器內育種

In vitro Breeding

Conventional breeding which is carried out mainly on the fiield in the growing season has many disadvantages including long duration needed to produce varieties. On the other hand, when the in vitro cultured protoplasts, cells, tissues, or organs are used as breeding materials, those defects of field breeding could be readily avoided or solved, enabling, in addition, to accomplish the genome alteration or redesigning of crop species through such alteratives to sexual means as the intercelluler gene transfer and somatic mutagenesis or by utilizing the recently developed genetic engineering techniques including the introduction of nif gene into non-leguminous plant species. Followings are some of the breeding targets expected to be achieved in in vitro breeding: (1). In vitro cultures as a tool in the production of clone. (2). Acquiring of virus-free or un-infected stocks. (3). Induction of haploid plants. (4). Selection of chromosome aberrants from cultured cells. (5). Triploid plants by endosperm culture. (6). Selection of induced mutants from Cultured cells. (7). Production in vitro of selfedseed from self-incompatible species. (8). Sexual production of interspecific hybrid seed by means of in vitro pollination. (9). Fusion of naked protoplasts as a tool in acquiring somatic cell hybrid. (10). Transformation and transgenosis. (11). Utilization of alien genes from distantly related plant species or from other organisms by genetic engineering techniques. (12). Introduction of nif genes into non-leguminous crops. (13). Freeze-storage of plant cells at super low temperature.