EmergenceRateIndex: Emergence Rate Index or Germination Rate Index

Description Usage Arguments Value Details References See Also Examples

View source: R/EmergenceRateIndex.R

Description

Compute the Emergence rate index or Germination rate index according to

\loadmathjax

Usage

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EmergenceRateIndex(
  germ.counts,
  intervals,
  partial = TRUE,
  total.seeds = NULL,
  method = c("melville", "melvillesantanaranal", "bilbrowanjura", "fakorede")
)

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.

total.seeds

Total number of seeds.

method

The method to be used. Either "melville", "melvillesantanaranal", "bilbrowanjura" or "fakorede". Default is "melville" (see Details).

Value

The value of the Emergence rate index.

Details

Several germination indices are referred to as Emergence rate Index (\mjseqnERI).

\insertCiteshmueliEmergenceEarlyGrowth1971;textualgerminationmetrics

It is estimated as follows.

\mjsdeqn

ERI = \sum_i=i_0^k-1N_i(k-i)

Where, \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), \mjseqni_0 is the time interval when emergence/germination started, and \mjseqnk is the total number of time intervals.

A modification for the same was suggested by \insertCitede_santana_alise_2004;textualgerminationmetrics \insertCiteranal_how_2006germinationmetrics and is estimated by dividing Emergence rate index (\mjseqnERI) by total number of emerged seedlings (or germinated seeds) as follows.

\mjsdeqn

ERI_mod = \frac\sum_i=i_0^k-1N_i(k-i)N_g = \fracERIN_g

Where, \mjseqnN_g is the total number of germinated seeds at the end of the test, \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), \mjseqni_0 is the time interval when emergence/germination started, and \mjseqnk is the total number of time intervals.

\insertCitebilbroSoilCrustsCotton1982;textualgerminationmetrics

It is the estimated as follows.

\mjsdeqn

ERI = \frac\sum_i=1^kN_i\overlineT = \fracN_g\overlineT

Where, \mjseqnN_g is the total number of germinated seeds at the end of the test, \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), and \mjseqn\overlineT is the mean germination time or mean emergence time.

\insertCitefakoredeRelationSeedlingVigor1980,fakoredeVariabilitySeedlingVigour1981,fakoredeHeteroticEffectsAssociation1983;textualgerminationmetrics

It is estimated as follows.

\mjsdeqn

ERI = \frac\overlineTFGP/100

Where, \mjseqn\overlineT is the Mean germination time and \mjseqnFGP is the final germination time.

Others

Apart from the above the above, the name Emergence rate index (\mjseqnERI) has also been used to for the mathematical expressions for Speed of germination (GermSpeed) \insertCiteallan_seedling_1962,erbachTillageContinuousCorn1982germinationmetrics, Timson's index (TimsonsIndex) \insertCitechaudharyEffectTemperatureAssociated1970germinationmetrics, and George's index (GermRateGeorge) \insertCitechopraEffectSoilTemperature1980germinationmetrics.

References

\insertAllCited

See Also

GermSpeed, TimsonsIndex, GermRateGeorge

Examples

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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
#----------------------------------------------------------------------------
EmergenceRateIndex(germ.counts = x, intervals = int)
EmergenceRateIndex(germ.counts = x, intervals = int,
                   method = "melville")
EmergenceRateIndex(germ.counts = x, intervals = int,
                   method = "melvillesantanaranal")
EmergenceRateIndex(germ.counts = x, intervals = int,
                   method = "bilbrowanjura")
EmergenceRateIndex(germ.counts = x, intervals = int,
                   total.seeds = 50, method = "fakorede")

# From cumulative germination counts
#----------------------------------------------------------------------------
EmergenceRateIndex(germ.counts = y, intervals = int, partial = FALSE,)
EmergenceRateIndex(germ.counts = y, intervals = int, partial = FALSE,
                   method = "melville")
EmergenceRateIndex(germ.counts = y, intervals = int, partial = FALSE,
                   method = "melvillesantanaranal")
EmergenceRateIndex(germ.counts = y, intervals = int, partial = FALSE,
                   method = "bilbrowanjura")
EmergenceRateIndex(germ.counts = y, intervals = int, partial = FALSE,
                   total.seeds = 50, method = "fakorede")

germinationmetrics documentation built on Feb. 17, 2021, 5:09 p.m.