scholarly journals Yield and Dry Weight of Dehydrator Onions after Uprooting at Maturity and Delaying Harvest

HortScience ◽  
1999 ◽  
Vol 34 (6) ◽  
pp. 1068-1070 ◽  
Author(s):  
Arthur D. Wall ◽  
Joe N. Corgan
Keyword(s):  
Treatment Effects ◽  
Dry Weight ◽  
Yield Losses ◽  
Time Intervals ◽  
Basal Rot ◽  
Fusarium Basal Rot ◽  
Dry Climates

In dry climates, onions usually have the roots undercut at maturity before harvest. In a 2-year study, dehydrator onions were uprooted at maturity to simulate undercutting, and harvest was delayed for several time intervals. Treatment effects on fresh and dry yield, the number of bulbs per plot, bulb fresh and dry weights, and percent dry weight of bulbs were measured. Plots were considered mature when 80% of the tops had fallen. Delaying harvest 15 days after maturity without uprooting did not reduce yield significantly. Yield and both bulb weight and percent dry weight tended to decline when harvest was delayed >15 days after maturity, especially if plants were uprooted. This suggests that undercutting of onions should not be performed until just prior to harvest and that harvest should not be delayed >15 days past maturity. Yield losses in delayed harvest treatments were attributed primarily to Fusarium basal rot.

scholarly journals Fusarium basal rot: profile of an increasingly important disease in Allium spp.

2021 ◽  
Author(s):  
Dung Le ◽  
Kris Audenaert ◽  
Geert Haesaert
Keyword(s):  
Disease Management ◽  
Cultural Practices ◽  
Current Knowledge ◽  
Management Strategies ◽  
Future Directions ◽  
Basal Rot ◽  
Major Constraint ◽  
Fusarium Basal Rot ◽  
Chemical Pesticides ◽  
Important Disease

AbstractFusarium basal rot (FBR) is a soil-borne disease that affects Allium species worldwide. Although FBR has long been recognized as a major constraint to the production of economically important Allium species, information that could support disease management remains scattered. In this review, the current knowledge on the causal agents, symptomology and epidemiology, impact, and management strategies of FBR is synthesized. We highlight that FPR is associated with different complexes of several Fusarium species, of which Fusarium oxysporum and F. proliferatum are the most prevalent. These pathogenic complexes vary in composition and virulence, depending on sites and hosts, which can be challenging for disease management. Research to improve disease management using chemical pesticides, resistance cultivars, biocontrol agents, and cultural practices has achieved both promising results and limitations. Finally, research needs and future directions are proposed for the development of effective FBR management strategies.

scholarly journals Evaluation of Green Manure Amendments for the Management of Fusarium Basal Rot (Fusarium oxysporumf.sp.cepae) on Shallot

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Assefa Sintayehu ◽  
Seid Ahmed ◽  
Chemeda Fininsa ◽  
P. K. Sakhuja
Keyword(s):  
Green Manure ◽  
Agricultural Research ◽  
Disease Incidence ◽  
Limiting Factors ◽  
Lepidium Sativum ◽  
Ethiopian Mustard ◽  
Basal Rot ◽  
Fusarium Basal Rot ◽  
Manure Amendments

Shallot (Allium cepaL. var.ascalonicum) is the most traditional vegetable crop in Ethiopia. Shallot is susceptible to a number of diseases that reduce yield and quality, among which fusarium basal rot (FBR) caused byFusarium oxysporumf.sp.cepae (Foc)is one of the most important yield limiting factors in Ethiopia. The present study was designed to evaluate the effectiveness ofBrassicacrops for the management of shallot FBR on shallot. The experiments were carried out at Debre Zeit Agricultural Research Center using cabbage (Brassica oleracea), garden cress (Lepidium sativum), Ethiopia mustard (B. carinata), and rapeseed (B. napus). The evaluations were done underin vitroand greenhouse conditions. Underin vitrotest condition it was confirmed that extracts of Ethiopian mustard and rapeseed showed higher inhibition on the growth ofFocpathogen compared to control. Data on seedling emergence, plant height, plant stand, disease incidence, severity, cull bulbs, and bulb weight were collected in greenhouse experiment. The green manure amendments of rapeseed and Ethiopian mustard significantly reduced disease incidence by 21% and 30% and disease severity by 23% and 29%, respectively. However the plant emergency was not significantly different among treatments in greenhouse test. These results indicated that Ethiopian mustard and rapeseed crops have potential as green manure for the management of FBR disease of shallot crop.

