fw_test: Perform Finlay-Wilkinson Test

In nad7wf/FW: Run Finlay-Wilkinson Test

Description

Use Finlay-Wilkinson test to test for GxE interaction by comparing (GE ~ Location mean) regression coefficient against a slope of 1.

Usage

fw_test(GE_dat, Loc_dat, plot_GE = as.numeric(NA), test_slope = 1)

Arguments

GE_dat	A data.frame containing yield values for each GE at tested locations. The first two columns must be 'GE' and 'Year', followed by columns of yield data at each location. See example data below.
Loc_dat	A data.frame of location means for each location in GE_dat. Col names: 'Loc', 'Year', 'Loc_mean'.
plot_GE	(optional) A numeric GE ID to be plotted.
test_slope	The slope that the FW test should be performed against (default = 1).

Value

If plot_GE is not specified: returns a data.frame containing a slope and p-value for each GE/Year combination.

If plot_GE is specified: returns a list, where the first element is a data.frame of slopes and p-values for all GE/Year combinations, and the second element is a gtable containing the plot for the specified GE. The plot can be drawn using grid::grid.draw(list_name[2]).

Examples

set.seed(1)

ge <- matrix(rnorm(405, c(75, 78)), nrow = 27, ncol = 15) %>%
    as.data.frame() %>%
    stats::setNames(paste0("Loc", seq(1, 15))) %>%
    dplyr::mutate(GE = rep(1:9, each = 3),
                  Year = rep(2018:2020, times = 9)) %>%
    dplyr::select(GE, Year, everything())

loc <- plyr::ddply(ge, "Year", function (Year_group) {
    purrr::map_dfr(Year_group[, 3:ncol(Year_group)], mean)
}) %>%
    tidyr::gather(key = "Loc", value = "Loc_mean", -Year) %>%
    dplyr::select(Loc, Year, Loc_mean)

results <- fw_test(ge, loc, 6)

nad7wf/FW documentation built on Sept. 16, 2020, 12:48 a.m.