02195naa a2200157 a 450000100080000000500110000800800410001910000130006024500910007326000090016452017420017365000140191565300290192970000210195877300580197912800082025-06-10       1990    bl uuuu     u00u1 u    #d1 aTORO, M.  aOptimization of selection response under restricted inbreeding.h[electronic resource]  c1990  aA reasonable objective for selection programs in small populations is the maximization of response, with a restriction on the increase of inbreeding. This restriction will be especially important when information on relatives is used for evaluation of candidates for selection. To achieve this objective, different strategies have been proposed: (i) to reduce the intensity of selection; (ii) to lower the weight given to family information in an index below the optimal value; (iii) to restrict the variation of family size, (iv) to make matings between the selected animals, so as to minimize the average coancestry coefficient; and (v) to find a general solution using linear programing. These strategies have been illustrated by genetic simulation of a simple example. The population consisted of 8 males and 8 females selected from 32 animals evaluated in each sex. The candidates were evaluated by an index using information on the individual and its 7 sibs. Five generations of selection were practised. It was concluded that there are several alternative strategies which ensure that inbreeding is below the fixed level (5% per generation) without a significant loss of response, in comparison with classical strategies, where inbreeding is not restricted. A substantial reduction of inbreeding was found with the use of matings having minimal coancestry. However, this reduction was due principally to a delay of 1 generation in the appearance of inbreeding. Linear programing was also efficient in achieving these aims. It is, in principle, more flexible than the other strategies, but its heavy cost of computation is a disadvantage, and, in practice, comparable results can probably be obtained using much simpler strategies.  aEndogamia  aConsanguinidade restrita1 aPEREZ-ENCISO, M.  tGenetics Selection Evolutiongv. 22, p. 93-107, 1990.