A further examination of the relative efficiency of three methods of selection for genetic gains under less-restricted conditions
A further examination of the relative efficiency of three methods of selection for genetic gains under less-restricted conditions
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进一步检验在较少限制条件下遗传收益的三种选择方法的相对效率
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发表时间：
1961
期刊：
影响因子：
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通讯作者：
S. S. Y. Young
中科院分区：
文献类型：
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作者：
S. S. Y. Young
三种选择方法（指数，独立淘汰水平和串联）的相对效率进行了比较，在经济单位的遗传增益。比较涵盖的情况下，方差，遗传力和经济权重是不平等的，而两个相关的字符的情况下也进行了检查。影响相对效率的因素很多，包括选择强度、选择性状的数量、选择性状的相对重要性（以因子λ表示，因子λ是经济体重、遗传力和表型标准差的乘积）以及它们之间的相关性。结论如下：（i）在所有情况下，索引的效率永远不会低于独立剔除水平，尽管在某些情况下它并不比独立剔除水平更有效。反过来，独立淘汰也不会比串联选择更少，但在某些情况下并不比串联选择更有效。(ii)该指数优于其他方法的优势增加了越来越多的选择下的性状，但减少了相对重要性的差异，其优势是在最大时，性状是同等重要性。该指数的优势，独立淘汰水平下降，增加选择强度，但其优于串联选择是独立的强度。(iii)独立淘汰优于串联选择的优势随着选择强度的增加或选择性状数量的增加而增加，但随着相对重要性差异的增加而减少。(iv)当性状具有同等重要性时，该指数相对于其他方法的效率受性状间表型相关的影响较大，当性状间表型相关较低或为负时，该指数的相对效率较高。遗传相关的影响仅在性状重要性不相等时才明显，其对相对效率的影响随其它参数的变化而变化。(v)选择方法的相对效率可能因它们用于特殊目的而改变。
The relative efficiency of three methods of selection (index, independent culling levels and tandem) is compared in terms of genetic gains in economic units. The comparison covers cases where variances, heritabilities and economic weights are unequal, while the case of two correlated characters is also examined. Various factors may influence the relative efficiency, including selection intensity, the number of traits under selection, the relative importance of those traits (in terms of a factor λ, which is the product of economic weight, heritability and phenotypic standard deviation), and the correlations between them. The conclusions are: (i) In all circumstances the index is never less efficient than independent culling levels, though in some cases it is no more efficient. Independent culling is, in turn, never less, but in some cases no more efficient than tandem selection. (ii) The superiority of the index over other methods increases with an increasing number of traits under selection, but decreases with increasing differences in relative importance, its superiority being at a maximum when the traits are of equal importance. The superiority of the index over independent culling levels decreases with increasing selection intensity, but its superiority over tandem selection is independent of intensity. (iii) The superiority of independent culling over tandem selection increases with increasing selection intensity or an increasing number of traits under selection, but decreases with increasing differences in relative importance. (iv) The relative efficiency of the index over other methods is much affected by the phenotypic correlation between traits when the traits are of equal importance, the relative efficiency of the index being higher when the phenotypic correlation is low or negative. The effect of genetic correlation is only apparent when the traits are of unequal importance and its influence on relative efficiency changes with changes in other parameters. (v) The relative efficiency of selection methods may be changed by their use for special purposes.