close breeding
2.Duroc was selected and bred using the method of combination with close and open breeding and composed base population . Daily gain and lean meat percentage of the base population were major selective traits by the results of productive performance testing . After five years selecting , male daily gain was 856 g , famale daily gain was 833 g and increased 6.87% , 5.98 % respectively ;
3.It is thus speculated that dominant dwarfing genes are of multiple-allelic polymorphism, in other words, dominant dwarfing genes, which are ultra-dwarfing, are liable to develop by mutation into a group of multiple alleles with plant height enhanced to different extents and some may have a height close to the ideal plant height for wheat breeding.
4.Although breeding between close kin is thought to be generally unfavorable from an evolutionary standpoint, in part because harmful mutations are more easily propagated through populations in this way, theory predicts that under some circumstances, the benefits of inbreeding may outweigh the costs.
