scholarly journals Developing Rainfall- and Temperature-Based Models to Describe Infection of Canola Under Field Conditions Caused by Pycnidiospores of Leptosphaeria maculans

2009 ◽  
Vol 99 (7) ◽  
pp. 879-886 ◽  
Author(s):  
Kaveh Ghanbarnia ◽  
W. G. Dilantha Fernando ◽  
Gary Crow
Keyword(s):  
Plant Growth ◽  
Growth Stage ◽  
Leptosphaeria Maculans ◽  
The Other ◽  
Field Conditions ◽  
Maximum Temperature ◽  
Growth Stages ◽  
Upper Limit ◽  
Average Maximum ◽  
Two Stages

Blackleg, also known as Phoma stem canker, caused by Leptosphaeria maculans (Phoma lingam), is one of the most serious diseases of canola worldwide. In this study, the mean disease severity (Ds) and incidence (Di) of canola cv. Westar plants infected at the cotyledon, three-leaf, and six-leaf stages by pycnidiospores of L. maculans were monitored in the greenhouse after infection of the plants under field conditions in two successive years and associated with meteorological data during infection time. Pearson's correlation coefficient showed that total rainfall per week (R) was significantly correlated to Ds on plants infected at the cotyledon, three-leaf, and six-leaf stages, and average maximum temperature per week (Tmax) only showed significant correlation with plants infected at the cotyledon and six-leaf stages. These results also indicated that there is correlation between Di and R for plants infected at all three growth stages. A nonlinear model was developed to evaluate the combined effects of R and Tmax on Ds. The best model comprised monomolecular function and β probability density function for plants infected at the above three growth stages. Parameters, including maximum potential for Ds at a given rainfall (dmax), rate of changes with respect to rainfall (k), constant of integration (B), maximum potential for Ds with respect to Tmax (e), rate of increase with increasing Tmax to optimum (n), and rate of decrease as Tmax increased and passed the optimum Tmax (p), were estimated for plants infected at the above three growth stages. The effect of plant growth stage was characterized by differences in the upper limit parameter a. This parameter was greater for the plants infected at the cotyledon stage than for plants infected at the other two stages. The estimate of parameter k was the same for the plants infected at the cotyledon and three-leaf stages. This parameter was much lower for the plants infected at the six-leaf stage compared with two other stages. The logistic model could describe the disease incidence with respect to R slightly better than the other two models in the plants infected at all three growth stages. Based on the model, upper-limit estimate (dmax) was ≈100, 94.4, and 88.8% in the plants infected at cotyledon, three-leaf, and six-leaf stages, respectively. Di increased until rainfall reached ≈18, 10, and 13 mm/week and became constant in the plants at cotyledon, three-leaf, and six-leaf stages, respectively. Effects of plant growth stage on the rate of change with respect to R (parameter k) were lower in the plants infected at cotyledon than at the other two stages. The accuracy of the nonlinear models suggests that they could be used to develop a comprehensive model to evaluate epidemics of blackleg based on pycnidiospores as sources of inoculum. However, additional years of data collection should improve model fit and evaluation of introduced models and contribute to the development of a more robust predictive model.

scholarly journals Hormesis with glyphosate depends on coffee growth stage

2013 ◽  
Vol 85 (2) ◽  
pp. 813-822 ◽  
Author(s):  
LEONARDO B. DE CARVALHO ◽  
PEDRO L.C.A. ALVES ◽  
STEPHEN O. DUKE
Keyword(s):  
Plant Growth ◽  
Weed Management ◽  
Growth Stage ◽  
Growth Stages ◽  
Coffee Plant ◽  
Herbicide Application ◽  
Coffee Plantations ◽  
Plant Growth Stages ◽  
Coffee Plants ◽  
Almost All

Weed management systems in almost all Brazilian coffee plantations allow herbicide spray to drift on crop plants. In order to evaluate if there is any effect of the most commonly used herbicide in coffee production, glyphosate, on coffee plants, a range of glyphosate doses were applied directly on coffee plants at two distinct plant growth stages. Although growth of both young and old plants was reduced at higher glyphosate doses, low doses caused no effects on growth characteristics of young plants and stimulated growth of older plants. Therefore, hormesis with glyphosate is dependent on coffee plant growth stage at the time of herbicide application.

