【摘要】 <正> 一、引言北京黑猪系北京双桥农场和北郊农场于1958年开始,从华北民猪、深县猪、涿县猪、昌黎猪、定县猪、新金猪、巴克夏、约克夏、苏白猪和高加索猪多品种杂交猪中选择培育而成。60年代受苏联形态遗传学的影响,纯选育种工作进展很慢。北京地区经过多年多品种猪更多还原

【Abstract】 The Beijing Black pig has been selected for 24 years and has become a local breed in Beijing-Tianjing area.But taere are some charaeters still need improving,such as the spotted offspring measured about 5%, and the gene frequency,34.22%. According our experience and modern breeding method used in Canada and Japan,as well as considering local condition,the perfor- mance of big litter size（9—10）,high growth rate,higher meat per- centage of carcass（47—48%）,well setlegs,vigorous and good-quality pork will be expected. The original generation were selected in Autumn 1976.It consisted of 8 males and 40 females.It is possible to attain coefficient of inbr- eeding up to 12.5% in six successive generation and obtained an effect of enhancing the allelomorphic homogeneity so hereditery can be imp- roved,through one generation per year. Indes of selection were,at 60 days of age Ⅰ=2（x₁+2.2x₂+0.14x₃）, at 6 months of age for male Ⅰ=x₁-200x₂ and female Ⅰ=x₁+0.2x₂. The performances of Second genvation were:litter size 9.18±1.75kg litter weight（60 days）139.45±34.69kg,mortality 20.2%.Live weight （six months）87.31kg（third generation）,75.17kg（fourth generation）re- spectively.Daily gain was 134 g more and back fat thickness was 0.09 less in third generation than original one. At finishing period daily gaily gain of second generation was 43g more than that of the original,with 0.1—0.4kg more feed consumption per kg gain.The performance of finishing pig in second generation were:dressing percentage 75.75%,back fat thickness 3.87 cm;meat% of carcass 47.83,ham in carcass 27.1% and meat% was 16.7 more than that of the original. Two of original boars were culled in zero generation.The progeny of boar No 1025 consisted 30% of the second generation,while three of others 20% each.57 original females were only kept 9 in second gener- ation.The progeny of sow No 98 consisted 26.8%,sow No 32 19.5%, sow 194 12.2%,the others were 10% each. Inbreeding coefficient in second generation were 3.74%.The cumu- lation in breeding coefficient was 6.35%,averaging 2.12% for each ge- neration.更多还原