Evidence of cross-over interaction involving four spring wheat cultivars
Cross-over interaction is the most extreme case of genotype-environmental (G x E) interaction. Genotypic rank reversals from one environment to the next may be indicative of yield instability. If not repeatable, cross over interaction is undesirable from both the cultivar recommendation and plant breeding perspectives. The objective of this study was to investigate the erratic yield performance of 'Oslo' and 'Fielder' spring wheat. Oslo, 'HY 320', Fielder and, 'Columbus' were grown in seven environments (four dryland, three irrigated) spanning three years (1986-1988). Significant (p=0.05) G x E interaction was detected for all traits measured: grain yield , harvest index, spikelets/spike, kernels/spike, kernel weight and spikes/m2. Cross-overs were not statistically significant for kernels/spike and spikes/m2. Half of the significant crossovers were caused by the differential reaction of the four cultivars to rust at Outlook in 1986. Yield rank reversals between Oslo and Columbus appeared to be related to spikelets/spike and kernels/spike. Changes in rank between Fielder and HY 320 were associated with harvest index and kernel weight.
Soils and Crops Workshop