选择效率世代指数研究

Research on the generation index of selection efficiency

【目的】在假定没有突变和迁移等产生新的变异且环境不变的情况下,对数量遗传学中的选择效率问题进行探讨。【方法】根据数量性状改良的选择理论,以各世代的遗传进展与第1代遗传进展之比构建了选择效率世代指数,以度量各世代的选择效果和潜力。【结果】在已知育种群体0世代遗传力的情况下,可计算出该群体各世代的选择效率世代指数：在第1世代时为1,以后世代可由遗传力推算得到。在留种率不变时,不同遗传力对应的选择效率世代指数在前3代变化较快,很快就趋于稳定;在固定低、中、高3种遗传力水平时,不同留种率的群体在第1代的遗传进展随着留种率增大而单调递减,且遗传力水平越高,遗传进展越大,选择效率世代指数也越大。【结论】影响选择效率的主要因素是遗传力,遗传力越大,选择效率越高,且育种群体的选择潜力通常只有2-3代,因此在育种中可引入新的选择反应。

【Objective】 Under the assumption that there were no new variation caused by mutation and migration,and the environment remained unchanged,the selection efficiency in quantitative genetics was studied.【Method】 According to the selection theory to improve quantitative characters,generation index of selection efficiency was constructed with the ratio of the genetic progress of generations to the genetic progress on the first generation in order to measure the selection effect and potential.【Result】 If the heritability of zero generation of the breeding population was known, the generation index of generations can be calculated： On the first generation it was 1, and on later generations it can be calculated by heritability. When the selection proportion was invariant and the heritability of zero generation was in different situations,the corresponding generation index changed fast on the former three generations of selection, but quickly stabilized. When the heritability was fixed in low,medium and high levels respectively, the genetic progress on the first generation of the population, when in different selection proportion, decreased as the selection proportion increased,and the higher the level of heritability,the greater the genetic progress and also the larger the generation index of selection efficiency. [Conclusion] The main factor which could influence selection efficiency was heritability,and the greater the heritability, the higher the selection efficiency. And the selection potential of the population was only 2 to 3 generations, so new selection response could be brought into breeding.