EFFICIENCY OF ETHYLENE APPLICATION ON SEED POTATO TUBERS

Abstract

Potato (Solanum tuberosum L.) is one of the most important agricultural crops in Russia. Potato tubers contain protein of high biological value, starch and vitamins necessary for humans. There are various ways to increase the yield of the crop, currently, it is mainly due to application of mineral fertilizers. However, this method has limitations, since an increase in doses of fertilizers is associated with deterioration of consumer quality and culinary indicators of tubers. One possible alternative is the gassing of seed tubers with ethylene. This phytohormone is widely used on various crops, but its effect on potatoes has not yet been fully studied. It is known that depending on the treatment modes it can act as both a stimulator and an inhibitor of tuber germination. We have developed a new method for increasing potato yield based on the property of phytohormone ethylene to suppress apical dominance at the beginning of tuber germination and thereby promote the formation of a larger number of lateral sprouts from which additional stems are formed. The aim of the research was to determine the effect of seed potato tubers treatment with ethylene on their biochemical parameters, as well as on the growth, development and tuber yield of the crop. The experiments were conducted on the basis of storage facilities of JSC Ozyory (Ozyorsky District, Moscow Province). For gassing, the adapted technology of the company «Restrain Company Ltd» (Great Britain) was used. The storage temperature for seed potatoes was 4 °С; the period of ethylene gassing was from November to the end of April. The treatment with ethylene was stopped 3-5 days before planting. Ethylene-treated potatoes were planted in 2015-2017 on the territory of the Moscow region. A two-factor small-plot field trial was conducted in the Lyuberetsky District at the Korenevo experimental base, the soil was sod-podzolic sandy loam. Seed tubers of potato varieties Lady Claire (early), Gala (mid-early) and Saturna (mid-late) were treated with ethylene. In the control, ethylene was not applied. A three-factor large-scale (40 ha) field trial was performed during commercial potato growing of the same varieties (JSC Ozyory, Ozyorsky District, Moscow Province, sod-podzolic loamy soil). We used the same treatment as in experiment 1 added with 2-3 irrigation (200 m3/ha). In both experiments, the potatoes were planted in the first decade of May (45 thousand tubers per hectare, row spacing width of 75 cm; N60P120K120 applied locally). Biochemical, biometric parameters, and potato yield were measured.It was found that the treatment of potato seed tubers with ethylene at 4 °С changes their biochemical parameters, i.e., dry matter content decreases by 0.2-0.5 % while sucrose increases by 0.03-0.08 %, which indicates the breakdown of tubers’ dormancy. There was a suppression of apical dominance and the formation of more lateral sprouts on tubers, a greater number of stems per plant (by 19.9-36.0 %), and an increase in number of tubers per plant (by 6.3-19.0 %, especially in the Gala variety). Potato yield increased by 9.9-19.0 % depending on the variety, growing area and irrigation. The produced potato tubers were more uniform and marketable. Depending on the common agricultural level and the technology used at a farm, a differentiated approach is proposed in choosing the planting rate. If low agricultural technology and no irrigation, the planting rate of ethylene-treated tubers reduced by 10-15 % allows for the same yield as that for high technology and irrigation.