A comparison of anther and microspore culture as a breeding tool in Brassica napus.

A direct comparison of microspore culture and anther culture was made in Brassica napus using F1 crosses of Regent (canola) by Golden (rapeseed), and their reciprocals, as well as a hybrid between Reston and a highly embryogenic, canola-quality breeding line (G231) as donor plants. The study confirmed that microspore culture can be ten times more efficient than anther culture for embryo production. Embryo yields from cultures initiated from the Reston x G231 were four-fold greater than those initiated from the Regent x Golden crosses, and significant differences were also detected among cultures initiated from the different Regent x Golden crosses. These results illustrate the influence that donor plant genotype has on embryo production. However, superior embryogenic potential among donor material was not always coincident with superior plant production. The average haploid-todiploid ratio in microspore-derived regenerates was 2∶1 for the population obtained from the Regent x Golden crosses but 1∶1 for the Reston x G231 cross. For both types of material, the frequency of diploids increased upon repeated cycles of explanting. A field study showed that there were no differences between the populations of anther-derived and microspore-derived spontaneous diploid and doubled haploid lines, with respect to the days required for them to flower or to mature. The information is valuable for canola breeding programs considering the use of haploidy.