Effect of a pre-planting treatment of seed tubers with low-frequency pulse electric field on the growth of potato plants of different varieties

In spite of high biological potential demonstrated in field trials, many potato cultivars did not show a full productivity at a large-scale production that can be caused by both external (cultivation conditions) and internal (quality and adaptive potential of seed material) factors. To date, a number of seed-stimulating technologies based on the use of the laser, ultrasound, cold plasma, magnetic and electromagnetic fields have been developed. A pre-planting treatment of seeds with low-frequency pulse electric field (LF-PEF) was proved to have a positive effect on the seed qualities and productivity of some agricultural crops including lettuce, parsley, red beet, and carrot. However, the mechanisms of this effect still remain unclear. In this study we assessed the response of 13 different potato varieties to the LF-PEF treatment on several morphometric traits. The study was carried out at three geographical points: Tuberosum Technologies LLC (Saskachewan, Canada, 2009, 11 varieties of different reproductions used for the baby potato production), the field of All-Russian Research Institute of Phytopathology (ARRIP, Moscow Province, 2011; variety Saturna), and Ozery LLC (Moscow Province, 2012; variety Lady Clair). For each variety, 20 kg (Tuberosum Technologies), 200 kg (ARRIP), and 2 tons (Ozery) of seed potato were treated 3-5 days prior the planting using an experimental LF-PEF generator developed by the Intelpro LLC (Russia). Generated electric field was characterized by a broadband frequency range and had the following parameters: carrier frequency 16±10 kHz, repetition rate of the modulating pulse pattern 200 Hz, generated field intensity 20 kV/m. According to the earlier optimized mode, the seed potato was exposed to LF-PEF for 24 h. Protective treatments with fungicides were the same for both treated and untreated plants used as control. Plant height, number of stems per plant, number of leaves per stem, fresh weight of above-ground parts, and the number and total weight of tubers per plant were measured at flowering; each variant (control or treatment) included 10 plants in four repetitions. For the majority of the studied varieties, the LF-PEF treatment did not significantly influence on plant height, number of leaves per stem, and fresh weight of above-ground parts of plants. At the same time, the number of stems per plant and the number and weight of tubers per a plant increased; the revealed changes were reliable and significant for the majority of varieties (80-95 %). The variety-averaged increase in the number of stems and the number and weight of tubers per plant made 27.0, 28.3 и 31.1 %, respectively, as compared to the control. The obtained data agree with the results of our earlier large-scale trials of the LF-PEF technology arranged in different regions of Russia.