Mapping quantitative trait loci controlling early growth in a (longleaf pine × slash pine) × slash pine BC₁ family

Abstract.

Random amplified polymorphic DNA (RAPD) markers were employed to map the genome and quantitative trait loci controlling the early growth of a pine hybrid F₁ tree (Pinus palustris Mill. × P. elliottii Engl.) and a recurrent slash pine tree (P. elliottii Engl.) in a (longleaf pine × slash pine) × slash pine BC₁ family consisting of 258 progeny. Of the 150 hybrid F₁ parent-specific RAPD markers, 133 were mapped into 17 linkage groups covering a genetic distance of 1,338.2 cM. Of the 116 slash pine parent-specific RAPD markers, 83 were mapped into 19 linkage groups covering a genetic distance of 994.6 cM. A total of 11 different marker intervals were found to be significantly associated with 13 of the 20 traits on height and diameter growth using MAPMAKER/QTL. Nine of the eleven marker intervals were unique to the hybrid parent 488 genome, and two were unique to the recurrent parent 18–27 genome. The amount of phenotypic variance explained by the putative QTLs ranged from 3.6% to 11.0%. Different QTLs were detected at different ages. Two marker intervals from the hybrid parent 488 were found to have QTL by environment interactions.