A simple technique for the identification of embryo-carrying seeds from wheat x maize crosses prior to dissection

Embryo rescue is an important step in the wheat x maize system of induced haploidy in wheat. On average, only one-third of the seeds carry embryos, but they all have to be dissected because no morphological distinction is available to distinguish between seeds with and without embryos. We here report a simple technique in which immature seeds from wheat x maize crosses are placed on a transparent surface and illuminated from above. The free-floating embryo, settled at the bottom of the seed, can be seen from below or in an image reflected on a plane mirror. Using this technique 97.8% of the embryo-containing seeds could be detected prior to dissection. The technique will be useful in reducing the time and labour involved in embryo culture, thereby scaling up haploid production.