Inbreeding Depression in the Red-Legged Partridge

Abstract

Inbred lines were established in 1967 (Experiment 1) and 1978 (Experiment 2). They were continued for one and two additional generations of full-sib matings in the first and second experiments, respectively. In both experiments, alternating periods of stimulatory and nonstimulatory light were used to induce egg production in two 15-week production periods. In Experiment 1, 10 of 22 full-sib lines were lost after only one generation of full-sib mating. Of the 29 initial full-sib lines established in Experiment 2, only 6 survived two generations of full-sib inbred matings (F = .375). Egg weight, sexual maturity, and body weight were depressed significantly (P<.01) in birds 37.5% inbred. The two traits most severely affected were egg production and hatchability, which were reduced substantially after only one generation of full-sib mating. The results indicate that establishment and maintenance of highly inbred lines of partridge will require selection of matings from families having superior reproductive traits as well as alternating cycles of inbreeding such as by full-sib mating with crosses of unrelated inbred lines.