Improvement in efficiency of microspore culture to produce doubled haploid lines of Ethiopian mustard

Factors affecting microspore embryogenesis of Ethiopian mustard (Brassica carinata A. Braun) were evaluated, including flower bud length, pollen developmental stage, and microspore density. An embryogenic frequency of 300 embryos per Petri plate was observed with NLN (Nitsch-Lichter-Nitsch) medium supplemented with 13% sucrose, 3.0-3.4-mm-long buds, and a plating density of 65,000 microspores/ml. About 65% of the microspores from buds 3.0-3.4-mm long were at the late uninucleate stage. Microspore-derived embryos were successfully transferred to solid medium for germination. After 4 wk, the resulting plantlets were transplanted to a soilless potting mixture and grew well under greenhouse conditions.