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

水稻的大部分重要农艺性状是由多个主基因控制的。为了研究这类数量性状的遗传特性，利用一些与控制它们的基因密切相关的maker基因（QRLs）是有帮助的。RFLP位点等DNA标记由于在染色体间分布均匀，一般对农艺性状无影响或影响不大，是农艺性状遗传研究的理想制造者。然而，到目前为止，由于RFLP在日本水稻品种中很少出现，阻碍了RFLP分析的应用。本研究将籼型品种（Kasalath: K）的RFLP位点引入到粳稻品种（Nipponnbare: N）的遗传背景中，最终培育出可用于日本水稻品种qtl遗传分析的近等基因系。N与21株B_1F_2杂交得到89株B_1F_1，其中6株B_1F_1为N//N/K杂交的自交后代。将所有的B_2F_1植株回交至n。随机选取30株B_2F_1植株，提取叶片总DNA，检测65个RFLP位点的基因型。为了研究RFLP位点与位于7号染色体的细长颖片（slg）位点的密切连锁，选择了含有7号染色体K上RFLP位点的短粒（粳稻型）B_1F_2植株与细长颖片系（IM294）杂交。连锁分析结果表明，slg位点位于XNpb0033和0022的两个RFLP位点之间，slg位点与0020和0033的重组值分别为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.