Rust resistance was shown to be highly heritable, and most genetic var
iance was shown to be additive. Thus, selection of rust-resistant pare
nts should be effective in producing resistant progeny. Crosses betwee
n susceptible parents are rejected by the Bureau of Sugar Experiment S
tations computerised system for choosing crosses, and this strategy ha
s resulted in the planting of very few crosses with high rust suscepti
bility.