Search Results - (Author, Cooperation:J. D. Clarkson)

2014-12-19

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2016-01-28

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2016-03-05

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

A single-shoot assessment method was used at 18 locations in England and Wales from 1976 to 1981 to compare the average yield of large numbers of shoots naturally infected with sharp eysspot (Rhizoctonia cerealis) with the yield of healthy shoots. Slight sharp eyespot infection had. on average, little effect on yield. Moderate infection significantly reduced yield per ear and 1000-grain weight by 5 and 4% respectively. Severe infection significantly reduced yield per ear and its components, grain number per ear and 1000-grain weight, by 26, 20 and 11% respectively. Application of the formula y = 0-05 x1+ 0.26 x2 (where y = percentage yield loss, X1= percentage of moderately Infected shoots and x2= percentage of severely infected shoots) to the results of ADAS winter wheat disease surveys from 1975 to 1982 gave estimated national yieid losses due lo sharp eyespot ranging from less than 0.1 to 0.9%. Survey results indicated that increased disease incidence and associated yield losses are associated with trends towards earlier drilling and, possibly, with increased use of carbendazimgenerating fungicides, combined with more favourable infection weather.

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Random samples of 500–600 single plants were taken from four winter wheat crops in eastern England during 1977–79 to establish the relationship between grain yield and severity of take-all (Gaeuman- nomyces graminis(Sacc.) Arx & Olivier var. tritici J. Walker) on the roots at harvest. In each crop separate samples were taken from areas of stunted plants with much take-all infection and from areas with apparently normal growth.The root system of each plant was assessed for take-all severity using four infection categories: healthy, slight (less than 25 per cent of the root system infected), moderate (25–75 per cent) and severe (more than 75 per cent). The assessment figures were compared with ear number, grain number and grain dry weight, which were also recorded for each plant individually.Shght take-all had no effect on yield. Moderate take-all had no effect on the number of ears per plant but significantly reduced grain number per plant, 1000-grain weight and grain dry weight per plant by 6–9, 10–6 and 15–6 per cent respectively. The reduction in grain dry weight per plant associated with severe take-all was between 53.1 and 61.6 per cent.Estimates of minimum national loss caused by take-all in winter wheat in the years 1977–79 were 0-9, 2–6 and 2–8 per cent respectively.

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Isolates of Fusarium solani, F. solani var, coeruleum, F. oxysporum, F. oxysporum var. redolens, F. avenaceum, F. graminearum, F. sambucinum var. coeruleum and F. equiseti were obtained from field samples of Pisum sativum, Phaseolus vulgar is, P. coccineus and Vicia faba with foot-rot symptoms. Their pathogenicity was tested in the glasshouse using artificially infested soiJ. All isolates originally identified as F. solani var. coeruleum and F. oxysporum var. redolens were later regarded as strains of F. solani on the evidence of their pathogenicity.Virulent isolates of F. solani from Pisum sativwn were also pathogenic to Phaseolus vulgar is but usually not to V. faba, although an isolate from V. faba was strongly pathogenic to Pisum sativum. Less virulent isolates from P. sativum, Phaseolus vulgar is and P. coccineus were generally equally pathogenic to both Pisum sativum and Phaseolus vulgar is. Isolates from Pisum sativum infected other legumes, particularly Trifolium pratense and Medicago sativa and an isolate from Trifolium sp. caused severe foot-rot of P. sativum.Isolates of F. avenaceum, F. graminearum and F. sambucinum var. coeruleum showed non-specific pathogenicity to P. sativum, Phaseolus vulgar is and V. faba, generally causing seedling death. F. avenaceum and F. sambucinum var. coeruleum were also pathogenic to other legumes, particularly M. sativa.

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Between 500 and 1000 winter wheat plants were taken at random immediately before harvest from crops with naturally or artificially created attacks of eyespot (Pseudocercosporella herpotrichoides (Fron) Deighton) at eight sites in eastern England from 1975 to 1979. The individual shoots of each plant were placed in one of four categories: healthy, or slightly, moderately or severely infected with eyespot. Healthy shoots were sub-divided into those from plants with all shoots healthy and those from plants with at least one infected shoot. Ears were threshed individually and average dry weight of grain per ear, grain number per ear and 1000-grain dry weight were computed for each infection category and both healthy shoot categories.Slight eyespot had no effect on yield. Moderate eyespot reduced yield per ear, grain number per ear and 1000-grain weight by 10, 8 and 5 per cent respectively; severe eyespot caused corresponding losses of 36, 29 and 15 per cent.Healthy shoots showed no apparent compensation for yield loss in eyespot-infected shoots on the same plant.The equation y= O.lX1+ 0.36x2, where y= percentage yield loss, x1= percentage of moderately infected shoots and x2= percentage of severely infected shoots, was applied to the results of ADAS winter wheat disease surveys from 1975 to 1980. National yield losses due to eyespot in these years were estimated tobe 0.9, 0.3, 1.1, 1.2, 0.7 and 0.3 per cent respectively.

Electronic Resource

0037-6795

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Slavonic Studies

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