PDF file: Annual Report 2002/2003 - Scottish Crop Research Institute

Director’s Report
In 1903, W. S. Sutton (1876-1916) pointed out that
the Mendelian ratios could be explained by the cytological
behaviour of the chromosomes. In 1911, T.
H. Morgan (1866-1945) claimed that certain traits
were genetically linked on the chromosome, arranged
as genes in a linear file, thereby stimulating the construction
of genetic maps. In 1930, R. A. Fisher
(1890-1962) in The Genetical Theory of Natural
Selection established that superior genes have a significant
selective advantage, supporting the view that
Darwinian evolution was compatible with the science
of genetics. Thereafter, the relationships between
mutant genes and metabolism described in 1941 by
G. W. Beadle (1903-1989) and E. L. Tatum (1909-
1975), and the work of O. T. Avery (1877-1955) et
al. in 1944 on the transfer of DNA molecules in
pneumococcus bacteria, were able to provide a background
to the groundbreaking model of the structure
of DNA by F. H. C. Crick (born 1916) and J. D.
Watson (born 1928) in 1953. This model could
account for gene replication and the transfer of genetic
information. From such work has developed modern
molecular genetics.
Plant and animal breeding advances, however, were
not reliant on genetical science per se. Selection and
breeding of crop plants had started with the onset of
agriculture, and gained momentum with organised
learning. Competent and invaluable crossing and
selection programmes were well underway in the latter
part of the 19 th century, providing crucial parental
material for modern cultivars. After his On the
Origin of Species by Means of Natural Selection (1859)
and The Variation of Animals and Plants under
Domestication (1868), Charles Darwin (1809-1882) in
1876 had noted that inbreeding usually reduced plant
vigour but that crossbreeding restored it, a fact that
was confirmed by G. H. Shull in 1908. Rarely cited
is the work of Johann Christian Fabricius (1745-
1808) the entomologist and economist, who proposed
that new species and varieties could arise through
hybridisation and by environmental influence on
anatomical structure and function. C. Saunders
adopted the plant breeding principles of planned
crossbreeding, rigorous selection protocols, replicated
trials, and checking performance for local use. His
work led to the introduction in 1900 of the technologically
advanced Canadian wheat cultivar, Marquis.
In 1917, D. F. Jones discovered the double-cross
hybridisation techniques. By 1921, the first hybrid
maize involving inbred lines were sold commercially.
In the last 50-60 years, through the rapid development
of crop genetics and genetical science, improved
strains of rice and wheat led to the Green Revolution,
other new hybrid crops were created, genetic engineering
was able successfully to produce transgenic plants,
and a systematic transfer took place from the original
‘crossing two of the best and hoping for the best’
approach of breeding and culling by numbers, to
rational and sophisticated crossing programmes, careful
selection of parents and the systematic introgression
of desirable genes. This has enabled robust
approaches to combat pests and diseases, and to
improve yields and quality characteristics. Several
articles in the SCRI Annual Report series describe
advances in modern plant genetics, breeding, and
pathology, as well as more recent discoveries in agricultural
environmental science, all underpinned by
biotechnological innovations. Parallel advances have
been made elsewhere in livestock breeding.
Modern-style pest and disease control through application
of such substances as arsenates, Bordeaux mixture
(copper sulphate and lime), derris, London
Purple, nicotine, paris green, pyrethrum, quassia, and
tar oils began in the latter half of the 19 th century,
aided in the 20 th century by new application devices
and improved synthetic chemistry. Synthetic pesticides
spun out of the discovery in 1942 by P. H.
Muller (1899-1965) of the persistent insecticidal
properties of dichlorodiphenyltrichloroethane (DDT),
a chlorinated organic compound originally synthesised
in 1874 by O. Zeidler. Other similar compounds
were introduced, such as chlordane (1945), methoxychlor
(1945), aldrin (1948), heptachlor (1948),
Toxaphene (1948), and endrin (1951). From military
research on poison gases in Germany during World
War II came the organophosphorus compounds such
as Schradan and parathion. Other synthetic compounds
were introduced, such as the dithiocarbarnates,
the methylthiuram disulfides, thaladimides, and
Malathion, and the pesticide industry produced an
array of insecticides, herbicides, fungicides, molluscicides,
growth regulators, rodent poisons etc. In
response to concerns about the environmental effects
and persistence of pesticides, not least through the
publication in 1962 of Silent Spring by R. Carson, the
efforts of diverse environmental groups, reports of
adverse health effects, the development in some
instances of pesticide resistance, and the regulatory
costs imposed on the agrochemical industry, interest
grew in organic farming methods and in integrated
control measures (ICM). These involve in various
combinations, pest- and disease-resistant cultivars,
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