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Sardi.sa.gov.au

Doubled Haploids in Plant Breeding
What is a doubled haploid plant?
Cells are the building blocks of plants.
A doubled haploid plant has
cells containing 2 gene sets
which are exactly identical.
Each cell contains 2 sets of genetic information which are almost
(but not exactly) identical.
For example, one gene set may carry a gene for disease resistance when How do doubled haploids accelerate breeding?
Plants selected from a conventional breeding population do not
Plants selected from a doubled haploid breeding
breed true.
population always breed true.
Selected Plant
Selected Plant
Progeny:
Progeny:
This attribute of doubled
haploids allows new
Progeny:
cultivars to be released 3
to 5 years earlier than with
conventional breeding.
Continue for 10-12 generations until
all offspring breed true to type
How are doubled haploids produced?
Tissue culture of immature pollen
Using tissue culture techniques referred to as “anther culture” and “isolated microspore culture”, immature pollen grains
can grow to produce colonies of cells. The colonies are transferred to media with different plant growth regulators and
sugars to induce growth of shoots and then roots.
colonies
shoot growth
root growth
genetic information (ie. It is
This genetic information is duplicated “haploid”)
in the culture process to produce a “doubled haploid”.
Crossing with other species
When barley is pollinated by the wild barley Hordeum bulbosum, the resulting embryos contain only the barley genes
because the Hordeum bulbosum genes are excluded from the embryo.
If the embryos are cultured in vitro they will grow into haploid plants.
Haploid
Doubled
Haploid
Plant
Haploid Plant
Doubled
Haploid
Haploid plants are sterile but can be converted to fertile doubled haploids by treating them with the chemical colchicine.
Wheat doubled haploids can be produced in a similar manner if wheat is pollinated with maize.
Doubled haploids:
tools for rapid oat breeding
Benefits
•
True breeding plants in one generation
Potential to produce cultivars 3 years earlier
More efficient screening for grain quality
and disease resistance

Source: http://www.sardi.sa.gov.au/__data/assets/pdf_file/0012/45030/crops_dh_plantbreeding.pdf