*3.3. Interaction between LTG QTLs*

Analysis of interactions among QTLs was carried out using the average low-temperature germination rate of nine genotypic classes at 7 DAI in the F2 population. Based on the general regression model, no significant interaction was detected between five QTLs. Although two QTL, *qLTG3* and *qLTG8* (*p* = 0.145) showed relatively high QTL interaction at 7 DAI, no significant QTL interaction at *p* < 0.05 was observed. In addition, the presence of *O. rufipogon* allele at the *qLTG8* locus increased LTG in three genotype classes at the *qLTG1* and *qLTG3* loci (Figure S3A,D). The highest LTG scores were observed in the genotype classes with *O. rufipogon* homozygous at *qLTG10.1* and Hwaseong homozygous at *qLTG10.2*. The results sugges<sup>t</sup> that the *O. rufipogon* alleles at *qLTG1*, *qLTG3*, *qLTG8*, and *qLTG10.1* and the Hwaseong allele at *qLTG10.2* increased LTG, and QTLs act in an additive manner to regulate LTG.
