Her Majesty the Queen in Right of Canada, As Represented by the Minister of Agriculture and Agri-food

Jiping Zhao

Daina H Simmonds

Carmen Gervais

William Newcomb

Embryogenesis from plant microspores is routinely induced with a 16-24 h temperature treatment of 32.5&deg; C. Continuous culture at 25&deg; C. results in pollen development. However, microspore treatment with anti-cytoskeletal agents, or protein synthesis inhibitors, at the non-inductive temperature of 25&deg; 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.

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Ottawa, Canada

Jiping Zhao