Application of new technologies to rice breeding

为了将细胞融合和基因操作等新技术应用于水稻育种，需要积累水稻植株分子水平的知识，并改进组织培养技术。在获得转基因植物后，应该需要一个有效的选择系统来改良一个新的品种。建立了水稻贮藏蛋白、谷蛋白和醇溶蛋白合成相关的多聚&lt；(A)+&gt；RNA的cDNA文库。结果表明，胚乳中的贮藏蛋白形成两种颗粒，即蛋白体和蛋白体，不可消化的蛋白体主要由醇溶蛋白组成。建立了水稻叶绿体DNA物理图谱，验证了Rubisco大亚基和ATPase亚基基因的定位。并测定了这些基因的碱基序列。在有丝分裂细胞DNA上，成功克隆了所有DNA片段，并找到了一个具有自主复制序列活性的片段。以种子和花粉诱导愈伤组织为材料，对不定芽形成和体细胞胚胎发生进行了研究，明确了植株再生过程中的遗传变异。在此基础上，成功地从种子愈伤组织来源的原生质体中诱导出植株再生。分析了从细粒突变体后代中获得的诱变子基因的特性，明确了该基因作为诱变剂的强烈作用。用亚硝基化合物处理受精卵细胞，获得了新的含糖和缩水突变体。在节间伸长过程中，研究了Dee-Geo-Woogen型半矮秆的基因表达，并对其抗旱性和蒸煮品质进行了相关性状的表型分析。

For the application of new technologies such as cell fusion and gene manipulation to rice breeding, it is necessary to accumlate the knowledges of molecular level in rice plants and also to improve the technologies in tissue culture. After getting gene-manipulated plants, an efficient selection system for improving to a new variety should be required.1. The cDNA library on poly <(A)^+> RNA which related to the synthesis of rice storage protein, glutelin and prolamin, was established. It was clearified that the storage protein in endosperm formed two kinds of granules, protein body <I> and <II> , and nondigestable protein body <I> mainly consisted prolamin.2. A physical map of rice chloroplast DNA was established and the location of the genes for large subunit of Rubisco and the subunits of ATPase was proved. The base sequences of the genes were also determined. On the mitocondorial DNA, cloning of all DNA fragments was succeeded and a fragment having activity of autonomously replicating sequence was found out.3. Adventive shoot formation and somatic embryogenesis from callus induced from seeds and pollen were investigated using many varieties, and genotypic variability in plant regeneration was clearified. On the basis of the results, plant regeneration was succesively induced from protoplasts originated from seed callus.4. Characteristics of mutator gene obtained from progenies of slender grain mutant was analyzed and strong effect of the gene as amutagen was clearified. New sugary and shrunken mutants were obtained by treating fertilized egg cells with nitroso compounds.5. Gene expression of semi-dwarfness of Dee-geo-woo-gen type was investigated in internode elongation, and also phenotypic expression of drought resistance and cooking quality were analyzed in their related characters.