Boosting rapeseed (Brassica napus L. var. oleifera) yield, nutritional profile and functional aspects: the role of variety, climate, and fertilization strategy
Description
Rapeseed (Brassica napus L. var. oleifera) is a globally significant vegetable oilseed crop valued for its versatility and economic impact, with seeds being sources of oil and protein for both food and industrial applications. This study investigates the influence of rapeseed variety, environmental and fertilization conditions on the agronomic parameters, fatty acid composition, and polyphenols content of rapeseed. We identified “Year” as a significant factor affecting grain yield, with variations attributed to sowing dates, rainfall patterns, and temperature trends. In 2020/21, earlier sowing and favorable weather conditions resulted in a grain yield of 2.16 Mg ha-1, while we had a 79% decline in 2022/23 under unfavorable climate. Higher nitrogen rates (140 and 190 kg N ha-1) increased the dry biomass at flowering and the grain yield at harvest, with intermediate rates (110 kg N ha-1) achieving comparable results to higher rates by optimizing timing, particularly in pre-sowing and early spring. Nitrogen fertilization also significantly impacted fatty acids composition and polyphenols accumulation, with higher nitrogen rates related with increased levels of specific fatty acids. Phenolic compounds analysis revealed significant fluctuations depending on the year, with anthocyanins, flavanols, and flavonols being the most susceptible. In 2020/21, the anthocyanins were the most abundant, while in 2022/23, the α-linolenic acid (10.9%) and eicosenoic acid (1.17%) displayed the highest content. Our findings emphasize the importance of strategic planning, environmental monitoring, and targeted nitrogen fertilization in optimizing rapeseed yield and quality under a changing climate. This comprehensive analysis provides valuable insights for sustainable rapeseed cultivation, promoting yield stability and enhancing the nutritional and functional properties of rapeseed products.