germinationmetrics (version 0.1.3)

TimsonsIndex: Timson's index

Description

Compute George's index george_influence_1961;textualgerminationmetrics, Timson's index or Timson's germination velocity index grose_laboratory_1958,timson_new_1965germinationmetrics and it's modifications by Labouriau ranal_how_2006germinationmetrics and khan_effect_1984germinationmetrics.

Usage

TimsonsIndex(germ.counts, intervals, partial = TRUE, total.seeds, max,
  modification = c("none", "labouriau", "khanungar"))
GermRateGeorge(germ.counts, intervals, partial = TRUE, max)

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.

max

The maximum interval value up to which Timson's index/George's germination rate is to be computed.

modification

The modification to be applied. Either "none", "labouriau" or "khanungar". Default is "none" (see Details).

Value

For TimsonsIndex The value of Timson's index.

For GermRateGeorge The value of George's germination rate.

Details

Timson's index timson_new_1965germinationmetrics is computed as follows grose_laboratory_1958,brown_representing_1988,baskin_seeds:_1998germinationmetrics.

Where, is the cumulative germination percentage in time interval and is the total number of time intervals.

For example ten summation (\(\Sigma 10\)) is expressed as follows:

Where are the cumulative germination percentage at day 1, 2, 3, , 10 respectively.

Similarly \(\Sigma 5\) or \(\Sigma 20\) can be estimated. For \(\Sigma 10\), the value can range from 0 (no germination) to 1,000 (100% germination after 24 hours).

It is the progressive total of cumulative germination percentage recorded at specific intervals for a set period of time. It combines onset, rate and total percentage of germination and estimates the area under the cumulative germination percentage curve.

goodchild_method_1971;textualgerminationmetrics, described the same in terms of partial germination percentage as follows:

Where, is the germination (not cumulative, but partial germination) in time interval

( varying from to ) and is the total number of time intervals and .

Timson's index is equivalent to the Germination Energy Index proposed by grose_laboratory_1958;textualgerminationmetrics.

Timson's index is similar to the germination rate proposed by george_influence_1961;textualgerminationmetrics as follows tucker_estimating_1965,nichols_two_1968germinationmetrics.

Where is the number of seeds germinated by th interval and is the number of intervals(e.g. days) until the end of the test.

This index uses number of seeds germinated instead of germination percentage.

As Timson's index is useful for comparison only when samples have similar germinabilities or final germination percentage, the following modification was suggested by Labouriau ranal_how_2006germinationmetrics.

Here Timson's index () is divided by the sum of partial germination percentages.

Similarly another modification was proposed by khan_effect_1984germinationmetrics, where Timson's index () is divided by number of intervals ().

References

Examples

# NOT RUN {
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
#----------------------------------------------------------------------------
# Wihout max specified
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50)
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50,
             modification = "none")
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50,
             modification = "labouriau")
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50,
             modification = "khanungar")
# With max specified
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50, max = 10)
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50,
             max = 10, modification = "none")
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50,
             max = 10, modification = "labouriau")
TimsonsIndex(germ.counts = x, intervals = int, total.seeds = 50,
             max = 10, modification = "khanungar")

# Wihout max specified
GermRateGeorge(germ.counts = x, intervals = int)
# With max specified
GermRateGeorge(germ.counts = x, intervals = int, max = 10)
GermRateGeorge(germ.counts = x, intervals = int, max = 14)

# From cumulative germination counts
#----------------------------------------------------------------------------


# Wihout max specified
GermRateGeorge(germ.counts = x, intervals = int, partial = TRUE)
# With max specified
GermRateGeorge(germ.counts = x, intervals = int, partial = TRUE, max = 10)
GermRateGeorge(germ.counts = x, intervals = int, partial = TRUE, max = 14)
# }