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

水稻的大多数重要农艺性状是由多个主基因控制的。为了研究这些数量性状的遗传学，利用一些与控制它们的基因紧密连锁的标记基因(QRL)是有帮助的。RFLP等DNA标记是进行农艺性状遗传研究的理想标记，因为它们均匀分布在染色体上，对农艺性状的影响一般不大或很小。然而，到目前为止，由于RFLP在日本水稻品种中的罕见出现，RFLP分析在日本水稻品种中的应用受到了阻碍。本研究将籼型品种(Kasalath：K)的RFLP基因座引入到粳型品种(日本晴：N)的遗传背景中，培育出可用于日本水稻QTL遗传分析的近等基因系。从N与21个B_1F_2杂交中获得了89个B_2F_1植株，从N/N/K杂交中获得了6个B_1F_1自交后代。将所有B_2F_1植株回交到N中，随机选择30个B_2F_1植株，提取叶片总DNA，检测65个RFLP基因座的基因分型。为了研究与7号染色体上的细长颖花(Slg)基因座紧密连锁的RFLP基因座，选择了7号染色体上含有来自K的RFLP基因座的短粒(日本稻型)B_1F2植株，并与细长颖片系(IM294)杂交。连锁分析结果表明，SLG基因座位于XNpb0033和0022两个RFLP基因座之间，SLG基因座与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.