# EmergenceRateIndex: Emergence Rate Index or Germination Rate Index In germinationmetrics: Seed Germination Indices and Curve Fitting

## Description

Compute the Emergence rate index or Germination rate index according to

• \insertCite

shmueliEmergenceEarlyGrowth1971;textualgerminationmetrics and it's modification by \insertCitede_santana_alise_2004;textualgerminationmetrics \insertCiteranal_how_2006germinationmetrics;

• \insertCite

bilbroSoilCrustsCotton1982;textualgerminationmetrics; and

• \insertCite

fakoredeRelationSeedlingVigor1980;textualgerminationmetrics, \insertCitefakoredeVariabilitySeedlingVigour1981;textualgerminationmetrics, and \insertCitefakoredeHeteroticEffectsAssociation1983;textualgerminationmetrics.

## Usage

 1 2 3 4 5 6 7 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

GermSpeed, TimsonsIndex, GermRateGeorge
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 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")