Rapid-cycling Brassica Species: Inbreeding and Selection of Brassica napus for Anther Culture Ability and an Assessment of its Potential for Microspore Culture

A study was made to determine the feasibility of producing,by inbreeding and selection, lines of rapidcycling Brassicanapus L. with high or low potential for anther culture. In contrastto previous observations of B. campestris L., a self-incompatiblespecies, the anther culture potential of the plants of successiveinbred generations of B. napus remained uniform, and antherefficiency was poor, with a maximum of 0.476 embryoids producedfor each anther plated. This negative response to selectionmay have been due to an absence of variation with respect toanther culture ability in the base population, resulting fromthe self-fertility of the species. Cytological studies of culturedanthers of B. napus indicated that in each generation therewas a poor correlation between pollen induction and embryoidproduction. In an attempt to improve the yield of haploid embryoids of B.napus, isolated microspore culture was attempted, and was foundto be at least 60 times more efficient than anther culture,with as many as 32 embryoids being produced from each anther.In experiments designed to ascertain the reasons for such differences,an inhibitory effect of the anther wall on the anther embryogenesisof B. napus was observed, and embryoid yields were improvedby centrifuging buds prior to anther extraction to simulatethe effects of the centrifugation which is a component of themicrospore preparation procedure. Brassica napus, L. anther culture, microspore culture, inbreeding, selection