Madoka Y, Kashiwagi T, Hirotsu N, Ishimaru K
National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8602, Japan.
Theor Appl Genet. 2008 Mar;116(5):603-12. doi: 10.1007/s00122-007-0693-z. Epub 2007 Dec 21.
Rice (Oryza sativa L.) chromosome segment substitution lines (CSSLs), in which chromosomal segments of the Indian landrace "Kasalath" replace the corresponding endogenous segments in the genome of the Japanese premium rice "Koshihikari", are available and together cover the entire genome. Chromosome regions affecting a trait (CRATs) can be identified by comparison of phenotypes with genotypes of CSSLs. We detected 99 CRATs for 15 agronomic or morphological traits. "Kasalath" had positively acting alleles in 53 CRATs. Its CRATs increased panicle number per plant by up to 23.3%, grain number per panicle by up to 30.8%, and total grain number by up to 15.1%, relative to "Koshihikari". CRATs were identified for grain size (grain thickness and width), with positive effects of about 5.0%. A CRAT on chromosome 8 almost doubled the weight of roots in uppermost soil layers compared to "Koshihikari". Additionally, "Kasalath" possessed CRATs for higher lodging resistance (reduction in plant height and increase in stem diameter). In some cases, multiple CRATs were detected in the same chromosome regions. Therefore, CSSLs with these chromosome segments might be useful breeding materials for the simultaneous improvement of multiple traits. Five CRATs, one for plant height on chromosome 1, one for stem diameter on chromosome 8, and three for heading date on chromosomes 6, 7, and 8 overlapped with the corresponding QTLs that already had been mapped with back-crossed inbred lines of "Nipponbare" and "Kasalath". In both "Koshihikari" CRATs and "Nipponbare" QTLs, "Kasalath" had similar effects.
水稻（Oryza sativa L.）染色体片段代换系（CSSLs），其中印度地方品种“Kasalath”的染色体片段取代了日本优质水稻“越光”基因组中的相应内源片段，这些代换系可用且覆盖了整个基因组。通过比较CSSLs的表型和基因型，可以鉴定出影响某一性状的染色体区域（CRATs）。我们检测到了与15个农艺或形态性状相关的99个CRATs。相对于“越光”，“Kasalath”在53个CRATs中具有正向作用的等位基因。其CRATs使单株穗数最多增加23.3%，每穗粒数最多增加30.8%，总粒数最多增加15.1%。还鉴定出了与粒形（粒厚和粒宽）相关的CRATs，其正向效应约为5.0%。与“越光”相比，第8号染色体上的一个CRAT使最上层土壤中的根重几乎增加了一倍。此外，“Kasalath”具有提高抗倒伏性的CRATs（降低株高和增加茎粗）。在某些情况下，在同一染色体区域检测到多个CRATs。因此，带有这些染色体片段的CSSLs可能是同时改良多个性状的有用育种材料。5个CRATs，一个位于第1号染色体上与株高有关，一个位于第8号染色体上与茎粗有关，三个位于第6、7和8号染色体上与抽穗期有关，它们与已经在“日本晴”和“Kasalath”的回交自交系中定位的相应QTLs重叠。在“越光”的CRATs和“日本晴”的QTLs中，“Kasalath”都具有相似的效应。
