Principles of Plant Genetics and Breeding

Resource investment
Human capital
In 1996, K. J. Frey of Iowa State University conducted a
survey to determine the number of science person-years
devoted to plant breeding research and development in
the USA. He observed that of the 2,241 science personyears
devoted to plant breeding, 1,499 (67%) were in the
private sector. Of the remainder, 529 were in the State
Agricultural Experimental Station system, while 177 were
in the USDA-ARS and 36 in the USDA Plant Materials
Centers. Private breeders dominate the crops that are
produced primarily as hybrids. Of 545 breeders in field
corn development, 510 were in the private sector.
Similarly, 41 of the 56 sorghum breeders were in the
private sector. On the other hand, 77 of the total of 131
wheat breeders were in the public sector, while 41 of 50
potato breeders were in the public sector. Other crops of
breeding interest are soybean, cotton, and tomato.
Frey also observed that 1,571 (71%) of plant breeders
in the USA were engaged in breeding agronomic crops
with 634 (29%) breeding horticultural crops. About 75%
of public breeders were engaged in agronomic crops
versus 25% in the private sector. In the US, 100% of all
maize production in 1997 was derived from private sector
cultivars, compared to about 24% from wheat. In
soybean, only about 8% of the acreage was planted to
the crop in 1980, while 70–90% of the crop acreage in
1997 was planted to private sector seed. About 93% of
Allard, R.W. 1988. Genetic changes associated with the evolution
of adaptedness in cultivated plant and wild progenitors.
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Burke, J.M., S. Tang, S.J. Knapp, and L.H. Rieseberg. 2002.
Genetics analysis of sunflower domestication. Genetics
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Frary, A., and S. Doganla. 2003. Comparative genetics of crop
plant domestication and evolution. Turk. J. Agric. Forest.
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Gepts, P. 2003. A comparison between crop domestication,
classical plant breeding, and genetic engineering. Crop Sci.
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Harlan, J.R. 1992. Crops and man. American Society of
Agronomy and Crop Science Society of America, Madison, WI.
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THE ART AND SCIENCE OF PLANT BREEDING 33
References and suggested reading
cotton acreage was also planted to private sector seed.
These trends indicate the surging role of genetically
modified (GM) cultivars in the production of these crops.
Duration and cost of plant breeding
programs
It is estimated that it takes about 7–10 years (or even
longer) to complete (cultivar release) a breeding program
for annual cultivars such as corn, wheat, and soybeans,
and much longer for tree crops. The use of
molecular techniques to facilitate the selection process
may reduce the time for plant breeding in some cases.
The use of tissue culture can reduce the length of breeding
programs of perennial species. Nonetheless, the
development of new cultivars may cost from hundreds
of thousands of dollars to even several million dollars.
The cost of cultivar development can be much higher if
proprietary material is involved. Genetically engineered
parental stock attracts a steep fee to use because of the
costs involved in their creation. The cost of breeding
also depends on where and by whom the activity is being
conducted. Because of high overheads, similar products
produced by breeders in developed and developing
economies, are produced at dramatically higher cost
in the former. Cheap labor in developing countries
can allow breeders to produce hybrids of some selfpollinated
species less expensively, because they can
afford to pay for hand pollination (e.g., cotton in India).
Society of Agronomy and Crop Science Society of America.
Madison, WI.
Koinange, E.M.K., S.P. Singh, and P. Gepts. 1996. Genetic
control of the domestication syndrome in common bean.
Crop Sci. 36:1038–1045.
Koornneef, M.P., and P. Stam. 2001. Changing paradigms in
plant breeding. Plant Physiol. 125:150–159.
Ladizinsky, G. 1998. Plant evolution under domestication.
Kluwer Academic Publishers, Boston.
Zizumbo-Villarreal, D., P. Colunga-GarciaMarin, E.P. de la
Cruz, P. Delgado-Valerio, and P. Gepts. 2005. Population
structure and evolutionary dynamics of wild–weedy–domesticated
complexes of common bean in a Mesoamerican
region. Crop Sci. 45:1073–1083.
Zohary, D., and M. Hopf. 1988. Domestication of plants in
the Old World. Clarendon, Oxford, UK.