to the leaf water content (LWC) were studied in a field experiment from 2013 to 2015. The results indicated that the LWC decreased continuously as drought stress continued and that the LWC decreased faster in the treatment with more irrigation. Vcmax25 showed a decreasing trend as the drought progressed but had no clear relationship to the growth stage in which the persistent drought occurred. Vcmax25 showed a significantly parabolic relationship (R2 = 0.701, p < 0.001) with the LWC, but the different degrees of persistent drought stress occurring in different growth stages had no distinct effect on the LWC values when Vcmax25 reached its maximum value or zero. The findings of this study also suggested that the LWC was 82.5 ± 0.5% when Vcmax25 reached its maximum value (42.6 ± 3.6 μmol m−2 s−1) and 67.6 ± 1.2% (extreme drought) when Vcmax25 reached zero. These findings will help to improve crop drought management and will be an important reference for crop drought identification, classification and monitoring as well as for the development of drought monitoring and early warning systems for other crops or maize varieties.

Effects of early season waterlogging on maize growth and yield

1987 ◽  
Vol 38 (1) ◽  
pp. 27 ◽  
Author(s):  
WK Mason ◽  
KE Pritchard ◽  
DR Small
Keyword(s):  
Plant Growth ◽  
Threshold Level ◽  
Growth And Yield ◽  
Yield Losses ◽  
Crop Water ◽  
Maize Crop ◽  
Early Season ◽  
Cultural Methods ◽  
Irrigation Treatments ◽  
Final Harvest

Five irrigation treatments (0, 2, 6 and 24 h ponding in furrows plus a 6-h flooded treatment) were applied at the first two irrigations after emergence of a maize crop. Water was ponded for 6 h in the furrows or on the flooded plots at each of the 10 subsequent irrigations.The irrigation treatments had a significant effect on plant growth, resulting in final DM yields of 22.3, 19.7, 19.2, 18.7 and 13.9 t/ha for the 0, 2,6, 24 h furrow irrigations and the 6 h flood treatment respectively. The 2, 6 and 24 h furrow treatments did not perform differently in any of the parameters measured, indicating that a threshold level of waterlogging was reached in all three compared with the zero ponding treatment.Nitrogen applications of 25 kg N/ha to the soil or foliage prior to each of the first two irrigations did not reduce the severity of the waterlogging treatments, despite herbage N levels being significantly depressed in the flooded plots. Similarly, soil fungicide application did not mitigate the waterlogging effects.Individual plants within the treatment populations differed greatly in their response to the waterlogging treatments. The effect on individual plants persisted until final harvest. Cultural methods which may prevent the yield losses associated with the first irrigation of maize are discussed.

scholarly journals WATER USE EFFICIENCY, GROWTH AND YIELD OF WHEAT CULTIVATED UNDER COMPETITION WITH Setaria

2015 ◽  
Vol 33 (4) ◽  
pp. 679-687 ◽  
Author(s):  
M.Z. IHSAN ◽  
F.S. EL-NAKHLAWY ◽  
S.M. ISMAIL
Keyword(s):  
Drought Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Harvest Index ◽  
Wheat Yield ◽  
Negative Association ◽  
Growth And Yield ◽  
Yield Losses ◽  
Wheat Production ◽  
Use Efficiency

ABSTRACT Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period ofSetaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressedSetaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association ofSetariadensity with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

Influence of Recovery Treatments on Dicamba-injured Soybean

2021 ◽  
pp. 1-20
Author(s):  
Brian R. Dintelmann ◽  
Shea T. Farrell ◽  
Kevin W. Bradley
Keyword(s):  
Yield Loss ◽  
Yield Losses ◽  
Soybean Yield ◽  
Injury Reduction ◽  
Stages Of Growth ◽  
Average Precipitation ◽  
Injury Event ◽  
Recovery Treatment ◽  
Micronutrient Fertilizer ◽  
Similar Yield

Abstract Non-dicamba resistant soybean yield loss resulting from dicamba off-target injury has become an increasing concern for soybean growers in recent years. After off-target dicamba movement occurs onto sensitive soybean, little information is available on tactics that could be used to mitigate the cosmetic or yield losses that may occur. Therefore, a field experiment was conducted in 2017, 2018, and 2019 to determine if certain recovery treatments of fungicide, plant growth hormone, macro- and micronutrient fertilizer combinations, or weekly irrigation could reduce dicamba injury and/or result in similar yield to soybean that was not injured with dicamba. Simulated drift events of dicamba (5.6 g ae ha−1) were applied to non-dicamba resistant soybean once they reached the V3 or R2 stages of growth. Recovery treatments were applied approximately 14 d after the simulated drift event. Weekly irrigation was the only recovery treatment that provided appreciable levels of injury reduction or increases in soybean height or yield compared to the dicamba-injured plants. Weekly irrigation following the R2 dicamba injury event resulted in an 1% to 14% increase in soybean yield compared to the dicamba-injured control. All other recovery treatments resulted in soybean yields similar to the dicamba-injured control, and similar to or lower than the non-treated control. Results from this study indicate that if soybean have become injured with dicamba, weekly irrigation will help soybean recover some of the yield loss and reduce injury symptoms that resulted from off-target dicamba movement, especially in a year with below average precipitation. However, yield loss will likely not be restored to that of non-injured soybean.

