Practical implication of improving the precision of genotype assessment in selection — A theory

Summary

A logical basis for evaluating the practical merit of improving genotype assessment method was defined. Numerical computations indicated that genotype assessment with a high precision is not always useful, and improvement of one process composing the assessment may be of little advantage unless other processes are improved simultaneously. The merit of improving selection criterion was examined using some experimental data reported hitherto. The conclusion was derived that trying a large number of selection units (plants, lines, or families) with a relatively simple selection criterion or index will be more efficient than trying fewer selection units by an elaborate but costly criterion. Breeder's first effort then should be made to increase the number of selection units to be tested, rather than to shape up the criterion for selection. Laborious and time-consuming assessment will be rewarding in the situation where a single or a few genotypes are to be selected from a relatively small number of promising genotypes as would be the case with the final stage of breeding.