Is bunch planting suitable for wheat? An evaluation based on yield and lodging resistance

Context or problem: Lodging is a major limiting factor for high-yielding wheat production due to its negative impact on yield and quality. However, little is known about the relationship between different planting patterns and the lodging resistance of wheat.Objective or research question: Different planting patterns alter the precise spatial distribution of crops in the field, which can further affect growth and grain yield. Compared with conventional row planting, more orderly use of growth resources by bunch planting contributed to plant growth and dry matter production. Stem growth is not only related to yield but also to lodging resistance. Based on this, we hypothesise that benefits in crop growth due to bunch planting pattern will promote stem growth to increase its lodging resistance and yield in the field.Methods: In this study, a three-year field experiment was conducted with two planting methods (bunch planting and row planting) at two planting densities (normal density, 3.00 x 106 seeds ha-1 (ND); appropriately increased density, 4.50 x 106 seeds ha-1 (ID)) using the multiple-spike wheat variety XN538 and heavy-spike wheat va-riety LKAZ8 to investigate the effect of bunch planting on wheat yield and lodging resistance and to assess the suitability of bunch planting for wheat production.Results: The results showed that high yields were obtained with both varieties under bunch planting, and overall bunch planting increased wheat yields safety factor by 3.2% and 26.5% respectively. Increasing the planting density further increased the yield of XN538 under bunch planting but reduced the yield of LKAZ8. Bunch planting promotes the morphological development of the basal stem, leading to higher stem diameter, stem wall thickness and stem density per unit length. It also promotes the accumulation of structural and non-structural carbohydrates, leading to lignin, cellulose, soluble sugar and starch contents increased by 23.3%, 28.6%, 26.2%, 54.3%, respectively. The altered morphological characteristics and chemical properties of the stem contributed to the higher mechanical strength and lodging safety factor of wheat under bunch planting at both densities.Conclusions: These results suggest that bunch planting could increase wheat yields and improve lodging resistance.Implications or significance: Our study provides insights into the relationship between planting pattern and crop lodging resistance, which may be of interest for field wheat production.