Up to 32 % yield increase with optimized spatial patterns of canola plant establishment in western Canada

Canola-Brassica napus L.-is an economically major crop in many parts of the world. The seed yield of canola is often limited by poor plant establishment. This issue is serious in areas with short growing seasons, such as western Canada, where canola plants have a limited time span plasticity to adapt and compensate for yield losses due to poor or non-uniform plant establishment. The effect of spatial patterns of canola plant stands on seed yield is actually unknown. Therefore, we studied the impacts of uniformity of plant stands on pod formation, seed set, and crop yield of canola. Field experiments were conducted at 16 site-years across the different soil-climatic zones of the Canadian prairies. At each site-year, the cultivar InVigorA (R) 5440, a glufosinate-resistant hybrid, was sown at 100, 80, 60, 40, and 20 plants per square meter with uniform and non-uniform stands. We found that spatially uniform stands increased seed yield by up to 32 % at low-yielding sites and by up to 20 % at the high-yielding sites compared to non-uniform plant stands. This effect is mainly due to increased number of fertile pods. The yield increase was more pronounced with plant densities lower than 60 plants per square meter. Also, canola seed yield depended largely on plant survival during the hot summer and was less affected by the rate of seedling emergence. We conclude that canola yield can be increased by improving the uniformity of plant spatial distribution patterns in the field regardless of environmental conditions.