Productivity and quality of potato tubers depending on protective measures

The article presents the most effective methods of pre-planting processing and the use of protective preparations of chemical and biological origin when processing tubers and plants during the growing season, aimed at obtaining a high yield and quality of tubers. The purpose of the research was to study the yield and product quality of early potato varieties depending on various protection systems. The task of the experiment: the effect of biological and chemical fungicides on the yield and quality of tubers during the pre-planting treatment of tubers and during the vegetation of plants. According to the results of analyzes, the best option is where potato tubers were treated with Celest Top fungicide before planting and sprayed during the growing season three times in phases 2-3 true leaves - Metaxil; budding - Ridomil and during the closing of the tops - Ordan. The use of biological preparations in potato cultivation had a positive effect on the formation of aboveground biomass, but did not contribute to the active formation of tubers. The amount of starch on average for three years varied from 15.5 to 21.7% in the Bellarosavariety, and from 17.6 to 18.0% in the Gala variety.


Introduction
Potatoes are the most important agricultural crop. It occupies one of the first places in world production as a food plant [1].
Agrotechnics and plant protection products play a significant role in increasing the yield of potatoes. The potato protection system includes the use of chemical and biological agents that directly affect the formation of vegetative mass, the quality indicators of tubers and their safety [2,3].
In the Republic of Mari El, in recent years, the most dangerous are two fungal diseases: late blight (in moderately warm and humid years) and alternaria (during hot periods during the growing season of plants), as well as a serious threat to potatoes is caused by rhizoctonia (Rhizoktoniasolani Kuhn). These diseases and their various strains cause great damage to the potato crop, which, with a high prevalence, can be 50% or more [4]. According to K.P. Alekseev, "... when diseases are affected, growth and development deteriorate, yield, quality and marketability of tubers decrease, internal necrosis occurs, which makes them practically unsuitable for both food consumption and industrial processing" [5]. Research in the field of protecting potatoes from diseases is primarily aimed at developing cultivation techniques that contribute to maintaining the material in a healthy state, improving biotechnological methods of growing healthy starting material [6].
According to S. Khavanov and other scientists, "... the impact of protective equipment on yield and quality is enormous, and in the structure of the prime cost, they do not exceed 10-15% at expenses from  10 to 15 thousand rubles. per 1 hectare. Savings due to deviations from protection technology will not give a significant financial effect, but will definitely lead to irreparable consequences up to the complete loss of the crop. This postulate is applicable for any type and size of farms, and the larger the enterprise, the higher the dependence" [7].
Increasing the efficiency of the potato growing industry is possible, according to E.V. Zasorin. and other scientists, "by increasing the yield and improving the quality of tubers through the widespread introduction of a complex of agrotechnical, preventive and protective measures. In the system of protective measures, widespread use of chemical and biological agents that directly affect the formation of vegetative mass, quality indicators of tubers and their safety" [8,9].
Kotikov M.V., Lobyrev I.S., Bogomaz M.V. believe that "... the use of plant protection products allows you to protect potatoes from diseases, since losses can be significant and amount to about 50%, receive significant yield increases and, most importantly, receive high-quality competitive products, which is very important in a market economy" [10].
Pre-planting treatment of potato tubers is a mandatory direction, which allows you to protect young sprouts of tubers from a wide range of pathogens, as well as to obtain increased productivity with high quality indicators and low cost [11]. Bashlakova O. N. believes that "the main task of pre-planting treatment is to protect mother tubers from the development of pathogens and the spread of diseases, since their manifestation, especially in the first half of the growing season of plants, negatively affects the size and quality of the crop" [12]. Factors such as low-quality seed material, violation of harvesting technology and storage conditions, lack or insufficient level of chemical protection affect the degree of development of diseases during the period of cultivation and storage. The protection of potatoes against disease should be based on phytosanitary monitoring data. Treatment with fungicides should be carried out taking into account the identification of the causative agent of the disease in order to prevent the occurrence of epiphytotics. The final stage is an economic assessment of the effectiveness of the planned protection measure. In this regard, the protection of potato plants is becoming an indispensable element of cultivation technology and a promising direction for increasing its yield [13,14].
An urgent topic of the modern period of development of potato growing is insufficient knowledge of the agrobiological properties of modern varieties and their response to biological and technological methods of growing potatoes aimed at increasing yields, product quality, storage and processing conditions [15,16].
The purpose of the work is to study in the conditions of the Republic of Mari El the influence of various systems of protection against diseases, on the yield and quality of products, of two varieties of potatoes.
Scientific novelty. For the first time on the sod-podzolic soil of the Republic of Mari El, a comparative assessment of the fungicidal properties of new systems for protecting early potato varieties from diseases was carried out and their effect on the yield and quality of potato tubers was analyzed.

