马尾松优良家系入选率对遗传增益的影响

Effect of Selection Rate of Superior Family on Genetic Gain of Pinus massoniana

马尾松(Pinus massoniana)优良家系选择是选育马尾松良种的重要环节。该研究以马尾松初级种子园的10组自由授粉子代测定试验为研究材料,根据家系材积均值和家系内材积变异系数设置不同的选择强度,以研究不同选择策略对家系选择效果的影响。研究结果表明:随着入选率的扩大,家系选择所得到的遗传增益逐渐降低,但入选的家系数量明显增加。为保证获得足够的遗传增益,家系入选率应不大于20%。变异系数40%的入选率与30%的入选率相比,遗传增益下降0.57%,变异系数增加2.82%,而入选家系数目增加了9.8%～15.5%。说明适当放宽变异系数的入选率可以大量增加入选家系量,而在遗传增益和变异稳定性上的损失却不大。

Superior family selection of Pinus massoniana is an important part in breeding of fine varieties.Based on 10 groups open-pollinated progeny tests in primary seed orchard of P.massoniana,and setting different choice intensity according to family volume mean and the volume variation coefficient within family,effects of different selection strategies on the family selection were studied.Results showed that with the expansion of the selection rate,the genetic gain from family selection decreased gradually,but the number of selected families increased significantly.In order to ensure the adequate genetic gain,family selection rate should be less than 20%.Comparing variation coefficients of the selection rate of 40%and 30%,genetic gain decreased 0.57%and variation coefficien increased 2.82%,but the number of selected families increased 9.8%to 15.5%.It could increase the number of selected family to certainly relax selection rates of variation coefficient,and the losses of genetic gain and variation stability were little.