GermPercent {germinationmetrics}

Germination percentage

Description

Compute the following metrics:

GermPercent

Germination percentage or Final germination percentage or Germinability (ISTA 2015).

PeakGermPercent

Peak germination percentage (Vallance 1950; Roh et al. 2004).

Usage

GermPercent(germinated.seeds, germ.counts, total.seeds, partial = TRUE)

PeakGermPercent(germ.counts, intervals, total.seeds, partial = TRUE)

Arguments

germinated.seeds

Number of germinated seeds

germ.counts

Germination counts at each time interval. Can be partial or cumulative as specified in the argument partial.

total.seeds

Total number of seeds.

partial

logical. If TRUE, germ.counts is considered as partial and if FALSE, it is considered as cumulative. Default is TRUE.

intervals

The time intervals.

Details

Germination percentage is computed as follows (ISTA 2015).

\[GP = \frac{N_{g}}{N_{t}} \times 100\]

Where, \(N_{g}\) is the number of germinated seeds and \(N_{t}\) is the total number of seeds.

The value of \(N_{g}\) can be either specified using the argument germinated.seeds or is computed from the germ.counts argument.

Peak germination percentage is computed as follows (Vallance 1950; Roh et al. 2004).

\[PGP = \frac{N_{max}}{N_{t}} \times 100\]

Where, \(N_{max}\) is the maximum number of seeds germinated per interval.

Value

The germination percentage (%) value.

References

ISTA (2015). “Chapter 5: The germination test.” In International Rules for Seed Testing. International Seed Testing Association, Zurich, Switzerland., volume 2015, i–5–56. International Seed Testing Association.

Roh M, Bentz J, Wang P, Li E, Koshioka M (2004). “Maturity and temperature stratification affect the germination of Styrax japonicus seeds.” The Journal of Horticultural Science and Biotechnology, 79(4), 645–651.

Vallance KB (1950). “Studies on the germination of the seeds of Striga hermonthica I. The influence of moisture-treatment, stimulant-dilution, and after-ripening on germination.” Annals of Botany, 14(55), 347–363.

Examples

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)
z <- c(0, 0, 0, 0, 11, 11, 9, 7, 1, 0, 1, 0, 0, 0)
int <- 1:length(x)

# From partial germination counts
#----------------------------------------------------------------------------
GermPercent(germ.counts = x, total.seeds = 50)
PeakGermPercent(germ.counts = x, intervals = int, total.seeds = 50)
# For multiple peak germination times
PeakGermPercent(germ.counts = z, intervals = int, total.seeds = 50)

# From cumulative germination counts
#----------------------------------------------------------------------------
GermPercent(germ.counts = y, total.seeds = 50, partial = FALSE)
PeakGermPercent(germ.counts = y, intervals = int, total.seeds = 50,
                partial = FALSE)
# For multiple peak germination times
PeakGermPercent(germ.counts = cumsum(z), intervals = int, total.seeds = 50,
                partial = FALSE)

# From number of germinated seeds
#----------------------------------------------------------------------------
GermPercent(germinated.seeds = 40, total.seeds = 50)