The expected degree of heterozygosity in a double-cross hybrid population.

HERE have been several recent studies of the relationship between the heterozygosity of plant material and the magnitude of some quantitative character, usually yield or stability over a range of environments (YERMANOS and ALLARD 1961; FINLAY 1963; ROWE and ANDREW 1964). In each of these studies, single crosses and their derivatives have been used as the experimental material so that estimation of the average degree of heterozygosity, for each generation of plants, presents no difficulty. It may be desired, however, to include double-cross hybrid material in such an investigation. The present study gives prediction formulae for the average degree of heterozygosity in double-cross hybrid populations, for a range of genetic and sampling situations.