| In view of the present situation and needs of quality chicken production in china, anew dwarf dam line with dark-shank and spotty plumage would be bred and then across-combination within this new line andï¿¥sire line that has selected for long timefrom native chicken would be established and applied in production.(1) By designing breeding project and introducing dw gene to native chicken, S2 linewhich is a dwarf dam line with dark-shank and spotty plumage was bred. Thephenotype characters of S2 line are almost the same and the heredity of maineconomical characters are stable and its performance is excellent. The consumed feed ofeach bird of dam line (S2) during 66 weeks is 36.9kg and hen-housed egg production ofS2 line during 66 weeks is 181.2.(2) The significant genetic progress has been gotten by reducing selection proportionand raising selection pressure during selection. The age of the first egg of S2 line haschanged from 148 days at 0 generation to143.5 days at 6 generation, hen-housed eggproduction of S2 line during 43 weeks and 66 weeks have been raised from 79.9 and161.1 at 0 generation to 89.8 and 181.2 at 6 generation respectively, the rate of averagegenetic improvement are 2.07ï¼…and 2.0ï¼…% respectively.(3) The genetic parameters of main laying characters of S2 were estimated and thenapplied to making multiple selection index. The results indicated that heritability of the age of the first egg, body weight and egg weight at first egg, egg weight at 43week-old, the sum of eggs during 43 weeks and the sum of eggs during 66 weeks were0.2540, 0.5631, 0.2597, 0.4759, 0.2621 and 0.3081 respectively.(4) The homogeneous mating-system and individual selection for body weight andshank length and family selection for evenness have been taken to raise frequency ofdwgene and evenness of the population. The variability rate of body weight is less than10ï¼…from 3 generation ,which showed good selection effects.(5) With the method of genetic marker assisted selection, the domestic chicken wasselected as sire line and S2 line was selected as dam line, Shaobo quality chicken hasbeen bred with the two-way crossing system after testing combining ability. The averagebody weight of commercial Shaobo chicken at 90-days age is 1350g, food conversionratio is 3.71:1 and viability rate is 96.5ï¼….(6) 21 breeder demonstration farms and 37 broiler farms in Jiangsu, Zhenjiang, Anhui,Shandong, Sichuan, Jiangxi, Henan, Jiling and other provinces have been built by now.The popularized number of PS and CS of Shaobo quality chicken are 245,500 and 17million, respectively. Significant social and economical benefits have been got throughour project.
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