Utilization of RFLP maps for rice breeding

为了将传统的染色体图谱与新的RFLP图谱相结合，进行了以下研究。(1)新构建的染色体图谱包含142个标记和8个新的连锁关系。(2)在北海道大学的Jodon标记与连锁测验子杂交的F_2群体中，将19个常规标记位点分配到10张RFLP图谱上。在新的RFLP图谱中，第3、第10和第11染色体的方向顺序相反。(3)在第1和第10染色体上进行了半矮秆和花粉恢复等2个经济基因的基因标记。结果表明，这两个基因分别与RFLP标记RZ 276和RG 561紧密连锁。(4)在稻瘟病抗性基因方面，Pi-k、Pi-z、Pi-ta和Pi-i基因座分别与第I、II、III和VI类稻瘟病抗性基因有关。(5)利用野生种与水稻原生质体融合获得体细胞杂种。在156个杂交种中，有1个二倍体植株从0。利用rDNA的DNA片段进行RFLP分析，发现了一个斑点状的菌株。(6)用流式细胞仪精确测定了水稻品种IR 36核基因组DNA含量为0.90ng/2C。与印度株相比，日本株的基因组较小。此外，在籼粳交F_2群体中，DNA含量的变异模式为0.87 ng/2C，表明DNA含量存在连续变异。因此，RFLP分析可用于水稻基因组的各种研究，并可用于水稻的高效育种。

In order to integrate the conventional chromosome map with the new RFLP maps, the following studies were carried out.(1) New chromosome maps containing 142 markers and 8 new linkage relationships were newly constructed.(2) In the F_2 populations of the crosses between Jodon's markers and linkage testers in Hokkaido Univ, 19 loci from conventional markers were allocated to 10 RFLP maps. The orientation of the third, tenth and eleventh chromosomes was in reverse order in the new RFLP maps.(3) Gene tagging of two economical genes such as semi-dwarfness and pollen restoration was carried out in the first and tenth chromosomes. It was found that both genes closely linked with RFLP markers, RZ276 and RG561, respectively.(4) As for blast resistance genes in NlLs, it was identified that Pi-k, Pi-z, Pi-ta and Pi-i loci are responsible for I, II, III and VIth groups of NlLs respectively.(5) Somatic hybrid plants were produced through the protoplast fusion between wild species and rice. Among 156 hybrids, a diploid plant having a clear band transferred from 0. punctata was found by RFLP analysis with DNA fragment of rDNA.(6) By using the flow cytometer DNA contents of rice nuclear genome were measured precisely as 0.90 ng/2C in the cultivar IR36. Japonica strains indicated a smaller size of genome in comparison with lndica strains. In addition, a continuous variation of DNA contents was indicated in a F_2 population of Japonica X Indica cross showing a mode of 0.87 ng/2C.Thus, RFLP analysis will be applied for various studies of rice genome and also utilized for efficient rice breeding.