Embryogenesis from
plant microspores is routinely induced with a 16-24 h
temperature treatment of 32.5° C. Continuous culture at 25° C. results in
pollen development. However,
microspore treatment with anti-cytoskeletal agents, or
protein synthesis inhibitors, at the non-inductive temperature of 25° C., can induce
embryogenesis, thus demonstrating that
heat shock is not required for embryogenic induction. Furthermore, when anti-
microtubule agents (e.g.
colchicine) are used,
embryo induction and
chromosome doubling occur simultaneously, thus generating doubled haploids, whereas heat induction generates haploids. Thus, the use of
microtubule inhibitors will provide a simple one-step process to simultaneously induce
embryogenesis and
chromosome doubling for the production of fertile plants, thus providing minimal manipulation which will be very advantageous for genetic studies and
plant breeding programs. As noted,
heat shock induces haploids. A low level of
chromosome doubling can be obtained by adding
colchicine to
microspore cultures during the heat treatment. However, the use of
trifluralin with the heat treatment, to generate doubled haploid plants results in an improved
recovery of fertile doubled haploid plants than previously shown in the prior art.