|
Index Selection
Index selection is a method of artificial selection Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ... in which several useful traits are selected simultaneously. First, each trait that is going to be selected is assigned a weight – the importance of the trait. I.e., if you were selecting for both height and the coat darkness in dogs, if height were the more important of the two one would assign that a higher weighting. For instance, height's weighting could be ten and coat darkness could be one. This weighting value is then multiplied by the observed value in each individual animal and then the score for each of the characteristics is summed for each individual. This result is the index score and can be used to compare the worth of each organism being selected. Therefore, only those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Selection
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, cultivars, or breeds. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals. In animal breeding, techniques such as inbreeding, linebreeding, and outcrossing are utilized. In plant breeding, similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tandem Selection
Tandem selection is a method of artificial selection in which useful traits are selected for sequentially. For instance, one could select for both increased milk yield and increased milk fat content in cows via tandem selection by first selecting those with the best of one trait, production of high milk yield, and then when that trait is at a satisfactory level, by starting to select for those cows that produce milk with the greatest milk fat content instead. However, for cows to produce milk with greater fat content, yield may have to go down due to limits of the cows metabolism. So while cows are being selected based on increased milk fat content, the yield of milk they are producing may also go down, thus reversing the selection process previously performed to increase it. Therefore, tandem selection has a major disadvantage to other major types of artificial selection for multiple traits, such as culling and index selection Index selection is a method of artificial selection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