scholarly journals Scale-Dependent Effects of Growth Stage and Elevational Gradient on Rice Phyllosphere Bacterial and Fungal Microbial Patterns in the Terrace Field

2022 ◽  
Vol 12 ◽  
Author(s):  
Pei Wang ◽  
Jianping Dai ◽  
Luyun Luo ◽  
Yong Liu ◽  
Decai Jin ◽  
...  
Keyword(s):  
Plant Growth ◽  
Growth Stage ◽  
Elevational Gradient ◽  
Fungal Communities ◽  
Growth Stages ◽  
Strong Positive Correlation ◽  
Elevation Gradients ◽  
Positive Correlation ◽  
Α Diversity ◽  
Phyllosphere Bacteria

The variation of phyllosphere bacterial and fungal communities along elevation gradients may provide a potential link with temperature, which corresponds to an elevation over short geographic distances. At the same time, the plant growth stage is also an important factor affecting phyllosphere microorganisms. Understanding microbiological diversity over changes in elevation and among plant growth stages is important for developing crop growth ecological theories. Thus, we investigated variations in the composition of the rice phyllosphere bacterial and fungal communities at five sites along an elevation gradient from 580 to 980 m above sea level (asl) in the Ziquejie Mountain at the seedling, heading, and mature stages, using high-throughput Illumina sequencing methods. The results revealed that the dominant bacterial phyla were Proteobacteria, Actinobacteria, and Bacteroidetes, and the dominant fungal phyla were Ascomycota and Basidiomycota, which varied significantly at different elevation sites and growth stages. Elevation had a greater effect on the α diversity of phyllosphere bacteria than on that phyllosphere fungi. Meanwhile, the growth stage had a great effect on the α diversity of both phyllosphere bacteria and fungi. Our results also showed that the composition of bacterial and fungal communities varied significantly along elevation within the different growth stages, in terms of both changes in the relative abundance of species, and that the variations in bacterial and fungal composition were well correlated with variations in the average elevation. A total of 18 bacterial and 24 fungal genera were significantly correlated with elevational gradient, displaying large differences at the various growth stages. Soluble protein (SP) shared a strong positive correlation with bacterial and fungal communities (p < 0.05) and had a strong significant negative correlation with Serratia, Passalora, unclassified_Trichosphaeriales, and antioxidant enzymes (R > 0.5, p < 0.05), and significant positive correlation with the fungal genera Xylaria, Gibberella, and Penicillium (R > 0.5, p < 0.05). Therefore, it suggests that elevation and growth stage might alter both the diversity and abundance of phyllosphere bacterial and fungal populations.

scholarly journals Post-emergence selectivity of metribuzin to carrot

Revista CERES ◽  
2018 ◽  
Vol 65 (4) ◽  
pp. 314-320
Author(s):  
Núbia Maria Correia ◽  
Agnaldo Donizete Ferreira de Carvalho
Keyword(s):  
Plant Growth ◽  
Chemical Treatment ◽  
Growth Stage ◽  
Block Design ◽  
Greenhouse Experiment ◽  
Application Time ◽  
Application Timing ◽  
Time Of Application ◽  
Randomized Complete Block Design ◽  
Two Stages

ABSTRACT When selecting a weed chemical treatment (herbicide, product mixtures, dose, or application timing), an important issue to consider is its selectivity to the crop of commercial interest. The objective of this study was to evaluate the selectivity of the herbicide metribuzin to carrot plants as a function of genotype, dose, and plant growth stage at the time of application. Two experiments were carried out, one in a greenhouse and another in the field. The greenhouse experiment was arranged in a completely randomized, 5 x 2 x 3 factorial design, with four replications. Metribuzin doses (0, 72, 96, 144, and 192 g ha-1) were sprayed on plants with 2-3 and 4-5 true leaves of the cultivars Maestro, BRS Planalto, and Verano. Cultivar Maestro was cultivated in the field in a 2 x 5 factorial experiment in randomized complete block design, with four replications. Carrot plants, at two stages of development (2 and 5 true leaves), were sprayed with the same doses of metribuzin applied in the greenhouse experiment. Metribuzin, regardless of application time and dose tested, was selective for cultivars BRS Planalto and Verano (greenhouse) and Maestro (both greenhouse and field), without reduction in quality and yield of roots.