Material and methods
The research was carried out with two zoned varieties Gala and Bellarozav 2017-2019.
We used the preparations Celest Top -0.4 l/t, Tabu + Gamair (0.1 l/t + 3g/t) during planting. During the growing season, we worked with such drugs as: Ordan, Metaxil, Ridomil with a consumption rate of 2.5 kg/ha, Fitosporin -1 l/ha, Gamair -40 g/ha. The treatment was carried out three times according to the experimental scheme with a knapsack sprayer in the morning.
Agrotechnics are common for the zone. The experiment was laid in 4-fold repetition, using the split plots method.
Harvesting was carried out manually using a scale with an accuracy of 0.1 kg. The weather conditions for all the years of research were both favorable and unfavorable for the growth and development of potatoes.
The growing season of 2017 was extremely unfavorable. The growth and development of potatoes took place in conditions of excess moisture against the background of low heat supply at the beginning of the growing season. During the harvesting period, there were frequent heavy rainfalls, which led to waterlogging of the arable soil layer and to a decrease in the yield and quality of potatoes. GTC for the growing season was 1.8.
In 2018, the weather was mostly warm with occasional precipitation for most of May. The maximum air temperature was 21-26 ° С, on the coldest days it did not exceed 6-12 ° С. In total, 62.2% of the norm of precipitation fell for the month. July was warm, at the beginning of the decade, abnormally hot weather with showers, hail and thunderstorms. The air temperature averaged over a decade turned out to be 2.5 ° C higher than the average long-term values. The rains were different in intensity. In total, 78.3% of the norm of precipitation fell for the month. August was warm with intermittent cold snaps. Rains were rare. The maximum air temperature was 25-30 ° C. The GTC was 0.9.
In 2019, at the beginning of the growing season, the weather was abnormally hot. The average air temperature turned out to be 3.2 ° C higher than the average long-term values. In June, the weather was warm with occasional but heavy rains. The average air temperature turned out to be 1.6 ° C higher than the average long-term values. In July, the weather was moderately cold with frequent, in places heavy precipitation. In total, 180.7% of the precipitation rate fell in July. The last rains significantly replenished the moisture reserves in the soil, which favorably affected the growth and development of potatoes. August was cold with heavy rainfall at times. The maximum air temperature was generally 16.7 ° C. GTC for the growing season was 1.6.
Thus, analyzing the weather conditions for the growing season of 2017 and 2018, we can say that the conditions for the growth and development of potatoes were not very favorable. In 2019, conditions for the formation of potato tubers were favorable.

