Median germination time
Compute the median germination time (\(t_{50}\)). Median germination time is the time to reach 50% of final/maximum germination.
t50(germ.counts, intervals, partial = TRUE, method = c("coolbear", "farooq"))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 |
method |
The method for computing median germination time. Either
|
With argument method specified as "coolbear", median
germination time is computed according to the formula by
Coolbear et al. (1984) as follows.
Where, \(t_{50}\) is the median germination time, \(N\) is the final number of germinated seeds, and \(N_{i}\) and \(N_{j}\) are the total number of seeds germinated in adjacent counts at time \(T_{i}\) and \(T_{j}\) respectively, when \(N_{i} < \frac{N + 1}{2} < N_{j}\).
Similarly with argument method specified as "farooq", median
germination time is computed according to the formula by by
Farooq et al. (2005) as follows.
Where, \(t_{50}\) is the median germination time, \(N\) is the final number of germinated seeds, and \(N_{i}\) and \(N_{j}\) are the total number of seeds germinated in adjacent counts at time \(T_{i}\) and \(T_{j}\) respectively, when \(N_{i} < \frac{N}{2} < N_{j}\).
The median germination time (\(t_{50}\)) value in the same unit
of time as specified in the argument intervals.
Coolbear P, Francis A, Grierson D (1984).
“The effect of low temperature pre-sowing treatment on the germination performance and membrane integrity of artificially aged tomato seeds.”
Journal of Experimental Botany, 35(11), 1609–1617.
Farooq M, Basra SMA, Ahmad N, Hafeez K (2005).
“Thermal hardening: A new seed vigor enhancement tool in rice.”
Journal of Integrative Plant Biology, 47(2), 187–193.
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 #---------------------------------------------------------------------------- t50(germ.counts = x, intervals = int, method = "coolbear") t50(germ.counts = x, intervals = int, method = "farooq") # From cumulative germination counts #---------------------------------------------------------------------------- t50(germ.counts = y, intervals = int, partial = FALSE, method = "coolbear") t50(germ.counts = y, intervals = int, partial = FALSE, method = "farooq")
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