Milling & Baking News - June 29, 2021 - 25

TUES | 06 29 2021
strict regulations that limit the acreage
on which they may be applied, and the
sterilization procedure itself is very
sensitive in terms of timing, environmental
conditions, crop physiology,
etcetera. For hybrid wheat to gain market
share, an alternative hybridization
system that can be deployed at large
scale is essential. "
Companies like Syngenta are using
non-chemical techniques in breeding
programs to create male sterile plants.
Called cytoplasmic male sterility (CMS),
the technique breeds a desirable female
parent by replacing its cytoplasm, a cell
component essential for plant growth
and reproduction, by an alternative
cytoplasm that fails to support the
development of anthers or pollen. This
cytoplasm switch, conducted by a multigenerational
breeding process, neuters
the plant's male parts (stamen or anthers)
but leaves the parental line otherwise
intact and ready to be pollinated by the
second breed or male parental line. In
crops like sunflower, sugarbeet, rapeseed
but also barley and rye, similar
CMS systems have successfully
produced hybrid seed for many
years.
In the case of wheat, the
female (neutered) seeds are
planted with male parents by
Syngenta in a blend of about
95:5, the male plants assuring
proper pollination of the
female plants.
" The seed is then harvested
together, " Mr. Gielen said.
" Hybrid wheat therefore is
not as uniform as corn since the
hybrid seed will also contain a
low percentage of the male plants
using this technique. "
Other breeders use a technique similar
to production of hybrid corn, in
Jan Gielen
rat' wheat variety called Chinese spring,
which is very different from modern
wheat varieties. The more recent
genome 'assemblies' provide us with
much more relevant information for us
to use in our breeding programs. There
have also been major advances in how
we, and everyone, can access the data,
through publicly available web-based
tools. These have helped people without
specialist computer programming capabilities
to utilize the information. "
Breeders increasingly are embracing
the tools made possible by the sequencing
of the wheat genome, Dr. Devaux said.
" In the early days, some breeders
were doubtful about the use of new technologies,
e.g. molecular markers, especially when
their breeding programs were running very
well, " he said. " But now all the wheat breeding
community is convinced about the benefit of
such technologies and has been using them routinely
and at high levels. "
Dr. Appels was more blunt about reticence
among veteran breeders and tipped his cap to
Stephen Baenziger, professor emeritus at the
University of Nebraska Lincoln, as an exception
among this group.
" Adoption of the molecular tools and high
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throughput phenotyping in breeding has required
commitment from visionary individuals such
as Stephen Baenziger as well as the younger
breeders coming through the education system, "
Dr. Appels said. " In general the adoption by the
older breeders has not been good because they
(correctly) insisted on 'show me' the results. This
'show me' test is now being achieved particularly
with the application of SNP chips for the rapid
genotyping of individuals in a breeding program. "
Single nucleotide polymorphisms (SNPs) are
used to study small variations between whole
genomes to identify traits, including disease
susceptibility/resistance.
Mr. Burt said many breeders found
data from wheat genome sequencing
" quite removed " from their work in the
field, adding that the wheat breeding
community is using the new technology
to some extent " even if they aren't
entirely aware of how they are using it. "
Tackling the threats posed by
climate change is among the most
important potential benefits that could
emanate from the sequencing of the
Pierre Devaux
wheat genome, Dr. Devaux said.
" Agriculture is facing many challenges,
including global warming,
extremely changing weather conditions
e.g., flooding, extreme drought, heat, increasing
population over the world, ban of pesticides,
organic agriculture and more, " he said. " This
means that breeding programs have to adapt
to these new situations, and as far as there are
genes controlling the traits, the breeders can
have a response to that. With better knowledge
of the wheat genome and more recently of the
wheat genomes (at least 15 have been sequenced
so far), more areas of the genome that contribute
to increase yield, quality... will be identified and
combined to improve these traits. In addition, we
have better information on what parents we have
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Milling & Baking News - June 29, 2021

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