Economic and interference threshold densities of quackgrass (Elytrigia repens) in potato (Solanum tuberosum)

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 176-180 ◽  
Author(s):  
Régis Baziramakenga ◽  
Gilles D. Leroux
Keyword(s):  
Yield Loss ◽  
Dry Weight ◽  
Field Studies ◽  
Potato Yield ◽  
Hyperbolic Function ◽  
Yield Losses ◽  
Economic Threshold ◽  
Elytrigia Repens ◽  
Shoot Number ◽  
Dry Biomass

Field studies were conducted in 1989 and 1990 at St-Augustin, Quebec, Canada, to determine the economic threshold density of quackgrass in potato. Potato yield losses due to quackgrass interference increased with quackgrass population density. Potato yield ranged from 33 to 73% in 1989, and from 19 to 44% in 1990. The relationship between potato yield losses and quackgrass densities was described by a rectangular hyperbolic function. Dry weight of quackgrass proved to be the best predictor of potato yield loss compared to shoot number. The interference thresholds for 10% potato yield loss amounted to 25 shoots m−2or 20 g total dry biomass m−2. The economic threshold varied between 0.04 and 2 shoots m−2or 0.0165 and 1.5 g total dry biomass m−2, depending on the variables considered.

scholarly journals Comparing Efficiencies of Two Selection Approaches for Improving Fusarium Basal Rot Resistance in Short-Day Onion after a Single Cycle of Selection

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 26
Author(s):  
Subhankar Mandal ◽  
Ashish Saxena ◽  
Christopher S. Cramer ◽  
Robert L. Steiner
Keyword(s):  
Environmental Factors ◽  
Random Distribution ◽  
Single Cycle ◽  
Field Screening ◽  
Selection Cycle ◽  
Short Day ◽  
Basal Rot ◽  
Fusarium Basal Rot ◽  
Consistent Method ◽  
Screening Approaches

The development of Fusarium Basal Rot (FBR)-resistant onion cultivars through field and seedling screening approaches faces tremendous challenges due to non-uniform distribution of the disease pathogen and possible multiple mechanisms of host–plant resistance. This study compared the efficiencies of these two methods for increasing FBR resistance of short-day onion after a single selection cycle. Asymptomatic plants or bulbs of seven onion cultivars were selected using a seedling screen performed in a growth chamber or a field screening of mature bulbs. Original and selected populations were evaluated for their responses to FBR stress thereafter employing the same two methods used for screening. The field screening of mature bulbs was found unreliable in both selection and evaluation, likely due to a non-random distribution of the FBR pathogen and variable environmental factors present in the field. The seedling screening successfully increased FBR resistance in the selected cultivar populations revealed by a seedling evaluation. From the results, it is recommended to use a consistent method for both screening and evaluation to make the most selection progress.

scholarly journals Assessing Quantitative Criteria for Characterization of Quality Categories for Grafted Watermelon Seedlings

Horticulturae ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Filippos Bantis ◽  
Athanasios Koukounaras ◽  
Anastasios Siomos ◽  
Georgios Menexes ◽  
Christodoulos Dangitsis ◽  
...  
Keyword(s):  
Dry Weight ◽  
The Other ◽  
Time Intervals ◽  
Important Species ◽  
Shoot Dry Weight ◽  
Shoot Ratio ◽  
Quality Categories ◽  
Critical Limits ◽  
Experienced Personnel

