Construction of Genetic Linkage Maps of Larch (Larix Kaempferi × Larix Gmelini) by Rapd Markers and Mapping of QTLS for Larch

Abstract

ABSTRACTGenetic linkage mapping was performed with an interspecific mapping pedigree of 145 full-sib hybrids individuals of Japanese larch x Chinese larch (Larix kaempferi x Larix gmelini). A total of 210 random amplification of polymorphic DNA (RAPD) primers were used for mapping, and 581 segregating loci were identified. According to pseudo-testcross mapping strategy, we used mapping software to construct parent-specific linkage maps. The constructed linkage maps consisted of 48 sites in 5 linkage groups (four or more sites per group), 4 triplets, 6 linkage pairs for the maternal parent, and covered the map distance of about 546.5 cM, with the average map distance of 11.9 cM between adjacent markers. In addition, 91 sites in 9 linkage groups (four or more sites per group), 2 triplets, and 5 linkage pairs for the male parent covered the map distance of about 262.0 cM; the average map distance between adjacent markers was 6.1 cM. We detected the quantitative traits of the group by composite interval mapping, and analyzed the quantitative trait loci (QTL) with LOD ≥1.5. During analysis of the relationship between marker loci and traits, we obtained 4 and 20 QTLs, which were related to growth and timber characteristics. We found one QTL each for tracheid length and tracheid Length to Width ratio in Larix Kaempferi and nine, four, and five QTLs for specific gravity of wood, tracheid Length tracheid Width, respectively, in Larix gmelini. The LOD of every QTL was 1.5∼11.9, and the contribution rate was 0.0105∼45.9986%.