Rapid-cycling Brassica Species: Inbreeding and Selection of B. campestris for Anther Culture Ability

A study was made to determine the feasibility of producing,by inbreeding and selection, lines of rapid-cycling Brassicacampestris with high or low potential for anther culture. Sincethe base population of rapid-cycling B. campestris is self-incompatible,inbreeding was achieved by a combination of bud-pollinationand the application of pollen to the cut surfaces of decapitatedstigmas. Three inbred generations were raised, and in each generationplants were selected for high or low potential for anther embryogenesis.The proportion of viable pollen present in anthers, as indicatedby a fluorochromatic reaction and a germination test, was alsodetermined at each stage. Lines of rapid-cycling B. campestriswith clearly defined high or low potential for anther embryogenesiswere isolated in these experiments. Within each line, however,continuous variation was always observed. Pollen viability andanther efficiency were not correlated. Although inbreeding depressioncaused a significant decrease in pollen viability over the threegenerations, there were no obvious deleterious effects on antherefficiency. In general, over the three generations of inbreeding,no segregation in plant morphological characters was observed,although many developmental abnormalities were seen in the 3rdinbred generation and there was a marked reduction in the numberof seeds set. No association between plant vigour and high orlow anther efficiency was noted. All plants regenerated fromanther embryoids of rapid cycling B. campestris were haploid.By treating anther-derived embryoids, axillary buds and wholeplants with colchicine, dihaploid plants were produced, butthese failed to set seed after self-pollination. The diploidnature of the plants was confirmed, however, when they producednormal seeds after cross-pollination with plants of the basepopulation. Brassica campestris, anther culture, inbreeding, selection