XXIIIrd International Eucarpia symposium, Section Ornamentals ...

L8
Virginia Gitonga
Robert Stolker
Simon Ribot
Carole Koning-
Boucoiran
Frans Krens
Wageningen University and
Research Center, Plant
Breeding, P.O. Box 16,
6700 AA Wageningen, The
Netherlands
virginia.gitonga@wur.nl
INHERITANCE OF DETERMINANTS OF
FLOWER COLOUR IN TETRAPLOID ROSES
The choice of selection breeding for crop improvement in rose requires a better
understanding of biological mechanisms and knowledge of the inheritance of the major
target traits which can lead to new or improved screening methods. One of the problems
in cut roses is that flower colour of some genotypes is not stable across growing
environments. The dependency upon genotype suggests that this is a heritable trait. In
general in rose, the genetic knowledge is still limited. Wageningen UR Plant Breeding
together with international partners has produced one of the rose diploid maps and work
is currently going on to create a highly dense tetraploid map using the progeny (181
individuals) from a cross between two tetraploid rose genotypes (P540 and P867) made
available by Terra Nigra b.v.. The map will contain both phenotypical traits as well as
molecular markers. The two parents were chosen to ensure sufficient genetic variation
and segregation in the progeny for many morphological traits including colour, but also
for disease resistance/susceptibility.
The current mapping population will be characterized for flower colour, by using
colour charts such as the official chart of the Royal Horticultural Society, and additionally,
by image analysis and measuring reflectance using a spectrocolorimeter. The genetics
of flower colour will be determined by QTL analysis. In addition, flower petals of all
genotypes will be analysed by HPLC to characterize secondary metabolic components
that determine flower colour, such as anthocyanins. The inheritance of these
components will also be assessed and compared to that of flower colour.
24 Session Flower colour