Li Wenhui, Guo Jian, Li Fanwen, Niu Chune
Gansu Provincial Sheep Breeding Technology Extension Station, Huang Cheng town, Sunan, Gansu, China.
Lanzhou Institute of Husbandry and Pharmaceutical Sciences, CAAS, Jiangouyan Street, Lanzhou, China.
PLoS One. 2016 Nov 10;11(11):e0166374. doi: 10.1371/journal.pone.0166374. eCollection 2016.
Crossbreeding of Australian Superfine Merinos (ASMs) with Gansu Alpine Finewool (GAF) sheep and an evaluation of the potential benefits of this genetic cross has not been previously conducted. 13 ASMs were crossbred with GAF sheep over a five year period with backcrossing designed to assess heterosis. Data from 11,178 lambs sired by 189 rams were used in the study. Genotype, birth year, birth type, dam age, sex and/or management group, and record age were fitted as fixed effects and within-genotype sire fitted as a random effect. Crossbreeds of 1/2 ASM expressed the most desirable effects for improving average fiber diameter (AFD), clean fleece weight (CFW), yield, coefficient of variation of AFD (CVAFD), yearling staple length (YSL) to AFD ratio (YSL/AFD), and CFW to metabolic yearling bodyweight (YWT0.75) ratio (CFW/YWT0.75) but showed the least post-weaning average daily gain (powADG) and YWT. Genotype of backcrossing with 1/4 ASM obtained moderate improvements in AFD, CFW, CVAFD, and YSL/AFD but the highest YSL, WWT, and prwADG. Except for yield (-1.42%) and CFW/YWT0.75 (-1%), heterosis estimates were generally low and positive, and ranged from 0.1% for CVAFD to 4% for powADG, which indicates the potential to improve relevant traits through exploiting heterosis to a varying extent. The ASMs sampled in this study were found to be superior to GAFs for AFD, CFW, yield, and CVAFD by 19.82%, 11.68%, 14.47%, and 6.99%, respectively, but inferior for YSL, PowADG, and YWT by 4.36%, 50.97%, and 16.93%, respectively. ASMs also appeared to be more efficient than GAFs in clean wool production (25.34%) and staple length growth (16.17%). The results of our study strongly suggest that an infusion of ASM genes via crossbreeding is an effective and appropriate approach to improve wool microns and wool production from GAF sheep, and we make recommendations to tackle the undesirable traits of YWT and YSL from ASM introduction.
此前尚未开展过澳大利亚超细美利奴羊（ASMs）与甘肃高山细毛羊（GAF）的杂交育种以及对这种基因杂交潜在益处的评估。在五年时间里，将13只ASMs与GAF羊进行杂交，并通过回交来评估杂种优势。本研究使用了189只公羊所产11,178只羔羊的数据。将基因型、出生年份、出生类型、母羊年龄、性别和/或管理组以及记录年龄作为固定效应，将基因型内的父系作为随机效应。1/2 ASM的杂交后代在改善平均纤维直径（AFD）、净毛量（CFW）、产毛量、AFD变异系数（CVAFD）、周岁毛长（YSL）与AFD的比值（YSL/AFD）以及CFW与周岁代谢体重（YWT0.75）的比值（CFW/YWT0.75）方面表现出最理想的效果，但断奶后平均日增重（powADG）和周岁体重（YWT）最低。与1/4 ASM回交的基因型在AFD、CFW、CVAFD和YSL/AFD方面有适度改善，但YSL、周岁体重（WWT）和断奶后平均日增重（prwADG）最高。除了产毛量（-1.42%）和CFW/YWT0.75（-1%）外，杂种优势估计值总体较低且为正值，范围从CVAFD的0.1%到powADG的4%，这表明通过不同程度地利用杂种优势来改善相关性状具有潜力。本研究中采样的ASMs在AFD、CFW、产毛量和CVAFD方面分别比GAFs优19.82%、11.68%、14.47%和6.99%，但在YSL、powADG和YWT方面分别比GAFs劣4.36%、50.97%和16.93%。ASMs在净毛生产（25.34%）和毛长增长（16.17%）方面似乎也比GAFs更高效。我们的研究结果强烈表明，通过杂交引入ASM基因是改善GAF羊羊毛细度和羊毛产量的有效且合适的方法，并且我们针对引入ASM后出现的YWT和YSL不良性状提出了建议。
