Optimization of maize microspore isolation and culture conditions for reliable plant regeneration.

The effects of different factors were investigated in the process of isolated microspore culture of Zea mays L., Using donor plants grown in standard conditions and an efficient isolation technology, homogeneous populations of viable microspores at specific developmental stages were obtained and tested in culture. The cytological evolution of the microspores during the first week of culture was monitored using a DNA-specific fluorochrome. It was found that developmental stages of microspores, number of days of pretreatment at 7°C of the tassel, and culture density greatly influenced the number of microspore-derived embryos. Optimal conditions required for embryo and plant production are described.