作　　者： ; ; ; ; ;

机构地区： 华南农业大学动物科学学院

出　　处： 《Acta Genetica Sinica》 2005年第7期696-703,共8页

摘　　要： 利用MonteCarlo模拟,研究了群体大小、公母比例和每窝测定猪头数对父系猪的近交系数、选择反应及其变异系数的影响。设定基础群母猪规模大小为100头到500头共5个规模,公母猪比例为1∶10和1∶20,每窝测定猪头数为2头和4头,公母猪各半。选择的性状为一般父系猪的选择性状,即断奶后生长速度和达100kg体重时的活体背膘厚,利用多性状BLUP估计性状的育种值,选择指数中后一性状的经济加权系数是前一个的2.5倍,选择共进行了5个世代。结果表明,随着选择群母猪头数的增加,第五世代累积选择反应提高,近交系数上升速度变慢,第五世代累积选择反应的变异系数下降。随每窝测定仔猪头数的增加和公母比例的升高,累积选择反应加快,近交系数上升速度提高,第五世代累积选择反应的变异系数上升。保持公母猪比例不变和每窝测定仔猪头数不变,基础群母猪头数从100头增加到300头,累积选择反应有显著增加,近交系数上升速度显著减慢。母猪头数300头和400头以上的相比,第五世代的累积选择反应增加有限,近交系数下降速度减低。综合评价,对于父系猪的短期选育来说,基础群需要400头母猪以上,每窝测定4头仔猪,公母比例以1∶20较好。 The effects of the population size,boar to sow ratio,and the number of pigs tested per litter on the selection response and its coefficient of variation,inbreeding coefficient of sire line selection were studied.Pig populations of 100 to 500 sows were simulated with Monte Carlo method,and the ratios of boar to sow were 1∶10 and 1∶20.The number of pigs tested per litter were 2 and 4 composed equally of boars and gilts.The traits selected were average daily gain after weaning (ADG) and backfat thickness (BF) at 100 kg live weight.Breeding pigs were selected according to multiple-trait BLUP,and economic weight of BF was set as 2.5 times of that of ADG.After five generation selection,the results showed that the more the number of sows of the breeding population,the higher the cumulative selection response at 5th generation,and the slower the coefficient of inbreeding increment per generation,the smaller the coefficient of variation of the cumulative selection response at 5th generation.Increasing the number of pigs tested per litter and/or the boar to sow ratio increased the cumulative selection response at 5th generation,inbreeding coefficient increment per generation,and the coefficient of variation of the cumulative selection response at 5th generation.The cumulative selection response got higher and the increment of inbreeding coefficient slowed down significantly when the number of sows in the breeding population increased from 100 to 300,and the ratio of boar to sow and the number of pigs tested per litter were fixed.When the sow number of breeding population was increased from 300 to 400 above,the cumulative selection response only increased slightly,and the coefficient of inbreeding continued to decrease but at a diminished rate.In conclusion,for the short-term selection of sire line,it is recommended that the breeding population should be composed of 400 or above sows,4 pigs tested per litter,and the ratio of boar to sow should be maintained at 1∶20.

关 键 词： 猪 遗传评估 性能测定 选择反应 近交系数

领　　域： [农业科学] [农业科学]