Effect of potassium fertilizer, genetic makeup, and environment on the potato tuber nutrition

Potatoes are a globally significant food crop, valued not only for their caloric content but also for their significant contribution to vital nutrients for human health, such as vitamins, amino acids, and phenolic compounds. The chemical composition of potatoes—including ascorbic acid (a.k.a. vitamin C), tyrosine, chlorogenic acid, tryptophan, phenylalanine, protein, and thiamine (a.k.a. vitamin B1)—is highly influenced by nutrient management. However, the impact of potassium (K) fertilizer rates on potato quality remains largely unknown. Conducted over two years in Idaho and Oregon, this study investigates how K fertilization and cultivar impact the biochemical composition of potato tubers. Results showed that ascorbic acid content was higher in tubers grown in Idaho, especially in the cultivar Clearwater Russet, with a significant increase observed at the highest K fertilizer rate (896 kg ha -1 ). Tyrosine levels were largely influenced by cultivar, with Russet Burbank exhibiting substantially higher content, while K fertilization generally reduced tyrosine levels. Chlorogenic acid content was also higher in Idaho-grown tubers, while tryptophan and phenylalanine contents were notably higher in Russet Burbank, with tryptophan levels peaking in Oregon-grown tubers. The protein content of tubers was 23% higher in 2020 compared to 2021, and on average, Russet Burbank had approximately 13% higher protein content than Clearwater Russet. Thiamine content varied significantly between years, with a marked increase observed in 2021. These findings underscore the crucial role of environmental conditions, genetic factors, and nutrient management on the nutritional quality of potato tubers, offering valuable insights for optimizing crop production. • Potassium fertilizer rates significantly affect potato tuber biochemical composition. • Ascorbic acid content increases with higher K fertilizer rates, especially in Idaho. • Chlorogenic acid and Tryptophan levels vary by location of potato growth. • Russet Burbank had 13% higher protein content than Clearwater Russet.