Congruence in QTL for adventitious rooting in Pinus elliottii x P. caribaea hybrids resolves between and within-species effects
Shepherd, M, Huang, SW, Eggler, P, Cross, M, Dale, G, Dieters, MJ & Henry, RJ 2006, 'Congruence in QTL for adventitious rooting in Pinus elliottii x P. caribaea hybrids resolves between and within-species effects', Molecular Breeding, vol. 18, no. 1, pp. 11-28.
The original publication is available at www.springerlink.com at http://dx.doi.org/10.1007/s11032-006-9006-5
Targeting between-species effects for improvement in synthetic hybrid populations derived from outcrossing parental tree species may be one way to increase the efficacy and predictability of hybrid breeding. We present a comparative analysis of the quantitative trait loci (QTL) which resolved between from within-species effects for adventitious rooting in two populations of hybrids between Pinus elliottii and P. caribaea, an outbred F1 (n=287) and an inbred-like F2 family (n=357). Most small to moderate effect QTL (each explaining 2–5% of phenotypic variation, PV) were congruent (3 out of 4 QTL in each family) and therefore considered within-species effects as they segregated in both families. A single large effect QTL (40% PV) was detected uniquely in the F2 family and assumed to be due to a between-species effect, resulting from a genetic locus with contrasting alleles in each parental species. Oligogenic as opposed to polygenic architecture was supported in both families (60% and 20% PV explained by 4 QTL in the F2 and F1 respectively). The importance of adventitious rooting for adaptation to survive water-logged environments was thought in part to explain oligogenic architecture of what is believed to be a complex trait controlled by many hundreds of genes.