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How green is green? Sampling and perception in assessing green seeds and chlorophyll in canola
Author(s) -
Daun James K.,
Symons Stephen
Publication year - 2000
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-000-0188-0
Subject(s) - canola , rapeseed , mathematics , chlorophyll , stratified sampling , sampling (signal processing) , statistics , environmental science , agronomy , biology , botany , engineering , telecommunications , detector
Green seeds are used as a grading factor in estimating chlorophyll in canola and rapeseed in the Canadian and U.S.A. grading systems. This work examines the effect that sampling and perception have on the estimation of green seeds as well as the effect that sampling has on the determination of chlorophyll. Individual seed analysis indicated that in order to be considered as green, seeds needed to contain between 200 and 400 mg/kg chlorophyll. Variation due to binomial sampling played a predominant role in the error in determining the green seed levels in canola. Sampling of large numbers of seeds, as in the loading of export shipments, reduced the error. Binomial sampling also contributed to the error in chlorophyll determination even with sample sizes as large as 500. Differences in perception of green also were noted between individuals with coefficients of variation as high as 50% at the 1% green seed level. The combination of perception error and sampling error may result in samples of 1,000 seeds drawn from a mass with 2% green seeds having green seed counts ranging from 0.96 to 3.04%, 19 times out of 20.