Compute the Coefficient of uniformity of germination (CUG).
CUGerm(germ.counts, intervals, partial = TRUE)Germination counts at each time interval. Can be partial
or cumulative as specified in the argument partial.
The time intervals.
logical. If TRUE, germ.counts is considered as
partial and if FALSE, it is considered as cumulative. Default is
TRUE.
The value of the coefficient of uniformity of germination as
\(\mathrm{time^{-2}}\).
CUG is computed as follows (Heydecker 1972; Bewley and Black 1994) .
\[CUG = \frac{\sum_{i=1}^{k}N_{i}}{\sum_{i=1}^{k}(\overline{T}-T_{i})^{2}N_{i}}\]
Where, \(\overline{T}\) is the the mean germination time, \(T_{i}\) is the time from the start of the experiment to the \(i\)th interval, \(N_{i}\) is the number of seeds germinated in the \(i\)th time interval (not the accumulated number, but the number corresponding to the \(i\)th interval), and \(k\) is the total number of time intervals.
Bewley JD, Black M (1994).
Physiology of Development and Germination.
Plenum Publishing Corporation, New York, USA.
ISBN 0-306-44748-7, tex.ids= bewley_ seeds:_1994, bewley_ seeds:_1994-1, bewley_ seeds:_1994-2 googlebooksid: W6EbrewcpDwC.
Heydecker W (1972).
Seed Ecology. Proceedings of the Nineteenth Easter School in Agricultural Science, University of Nottingham, 1972.
Pennsylvania State University Press, University Park, USA.
x <- c(0, 0, 0, 0, 4, 17, 10, 7, 1, 0, 1, 0, 0, 0)
y <- c(0, 0, 0, 0, 4, 21, 31, 38, 39, 39, 40, 40, 40, 40)
int <- 1:length(x)
# From partial germination counts
#----------------------------------------------------------------------------
CUGerm(germ.counts = x, intervals = int)
#> [1] 0.7092199
# From cumulative germination counts
#----------------------------------------------------------------------------
CUGerm(germ.counts = y, intervals = int, partial = FALSE)
#> [1] 0.7092199