Revised calculation of the coefficient of parentage in plant breeding

The Coefficient of Parentage (COP) between two individuals is the expected inbreeding of their offspring. Originally exploited by animal breeders, is now a routine calculation among plant breeders as part of crop improvement programs. Here we show that the COP between strains requires a different calculation than the used to calculate the COP between individuals. Failure to do so may result in an overestimation of the amount of inbreeding. Here we provide a simple methodology to calculate the correct coefficient of parentage between strains.