Nestor K E, Anderson J W
Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA.
Poult Sci. 1998 Nov;77(11):1601-7. doi: 10.1093/ps/77.11.1601.
Published research indicated that a line (FL) of turkeys selected for increased shank width and exhibiting good walking ability (WA) and improved leg structure was useful in improving WA of a cross with an unimproved commercial sire line while remaining competitive in BW and body conformation. The purpose of the present study was to determine whether the FL line was useful in improving WA of two improved commercial primary-breeding sire lines and to study the inheritance of BW traits in the pure lines and reciprocal crosses of the pure lines. Samples of a primary breeding sire line from each of two major commercial turkey breeders were obtained as unpedigreed eggs and designated as Lines A and B. Lines A and B were reciprocally crossed with the FL line that had been selected for increased shank width for 16 generations. Pure lines and reciprocal crosses were produced by artificially mating 10 males to 15 females using pooled semen. The same semen pools were used to produce both the pure lines and the crosses. Traits measured included BW at 8, 16, and 20 wk of age, and length, width, and depth of the shank, width of the breast, and WA at 16 wk of age. The A and B lines were larger and had wider breasts and narrower and shorter shanks than the FL line. Line B was larger than Line A. Shank measurements and WA score did not differ between Lines A and B in either sex. Breasts of Line B females were wider than those of Line A females, but there was no sire line difference in breast width of males. Heterosis in BW was greater in Line A crosses (average of 4.6% with a range of 2.5 to 7.2% for BW at different ages) than in Line B crosses (average of 2.2% with a range of 0.1 to 5.3%). Heterosis in WA score was negative (crosses had better WA than pure lines) for males [14% for the Line A and FL crosses (P < or = 0.001) and 4% for the Line B and FL crosses (P < or = 0.05)], but was positive and nonsignificant for females of the above crosses (average of 2.6 %). With one exception, heterosis was not an important source of variation for shank width or shank depth and there was a low level of heterosis for shank length. No heterosis was observed for breast width. Reciprocal effects were an important source of variation in BW and shank measurements for females but not for males in both sets of crosses. The results of the present study indicated that use of the FL line to improve WA of improved primary-breeding commercial sire lines was not a feasible alternative. The slight improvement noted in WA of the male crosses was offset by the reduction in BW and breast width of the crosses relative to the pure commercial sire lines.
已发表的研究表明，一个经过选育以增加胫宽、具有良好行走能力（WA）和改良腿部结构的火鸡品系（FL），在与未经改良的商业父本品系杂交时，有助于提高杂交后代的WA，同时在体重（BW）和体型方面仍具有竞争力。本研究的目的是确定FL品系是否有助于提高两个改良的商业原种父本品系的WA，并研究BW性状在纯系及其正反交中的遗传情况。从两个主要商业火鸡育种公司各获取一个原种父本品系的样本，以无系谱鸡蛋的形式获得，并分别命名为A系和B系。A系和B系与已选育增加胫宽16代的FL品系进行正反交。通过使用混合精液将10只雄性与15只雌性人工交配来产生纯系和正反交后代。用于产生纯系和杂交后代的精液池相同。所测量的性状包括8周龄、16周龄和20周龄时的BW，以及16周龄时胫部的长度、宽度和深度、胸部宽度和WA。A系和B系比FL品系体型更大，胸部更宽，胫部更窄更短。B系比A系体型更大。A系和B系在胫部测量和WA评分方面，无论雌雄均无差异。B系雌性的胸部比A系雌性更宽，但雄性胸部宽度在父本品系间无差异。A系杂交后代的BW杂种优势（不同年龄BW的平均值为4.6%，范围为2.5%至7.2%）大于B系杂交后代（平均值为2.2%，范围为0.1%至5.3%）。WA评分的杂种优势对雄性为负（A系和FL系杂交后代为14%，P≤0.001；B系和FL系杂交后代为4%，P≤0.05），但对上述杂交后代的雌性为正且不显著（平均值为2.6%）。除一个例外，杂种优势不是胫宽或胫深变异的重要来源，胫长的杂种优势水平较低。未观察到胸部宽度的杂种优势。正反交效应是两组杂交中雌性BW和胫部测量变异的重要来源，但对雄性不是。本研究结果表明，使用FL品系来提高改良的原种商业父本品系的WA不是一个可行的选择。杂交后代相对于纯商业父本品系在BW和胸部宽度上的降低抵消了雄性杂交后代在WA上的轻微改善。
