TESTING OF MAIZE HYBRIDS OF DIFFERENT MATURITY GROUPS IN THE CONDITIONS OF THE SOUTH-WESTERN FOREST-STEPPE OF UKRAINE

The research results of maize hybrids of different maturity groups (FAO 199–399) during 2018–2020 in the conditions of the South-Western part of the Forest-Steppe of Ukraine are presented. 54 domestic registered and perspective hybrids of selection of various research institutions of Ukraine (SE Institute of Grain Crops NAAS, Plant Production Institute named after V. Ya. Yuriev of NAAS, Selection and Genetics Institute – National Center for Seed Production and Variety Studying, National Research Center Institute of Agri-culture of NAAS, Bukovynian State Agricultural Research Station of the Institute of Agriculture of the Carpa-thian Region of NAAS) were studied. The planting density of early ripening hybrids was 70, mid-early ripening – 60, mid-ripening – 50 thousand plants/ha. Plants were evaluated for uniformity, resistance to stem breakage below the productive ear, the damage degree by boil smut, resistance to root lodging and general condition were determined. All maize hybrids were characterized by high rating (8–9 points) on these traits. Over the years of research, the mid-early hybrids were more productive in the conditions of Bukovyna (9.06 t/ha), the mid-ripening hybrids - the least adapted to these conditions – (8.62 t/ha). The best samples with high grain yield and low grain moisture content at harvest were identified. On average for three years, DB Lada (9.64 t/ha) and DN Synevyr (9.43 t/ha) had the highest grain yield among the early-ripening hybrids, and DB Varta (10.81 t/ha), DB Khotyn (9.96 t/ha), and Kitsmanskyi 215 SV (9.61 t/ha) – among the middle-early one. It was found that DN Synevyr and DB Lada early-ripening hybrids and Kitsmanskyi 215 SV, DB Kho-tyn, DB Varta mid-early hybrids significantly exceeded the standards each year. In view of this, the hybrids of these maturity groups merit attention in the conditions of the South-Western Forest-Steppe of Ukraine.