scholarly journals Sumatran Fleabane Control using Glyphosate in Association with Halauxifen-Methyl Formulations

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
L.H.S. ZOBIOLE ◽  
F.H. KRENCHINSKI ◽  
G. MORATELLI ◽  
N.V. COSTA
Keyword(s):  
Experimental Design ◽  
Weed Control ◽  
Growth Stage ◽  
New Product ◽  
Development Stage ◽  
The Other ◽  
Growth Stages ◽  
Agricultural Systems ◽  
Stage 1 ◽  
Different Growth Stages

ABSTRACT: The effectiveness of a new product has a great importance to weed control, especially those that are difficult to control or resistant to, such as the sumatran fleabane (Conyza sumatrensis). The objective of this research was to evaluate the control of C. sumatrensis at different growth stages, using halauxifen-methyl in combination with other herbicides. The experimental design used was a randomized blocks in a 3x10 factorial scheme, with four replications. The plants of C. sumatrensis were evaluated at different growth: stage 1: plants with 8 leaves; Stage 2: plants with 19 leaves and stage 3: plants with 45 leaves fully expanded. The herbicides used were the association of glyphosate with the herbicides 2,4-D at 806, 943 and 1,209 g a.e. ha-1, halauxifen-methyl + diclosulam at 5.06 g a.e. ha-1 + 25.52 g a.i. ha-1 and 6.32 g a.e. ha-1 + 31.87 g a.i. ha-1, halauxifen-methyl + 2,4-D at 5.00 + 783 g a.e. ha-1 and 6,0 + 940 g a.e. ha-1 and halauxifen-methyl at 5.0 and 6.0 g a.e. ha-1 and untreated, totaling 10 treatments. The herbicides demonstrated satisfactory control of the plants in Stage 1 at 50 DAA, with the exception of the glyphosate + 2,4-D treatment at the lowest rate. However for Stages 2 and 3 the halauxifen-methyl + diclosulam in both rates, provided superior controls in relation to the other treatments. The control of sumatran fleabane was facilitated when their management occurs in the early stages of development, however independent of the development stage, the best controls obtained were with the treatment containing glyphosate + halauxifen-methyl + diclosulam at 1,440 g a.e. ha-1 + 6.32 g a.e. ha-1 + 31.87 g a.i. ha-1. Thus, combinations of herbicides containing halauxifen-methyl are another option to control C. sumatrensis in agricultural systems.

Efficacy ofColletotrichum coccodesand Thidiazuron for Velvetleaf (Abutilon theophrasti) Control in Soybean (Glycine max)

1988 ◽  
Vol 2 (4) ◽  
pp. 473-480 ◽  
Author(s):  
Richard H. Hodgson ◽  
Lee A. Wymore ◽  
Alan K. Watson ◽  
Robert H. Snyder ◽  
Anne Collette
Keyword(s):  
Glycine Max ◽  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Growth Stage ◽  
Pathogenic Fungus ◽  
Abutilon Theophrasti ◽  
Colletotrichum Coccodes ◽  
Growth Stages ◽  
Wet Weather

