Joint modelling of spatial variability and interplot competition
by
Jo Stringer
Bureau of Sugar Experiment Stations, Queensland/School of Land and Food Sciences, The University of Queensland
Coauthors: Brian Cullis (NSW Agriculture)

The early stages of selection for improved plant varieties include a large number of genotypes in small single-furrow plots, because of limitations on planting material and resources. Variety contrasts for yield in such trials may be subject to bias from spatial trends and interplot competition.

An approach to the simultaneous modelling of spatial variability and interplot competition is described. We extend the genotypic interference model of Besag and Kempton (1986) to initially allow for random variety effects and then to model both spatial variability and interplot competition. The joint modelling and standard approaches are compared using two sugarcane data sets for yield in trials of 193 and 206 varieties. In these trials there was 72 and 77% agreement between the two approaches in selected varieties rated in the top 15% for yield. This indicates that appropriate modelling of interplot competition and spatial variability can have a large effect on varieties to be advanced to the next stage of selection.

Date received: October 29, 2002

Copyright © 2002 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cajn-56.