Genetic improvement of wheat early vigor promote weed-competitiveness under Mediterranean climate

Chemical weed control is the most effective practice for wheat, however, the rapid evolution of herbicide-resistant weeds threat food-security and calls for integration of non-chemical practices. We hypothesis that integration of GAR dwarfing-genes into elite wheat cultivars can promote early vigor and weed-competitiveness under the Mediterranean climate. We develop near-isogenic lines of bread wheat cultivars with GAR dwarfing genes and evaluate them for early vigor and weed-competitiveness under various environmental and management conditions to identify promising NIL for weed-competitiveness and grain yield. While all three NILs, OC1 (Rht8,12), ZC4 (Rht12,13), and BNMF12 (Rht12), responded to gibberellic acid, they exhibited differences in early vigor. Greenhouse and field evaluation highlighted OC1 as a promising line, with a significant advantage in early vigor over its parental. To facilitate accurate and continuous early vigor data collection, we applied non-destructive image-based phenotyping approaches which offers a non-expensive and end-user friendly solution for selection. NIL OC1 was tested under different weed density levels, infestation waves, and temperatures and highlight the complex genotypic x environmental x management interactions. Our findings demonstrate the potential of genetic modification of dwarfing genes as a promising approach to improve weed-competitiveness and serve as a basis for future breeding efforts to support sustainable wheat production under semi-arid Mediterranean climate.