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Size and shape of sampling units for estimating incidence of sharp eyespot, Rhizoctonia cerealis, in plots of wheat

Published online by Cambridge University Press:  27 March 2009

C. A. Gilligan
Affiliation:
Department of Applied Biology, University of Cambridge, Pembroke Street, Cambridge, CB2 3DX

Extract

It has long been known that the size and shape of sampling units used to assess crop yield may have significant effects upon the precision of the estimates (Smith, 1938; Hudson, 1939) but little is known about the effects when estimating incidence of disease. Gilligan (1980) showed that estimates of the incidence (i.e. presence or absence of disease) of stem canker (Phomx, lingam, perfect state Lepto sphaeria maculans)of oil-seed rape were more precise when large square sampling units rather than long rectangular units of similar area or small square sampling units were used. Moreover, estimates derived from the frequently used method of sampling by removal of 25 stems, supposedly at random from each plot, were shown to be biased.

Type
Short Note
Copyright
Copyright © Cambridge University Press 1982

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References

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