The production of doubled haploid (DH) lines of Brassica rapa could be an e
fficient procedure for the development of inbred parents for hybrid product
ion. A total of 162 B. rapa DH lines were evaluated in field tests at Saska
toon, Canada, in single row, replicated tests and 10 DH lines were tested i
n four-row plot, multilocation, replicated tests. Seed of DH lines was prod
uced by bud selfing in the greenhouse. Approximately one-fifth of all DH li
nes tested were chlorophyll deficient, presumably due to the expression of
recessive alleles. Inbreeding depression was evident in low seed and biolog
ical yields, low number of seeds per pod and delayed flowering. Seed yield
of DH lines was positively associated with the number of seeds per pod, ear
ly flowering and a long pod-filling period. One DH line was equal in yield
to its donor population (DP), suggesting that dominance deviation was the g
enetic basis for high seed yield in this species. The consistent performanc
e of DH lines over years and locations indicated that DH lines may be selec
ted after 1 year of evaluation for combining ability testing. Higher yieldi
ng DH lines of B. rapa must be selected before they can be used as parents
for hybrid development.