FIELD EVALUATION OF A MODIFIED AUGMENTED DESIGN (TYPE 2) FOR SCREENING BARLEY LINES

Abstract

The modified augmented design, which adjusts for environmental heterogeneity when large numbers of test lines are being evaluated in nonreplicated plots, was used in a barley (Hordeum vulgare L.) breeding program at two locations in 3 years. The design offered advantages in flexibility of field operations and was satisfactory for statistical preparation and analyses of the tests. Adjustments in yield based on either the row-column effects or covariance were required in the majority of tests. The relative efficiencies verified the choice of adjustment method indicated by the analysis of variance in 12 of 19 tests. The average change in rank of test lines due to adjustment was often large whereas the average change in yield was generally less than 8%. The design has definite advantages for screening barley breeding lines; however, the agreement between rankings of lines based on the adjusted values and the best estimate of their true ranking needs to be investigated.Key words: Modified augmented design, Hordeum vulgare, barley, screening