Interpretation of genotype x environment interaction for winter wheat yield in Ontario

An understanding of the causes of genotype x environment (GE) interaction c an help identify traits that contribute to better cultivar performance and environments that facilitate cultivar evaluation. Through subjecting enviro nment-centered yield of a multi-environment trial data to singular value de composition, the portion of yield variation that is relevant to cultivar ev aluation is partitioned into noncrossover and crossover GE interaction, qua ntified by the first two principal components (PC), respectively. Each PC i s a set of genotypic scores multiplied by a set of environmental scores. By relating the PC scores to genotypic and environmental covariates, GE inter action represented by each PC can be interpreted in terms of trait X factor interactions. This strategy was employed in analysis of the 1992 to 1998 O ntario winter wheat (Triticum aestivum L,) performance trial data, Results indicated that plant height and maturity were the major genotypic causes of GE interaction, whereas cold temperature in the winter and hot temperature in the summer were the major environmental causes of GE interaction. Posit ive interactions were found between earlier maturity vs, warmer winters or hotter summers, and between shorter plant height vs, warmer winters or cool er summers. In addition, better resistance to septoria lear blotch (caused by Septoria secalis Frill, & Delacr,) was frequently associated with overal l performance. The results of this study should help in determining breedin g objectives and Tor selecting test sites or environments Tor winter wheat breeding in Ontario.