Vegetable grafting is a practice employed worldwide since it helps prevent biotic and abiotic disorders, and watermelon is one of the most important species grafted. The objective of this study was to set critical limits for the characterization of quality categories for grafted watermelon seedlings. Specifically, watermelon (scion) seedlings were grafted onto squash (rootstock) seedlings, moved into a healing chamber for 7 days, and then transferred into a greenhouse for seven more days. At 7 and 14 days after grafting, experienced personnel assessed grafted seedling quality by categorizing them. The categories derived were Optimum and Acceptable for both time intervals, plus Not acceptable at 14 days after grafting. Optimum seedlings showed greater leaf area, and shoot and root fresh and dry weights at both time intervals. Moreover, they had greater stem diameter, root-to-shoot ratio, shoot dry weight-to-length ratio and Dickson’s quality index compared to the other category at 14 days after grafting. Therefore, Optimum seedlings would likely develop into marketable plants of high quality, with better establishment in the field. Not acceptable seedlings showed considerably inferior development, while Acceptable seedlings were between the other categories, but were still marketable.

Studies in citrus nutrition i. Leaf growth and composition

1956 ◽  
Vol 7 (4) ◽  
pp. 248 ◽  
Author(s):  
RF Williams ◽  
CT Gates
Keyword(s):  
Organic Matter ◽  
Treatment Effects ◽  
Nitrogen Nutrition ◽  
Leaf Growth ◽  
Dry Weight ◽  
Nitrogen Supply ◽  
Dominant Factor ◽  
Nitrogen And Phosphorus ◽  
Citrus Grove ◽  
Four Levels

Vegetative shoots from the spring flush of an experimental citrus grove tagged and sampled on three occasions at intervals of 6 months. The effects of four cultural treatments, four levels of nitrogen supply, four combinations of stock and scion, and of time on leaf area and dry weight, and on relative and absolute contents of water, nitrogen, and phosphorus are presented and discussed. While nitrogen nutrition is still the dominant factor, the evidence strongly suggests that phosphorus nutrition has become important as a determinant of treatment effects within the experimental grove. The possible relevance of soil temperature and soil organic matter for some of the cultural treatment effects is discussed.

Dicamba, Chlorsulfuron, and Clopyralid as Sprayer Contaminants on Sunflower (Helianthus annuus), Mustard (Brassica juncea), and Lentil (Lens culinaris), Respectively

Weed Science ◽  
1989 ◽  
Vol 37 (4) ◽  
pp. 616-621 ◽  
Author(s):  
Douglas A. Derksen
Keyword(s):  
Helianthus Annuus ◽  
Lens Culinaris ◽  
Field Experiments ◽  
Yield Loss ◽  
Dry Weight ◽  
Yield Losses ◽  
Crop Tolerance ◽  
Crop Injury ◽  
Untreated Check ◽  
Grass Weed

Simulated sprayer tank residues of the broadleaf weed herbicides dicamba, chlorsulfuron, and clopyralid applied alone and with the grass weed herbicides sethoxydim and diclofop on sunflower, tame mustard, and lentil, respectively, caused visible crop injury and reduced dry weight and yield. Dry weight production in the greenhouse and crop tolerance ratings in the field indicated that the grass weed herbicides enhanced crop injury from dicamba, chlorsulfuron, and clopyralid. Yield reductions in field experiments were also greater when dicamba and clopyralid were mixed with grass weed herbicides and applied on sunflower and lentil, respectively. This did not occur with chlorsulfuron applied to mustard. When mixed with simulated broadleaf weed herbicide residues, diclofop enhanced dry weight reductions and crop injury and reduced yield to a greater extent than sethoxydim. Crop tolerance ratings differentiated treatments and rates but were not a good estimate of the extent of yield loss. When broadleaf weed herbicides were applied at rates simulating sprayer tank residues alone or combined with grass weed herbicides, yield losses ranged up to 40% in sunflower, 70% in mustard, and 95% in lentil, compared to the untreated check.

