Agriculture Reference
In-Depth Information
depending upon regional opportunities,
support, and laws. However, all plant
breeding is becoming progressively more a
private-sector activity. Regardless in which
sector wheat breeding is done, it will remain
a profession that is fi lled with the joy and
satisfaction of creating new cultivars that
can change human lives for the better.
BRIEF HISTORY OF WHEAT BREEDING
assortment and independent segregation of unit
factors that control traits. Mendel's work went
unnoticed until rediscovered independently by
Correns of Germany, de Vries of Holland, and
von Tschermak of Austria. Selection within
landraces and subsequent progeny testing was
used to identify strains that performed better
than the original population from which they
were selected. This technique was practiced
simultaneously in various countries: Knight, Le
Couteur, and Sheriff in the UK; Vilmorin in
France; and Rimpau, Heine, Beseler, and Strube
in Germany (Bonjeau and Angus 2001). Two
principles of selection evolved: (i) selection does
not create genetic variation but only acts upon
genetic variation already in the population
and (ii) selection acts effectively only on heritable
differences.
The realization that selection was effective only
upon heritable variation led early plant breeders
to use the nascent understanding of sexuality of
plants to hybridize different wheat parents. The
practice of hybridization followed by selection as
a wheat improvement strategy was initiated in the
latter part of the 19th century by Vilmorin (cul-
tivar Dattel) in France about 1874 and by Wilhelm
Rimpau ('Rimpaus früher Bastard') in Germany
in 1875 (Bonjeau and Angus 2001). Almost simul-
taneously, crossbreeding and selection was prac-
ticed by Saunders ('Marquis') in Canada, by
Pringle ('Pringle's Defi ance') in the US, and by
Robin ('Robin's Rust Proof ') in Australia.
Initial wheat cultivar improvement and release
was undertaken as private enterprise primarily in
European countries. In the New World, federal
and state governments supported cultivar
improvement as a means to support the develop-
ment of commercial agriculture (e.g., Australia,
Canada, and the US). With implementation of
intellectual property protection and means to
track cultivars by seed pedigree programs and
People express their preferences for food, feed,
and milieu by deliberately choosing plants that
meet these preferences. They have observed and
retained propagules of the new variants that met
their preferences. These new strains are perpetu-
ated if they have a heritable advantage. Examples
include mutations that did not disarticulate the
spikelet from the spike and provided the free-
threshing characteristic in which the lemma,
palea, and glumes separated from the kernel to
leave a naked wheat grain. The gatherers of grain
from wild wheat relatives were most likely women,
and therefore they were most likely the ones who
observed these extremely valuable mutations for
the production of food. These mutations contrib-
uted to a major reduction in the work required to
gather and prepare wild wheat for food.
Principles underlying wheat improvement
include biology of sexual recombination, Mende-
lian laws of inheritance, and selection. Those who
fi rst practiced plant improvement may never be
known to us. We only know those who left a
record that has been found. A summary of the
history of principles of plant breeding and genet-
ics has been presented by other authors (Acquaah
2007), which will be further condensed to salient
features related to wheat improvement. Archeo-
logical records indicate that Assyrians and
Babylonians artifi cially pollinated date palm by
700 BC. In 1694, R.J. Camerarius demonstrated
sex in plants and suggested that hybridizing
between different individuals might produce new
plant types. Between 1771 and 1776 J. Köelreuter
of Germany demonstrated that hybrid offspring
of tobacco expressed traits from both parents. A
century later in 1866, Gregor Mendel published
his famous work with peas, formulating the laws
of inheritance and postulating unit factors later
called genes. Mendel formulated the concepts of