Maize (Zea mais L.) is one of the most important crops.It is one of the four most profitable crops along with wheat, soybeans and sunflowers in the world, and it is a major component of food and feed resources due to its high yield.Maize grain is both a high-energy feed for livestock animals and a valuable food product for the population, and also a raw mate-rial for industry [1][2][3].The constant selection and genetic improvement of maize is a promising reserve for increasing its yield [4][5].
Over the past five years, acreage of maize significantly increased in Ukraine.In 2016, the area under maize was 4.4 million hectares, and in 2020 -5.4 million hectares.It should be noted the in crease in maize grain export.If in 2015 more than 11 million tons of maize grain were exported, in 2021 this indicator may reach 28.5 million tons.Thus, Ukraine can rank in the top 5 largest exporters of maize on the world market [6][7].
Due to the increase in maize acreage in Ukraine, a demand for the new domestic hybrids with high genetic yield potential and higher resistance to major diseases and pests is constantly increasing.The scientifically substantiated selection of maize hybrids according to maturity group for different natural and climatic zones of Ukraine causes an increase in yield and a decrease in grain moisture content at harvest, which will significantly reduce energy consumption for its post-harvest drying.Hybrids of early-ripening and mid-early groups are priority for the conditions of the Forest-Steppe zone, earlyripening hybridsfor Polissia, early-ripening, mid-early and mid-ripeningfor Steppe [8][9][10][11][12][13][14].
The Bukovynian State Agricultural Research Station of the Institute of Agriculture in the Carpathian Region NAAS (BSARS IACR) operates in an area with a short growing season and the sum of active temperatures 2400-2700 °C.Its breeding work on maize is aimed at creating precocious hybrids with high yields, cold resistance, resistance to major diseases and pests and high adaptation to the conditions of the Western Forest-Steppe of Ukraine.A demonstration plot is established at the Research Station for comparative study of hybrids of domestic selection, promotion of own scientific products to the market and in accordance with the work plans of the Regional Center of Scientific Support of the agro-industrial complex of Chernivtsi region.The purpose of the research is to study and analyze new registered maize hybrids belonging to different maturity groups  in the conditions of the South-Western Forest Steppe of Ukraine according to the main economically valuable traits.
Materials and мethods.The research was conducted in 2018-2020 in the selection crop rotation of Bukovynian State Agricultural Research Station.Soil was heavy loam meadow chernozem.Sowing was carried out with hand planters in the optimal time, from April 25 to May 10.Demonstration plot was established with a given plant density: for early-ripening hybrids -70, mid-early -60 and mid-ripening -50 thousand plants/ha.The accounting area of the plot was 14.7 m 2 , replicationthree times.Before sowing, early spring and pre-sowing cultivation and soil rolling were carried out.Harness soil herbicide (2.5 l/ha) was applied before sowing, and MaisTer Power herbicide (1.5 l/ha) was applied in the 7-8 leaves stage.Ammonium nitrate phosphate fertilizer were applied with doses of 80 kg a. i./ha.Harvest was carried out manually.
The field trails were carried out in accordance with the "Guidelines for field and laboratory study of genetic resources of maize [15] and "Methods of examination of grain crops, cereals and grain legume varieties for suitability for dissemination in Ukraine" [16].
The reliability of the results of experimental studies was determined by the B. O. Dospek-hov's method [17].
Results.Comparative characteristics of hydrothermal conditions of growth season of 2018-2020 and average long-term data are given in Table 1.
The average daily air temperature for the period April -September was higher than the long-term average during all studied years.The 2018 year was hottest.As for the amount of precipitation, only in 2020 it fell more than the average long-term norm.However, in 2020 their distribution was the most uneven by months.The most optimal for the growth and development of maize plants were 2018 and 2019.
During the growing season each year, visual assessments of plant uniformity were performed, resistance to stem breakage below the productive ear, the degree of common smut dama-ge, resistance to root lodging and their general condition were determined.All registered maize hybrids of domestic selection were characterized by high rating (8-9 points) of these traits.The main stage of research was accounting yield and determination of grain moisture content.
Significantly higher grain yield in the mid-ripening group compared to DK Burshtyn standard (9.54 t/ha) was formed by hybrids DN Sarmat and DN Tala -0.6 and 1.88 t/ha, respectively.Yield coefficients were the highest in hybrids of DN Dnipro (0.39) and DN Tala (0.40), and the harvesting moisture was lowest (24.1 and 28.7 %, respectively).
In 2019, we studied 7 hybrids of the earlyripening group, 19mid-early and 4mid-ripening hybrids (Table 3).In the early-ripening group, only hybrids Zaislav M (8.81 t/ha), DN Synevyr (9.03 t/ha) and DB Lada (9.28 t/ha) formed grain yields at the level of the Pochaivskyi 190 MV standard (9.09t/ha).Only the hybrid DB Lada provided an increase in yield to the standard of 0.19 t/ha (2.09 %).Among these samples, the least wet grain during harvesting was in the Zaislav M hybrid (27.2 %).
All hybrids of the mid-ripening group formed a grain yield significantly below the standard of Donor MV in 2019.
DN Slavytsia, DB Varta and Otrada hybrids were marked by the highest yield coefficients (0.29, 0.30 and 0.33, respectively).The harvesting moisture content of last hybrid grain was lowest (31.3 %).
Regarding the mid-ripening group, the maximum grain yield was formed by DN Veld hybrid (10.19 t/ha), which is by 0.65 t/ha (6.81 %) more than the of DK Burshtyn standard (9.54 t/ha), the harvesting moisture content of the DN Veld hybrid grain was lowest (36.0 %), and the yield coefficient was highest (0.28).
Conclusions.Thus, 54 domestic maize hybrids of different maturity groups (FAO 199-399) were studied according to the main economically valuable traits.It was found that the best hybrids of the mid-early group provided the maximum level of grain yield and its increase to the standard (11.23-12.41and 18.71-31.18%, respectively).Over the years of research, the best early ripening hybrids were noted by the lowest harvesting moisture content of grain (19.5-20.9%).According to the results of threeyear research, it was selected DN Synevyr, DB Lada hybrids of early-ripening group and Kitsmansky 215 SV, DB Khotyn, DB Varta hybrids of mid-early group, which constantly exceeded hybrids-standards in terms of grain yield.
Taking into account the obtained data, it is possible to objectively evaluate maize hybrids and recommend the best of them to agricultural producers of various forms of ownership for cultivation in the conditions of the South-Western Forest-Steppe of Ukraine.
Station of the Institute of Agriculture of the Carpathian Region of NAAS (BSARS IACR) are sown here.Every year almost 30 hybrids are tested and entered in the State Register of Plant Varieties Suitable for Dissemination in Ukraine.

Table 2 . Varietal testing of maize hybrids of selection of research institutions of Ukraine in 2018
In terms of grain yield in the early ripening group, the Pochaivskyi 190 MV standard (8.64 t/ha) was significantly dominated by three hybrids: DN Latorytsia (9.36 t/ha), DN Synevyr (9.41 t/ha) and DB Lada (10.01 t/ha).Their increase in grain yield ranged from 8.33 to 15.86.The Stizhok 192 SV hybrid (8.41 t/ha) according to this indicator was at the standard level.Among the best samples selected for grain yield, DN Synevyr (19.5 %) and DN Latorytsia (20.9 %) hybrids were noted by the lowest grain moisture at harvest.Their yield coefficients (the