Suitable hybrids of very early watermelon and their fertilizer rates when grown under temporary film cover

. The article presents the results of studying the growth, development, productivity, yield and quality of fruits of varieties and hybrids of watermelon under conditions of film shelters. It was revealed that the largest early yield (159.6-196.4 c/ha) with high qualities (sugar content 7.0-7.6%) was observed in heterotic hybrids - Montana F1, Talisman F1, Dolby F1, Hollar F1, Super Crimson F1. The isolated watermelon hybrids proved to be favorable for growth and formation of the optimal leaf surface area, powerful tops, root system and productive bushes when applying organomineral fertilizers at a rate of 10 t/ha of manure + N 125-150 P 100-120 K 62-75 kg/ha or per each nest 1.0 kg of manure + N 13.0-15.8 P 10.5-12.6 K 6.6-8.0 grams. At the same time, the marketable yield was 18-20 t/ha and more.


Introduction
In the republic melons and gourds are annually cultivated on an area of 60 thousand hectares, of which 60-65% of the area is occupied by watermelon. Superearly watermelon on protected temporary film shelters occupies 3.0-3.3 thousand hectares, mainly farmers of the Kashkadarya region are producers, and is a means of export. It is the most important food product among the people, a good diuretic, does not irritate the kidneys and urinary tract, so doctors recommend it for various kidney diseases.
Watermelon well cleanses the body of harmful substances and toxins, promotes the release of cholesterol. It is recommended for anemia, it contains a lot of iron and folic acid, which promote hematopoiesis, and is also useful for chronic liver diseases, atherosclerosis, metabolic disorders, and diseases of the cardiovascular system [1]. Contains vitamins (A, C, E and group B), magnesium, calcium, phosphorus, iron, sodium and other elements, 5-13% sugar. Due to the content of lycopene in fruits, it helps the human body in resisting various irradiations, including ultraviolet [2][3][4].
Obtaining an early and continuous harvest of watermelon in specific soil and climatic conditions largely depends on the correct selection of adapted, early ripening, resistant to stress factors, with intensive formation of a quality crop, transportability and storability of varieties and heterotic hybrids and the development of agricultural technologies -soil mulching, growing seedlings, cultivation under the film of temporary shelter.
In the southern region of the Kashkadarya region, the production of the early harvest of watermelon is specialized, a specialized cluster of farms has been created here, which is distinguished by the accumulation of sufficient experience.
Under these conditions, increasing the production and yield of early watermelon, conducting scientific research on the selection of adaptive, with intensive formation of the crop, resistant to adverse conditions, diseases and pests of hybrid varieties, as well as on the development of methods and techniques of agricultural technology is relevant, has important scientific and practical meaning.
The purpose of the study is to study the growth, development, formation of crops that are resistant to diseases and pests, the total and marketable yield of varieties and heterotic hybrids of watermelon under film in temporary shelters in conditions of conditionally irrigated light sierozem soils of the region and, on their basis, the selection of promising ones, as well as the development their main elements of agricultural technology are the preparation of seedlings, the norms of organomineral fertilizers for each nest (hole).

Materials and methods
Field experiments were carried out in the conditions of irrigated light sierozem soils of the MFI "Soybuyi", household plot of Yakhshiev Asadullo Chirokchinsky, now Kukdala district. The depth of groundwater in the experimental plot of light gray soils is 10-12 m, the mechanical composition is medium loamy. The arable horizon is characterized by a humus content of 1.13%; -0.13%, gross phosphorus -0.24%, gross potassium -2.10%, nitrogen nitrate -6.93 mg/kg, ammonium nitrogen -3.04 mg/kg, mobile phosphorus 20.5 mg /kg, exchangeable potassium 209 mg/kg.
In the variant of standard norms of mineral fertilizers, N31P17.5K8.8 g was applied at each nest.
Before planting the seedlings, organomineral fertilizers were mixed with the soil according to the experimental variants, applied to the nest, then the seedlings were planted, watered and immediately covered with a film using arcs. 5-7 days before planting, the seedlings were opened during the day, covered with foil at night, hardened. Then, 30-40-day-old seedlings with 3-4 true leaves were planted under a film in the field on March 15-19 according to the scheme (280+70)/2x60 cm with a density of 9520 plants per 1 ha.

The results and discussion
When cultivating varieties and hybrids of ultra-early watermelon under film, they differed significantly in growth, development, yield and quality of fruits. In the watermelon variety Dekhkon, the period from planting seedlings in the field to ripening was 66 days, the length of the main stem (lash) is 172 cm, the number of main shoots is 3.4, the number of fruits from a bush is 3.6, the yield of fruits from a bush is 16, 1 kg, and the yield per hectare is 11.1 tons, the sugar content of fruits is 5.9%. And for the watermelon variety Farmer, these figures were, respectively, 64 days, 187 cm, 3.7 pieces, 3.8 pieces, 18.7 kg, 13.1 tons and 6.4%. It was revealed that the Fermer variety had a yield of 2.0 t/ha, and the sugar content was 0.7% higher compared to the Dekhkon variety.
In the studied heterotic hybrids of watermelon, the period of "landing in the fieldripening" ranged from 60 to 73 days. The most precocious hybrids were Dolby F1, Hollar F1, Krimstar F1. And relatively late-ripening Oriji F1, Red star F1, Super crimson F1. The length of the main lash (stem) in varieties was 172-187 cm, and in heterotic hybrids 166-223 cm, the number of fruits per bush varied from 3.5 to 4.9 pcs. The lowest yield (11.1 t/ha) was noted in the Dekhkon variety, while in other varieties and heterotic hybrids, the yield varied from 13.1 to 19.6 tons per hectare. The highest yield of fruits (16.0-19.6 t/ha) with a sugar content of 7.0-7.6% was obtained from hybrids Montana F1, Talisman F1, Dolby F1, Hollar F1, Super crimson F1.
Growing isolated watermelon hybrids under film in temporary shelters at different norms of organomineral fertilizers at each nest has a significant effect on growth, formation of tops, roots and leaf surface area of plants, and with the joint application of organomineral fertilizers, the growing season is extended by 3-5 days, as a result of this the Dolby F1 hybrid had a growing season of 58-60 days, and the Montana F1 hybrid had a growing season of 66-68 days (Table 1).
In isolated watermelon hybrids, when cultivated under film in temporary shelters and applying various fertilizer rates, the yield ranged from 1 hectare from 13.2 to 21.8 tons (Table 2, Figure1).

Conclusions
The studied varieties and hybrids of very early watermelon, when cultivated under film in temporary shelters, differ significantly in growth, development, productivity, yield and fruit quality, the largest yield (16.0-19.6 t/ha) and quality (sugar content 7.0-7.6%) of fruits were observed in hybrids Montana F1, Talisman F1, Dolby F1, Hollar F1, Super crimson F1.
In isolated heterotic hybrids of very early watermelon when cultivated under a film and the joint application of organomineral fertilizers at a rate of 10 t/ha of manure + N125-150P100-120K62-75 kg/ha at the rate of 1.0 kg of manure + N13-15.8P10.5-12,6K6.6-8.0 g on each nest creates favorable conditions for growth, development, formation of the optimal leaf surface area, formation of powerful tops and root system and productivity indicators. As a result, this makes it possible to obtain an ultra-early harvest per hectare of 18-20 tons and more with good qualities.