Triple full-sibs: A method for estimating components of genetic variance and progeny selection in plants

Abstract

Quantifying the genetic variability present in plant populations is crucial for the success of selection plans. The partitioning of genetic variance into its components allows inferences about the inheritance of quantitative traits and prediction of the gain from selection. The present study aimed to present an alternative method to estimate components of genetic variance with applications in recurrent selection. The mating scheme is based on biparental cyclic crossing involving three parents in each chain, here called the triple full-sibs (TFS) family, each of which is composed of three biparental progenies in which individuals are full-sibs within each progeny and half-sibs among progenies. The progenies are evaluated in experimental trials, and the total effect of progenies is hierarchically partitioned into the effects of TFS families and progenies within families. From the components of variance, additive and dominance variance, as well as the associated errors, can be estimated. Simulated data are used to illustrate the method of analysis and parameter estimation. The method combines the advantages of North Carolina Design I regarding estimation of variance components with the practicality of conventional full-sib selection. The TFS method allows different selection strategies according to the selection unit and provides expected genetic gain equal to or greater than unrelated full-sib selection. There is no further advantage to using more than three parents in each chain-cross.