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A theoretical appraisal of the relative merits of 50 % hybrid and synthetic varieties of grasses

Published online by Cambridge University Press:  27 March 2009

A. J. Wright
A. J. Wright
Affiliation:
Plant Breeding Institute, Cambridge
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Summary

The expected merits of the semi-hybrid variety, produced by bulk interpollination of two populations (Foster, 1971a, 6, c), are examined in relation to those of the synthetic variety. With diploid inheritance, the mean expression of both types of variety is seen to be the same. Any postulated difference in productivity must depend not only on the preferential establishment and survival of a small fraction of the total population, but on the existence of a correlation between characters determining productivity and establishment. For two populations producing a heterotic hybrid, a correlation due to loose linkage or gene association without linkage may result in the superiority of the semi-hybrid, but tight linkage or pleiotropy are more likely to favour the synthetic variety. It is concluded that superiority of the semi-hybrid mode of varietal production can only be established by means of a direct comparison with its synthetic counterpart, and not solely by the demonstration of upper-parent heterosis for productivity.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 79 , Issue 2 , October 1972 , pp. 245 - 247
Copyright
Copyright © Cambridge University Press 1972

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References

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