scholarly journals He-Ne Laser Seed Treatment Improves the Nutraceutical Metabolic Pool of Sunflowers and Provides Better Tolerance Against Water Deficit

2021 ◽  
Vol 12 ◽  
Author(s):  
Saqib Mahmood ◽  
Beenish Afzal ◽  
Shagufta Perveen ◽  
Abdul Wahid ◽  
Muhammad Azeem ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Laser Treatment ◽  
Seed Treatment ◽  
Nutritional Value ◽  
Soluble Sugars ◽  
Growth And Yield ◽  
Oil Yield ◽  
Carotenoid Content ◽  
Leaf Biomass ◽  
Drought Tolerant

Water-scarce areas are continually increasing worldwide. This factor reduces the quantity and quality of crops produced in affected areas. Physical seed treatments are considered economical and ecofriendly solutions for such problems. It was hypothesized that a moderately drought-tolerant crop grown from seeds treated with a He-Ne laser utilizes water-limited conditions better than plants grown from untreated seeds. A field study was conducted, growing a moderately drought tolerant crop (sunflower) with supportive seed treatment (He-Ne laser treatment at 300 mJ) for 0, 1, 2, and 3 min. Thirty-day-old plants were subjected to two irrigation conditions: 100% (normal) and 50% (water stress). Harvesting was done at flowering (60-day-old plants) at full maturity. The sunflowers maintained growth and yield under water limitation with a reduced achene number. At 50%, irrigation, there was a reduction in chlorophyll a, a+b and a/b; catalase activity; soluble sugars; and anthocyanin, alongside elevated proline. The improved chlorophyll a, a+b and a/b; metabolisable energy; nutritional value; and yield in the plants grown from He-Ne-laser-treated seeds support our hypothesis. Seeds with 2-min exposure to a He-Ne laser performed best regarding leaf area; leaf number; leaf biomass; chlorophyll a, a+b and a/b; per cent oil yield; 50-achene weight; achene weight per plant; carotenoid content; and total soluble phenolic compound content. Thereafter, the leaves from the best performing level of treatment (2 min) were subjected to high-performance-liquid-chromatography-based phenolic profiling and gas-chromatography-based fatty acid profiling of the oil yield. The He-Ne laser treatment led to the accumulation of nutraceutical phenolic compounds and improved the unsaturated-to-saturated fatty acid ratio of the oil. In conclusion, 2-min He-Ne laser seed treatment could be the best strategy to improve the yield and nutritional value of sunflowers grown in water-limited areas.

scholarly journals Methionine-induced regulation of growth, secondary metabolites and oxidative defense system in sunflower (Helianthus annuus L.) plants subjected to water deficit stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259585
Author(s):  
Gull Mehak ◽  
Nudrat Aisha Akram ◽  
Muhammad Ashraf ◽  
Prashant Kaushik ◽  
Mohamed A. El-Sheikh ◽  
...  
Keyword(s):  
Drought Stress ◽  
Helianthus Annuus ◽  
Water Deficit ◽  
Soluble Sugars ◽  
Foliar Spray ◽  
Shoot Length ◽  
Stress Conditions ◽  
Growth And Yield ◽  
Water Deficit Stress ◽  
Growth Stages

Optimum water availability at different growth stages is one the major prerequisites of best growth and yield production of plants. Exogenous application of plant growth regulators considered effective for normal functioning of plants under water-deficit conditions. A study was conducted to examine the influence of exogenously applied L-methionine on sunflower (Helianthus annuus L.) plants grown under water-deficit conditions. Twenty-five-day old seedlings of four sunflower cultivars, FH331, FH572, FH652 and FH623 were exposed to control (100% F.C.) and drought stress (60% F.C.) conditions. After 30-day of drought stress, L-methionine (Met; 20 mg/L) was applied as a foliar spray to control and drought stressed plants. Water deficit stress significantly reduced shoot fresh and dry weights shoot and root lengths, and chlorophyll a content in all four cultivars. While a significant increase was observed due to water deficiency in relative membrane permeability (RMP), malondialdehyde (MDA), total soluble proteins (TSP), total soluble sugars (TSS), ascorbic acid (AsA) and activity of peroxidase (POD). Although, exogenously applied Met was effective in decreasing RMP, MDA and H2O2 contents, it increased the shoot fresh weight, shoot length, chlorophyll a, chlorophyll a/b ratio, proline contents and the activities of SOD, POD and CAT enzymes in all four cultivars under water deficit stress. No change in AsA and total phenolics was observed due to foliar-applied Met under water stress conditions. Of all sunflower cultivars, cv. FH-572 was the highest and cv. FH-652 the lowest of all four cultivars in shoot fresh and dry weights as well as shoot length under drought stress conditions. Overall, foliar applied L-methionine was effective in improving the drought stress tolerance of sunflower plants that was found to be positively associated with Met induced improved growth attributes and reduced RMP, MDA and H2O2 contents under water deficit conditions.

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