Studies on the Exploitation of New Functions of Rice by Biotechnology

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1. Establishment of new breeding techniques : Fusion between anther-derived haploid protoplasts successfully resulted in diploid plants. CO_2-gas supply to rice callus was effective for plant regeneration. Micronuclei were formed in suspension-culture cells by colchicine- and herbicide-treatments. A promoter gene enhancing the expression of reporter gene, necessary for efficient selection of transgenic plants, was found out. The physical map and clone bank of mitochondrial DNA in wild rices with B, C or E genome, were constructed. Nuclear DNA proved to have the sequences homologous with two small plasmidlike DNAs in mitochondria, B1 and B2. A herbicide (bialaphos) -resistant gene bar was successfully introduced into rice protoplast through electroporation. RFLP analysis revealed different direction of the linkage map with 1 and 2 linkage groups from that of old linkage map. New linkage map including isozyme-maker gene was constructed. The inheritance of slender-glume gene indispensable for activating mutator was clarified.2. Exploitation of new function : RFLP's maker proved to be effective by used for detecting the genetical variation in anther-derived plants. There were found close relationships of endosperm proteins alpha -1 and alpha -3 with the diversification of genus Oryza. Waxy gene proved to have a mechanism determining Wx protein content. The amino acid compositin of prolamin polypeptides and the nucleotide sequence of cDNA encoding glutelin in rice seeds were clarified. A embryoless diploid mutant induced by gammaーirradiation to tetraploid rice was closely analyzed for inheritance and developmental physiology. Alien cytoplasm and fertility-restoring gene were introduced to common wheat and a new male sterility-fertility restoration system was developed for hybrid-wheat breeding.