Godfrey AJWood GRGanesalingam SNichols MAQiao CG2008-04-032016-03-06NO_RESTRIC2008-04-032016-03-062002Godfrey, A. J. R.; Wood, G. R.; Ganesalingam, S.; Nichols, M. A.; Qiao, C. G. (2002). Two-stage clustering in genotype-by-environment analyses with missing data. Journal of Agricultural Science. Vol. 139, pp. 67-77.0021-8596https://hdl.handle.net/10179/592Cluster analysis has been commonly used in genotype-by-environment (G × E) analyses, but current methods are inadequate when the data matrix is incomplete. This paper proposes a new method, referred to as two-stage clustering, which relies on a partitioning of squared Euclidean distance into two independent components, the G × E interaction and the genotype main effect. These components are used in the first and second stages of clustering respectively. Two-stage clustering forms the basis for imputing missing values in the G × E matrix, so that a more complete data array is available for other G × E analyses. Imputation for a given genotype uses information from genotypes with similar interaction profiles. This imputation method is shown to improve on an existing nearest cluster method that confounds the G × E interaction and the genotype main effect.enFields of Research::270000 Biological Sciences::270200 Genetics::270207 Quantitative geneticsJournal articleMassey_DarkMassey_Dark