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 Brassica napus L. with high or low potential for anther culture. In contrast to previous observations of B. campestris L., a self-incompatible species, the anther culture potential of the plants of successive inbred generations of B. napus remained uniform, and anther efficiency was poor, with a maximum of 0.476 embryoids produced for each anther plated. This negative response to selection may have been due to an absence of variation with respect to anther culture ability in the base population, resulting from the self-fertility of the species. Cytological studies of cultured anthers of B. napus indicated that in each generation there was a poor correlation between pollen induction and embryoid production.In an attempt to improve the yield of haploid embryoids of B. napus, isolated microspore culture was attempted, and was found to 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 embryogenesis of B. napus was observed, and embryoid yields were improved by centrifuging buds prior to anther extraction to simulate the effects of the centrifugation which is a component of the microspore preparation procedure. © 1990 Annals of Botany Company.