For the use of RFLP analysis in the genetic study on QTL(Quantitative Traits Loci) in rice.

水稻的许多重要农艺性状是由多对主基因控制的。利用与控制这些数量性状的基因紧密连锁的标记基因（QRLs）来研究这些数量性状的遗传规律是有帮助的。RFLP等DNA标记在染色体上分布均匀，对农艺性状无影响，是研究农艺性状遗传的理想标记。然而，到目前为止，由于日本水稻品种中很少出现RFLP，限制性片段长度多态性分析在日本水稻品种中的应用一直受到阻碍。在本研究中，（Kasalath：K）的遗传背景引入粳稻型品种（日本晴：N与21个B_1F_2植株杂交，获得89个B_2F_1植株，随机抽取30株B_2F_1植株，提取叶片总DNA，分析65个RFLP位点的基因型。为了研究位于第7染色体上的与细长颖（slg）基因紧密连锁的RFLP位点，以具有第7染色体上K位点的短粒（粳稻型）B1F2为材料，与细长颖株系IM294杂交。连锁分析结果表明，slg位点位于XNpb0033和0022两个RFLP位点之间，slg位点与0020和0033的重组率分别为3.2%和3.0%。

Most of the agronomically important characters of rice are controlled by plural major genes. To study the genetics of such quantitative characters, it is helpful to use some maker genes closely linked to the genes controlling them(QRLs). DNA markers such as RFLP loci seems to be ideal makers for the genetic study on agronomic characters, because they are evenly distributed among the chromosomes and generally have no or little effect on agronomic characters. The use of RFLP analysis in Japanese rice varieties, however, so far has been prevented by the rare appearance of RFLP among them. In this study, the RFLP loci of indica-type variety(Kasalath : K) were introduced to the genetic background of japonica-type variety(Nipponnbare : N) eventually to raise the near-isogenic lines which can be used for the genetic analysis for the QTLs in Japanese rice varieties.Eighty-nine B_2F_1 plants were obtained from the crosses between N and 21 B_1F_2 plants, the selfed progenies of 6 B_1F_1 plants from the cross of N//N/K.All the B_2F_1 plants were back-crossed to N.As for the randomly selected 30 B_2F_1 plants, a total DNA was extracted from leaves, and then the genotypes of 65 RFLP loci were examined. To investigate the closely linked RFLP loci to the slender-glume(slg) locus located on 7th chromosome, short-grain(Japanese-rice type) B_1F_2 plant harboring RFLP loci from K on 7th chromosome was selected and crossed with slender glume line(IM294). The result of the linkage analysis shows that the slg locus is located between two RFLP loci of XNpb0033 and 0022, and that the recombination values of slg locus and 0020 and 0033 are 3.2% and 3.0%, respectively.