Fine mapping of grain weight QTL, tgw11 using near isogenic lines from a cross between Oryza sativa and O. grandiglumis

• Published in: Genes & genomics Vol. 33; no. 3; pp. 259 - 265
• Main Authors: Oh, J.M., Chungnam National University, Daejeon, Republic of Korea, Balkunde, Sangshetty, Chungnam National University, Daejeon, Republic of Korea, Yang, P., Chungnam National University, Daejeon, Republic of Korea, Yoon, D.B., Chungnam National University, Daejeon, Republic of Korea, Ahn, S.N., Chungnam National University, Daejeon, Republic of Korea
• Format: Journal Article
• Language: English
• Published: Heidelberg The Genetics Society of Korea 01-06-2011; 한국유전학회
• Subjects: Animal Genetics and Genomics; ARROZ; Biomedical and Life Sciences; Grain shape; Grain weight; Human Genetics; Life Sciences; Microbial Genetics and Genomics; Near isogenic line; Oryza grandiglumis; Plant Genetics and Genomics; QTL; Research Article; RICE; RIZ; 생물학; QTL, Grain weight; Grain shape; Near isogenic line; Rice
• ISSN: 1976-9571; 2092-9293
• DOI: 10.1007/s13258-011-0038-9

In our previous study, we reported the grain weight (GW) QTL, tgw11 in isogenic lines derived from a cross between Oryza sativa ssp. Japonica cv. Hwaseong and O. grandiglumis. The O. grandiglumis allele at tgw11 decreased GW in the Hwaseong background. To fine-map tgw11, one F∧5 plant homozygous for the O. grandiglumis DNA in the target region on chromosome 11 was selected from F₄ line, CR1242 segregating for tgw11 and crossed with Hwaseong to produce secondary F₂ and F₃ populations. QTL analysis using 760 F₂ plants confirmed the existence of tgw11 with an R² value of 15.0%. This QTL explained 32.2% of the phenotypic variance for GW in 91 F₃ lines. Substitution mapping with 65 F₃ lines with informative recombination breakpoints in the target region was carried out to narrow down the position of the tgw11. The result indicated that tgw11 was located in the 900-kb interval between two SSR markers, RM224 and RM27358. QTLs for grain width and grain thickness were also located in the same interval suggesting that a single gene is involved in controlling these three traits. Analysis of F₃ lines indicated that the variation in TGW is associated with variation in grain shape, specifically grain thickness and grain width. Genetic analysis indicated that the O. grandiglumis allele for small seed was dominant over the Hwaseong allele. SSR markers tightly linked to the GW QTL would be useful in marker-assisted selection for variation in GW in breeding program.