
%0 Journal Article
%A Stringer, J. K. 
%A Cullis, B. R. 
%T Application of spatial analysis techniques to adjust for fertility trends and identify interplot competition in early stage sugarcane selection trials
%J Australian Journal of Agricultural Research
%D 2002/07/19
%V 53
%N 8
%P 911-918
%K mixed model, statistical analyses, nearest neighbour, variogram, adjustment.
%R https://doi.org/10.1071/AR01151
%U https://www.publish.csiro.au/paper/AR01151 
%X Most sugarcane breeding programs in Australia use large unreplicated trials to evaluate clones in the early stages of selection. Commercial varieties that are replicated provide a method of local control of soil fertility. Although such methods may be useful in detecting broad trends in the field, variation often occurs on a much smaller scale. Methods such as spatial analysis adjust a plot for variability by using information from immediate neighbours. These techniques are routinely used to analyse cereal data in Australia and have resulted in increased accuracy and precision in the estimates of variety effects.   In this paper, spatial analyses in which the variability is decomposed into local, natural, and extraneous    components are applied to early selection trials in sugarcane. Interplot competition in cane yield and trend in sugar    content were substantial in many of the trials and there were often large differences in the selections between the    spatial and current method used by the Bureau of Sugar Experiment Stations. A joint modelling approach for tonnes    sugar per hectare in response to fertility trends and interplot competition is recommended. 