Results and its discussion
The highest yield was obtained on both varieties in 2019, since during this period the most favorable meteorological conditions were observed. Timely application of chemical fungicides is economically justified and provides significant profit. In the control variant, it was 21.1 ... 27.4 t/ha, and according to the variants it varied from 21.0 to 28.2 t/ha. Extremely unfavorable conditions for potatoes developed in 2017, which led to over moistening of the arable soil layer, which led to a decrease in yield and quality of tubers. Table 1 shows that the yield of potato varieties Bellarosa on average for three years ranged from 16.7 to 21.0 t/ha. The highest potato yield was at option No. 2 -21.0 t/ha. On it, the tubers were treated with the fungicide Celest Top before planting and the treatment for vegetation with preparations: Metaxil -2.5 kg/ha, Ridomil -2.5 kg/ha, Ordan -2.5 kg/ha. Potato yield in options 3 and 5 was at the same level and amounted to 18.6 and 18.2 t/ha. On options No. 6 and 7 with pre-planting treatment of tubers with a tank mixture Tabu + Gamair (0.1 l/t + 3g/t) and three times treatment with biological preparations, no increase in yield was observed. In the Gala variety, the average yield over three years varied from 14.2 to 21.1 t/ha. On option No. 2, the yield of tubers was at the level of 21.1 t/ha, or 13.4 % more than the control. The yield increase on options No. 3 and 5 was 1.4 and 1.9 t/ha, and when processing tubers with a tank mixture Tabu + Gamair (0.1 l/t + 3g/t) and three times treatment with biological preparations (Fitosporin, Gamair , Fitosporin), no increase in yield was observed.
A significant increase in yield was observed when potato tubers were treated before planting and during the growing season of plants with chemical fungicides, where an increase of 4.2 t/ha was obtained on the Bellarose variety (LSD05 = 2.2) and on the Gala variety 2.5 t/ha (LSD05 = 1,7).
For these variants, thanks to chemical fungicides, the highest yields of potato tubers were achieved, which increased by 25% in the Bellarosa variety and by 13.4% in the Gala variety.
The use of chemicals made it possible to increase the yield of potatoes in all variants of the experiment.
The most important indicator of the quality of potato tubers is the starch and dry matter content. Starch is the main component of potatoes; its average content is 18.5% in fresh tubers or 75-80% in dry matter.
The content of dry matter and starch in tubers is one of the main indicators when choosing raw materials for processing into various products.   The amount of starch on average over three years varied from 17.6 to 18.0 %, and the dry matter content from 18.9 to 20.1%. During the pre-planting treatment and treatment of plants for vegetation with chemical fungicides, the highest collection of starch and dry matter was observed. The lowest dry matter and starch values were observed for the variant with the use of biological preparations.
In general, according to experience, the cost of potatoes depended on the yield of potatoes due to the use of chemicals.
Calculations of economic efficiency have shown that cultivation of potato varieties Bellarosa and Gala is profitable with a yield of 21.0 t/ha and 21.1 t/ha, which provides 51.1 thousand rubles/ha and 52.1 thousand rubles/ha per hectare. ha of conditionally net income with a profitability of 32.1% and 33.2 % and a cost price of 1 centner/ha of tubers harvest 7.56 rubles. and 7.53 rubles, respectively, for varieties where potato tubers are treated before planting with Celest Top insect-fungicide and additional three-time treatment for vegetation with chemicals.

Conclusions
Treatment of tubers before planting with the fungicide Celest Top and treatment of potato plants during vegetation with the preparations Metaxil, Ridomil, Ordan, a high yield was obtained. On average, over three years, it amounted to 21.0 and 21.1 t/ha. In this variant, the starch content in tubers increased by 0.5-0.7 % for the Bellarosa variety and by 0.2-0.8 % for the Gala variety. A positive effect on the yield and quality of potato tubers on sod-podzolic soil is exerted by the treatment of tubers before planting and three times treatment of plants during the growing season.
An effective way to increase potato productivity and reduce disease is the treatment of potato tubers before planting Celest Top at a dose of 0.4 l/t and during the growing season with fungicides Metaxil-2.5 kg/ha, Ridomil-2.5 kg/ha, Ordan -2.5 kg/ha against late blight, rhizoctonia and alternaria.
In the production conditions of the Republic of Mari El in order to increase the esistance of potato plantings to phytophorosis, rhizoctoniosis, alternaria, it is possible to introduce an agricultural method of pre-planting potato tubers with Celest Top incectofugicide at a dose of 0.4 l/t and during the growing season by three times spraying with Metaxyl-2.5 fungicides kg /ha, Ridomil-2.5 kg/ha, Ordan-2.5 kg/ha.