Utilization of RFLP maps for rice breeding

为了将传统的染色体图谱与新的RFLP图谱进行整合，(1)新构建了包含142个标记和8个新的连锁关系的新染色体图谱，(2)在北海道大学Jodon‘s标记与连锁测定器杂交的F_2群体中，来自常规标记的19个座位被分配到10个RFLP图谱上。在新的RFLP图谱中，第3、第10和第11染色体的定位顺序相反。(3)在第1和第10染色体上进行了半矮秆和花粉恢复等两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RZ276和RG561紧密连锁。(4)近等基因系的抗稻瘟病基因分别由Pi-k、Pi-z、Pi-ta和Pi-I基因座控制。在156个杂交种中，有1个二倍体植株从0。用rDNA的DNA片段进行RFLP分析，发现有斑点。(6)利用流式细胞仪对水稻品种IR36的核基因组DNA含量进行了精确测定，结果为0.90 ng/2C。与籼稻品系相比，粳稻品系的基因组较小。此外，在水稻杂交组合F_2群体中，DNA含量呈0.87 ng/2C模式的连续变异。因此，RFLP分析将被应用于水稻基因组的各种研究，并可用于水稻高效育种。

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.