Most quality characteristics of potato tubers are affected by an interplay of plant genetic traits and environmental factors, including weed control. As a result, detailed studies on plant responses to changing agrotechnological factors seem to be justified. It was attempted in the present work to determine the effect of weed control methods on total and true protein content in two kinds of table potato tubers. The field experiment was designed as a split-plot arrangement of the following two factors: potato cultivars: Irga and Balbina, and four weed control methods: 1 – mechanical weed control – control treatment, 2 – mechanical weed control + the herbicide Plateen 41.5 WG at the rate of 2.0 kg·ha^-1, 3 – mechanical weed control + the herbicide Racer 250 EC at the rate of 3.0 dm³·ha^-1, 4 – mechanical weed control + the herbicide Sencor 70 WG at the rate 1.0 kg·ha^-1. The weed control methods examined in the study increased the total and true protein contents by an average of 0.04-0.14 and 0.02-0.06%, respectively. Compared with the control treatment, a significantly higher total protein content was found in treatment 3, where a combination of mechanical and chemical control had been applied (one hilling + spraying with Racer 250 EC at the rate of 3.0 dm³·ha^-1 10 days after planting), and in treatment 4, where mechanical and chemical control had been applied, too (two hillings combined with harrowing before emergence of potato plants + Sencor 70 WG at the rate of 1.0 kg·ha^-1 applied just before emergence. The highest true protein content was determined when weeds were controlled mechanically and chemically using Sencor 70 WG. The study results demonstrated that Irga had a higher concentration of total protein and true protein, on average 9.89 and 6.70%, respectively, compared with Balbina (9.11 and 6.44%, respectively). The weather conditions in the study years significantly affected the total and true protein contents which were the highest in 2007 when the temperature was the most suitable for potato development.

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