The plant pathogenic fungusColletotrichum coccodes(Cc) and the plant growth regulator thidiazuron (TDZ) were evaluated in Maryland and Quebec for velvetleaf control in ‘Williams' and ‘Maple Arrow’ soybean. TDZ was applied at 0, 0.1, 0.2, 0.3, and 0.4 kg ai/ha alone or was combined with Cc at 109spores/m2when velvetleaf was at the 1- to 2-leaf (Trial 1) or 4- to 6-leaf (Trial 2) growth stages. Velvetleaf control increased with TDZ rate, and TDZ combined with Cc further increased control. TDZ reduced velvetleaf biomass and height, and Cc increased velvetleaf mortality. In Quebec, Cc also reduced the biomass of velvetleaf treated in Trial 1 and interacted positively with TDZ at this growth stage. Cc nearly halved the rates of TDZ required for 90 and 75% mortality of velvetleaf treated at the 1- to 2-leaf and 4- to 6-leaf stages to 0.09 and 0.12 kg/ha, respectively, in Quebec. Cc similarly lowered the rate of TDZ required for 75% stand reduction of velvetleaf in Trial 1 to 0.17 kg/ha in Maryland. Cool wet weather in Quebec contrasted with warm, dry weather in Maryland. Soybean biomass and yield were increased significantly by treatment with TDZ plus Cc in Trial 1 at both locations.

scholarly journals Dosage of 2,6-Bis (1.1-Dimethylethyl)-4-Methylphenol (BHT) in the Plant ExtractMesembryanthemum crystallinum

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Bouftira Ibtissem ◽  
Mgaidi Imen ◽  
Sfar Souad
Keyword(s):  
Antioxidant Activity ◽  
Plant Growth ◽  
Plant Extract ◽  
Growth Stage ◽  
Mesembryanthemum Crystallinum ◽  
Growth Stages ◽  
Naturally Occurring ◽  
Plant Growth Stages

A naturally occurring BHT was identified in the leaves of the halophyte plantMesembryanthemum crystallinum. This phenol was extracted in this study by two methods at the different plant growth stages. One of the methods was better for BHT extraction; the concentration of this phenol is plant growth stage dependent. In this study, the floraison stage has the highest BHT concentration. The antioxidant activity of the plant extract was not related to BHT concentration. The higher antioxidant activity is obtained at seedlings stage.

Dinitrogen fixation in Phaseolus vulgaris at low temperatures: interaction of temperature, growth stage, and time of inoculation

1982 ◽  
Vol 60 (8) ◽  
pp. 1423-1427 ◽  
Author(s):  
R. J. Rennie ◽  
G. A. Kemp
Keyword(s):  
Phaseolus Vulgaris ◽  
Plant Growth ◽  
Root Growth ◽  
Low Temperatures ◽  
Growth Stage ◽  
Growth Stages ◽  
Trifoliate Leaf ◽  
Temperature Growth ◽  
Southern Alberta ◽  
Plant Growth Stages

Nodulation and N2 fixation have not been reported in beans (Phaseolus vulgaris L.) below a temperature of 13 °C but, in southern Alberta, temperatures at planting may be as low as 10 °C. Two varieties of pea beans, 'Aurora' and 'Kentwood,' were inoculated at three growth stages (seeding, primary leaf horizontal, or first trifoliate leaf open) and grown at 10, 12, 14, or 16 °C. Nodulation and acetylene (C2H2) reduction occurred in both varieties at temperatures as low as 10 °C. At the lower temperatures, cold adaptability of the plant for early root growth determined the ability for nodulation and N2 fixation. At higher temperatures, plant-growth stage was a determining factor. 'Aurora' was superior to 'Kentwood' at 10 °C in nodulation, dry matter (DM), N yield, and N2 fixation because of its tolerance to low temperatures during early root growth. Inoculation with Rhizobium phaseoli at more advanced plant-growth stages decreased the time for nodulation at all four temperatures but resulted in higher yield and more N2 fixation in 'Aurora' only at 14 and 16 °C. At 10 °C, inoculation at seeding was more effective than at the other two growth stages for both varieties. Thus plant growth stages and growth temperature both determined the ability of a bean variety to support N2 fixation at various low temperatures.

scholarly journals Morphometric Characteristics, Polyphenols and Ascorbic Acid Variation in Brassica oleracea L. Novel Foods: Sprouts, Microgreens and Baby Leaves

