Germination Index
Compute the Germination index according to Melville et al. (1980) and its modification by de Santana and Ranal (2004) (Ranal and de Santana 2006).
GermIndex(
germ.counts,
intervals,
partial = TRUE,
total.seeds,
modification = c("none", "santanaranal")
)germ.counts |
Germination counts at each time interval. Can be partial
or cumulative as specified in the argument |
intervals |
The time intervals. |
partial |
logical. If |
total.seeds |
Total number of seeds. |
modification |
The modification to be applied. Either |
Germination index (\(GI\)) is computed as follows (Melville et al. 1980).
Where, \(T_{i}\) is the time from the start of the experiment to the \(i\)th interval (day for the example), \(N_{i}\) is the number of seeds germinated in the \(i\)th time interval (not the accumulated number, but the number corresponding to the \(i\)th interval), \(N_{t}\) is the total number of seeds used in the test, and \(k\) is the total number of time intervals.
A modified germination index (\(GI_{mod}\)) was proposed by (de Santana and Ranal 2004) where total number of seeds tested (\(N{t}\)) is replaced by the total number of germinated seeds (\(N{g}\)) in the expression of Melville et al. (1980) to remove the effect of sample size (Ranal and de Santana 2006).
The term Germination index (\(GI\)) has also been used to describe the
mathematical expression for Speed of germination
(GermSpeed) by
AOSA (1983).
The value of the Germination index.
AOSA (1983).
Seed Vigor Testing Handbook.
Association of Official Seed Analysts, Ithaca, NY, USA.
Melville AH, Galletta GJ, Draper AD, Ng TJ (1980).
“Seed germination and early seedling vigor in progenies of inbred strawberry selections.”
HortScience, 15(6, I), 749–750.
Ranal MA, de Santana DG (2006).
“How and why to measure the germination process?”
Brazilian Journal of Botany, 29(1), 1–11.
de Santana DG, Ranal MA (2004).
Analise Da Germinacao: Um Enfoque Estatistico.
Universidade de Brasilia, Brasilia.
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
#----------------------------------------------------------------------------
GermIndex(germ.counts = x, intervals = int, total.seeds = 50)
GermIndex(germ.counts = x, intervals = int, total.seeds = 50,
modification = "none")
GermIndex(germ.counts = x, intervals = int, total.seeds = 50,
modification = "santanaranal")
# From cumulative germination counts
#----------------------------------------------------------------------------
GermIndex(germ.counts = y, intervals = int, partial = FALSE,
total.seeds = 50)
GermIndex(germ.counts = y, intervals = int, partial = FALSE,
total.seeds = 50,
modification = "none")
GermIndex(germ.counts = y, intervals = int, partial = FALSE,
total.seeds = 50,
modification = "santanaranal")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.