Genetic erosions in plant cell cultures, especially in chromosome number and ploidy level, have now been known for over 25 years. Until the mid -1970ssuch changes were consideredundesirable and thereforediscarded because the main emphasis wason clonal propagation and genetic stability of cultures. However, since the publication on somaclonal variation by Larkin and Scowcroft (1981) there has been a renewed interest to utilize these in vitro obtained variations for crop improvement. Studies conduc ted during the last decade have shown that callus cultures, especially on peridical subculturing over an extended period of time, undergo morpho logical and genetic changes, i. e. polyploidy, aneuploidy, chromosome breakage, deletions, translocations, gene amplification, inversions, muta tions, etc. In addition, there are changes at the molecular and biochemical levelsincluding changes in the DNA, enzymes,proteins, etc. Suchchanges are now intentionally induced, and useful variants are selected. For instance in agricultural crops such as potato, tomato, tobacco, maize, rice and sugarcane, plants showing tolerance to a number of diseases, viruses, herbicides and salinity, have been isolated in cell cultures. Likewise induction of male sterility in rice, and wheat showing various levels of fer tility and gliadin, have been developed in vitro. These academic excercises open new avenues for plant breeders and pathologists. Another area of tremendous commercial importance in the pharmaceuti cal industry is the selection of cell lines showing high levels of medicinal and industrial compounds. Already high shikonin containing somaclones in Lithospermum are being used commercially.

Somaclonal Variation in Crop Improvement I (Biotechnology in Agriculture and Forestry, 11)

Science & Math

Bajaj, Professor Dr. Y. P. S.

Biological Sciences

Springer

While working in the laboratory of Professor Dr. Jacob Reinert at the Freie Universitat Berlin (1974-1976), I had the opportunity to become deeply involved in studying the intricacies of the fascinating phenomenon of somatic embryogenesis in plant cells and protoplasts. In numerous stimu lating discussions with Professor Reinert on this subject, I was fully convinced that somatic embryogenesis would become one of the most important areas of study, not only regarding basic and fundamental aspects, but also for its application in crop improvement. During the last decade, we have witnessed tremendous interest and achievements in the use of somatic embryos for the production of synthetic seeds, for micro propagation, genetic transformation, cryopreservation, and conservation of germplasm. The en masse production of somatic embryos in the bioreactors has facilitated some of these studies. Somatic embryos have now been induced in more than 300 plant species belonging to a wide range offamilies. It was therefore felt that a compilation ofliterature/state of the art on this subject was necessary. Thus, two volumes on Somatic Embryo genesis and Synthetic Seed have been compiled, which contain 65 chapters contributed by International experts. Somatic Embryogenesis and Synthetic Seed I comprises 31 chapters, arranged in 3 sections: Section I Commitment of the cell to somatic embryogenesis; early events; anatomy; molecular basis; gene expression; role of polyamines; machine vision analysis of somatic embryos. Section II Applications of somatic embryos; technology of synthetic seed; fluid drilling; micropropagation; genetic transfor mation through somatic embryos; cryopreservation.

Somatic Embryogenesis and Synthetic Seed I (Biotechnology in Agriculture and Forestry, 30)

Crafts, Hobbies & Home

Gardening & Landscape Design

. . . . . . . . . . . . . . . . . . . . . . . . 11 5 Summary and Conc1usion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6 Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 II Anethum graveolens L.

Medicinal and Aromatic Plants VIII (Biotechnology in Agriculture and Forestry, 33)

Genetic erosions in plant cell cultures, especially in chromosome number and ploidy level, have now been known for over 25 years. Until the mid -1970ssuch changes were consideredundesirable and thereforediscarded because the main emphasis wason clonal propagation and genetic stability of cultures. However, since the publication on somaclonal variation by Larkin and Scowcroft (1981) there has been a renewed interest to utilize these in vitro obtained variations for crop improvement. Studies conduc ted during the last decade have shown that callus cultures, especially on peridical subculturing over an extended period of time, undergo morpho logical and genetic changes, i. e. polyploidy, aneuploidy, chromosome breakage, deletions, translocations, gene amplification, inversions, muta tions, etc. In addition, there are changes at the molecular and biochemical levelsincluding changes in the DNA, enzymes,proteins, etc. Suchchanges are now intentionally induced, and useful variants are selected. For instance in agricultural crops such as potato, tomato, tobacco, maize, rice and sugarcane, plants showing tolerance to a number of diseases, viruses, herbicides and salinity, have been isolated in cell cultures. Likewise induction of male sterility in rice, and wheat showing various levels of fer tility and gliadin, have been developed in vitro. These academic excercises open new avenues for plant breeders and pathologists. Another area of tremendous commercial importance in the pharmaceuti cal industry is the selection of cell lines showing high levels of medicinal and industrial compounds. Already high shikonin containing somaclones in Lithospermum are being used commercially.

Somaclonal Variation in Crop Improvement I (Biotechnology in Agriculture and Forestry)

While working in the laboratory of Professor Dr. Jacob Reinert at the Freie Universitat Berlin (1974-1976), I had the opportunity to become deeply involved in studying the intricacies of the fascinating phenomenon of somatic embryogenesis in plant cells and protoplasts. In numerous stimu­ lating discussions with Professor Reinert on this subject, I was fully convinced that somatic embryogenesis would become one of the most important areas of study, not only regarding basic and fundamental aspects, but also for its application in crop improvement. During the last decade, we have witnessed tremendous interest and achievements in the use of somatic embryos for the production of synthetic seeds, for micro­ propagation, genetic transformation, cryopreservation, and conservation of germplasm. The en masse production of somatic embryos in the bioreactors has facilitated some of these studies. Somatic embryos have now been induced in more than 300 plant species belonging to a wide range offamilies. It was therefore felt that a compilation ofliterature/state of the art on this subject was necessary. Thus, two volumes on Somatic Embryo­ genesis and Synthetic Seed have been compiled, which contain 65 chapters contributed by International experts. Somatic Embryogenesis and Synthetic Seed I comprises 31 chapters, arranged in 3 sections: Section I Commitment of the cell to somatic embryogenesis; early events; anatomy; molecular basis; gene expression; role of polyamines; machine vision analysis of somatic embryos. Section II Applications of somatic embryos; technology of synthetic seed; fluid drilling; micropropagation; genetic transfor­ mation through somatic embryos; cryopreservation.

Somatic Embryogenesis and Synthetic Seed I (Biotechnology in Agriculture and Forestry)