QTL mapping

Last changed: 14 December 2021

QTL mapping

We investigate the genetic basis of traits of interest by means of quantitative trait loci (QTL) mapping. For the QTL mapping we use the genetic linkage maps S1 and S3 developed in this project, and phenotypic data from all individuals in the mapping populations (see Linkage maps project section). We are conducting field, greenhouse and lab experiments to quantify the variation in resource economy in relation to growth (mainly water and nutrient use efficiency), tolerance to heat, resistance to leaf rust (Melampsora spp.) and to leaf gall midge (Dasineura marginemtorquens).

We also study phenology traits such as timing of bud burst and growth cessation, which are crucial for plant adaptation to the local climate. We study these traits both in field conditions and in a phytotron, where temperature and daylength can be controlled.
For all experiments the individuals of the mapping populations are vegetatively propagated and used in replicates to obtain accurate estimates of the phenotypes.

In the QTL analysis, we are quantifying the effect of QTL and the stability of QTL with plant age and under different environmental conditions. We also investigate if candidate genes, known from the literature to be connected to specific traits, co-locate with QTL in willow. This is possible because our genetic maps are largely based on SNP markers with known position in the poplar genome. In areas of high interest we have increased the SNP marker density and thus have better posibilities to anchor the Salix QTL to the sequenced Populus genome and to search for candidate genes. 

  

QTL area for growth cessation and SNP marker closest to LOD-peak in the Salix linkage group Ib indicated in blue

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