Genetic selection for wool quality.

Abstract

Abstract This paper reviews the feasibility of genetic selection for wool quality. More than 30 papers were studied in the present investigation. The traits which have been considered in the majority of the literature for inclusion in the selection programmes were: (a) wool quality traits (fibre diameter, staple length, staple strength, standard deviation of fibre diameter, coefficient variation of fibre diameter, yield and crimp frequency) and (b) wool weight traits (greasy fleece weight and clean fleece weight). Before the studied traits can be proposed as the selection traits, estimates of genetic parameters as well as their relationship with other production traits are needed. Weighted mean of estimates for direct heritability ( h 2 ), maternal heritability ( m 2 ) and variance ration due to permanent maternal environment ( P 2 ) from references 1-37 were calculated to be 0.30-0.61, 0.02-0.08 and 0.03-0.16, respectively. The studied breeds were wool breeds and dual-purpose (wool and meat) breeds. In wool breeds, the weighted mean estimates of genetic correlation were ranged from -0.53 to 0.84 among wool traits and were ranged from -0.38 to 0.25 between wool traits and other traits such as live bodyweight, litter size at birth, litter size at weaning and litter weight weaned. The high estimates of h 2 indicate that the response to selection may be reliable but the unfavourable genetic (phenotypic) correlations with other traits are a concern.