| Abstract: | Summary Immature zygotic embryo has been the widely used explant source to develop embryogenic callus lines, cell suspensions and
protoplasts for transformation of cereal crops including maize, wheat, rice, oat, barley, sorghum, and millet. However, the
lack of competence of immature embryos in certain elite lines is still a barrier to rontine production of transgenic cereal
crops in certain commercial cultivars. In addition, a great deal of effort is required to produce immature embryos, manipulate
cultures, of immature embryos or their cell suspensions, and cryoperserve cultures for further use. In addition, undifferentiated
cells may have reduced regenerability after a few months, of in vitro culture. Alternative explants and regeneration systems for efficient transformation of cereal crops are needed to avoid or
reduce the above limitations. During the past decade, scientists have successfully manipulated the shoot apical meristerms
from seedlings of maize oat, sorghum, millet, wheat, and barley in an effort to develop a less genetype-dependent and efficient
cereal regneration system that can be maintained in vitro for long pertiods of time without the need for cryopreservation. Furthermore, apical mesistem regeneration systems were used
to stably transform maize, wheat, rice, oat, barley, sorghum, and millet. |
