QTL detection for growth and form traits in three full-sib pedigrees of Pinus elliottii var. elliottii × P. caribaea var. hondurensis hybrids

Quantitative trait locus (QTL) analysis was conducted on three full-sib Pinus elliottii var. elliottii × P. caribaea var. hondurensis (PEE × PCH) hybrid families to identify genomic regions affecting two growth traits, height (Ht) and DBH at age 5, and seven morphological (“form”) traits. The QTL detection population consisted of family A containing 122 progeny, which was related to the validation population family B (n = 66) via a common PEE parent, but unrelated to the second validation population, family C (n = 107). Using a double pseudo-testcross QTL mapping approach, quantitative trait loci (QTLs) had been identified in the detection population for Ht, DBH, and three form traits. One QTL for Ht05 was validated in the shared common PEE lineage. For two other form traits, QTLs were validated by identifying QTLs that co-located to the same genomic regions in both validation populations. Two QTL, for another form trait and DBH05 were not identified in the original detection population but occurred in both validation populations. The QTL positions detected in this study provide a resource to identify form-trait loci using the Pinus genome or expressed sequence tag (EST) sequences, which may be useful for future association studies.