A comparative ideotype, yield component and cultivation value analysis for spring wheat adaptation in Finland

In this study Mixed structural covariance, Path and Cultivation Value analyses and the CERES-Wheat crop model were used to evaluate vegetation and yield component variation affecting yield potential between different high-latitude (> 60° N lat.) and mid-European (< 60° N lat.) spring wheat (Triticum aestivum L.) genotypes currently cultivated in southern Finland. Path modeling results from this study suggest that especially grains/ear, harvest index (HI) and maximum 1000 kernel weight were significant factors defining the highest yield potential. Mixed and Cultivation value modeling results suggest that when compared with genotypes introduced for cultivation before 1990s, modern spring wheat genotypes have a significantly higher yielding capacity, current high yielding mid-European genotypes even exceeding the 5 t ha-1 non-potential baseline yield level (yb). Because of a forthcoming climate change, the new high yielding wheat genotypes have to adapt for elevated temperatures and atmospheric CO2 growing conditions in northern latitudes. The optimized ideotype profiles derived from the generic high-latitude and mid-European genotypes are presented in the results. High-latitude and mid-European ideotype profiles with factors estimating the effects of concurrent elevated CO2 and temperature levels with photoperiodical daylength effects can be utilized when designing future high yielding ideotypes adapted to future growing conditions. The CERES-Wheat ideotype modeling results imply, that with new high yielding mid-European ideotypes, the non-potential baseline yield (yb) would be on average 5150 kg ha-1 level (+ 108 %) vs. new high-latitude ideotypes (yb 4770 kg ha-1, 100%) grown under the elevated CO2(700ppm)×temperature(+3ºC) growing conditions projected by the year 2100 climate change scenario in southern Finland.