Combining ability in a diallel cross of three lines of Coturnix coturnix japonica.

Three random-bred lines of Japanese quail were crossed in a 3 X 3 diallel to estimate their combining ability for hatchability, growth rate, and age at 25, 50, 75 and 100% lay. The experiment was conducted as a randomized complete block design with a 3 X 3 X 2 X 2 factorial arrangement of treatments (3 lines of sire X 3 lines of dam X 2 ambient-temperature stresses X 2 sexes). Approximately 1200 eggs in three hatches were set; 496 progeny measured for five week body weight; and 212 hens observed for age at maturity. General combining ability effects were highly significant for percent hatchability. Specific combining ability was not important for hatchability in the three lines tested. Data on body weight revealed highly significant effects due to general combining ability, specific combining ability, sire X sex interaction, hatch, ambient-temperature stress and sex. Data for age at 25, 50, 75 and 100% lay indicated that general and specific combining abilities as well as maternal effects were all highly significant.

Directional selection for growth at two ambient temperatures in Coturnix coturnix japonica.

Four lines of quail; random-selected, male-selected, female-selected and male- and female-selected lines, were subjected to 37 plus or minus 1-6 degrees C from 3 to 5 weeks of age while another four lines, similarly selected, were reared at room temperature (15 to 27 degrees C). Selection for increased growth was practised for two generations using ten females and five males as parents in each line. A significant interaction between time and temperature was observed in the third generation progeny; when exposed to heat stress, the stress-adapted lines showing a superior growth rate. A sex X temperature interaction was also observed and was due largely to the control females being more sensitive to stress than the males. A cumulative realised heritability estimate of 0-47 plus or minus 0-15 for 5-week body weight was obtained.