Optimizing winter wheat traits to improve resilience to a changing environment in rainfed crop systems of Turkey and Iran
Erratic weather patterns associated with climate change pose unique challenges for wheat breeders playing a key part in the fight to ensure global food security. Within the rainfed winter wheat areas of Turkey and Iran this erratic weather patterns may prevent attaining maximum potential increases in winter wheat genetic gains. This is primarily related with the fact that the ranking of tested varieties may greatly change from one year to the other. Erratic weather patterns may interfere with breeders decision on the ideotype(s) they should aim for during selection. To support breeding decisions, this study aimed at optimizing major traits through modelling different combinations of environments and defining probabilities of the range of variation of traits (phenology and pant height) that maximized grain yields. Optimal phenology was found to be highly related with the temperatures at which the winter wheat varieties were exposed at around heading time (20 days before and after heading). Specifically later winter wheat varieties were exposed to higher temperature both before and after heading and this exposure had a negative effect on grain filling duration and final grain yield. Finally, the use of at least five different wheat varieties in one production field (with different phenology and plant height) was compared to a field with monoculture to test for improved resilience. It was concluded that by selecting one best wheat variety in a wide range of environments it was possible to maximize grain yield and that using a set of diverse varieties was not beneficial.