I have the following plot where I wish to remove the black lines between columns but not the outline for a whole block e.g. wild and landrace. Is there a way to do so based on the code I'm using? Thanks in advance!

Example code:

library(tidyr)
library(dplyr)
library(tibble)
library(ggplot2)
library(forcats)
library(RColorBrewer)

tbl = read_table("path/to/test.3.Q", col_names=c('comp1','comp2','comp3'))
tbl

df2 <- pivot_longer(tbl, comp1:comp3)
df2

sampleID = c(rep("INLUP00165", 3), rep("INLUP00169", 3), rep("INLUP00208", 3), rep("INLUP00214", 3), rep("INLUP00228", 3), rep("INLUP00245", 3), 
             rep("INLUP00325", 3), rep("INLUP00332", 3), rep("INLUP00393", 3), rep("INLUP00418", 3), rep("INLUP00496", 3))
variety = c(rep("wild", 3), rep("landrace", 3), rep("wild", 6), rep("landrace", 3), rep("wild", 3), rep("landrace", 18))

tbl2 <- cbind(sampleID, variety, df2)
tbl2

colnames(tbl2)[3] <- "comp"
tbl2

k3plot <-
  ggplot(tbl2, aes(factor(sampleID), value, fill=comp)) +
  geom_col(color="black", size=0.1, width=1) +
  facet_grid(~fct_inorder(variety), switch="x", scales="free", space="free") +
  theme_minimal() + labs(x="Individuals", title="K=3", y="components") +
  scale_y_continuous(expand=c(0, 0)) +
  scale_x_discrete(expand=expand_scale(add=1)) +
  theme(
    panel.spacing.x=unit(0.1, "lines"),
    axis.text.x=element_blank(),
    panel.grid=element_blank()
  ) +
  scale_fill_brewer(palette="Paired", guide='none')
k3plot

and a dput(tbl)

structure(list(comp1 = c(0.000304534914903343, 7.25639850429616e-08, 
2.27430740759918e-42, 0, 1, 7.37646416837379e-07, 1, 6.76272702548886e-06, 
0, 3.04290442727506e-05, 4.25612745047488e-09, 1.18218178221686e-16
), comp2 = c(0.999695539474487, 0.99999988079071, 1, 1, 3.6168054052767e-30, 
0.999999284744263, 2.82813122498233e-29, 1.06498683288686e-43, 
1, 4.66462843997956e-16, 1, 1), comp3 = c(5.66402567378596e-16, 
7.41350128733039e-16, 1.40129846432482e-45, 1.26116861789234e-44, 
6.73797980640088e-16, 1.86443519971077e-23, 4.54367988546311e-14, 
0.999993205070496, 0, 0.999969601631165, 5.97792615408821e-09, 
3.16024730889457e-37)), class = c("spec_tbl_df", "tbl_df", "tbl", 
"data.frame"), row.names = c(NA, -12L), spec = structure(list(
    cols = list(comp1 = structure(list(), class = c("collector_double", 
    "collector")), comp2 = structure(list(), class = c("collector_double", 
    "collector")), comp3 = structure(list(), class = c("collector_double", 
    "collector"))), default = structure(list(), class = c("collector_guess", 
    "collector")), skip = 0), class = "col_spec"))