Combining results from augmented designs over sites

The class of augmented designs contains two kinds of treatments, standard o r check and new or augmented. The latter are usually considered to be rando m effects while the check treatments are considered as fixed effects. New t reatments are usually not replicated and the checks are replicated as point s of reference. An augmented experiment design is a screening design. It is obtained by selecting arty experiment design for the check treatments and then enlarging the blocks or increasing the number of rows and/or columns t o accommodate the new treatments. The new treatments are randomly distribut ed among the blocks or among the rows and columns. An augmented design has many advantages over systematic check arrangements and is useful for shorte ning the selection cycle over standard methods. Statistical procedures are available for recovering inter-block or inter-row-column and inter-variety information at each site, Procedures are presented herein for combining the results from single experiments over sites. Inter-site information may be recovered for random site effects. The method recommended for combining res ults is invariant to experiment design changes, variance heterogeneity, cha nges in checks from site to site, and different response models for each si te. An experiment involving 120 new wheat genotypes and checks was conducte d at three sites,It is used to illustrate the statistical procedure for com bining results over sites. The new wheat genotypes exhibited a relatively l arge genotype X site interaction, indicating their site and environmental s pecificity.