LAUSR

Among the main factors that affect the productivity of crops is deficiency of nutrients. Boron (B) is an essential micronutrient for plants, and sunflower is one of the most sensitive plants to deficiency of the element. Its inadequate supply can impair sunflower plants’ metabolism and grain and oil yield. The objective of this study was to assess the effect of different boron doses on the production of sunflower grains and the content and quality of the oil obtained from them. The experimental design was randomized blocks in a factorial scheme with three cultivars (Helio251, BRS323, BRS324) and four B doses (0, 2.5, 5.0, 8.0 kg ha). Two harvests were performed, the first in the R5 reproductive stage and the second at the end of the R9 cycle. In both cases, the levels of B in the capitulum were measured. At the end of the cycle, the grain yield, crude protein and oil content in the grains and fatty acid profile were analyzed. The cultivars responded differently to the treatments with B. The boron fertilization influenced the grain yield and oil content, but was not correlated with the profile of the majority unsaturated fatty acids and crude protein in the grains. Variations were observed in the fatty acid profile between the cultivars, an important aspect that needs to be evaluated according to the purpose of the production. In soil with lower availability of B, cultivar BRS323 was most efficient in B uptake, grain yield and oil content and quality.