Wide hybridization between oat and pearl millet belonging to different subfamilies of Poaceae

Oat (Avena sativa L.) and pearl millet (Pennisetum glaucum L.) belong to different subfamilies of Poaceae. When emasculated oat was pollinated by millet, fertilization took place and all seven millet chromosomes were retained along the complete haploid oat complement during early stages of embryogenesis. Fourteen days after pollination, we cultured 170 embryos onto rescue medium, of which 99 were attached with endosperm tissue. Twenty-one embryos germinated and showed shoot growth. One of them also developed roots. The shoots of the rootless embryos elongated, but rolled to the scutellum side and eventually died in light conditions. Chromosome observations and marker analyses indicated that the seedling plants were true hybrids that retained all of the oat and millet chromosomes. One exceptional embryo with shoot and root grew under light conditions. This was a haploid of oat and developed to a fertile adult plant. One embryo generated a callus after 6 months cultivation, and it was found to harbor four out of the seven millet chromosomes corresponding to linkage groups 2, 4, 6, and 7. The callus grew vigorously but did not develop shoots or roots.