Responses of the parental genotypes and their derived RI
lines to bruchid infestation
All seeds of the susceptible parent ('Berken') were damaged
in all four bruchid assays, while seeds of the resistant
parent ('ACC41') were damage free. A large proportion of
the RI lines used in each assay showed either 0% or 100%
damaged seeds, but RI lines with intermediate performance
were found in all four assays (Fig. 1). A 2-fold difference
in the average percentage of damaged seeds was found
among the different assays, with the lowest percentage
(27.8%) from the single Australian assay (brI) and the highest
percentage (55.0%) from the assay with seeds harvested
from the Guangxi site (br4) (Table 2). The difference was
also reflected in the proportions of RI lines that were 100%
damaged in the four assays, which were about 7% for brl,
48% for br2, 32% for br3, and 47% for br4 (Fig. 1). Correlation
coefficients among the four bruchid resistance assays
were strongly associated with the number of RI lines shared
between a particular pair of assays. The correlations were
moderate (r = 0.42-0.59) between brl (which used 80 RI
lines) and the other three assays; high (r = 0.93 and 0.95)
between br4 (191 lines) and br2 and br3, respectively; and
highest (r = 0.97) between br2 and br3, which shared 204
of the RI lines (Table 3).