In order to develop and optimize a procedure for producing double haploid lines in rapeseed breeding program, microspore culture was investigated in ten rapeseed cultivars. The cultivars included two winter (Orient, SLM 046) and eight spring cultivars (Cyclone, Quantum, Balero, Dakini, PF-7045/91, Shiralee, Option 500, Sponsor). The experiment was conducted on plants grown under greenhouse conditions in two different seasons of summer and fall 2001. The plants were grown during summer under 25-30°C and fall under 15-20°C temperature conditions and seasonal natural daylight. Microspores were cultured in recommended developmental stage (late uninucleate to early binucleate) with a density of 80000 to 100000 cells/ml on NLN media containing either 6.5% or 13% sucrose. No embryo induction occurred in microspores derived from plants grown under 25-30°C in summer, while from the same cultivars grown under 15-20°C in fall, embryos were developed only from microspores of the spring cultivar Quantum on B5 liquid media. Comparison of different sucrose levels in the media proved that 13% sucrose is a proper concentration for microspore culture in rapeseed. Nine out of 40 embryos produced from microspore culture in this cultivar were developed into putative haploid plantlets. Effects of cold pretreatment on regeneration of embryos into plantlets was significant at %1 level. Cytological analyses were carried out to verify the ploidy level in putative haploid plantlets. Six out of nine regenerated plantlets were confirmed to be haploids while three were diploids. Results in this study indicated that genotypic characteristics as well as growing conditions of donor plants are important factors in embryogenesis of microspores. The temperature in which plants were grown during flowering stage is a major determinant for success of microspore culture in rapeseed.
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