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 782 ◽  
Author(s):  
Maria Concetta Di Bella ◽  
Agnieszka Niklas ◽  
Stefania Toscano ◽  
Valentina Picchi ◽  
Daniela Romano ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Plant Growth ◽  
Growth Stage ◽  
Added Value ◽  
Growth Stages ◽  
Novel Food ◽  
Main Compound ◽  
Novel Foods ◽  
Freeze Dried

In the present study, we investigated the content and profile of polyphenols (PPH), ascorbic acid (AA), the Folin–Ciocalteu index (FCI), and antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxyl radical (ROO)) variation during three different plant growth stages (sprouts, microgreens and baby leaves) of two broccoli types, the traditional Sicilian sprouting broccoli landrace (‘Broccolo Nero’) and the broccoli standard (‘Cavolo broccolo Ramoso Calabrese’), and the standard commercial cultivar of kale (‘Cavolo Lacinato Nero di Toscana’). All biomasses collected were freeze-dried for PPH, AA, FCI, DPPH and ROO analysis. The highest polyphenol content was observed for ‘Broccolo Nero’ (BN) and ‘Cavolo Broccolo Ramoso Calabrese’ (CR), and generally sprouts showed significantly higher values compared to the microgreens and the baby leaves. The AA, FCI, DDPH and ROO significantly vary with regards to the cultivar and the plant growth stage, showing interaction between the two experimental factors analyzed. The interaction detected showed higher values for the antioxidant traits of the proposed novel food, especially for the two broccoli cultivars in the sprout growth stage in comparison to the microgreens and baby leaves. Our results suggest that the antioxidant activity is partially dependent on kaempferol and apigenin. The PPH compounds showed the highest values of kaempferol and apigenin for ‘Broccolo nero’, whereas for the other two cultivars studied, only kaempferol was the main compound represented. The data acquired are of interest for increasing the healthy traits of the novel food proposed showing the contribution offered by the neglected LRs until now underutilized and at risk of extinction. The germplasm conserved in several world genebanks could support and diversify the organic vegetable items, providing us with added-value products for organic food supply chains.

scholarly journals Plant Growth Regulators and Yields of Seed Potatoes

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 853F-853
Author(s):  
Manjula S. Bandara ◽  
Karen K. Tanino ◽  
Doug R. Waterer
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Seed Tuber ◽  
Russet Burbank ◽  
Field Conditions ◽  
Tuber Initiation ◽  
Growth Stages ◽  
Tuber Production ◽  
Cut Seed

Seed potato growers seek to maximize yields of desirable sized tubers. This study examined how foliar applications of plant growth regulators influence yields of drop or single-cut seed tubers under field conditions. In 1993, paclobutrazol (PTZ; 300, 450, and 600 mg·liter–1), kinetin (KIN; 10 and 20 mg·liter–1), and methyl jasmonate (MJ; 10–7, 10–6, 10–5, and 10–4 M) were applied to `Norland' (NOR) and `Russet Burbank' (RB) potatoes. In 1994, PTZ (300 mg·liter–1), KIN (both rates), and MJ (10–7 and 10–6 M) treatments were eliminated, and GA3 at 250 mg·liter–1 or KIN at 20 mg·liter–1 was applied to some of PTZ treatments. In 1994, the cultivar Shepody (SH) also was included. Plants were treated at two growth stages; NOR (1993), RB (1993 and 1994), and SH (1994) were treated when tubers were <10 mm or <20 mm in diameter. NOR (1994) was treated at stolon initiation (no tubers) or early tuber initiation (<8 mm in diameter). PTZ had no effect on seed tuber (25–50 mm in diameter) yield in NOR in either season. PTZ increased seed tuber number (STN) in RB by 29% to 40% and in SH by 57% to 70% over the controls. KIN had no effect on STN in any cultivar. MJ had no effect on STN in NOR (1993) or in RB in either season or in SH in 1994. In 1994, the highest rate of MJ (10–4 M) increased STN in NOR by 40% over the controls. GA3 had no beneficial effect on STN when applied after PTZ. This study suggests that, under field conditions, PTZ can increase seed tuber production in RB and SH while MJ was effective in NOR potatoes.

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