Calcium Biofortification in Solanum tuberosum L. plants: assessing the influence of calcium nitrate and calcium chloride on yield

Potato (Solanum tuberosum L.) is a widely consumed and essential food crop globally, making it an ideal food matrix for biofortification. Agronomic biofortification is one of the strategies used to enhance Ca content in edible parts of crops, considering the adverse health issues associated with Ca deficiency. This study aims to investigate the impact of Ca agronomic biofortification through four foliar applications after the beginning of tuberization, on yield of tubers of Solanum tuberosum L. (Picasso variety) produced in Lourinhã (Portugal) in 2018, focusing on the use of calcium chloride or alternatively, calcium nitrate at different concentrations applied (calcium chloride - 1, 3, 6 and 12 kg/ha or calcium nitrate - 0.5, 1, 2 and 4 kg/ha). Control plants and plants submitted to the different Ca treatments were implemented in plots of 20 x 24 m, having been carried out in quadruplicate (compass 60-80 cm). As such, Ca content in tubers was quantified by atomic absorption spectrophotometry in the different treatments. The Ca biofortification index with calcium chloride or calcium nitrate ranged between 5 – 40 %, being the treatment with 6 kg/ha CaCl₂ the one which presented the highest Ca content in tubers at harvest and 1 kg/ha CaCl₂ the treatment with the lowest Ca biofortification index. However, 6 kg/ha CaCl₂ despite presenting the highest Ca content wasn’t the treatment that presented the highest yield. Indeed, all the calcium nitrate treatments demonstrated a substantial increase in tubers yield, which varied between 2.3 (4 kg/ha Ca(NO₃)₂)– 24.3 % (2 kg/ha Ca(NO₃)₂). Statistical analysis was carried out in all the analyses using one-way ANOVA to assess differences among treatments in Solanum tuberosum L. (Picasso variety), followed by Tukey’s analysis for mean comparison, with a 95% confidence level. Furthermore, these findings emphasize the potential of Ca biofortification, especially calcium nitrate treatments, in enhancing the yield of Solanum tuberosum L. tubers.