Microspore embryogenesis and the development of a double haploidy protocol for cow cockle (Saponaria vaccaria).

Factors affecting microspore embryogenesis of cow cockle (Saponaria vaccaria) were evaluated including donor plant growing conditions, genotype, bud size, density, medium composition, and culture conditions. Of the two donor plant (day/night) temperature regimes evaluated (10/5 degrees C and 20/15 degrees C), plants grown at 20/15 degrees C were the most embryogenic. An embryogenic frequency of greater than 350 embryos/100 buds was observed in the most embryogenic genotype, cv. 'White Beauty'. Buds from 3-9 mm in length were evaluated for their embryogenic potential; buds that were 4-7.9 mm produced the most embryos/100 buds. Of all the media compositions evaluated, NLN medium with 15% sucrose resulted in the most embryos. Cow cockle microspores required an initial period of 32 degrees C for 3 days for production of microspore-derived embryos (MDEs).