Resistance, tolerance, and yield of western black cottonwood infected by Melampsora rust

1992 ◽  
Vol 22 (2) ◽  
pp. 183-192 ◽  
Author(s):  
J. Wang ◽  
B.J. van der Kamp
Keyword(s):  
Disease Severity ◽  
Volume Growth ◽  
Severe Infection ◽  
Dry Weight ◽  
Stem Volume ◽  
Yield Losses ◽  
Black Cottonwood ◽  
Total Dry Weight ◽  
Significant Discovery ◽  
The Relationship

Potted ramets of 14 western black cottonwood (Populustrichocarpa Torr. & Gray) clones from southern British Columbia were inoculated with Melampsoraoccidentalis H. Jacks to produce a range of disease severities, and their size and dry weight were determined after 1 or 2 years. Response to inoculation varied significantly between clones. Clones from drier interior locations were less resistant than those from coastal or moister interior locations. Local- (within leaf) or systemic-induced resistance was not detected. Yield (total dry weight) decreased linearly with disease severity. Percent reduction in yield was greater than the cumulative percent leaf area infected for all clones. Yield losses were substantial: dry weights of ramets with disease severity levels similar to those experienced by natural cottonwood populations were about 75% of controls; heavily infected ramets were <50% of controls. Stem:root ratios increased rapidly with increasing disease severity in all clones, and at significantly different rates. Severe infection resulted in substantial mortality in the following winter and reduced initial stem volume growth in the following growing season. Tolerance, defined as the relationship between disease severity and yield, varied significantly between clones. The most significant discovery of this study was that tolerance and resistance were correlated, greater tolerance being associated with reduced resistance. The concepts of resistance, tolerance, and disease hazard, as quantified in this study, can be used to predict yield and to select the most appropriate clones for different disease hazard conditions.

Yield losses caused by virus infection in four combinations of non-persistently aphid-transmitted virus and cool-season crop legume

2004 ◽  
Vol 44 (1) ◽  
pp. 57 ◽  
Author(s):  
L. J. Latham ◽  
R. A. C. Jones ◽  
B. A. Coutts
Keyword(s):  
Virus Infection ◽  
Mosaic Virus ◽  
Seed Yield ◽  
Faba Bean ◽  
Seed Weight ◽  
Dry Weight ◽  
Yield Losses ◽  
Cool Season ◽  
Individual Seed ◽  
Shoot Dry Weight

Field experiments provided quantitative information on the yield losses caused by virus infection within 4 different combinations of non-persistently aphid-transmitted virus and cool-season crop legume: Alfalfa mosaic virus (AMV) in chickpea, faba bean and lentil, and Cucumber mosaic virus (CMV) in lentil. Virus infection foci were introduced into plots and naturally occurring aphids spread infection from these to the other plants. Plants were tagged individually when typical virus symptoms first appeared during the growing period. Paired plant comparisons between symptomatic and asymptomatic plants were made to measure different yield loss parameters. Late infection with AMV in faba bean cv. Fiord diminished shoot dry weight by 41% and seed yield by 45%, but plants infected earlier recovered sufficiently from their initial shock reaction not to produce significant yield losses. In plants of lentil cv. Matilda first showing symptoms at different times, infection with AMV decreased shoot dry weight by 74–76%, seed yield by 81–87% and individual seed weight by 10–21%, while CMV diminished shoot dry weight by 72–81%, seed yield by 80–90% and individual seed yield by 17–25%. Early infection with AMV killed plants of chickpea cv. Tyson while later infection decreased shoot dry weight by 50%, seed yield by 98% and individual seed weight by 90%. The first tentative evidence for seed transmission of AMV in faba bean is reported with a transmission rate of 0.04%.

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