Probabilities of negative estimates of genetic variances

Summary The probability of negative analysis of variance estimates of genetic variance components due to sampling error (Ps) was investigated. The objectives were to evaluate the magnitude of Ps, to compare Ps for estimates of _A ² and _D ² , and to compare Ps for genetic variance component estimates from the nested and factorial mating designs. Ps was defined in terms of ratios of mean squares and the F distribution was used to calculate probabilities of the negative estimates. The results indicated that Ps is often greater than 0.20 for _D ² . It is generally lower for _A ² than for _D ² , and lower for the factorial mating design than the nested mating design.Technical Contribution No. 2589 from the South Carolina Agricultural Experiment Station, Clemson University