FirstGermTime: Time for first, last and peak germination

In germinationmetrics: Seed Germination Indices and Curve Fitting

Time for first, last and peak germination

Description

Compute the following metrics:

FirstGermTime

Time of first germination or Germination time lag (\mjseqnt_0) \insertCiteedwards_temperature_1932,czabator_germination_1962,goloff_germination_1975,labouriau_germinacao_1983,ranal_effects_1999,quintanilla_effect_2000germinationmetrics.

LastGermTime

Time of last germination (\mjseqnt_g) \insertCiteedwards_temperature_1932,labouriau_germinacao_1983,ranal_how_2006germinationmetrics.

TimeSpreadGerm

Time spread of germination \insertCiteal-mudaris_notes_1998,kader_comparison_2005germinationmetrics or Germination distribution \insertCiteschrader_seed_2000germinationmetrics.

PeakGermTime

Peak time of germination or Modal time of germination (\mjseqnt_peak) \insertCiteranal_how_2006germinationmetrics.

\loadmathjax

Usage

FirstGermTime(germ.counts, intervals, partial = TRUE)

LastGermTime(germ.counts, intervals, partial = TRUE)

PeakGermTime(germ.counts, intervals, partial = TRUE)

TimeSpreadGerm(germ.counts, intervals, partial = TRUE)

Arguments

germ.counts	Germination counts at each time interval. Can be partial or cumulative as specified in the argument partial.
intervals	The time intervals.
partial	logical. If TRUE, germ.counts is considered as partial and if FALSE, it is considered as cumulative. Default is TRUE.

Details

Time of first germination indicates time of germination of the faster seeds in a seedlot.

Lower value of time of first germination indicates faster initiation of germination and lower value of time of last germination indicates faster termination of germination.

\mjsdeqn

t_0 = \min \lbrace T_i : N_i \neq 0 \rbrace

\mjsdeqn

t_g = \max \lbrace T_i : N_i \neq 0 \rbrace

Where, \mjseqnT_i is the time from the start of the experiment to the \mjseqnith interval and \mjseqnN_i is the number of seeds germinated in the \mjseqnith time interval (not the accumulated number, but the number corresponding to the \mjseqnith interval).

Time spread of germination (\mjseqnt_g-t_0) indicates difference between faster and slower germinating members of a sample.

Peak time of germination is the time in which highest frequency of germinated seeds are observed. Multiple peak times of germination are possible and if detected are indicated by a warning message.

\mjsdeqn

t_peak = \lbrace T_i : N_i = N_max \rbrace

Where, \mjseqnN_max is the maximum number of seeds germinated per interval.

Value

For FirstGermTime, the time of first germination value in the same unit of time as specified in the argument intervals.

For LastGermTime, the time of last germination value in the same unit of time as specified in the argument intervals.

For TimeSpreadGerm, the time spread of germination value in the same unit of time as specified in the argument intervals.

For PeakGermTime, the time(s) of peak germination value(s) as a numeric vector in the same unit of time as specified in the argument intervals.

References

\insertAllCited

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
#----------------------------------------------------------------------------
FirstGermTime(germ.counts = x, intervals = int)
LastGermTime(germ.counts = x, intervals = int)
TimeSpreadGerm(germ.counts = x, intervals = int)
PeakGermTime(germ.counts = x, intervals = int)
# For multiple peak germination times
PeakGermTime(germ.counts = z, intervals = int)

# From cumulative germination counts
#----------------------------------------------------------------------------
FirstGermTime(germ.counts = y, intervals = int, partial = FALSE)
LastGermTime(germ.counts = y, intervals = int, partial = FALSE)
TimeSpreadGerm(germ.counts = y, intervals = int, partial = FALSE)
PeakGermTime(germ.counts = y, intervals = int, partial = FALSE)
# For multiple peak germination time
PeakGermTime(germ.counts = cumsum(z), intervals = int, partial = FALSE)

germinationmetrics documentation built on Aug. 19, 2023, 1:07 a.m.