Breeding rootstocks at the tetraploid level
Conventional breeding at the tetraploid level using selected
somatic hybrid rootstocks as parents provides an opportunity
to recombine alleles from three or four proven diploid
rootstocks, upon which to impose subsequent selection.
This powerful approach can maximize the genetic diversity
in zygotic progeny. We have coined the term ‘tetrazyg’ to
identify allotetraploid sexual hybrids produced in this
manner. Combining this with new approaches being
employed to evaluate new material has the potential to
greatly shorten the time required to release an improved
rootstock. This is a good example of combining biotechnology
with traditional breeding methods.