Identification of QTLs for Improvement of Plant Type in Rice (Oryza sativa L.) Using Koshihikari/Kasalath Chromosome Segment Substitution Lines and Backcross Progeny F2 Population

Thirty-nine chromosome segment substitution lines (CSSLs) population derived from a Koshihikari/Kasalath cross was used for quantitvative trait locus (QTL) analysis of plant type in rice (Oryza sativa L.). Putative rough QTLs (26.2 similar to 60.3cM of Kasalath chromosomal segments) for culm length, plant height, panicle number, chlorophyll content of flag leaf blade at heading and specific leaf weight, were mapped on the several chromosmal segments based on the comparison of CSSLs with Koshihikari in the field experiment for 3 years. In order to verify and narrow QTLs detected in CSSLs, we conducted QTL analyses using F2 populations derived from a cross between Kshihikari and target CSSL holding a putative rough QTL. The qPN-2, QTL for panicle number was mapped on chromosome 2. In traints of flag leaf, the qCHL-4-1 and 1CHL-4-2 for chlrophyll content was mapped on chromosome 4, and the qSLW-7 for specific leaf weight on chromosome 7. All QTLs were detected in narrow marker intervals, compared with rough QTLs in CSSLs. The qPN-2, qCHL-4-1 and qCHL-4-2 QTL analysis in the present study with the combination of CSSLs and backcross progeny F2 population can not only verify the rough QTLs detected in CSSLs but also estimat allelic effects on the QTL.