ARS | Publication request: Unreplicated Variety Trials: Effects of Check Plot Density and Fixed Versus Random Treatments

Submitted to: Applied Statistics In Agriculture Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2003
Publication Date: April 26, 2003
Citation: MAAS, T., STAFFORD, J.M., SEBOLAI, B., MARX, D., TRAVNICEK, D., PEDERSEN, J.F. UNREPLICATED VARIETY TRIALS: EFFECTS OF CHECK PLOT DENSITY AND FIXED VERSUS RANDOM TREATMENTS. APPLIED STATISTICS IN AGRICULTURE CONFERENCE PROCEEDINGS. 2003.

Technical Abstract: Crop researchers performing germplasm screening are often unable to replicate their plots due to scarcity of seed and the large numbers of genotypes being evaluated. The use of known check varieties is a common method of overcoming the difficulties of unreplicated trials. In this simulation we explored the effect of check plot density on the effectiveness of the resulting analysis. We also explored the effect of analyzing treatments as random vs fixed. Our study considers 10 different designs with check densities ranging from 5% of the plots to 50%. The designs and analyses were then compared on the basis of the correlation of the actual treatment effects with the following: ¿observed¿ yield, lsmeans for treatments fixed, and BLUPs for treatments random. Finally, we observed the frequency with which the analysis ranked the top 10% of the treatments within the top 15% of the lsmeans or BLUPs.