Improvement of isolated microspore culture of wheat (Triticum aestivum L.) through ovary co-culture.

Embryogenesis from isolated microspore cultures of wheat was improved by ovary co-culture when compared to a completely defined medium. This indicates that essential factor(s) in addition to PAA or its analogs may be supplied by the ovaries. Isolated microspores cocultured with 20 ovaries of wheat on the top of semi-solid MMS3 induction medium for 21-30 days gave the best response. Both the number and quality of the embryos was significantly increased. The maximum frequencies of dividing microspores and of embryogenesis were 94% and 2.4%, respectively. Up to 2583 embryos were formed per 100 anthers of cv 'Chris' and between 18% and 43% of the larger embryos regenerated into green plants upon transfer. Genotype differences for both induction and embryogenesis phases were reduced using ovary co-culture. However, there was still a strong genotype influence on plant regeneration with cv 'Chris', with the F1 of 'Chris' × 'Sinton' displaying the highest frequencies. These results are important with respect to enhancing haploidy applications in wheat biotechnology and plant breeding.