Cotton Yield Losses and Ambient Ozone Concentrations in California's San Joaquin Valley

ABSTRACT The ramularia leaf spot (RLS) disease causes cotton yield losses. Choosing a less susceptible cultivar and a sowing time that are less favorable to the pathogen contribute to the management of this disease. The objective of this work was to evaluate the severity of ramularia leaf spot on cotton cultivars sowed in two different times. The experiment was conducted in a triple factorial design (4x3x2), consisted of four cultivars, the three thirds of the plant and two sowing times, with four replications. Each plot was divided in two twin plots, one with fungicide application (with disease control) and the other without fungicide application (without disease control). The severity assessments were performed every seven days, considering each third of the plant with a diagrammatic scale. Yield was evaluated in each plot. There was a significant interaction between sowing times and the thirds of the plant in the plots without disease control for RLS severity, with the highest values of area under the disease progress curve (AUDPC) in the first sowing time (ST1) and in the lower third of the plant. The FMT705 cultivar had the highest and FM951LL the lowest value of AUDPC. The AUDPC of these cultivars were no statistically different in the second sowing time (ST2), but they had higher AUDPC values in the lower third. Highest yields were found with ST1 in plots with disease control, with no differences between the cultivars, however, lower yields were found in plots without disease control.

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Pathological anatomy of needles of Pinus strobus e×posed to carbon-filtered air or to three times ambient ozone concentrations, or infected by Canavirgella banfieldii

Canadian Journal of Botany ◽

10.1139/cjb-76-8-1331 ◽

1998 ◽

Vol 76 (8) ◽

pp. 1331-1339 ◽

Cited By ~ 1

Author(s):

N.G. Wenner ◽

W. Merrill

Keyword(s):

Pinus Strobus ◽

Pathological Anatomy ◽

Ambient Ozone ◽

Ozone Concentrations

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Changes in the yield quantity and quality of the pods of four legume crops in response to elevated ambient ozone in Riyadh

South Asian Journal of Experimental Biology ◽

10.38150/sajeb.3(2).p97-105 ◽

2013 ◽

Vol 3 (2) ◽

pp. 97-105

Author(s):

Ibrahem A.A. Almohisen ◽

Mohammed Nasser Alyemeni

Keyword(s):

Soluble Sugar ◽

Dry Weight ◽

Vigna Sinensis ◽

Ambient Ozone ◽

Ozone Concentrations ◽

Elevated Ozone ◽

Legume Crops ◽

Negative Effect ◽

Yield Responses

A field study was conducted to evaluate the effects of ambient ozone on the yield quantity and quality of the pods of four legume crops (Pisum sativum L., Vicia faba L., Glycine max and Vigna sinensis) grown under five ambient ozone concentrations: 17.80, 61.00, 71.50, 78.75 and 111.78 ppb and 21.25, 67.25, 96.5, 105.5 and141.25 ppb during winter and summer, respectively. The ozone levels significantly affected the yield of both the winter and summer species. As the ozone concentration increased, the number and dry weight of the pods decreased. The plants varied in their yield responses to stress; however, the degree of damage in all of the species was more severe under elevated ozone. The protein, fat, soluble sugar and polysaccharide content were significantly different in the pods. This investigation recorded high ozone concentrations at the studied sites with a high source of air pollution, especially during the summer, and demonstrated the negative effect of ozone on the yield quantity and quality of the tested species.

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