Mapping of QTLs associated with lodging resistance in rice ( Oryza sativa L.) using the recombinant inbred lines derived from two high yielding cultivars, Tachisugata and Hokuriku 193

Lodging is one of the major problems in rice production. In this study, we identified quantitative trait loci (QTLs) for lodging resistance traits using recombinant inbred lines (RILs) derived from a cross between two high yielding and superior lodging resistant rice cultivars, Tachisugata and Hokuriku 193. A total of 19 QTLs were detected on chromosomes (Chrs.) 2, 4, 6, 8, 9 and 10 in the F 6 and F 7 populations. In particular, one stable QTL for the section modulus (SM) and the outer diameter of the major axis (ODMA) was detected on Chr. 2 in both the F 6 and F 7 populations, and the positive allele was derived from Tachisugata. Correlation analysis showed that the SM and ODMA were positively correlated with the bending moment at breaking, the primary factor for the breaking type lodging resistance in rice. In addition, two QTLs for the spikelet number of the secondary branch and the spikelet number per panicle were also detected on Chr. 2, which overlapped with the stable QTL for the traits related to lodging resistance. These results indicated that the stable QTL might have combined effects on the traits associated with lodging resistance and grain yield. The novel QTL would be a promising target in marker-assisted selection to improve lodging resistance and grain yield in rice.