Compute the Weighted germination percentage \(WGP\) or Weighted germination index \(WGI\) (Reddy 1978; Reddy et al. 1985) .
WeightGermPercent(germ.counts, total.seeds, intervals, partial = TRUE)Germination counts at each time interval. Can be partial
or cumulative as specified in the argument partial.
Total number of seeds tested.
The time intervals.
logical. If TRUE, germ.counts is considered as
partial and if FALSE, it is considered as cumulative. Default is
TRUE.
The weighted germination percentage (%) value.
Weighted germination percentage was calculated by giving maximum weight to the seeds that germinate first and decreasing weight to the seeds that germinate subsequently. It is computed as follows (Reddy 1978; Reddy et al. 1985) .
\[WGP = \frac{\sum_{i=1}^{k}(k-i+1)N_{i}}{k \times N} \times 100\]
Where, \(N_{i}\) is the number of seeds that germinated in the time interval \(i\) (not cumulative, but partial count), \(N\) is the total number of seeds tested, and \(k\) is the total number of time intervals.
Reddy LV (1978).
Effect of temperature on seed dormancy and alpha-amylase activity during kernel maturation and germination in wheat (Triticum aestivum L.) cultivars.
Ph.D. Thesis, Oregon State University.
Reddy LV, Metzger RJ, Ching TM (1985).
“Effect of temperature on seed dormancy of wheat.”
Crop Science, 25(3), 455.
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
#----------------------------------------------------------------------------
WeightGermPercent(germ.counts = x, total.seeds = 50, intervals = int)
#> [1] 47.42857
# From cumulative germination counts
#----------------------------------------------------------------------------
WeightGermPercent(germ.counts = y, total.seeds = 50, intervals = int,
partial = FALSE)
#> [1] 47.42857