【摘要】 对山西瘦肉型猪新品系SD -Ⅱ系的选择效应进行了分析。经过 5个世代的选育 ,公、母猪 70～ 1 80日龄平均日增重由 0世代的 42 7 4g和 431 6g提高到 5世代的 5 34 6g和 5 74 3g ;背膘厚度分别由 0世代的 2 83cm和 2 96cm下降到 5世代的 1 2 3cm和 1 2 4cm ;其它性状都有很大的提高 ,易受环境影响的性状 (如背膘厚度 )变异系数较其它性状大 ,各性状变异系数随世代的增加呈减小的趋势 ,说明加性遗传方差减小 ,遗传性趋于稳定。更多还原

【Abstract】 The selection response of Shanxi Lean meat Pig SD-Ⅱwas analysed. The results showed that:after five generations of selection,sire and dam 70～180 days old daily gain was promoted from 427.4 g,431.6 g of zero generation to 534.6 g, 574.3 g of the fifth generation respectively; back fat was reduced from 2.83 cm,2.96 cm of zero generation to 1.23 cm,1.24 cm of the fifth generation respectively. The coefficient of variance of the traits subject to environment such as daily gain was greater than those of others, and other traits were also promoted greatly. The coefficient of variance of every trait appeared to decrease with the increase of generation. It meant that additive genetic variance was decreasing, the hereditary capacity was becoming steady.更多还原