The Genetic Control of Growth and Adult Body Weight in the Domestic Fowl ,

THE greatest single genetic contribution to increased efficiency of production of poultry meat has been the improvement in rate of growth and body weight. Although body size and growth rate inheritance have been extensively studied, very little specific information on the genetic control of growth and adult body size is available. A comprehensive review of the subject has been completed by Lerner (1937), while more recent reviews may be found in the books of Hutt (1949) and Jull (1952). In general, the genetic control is said to be quantitative, and the changes that are possible through breeding programs have been estimated. Heritability estimates of body weight at various ages range from 32 to 75% (Jull, 1952). In addition, some genes have been identified which produce marked and deleterious effects on the size of the organism or parts thereof. Examples of such genes which may be mentioned are Creeper (Cutler, 1925) . . .