Sorghum-Sudanese hybrid Dobrynya as a result of heterosis selection

. Sorghum-Sudanese hybrids, due to the heterosis effect, have not only increased productivity, but also uniformity, increased vitality, as well as resistance to various diseases and stress factors in comparison with parental forms. The purpose of the work: to characterize the new hybrid Dobrynya, created as a result of heterosis selection, according to the main morphological, biological, economically valuable indicators. The studies were carried out at the Federal State Budgetary Scientific Institution, Agrarian Research Center “Donskoy” (ARC “Donskoy”). The soil of the experimental plot is ordinary carbonate chernozem. The advantages of the hybrid include high foliage (13 leaves per plant) - 39-41% of the leaf mass of plants, good protrusion of the legs (30-35 cm), succulence, tillering, cold resistance. The duration of the period "sprouts-heading" on average for 2019-2022. was 55 days (mid-season), which is 5 days less than the standard. Sorghum-Sudanese hybrid Dobrynya is characterized by a high yield of green mass - 63 t/ha (in total for 2 cuttings) and dry matter - 13.0 t/ha, which is higher than the standard by 28.6 and 31.3%, respectively. - essentially. And in terms of the content of crude protein and the collection of digestible protein, it significantly exceeds it by 1.1% and 0.24 t/ha. According to the results of the assessment in natural conditions, Dobrynya is distinguished by high or practical resistance to loose smut and bacteriosis. The sorghum-Sudanese hybrid has been included in the State Register of Breeding Achievements since 2023 and is recommended for use for green fodder and silage in the Central Black Earth, North Caucasus and Lower Volga regions of Russia.


Introduction
To increase the production of succulent fodder, an important role is played by the scientifically based introduction of high-yielding fodder crops, among which sorghum-Sudanese hybrids should be noted [1][2]. Their main advantage is high productivity and quality of green mass even in dry conditions. It has been established that per 1 mm of precipitation per 1 hectare of crops, grass sorghum forms up to 26 kg of dry matter, while spring cereals -6.3 ... 14.7 kg [3]. During a drought, corn leaves wither, sorghum leaves curl up until more favorable conditions occur [4][5][6]. Compared to corn, sorghum-Sudanese hybrids have a smaller leaf area, a more developed root system, a waxy surface of leaves, a large amount of carbohydrates in the cell sap, and a special structure of the stomatal apparatus, which helps to resist drought [5][6][7][8].
Sorghum-Sudanese hybrids, due to the heterosis effect, have not only increased productivity, but also uniformity, increased vitality, as well as resistance to various diseases and stress factors in comparison with parental forms. Plants of sorghum-Sudanese hybrids are tall with good foliage and bushiness. The high intensity of initial growth and postcutting regrowth in hybrids has a positive effect, firstly, on the competitiveness with weeds for light, water, nutrients, and secondly, it makes it possible to obtain 2-3 full-fledged cuttings of green mass.
In terms of nutritional value, the green mass of sorghum-Sudanese hybrids is not inferior to one-year-old crops and contains a sufficient amount of nutrients (carbohydrates, fats, vitamins), due to which it can be used for silage, haylage, hay, green fodder, grass meal, grazing [2 , 4, 9]. The content of crude protein in the dry matter of Sudanese grass varieties is up to 9.0%, in hybrids -up to 12.0% [4,9]. In addition, it was found that in the study of sorghum-Sudanese hybrids, chumiza, paisa, Sudanese grass, sugar sorghum, it was in hybrids that the highest values of green mass yield, dry matter, digestible protein and digestibility (72 ... 74%) were noted.
Sorghum crops are not demanding on soils; they can grow on all soils, except for waterlogged ones, including saline ones. They form high yields of grain and green mass without fertilization, but respond well to irrigation [10,11,12]. Seedlings, shoots, roots and leaves of sorghum-Sudanese hybrids secrete allelopathic compounds that suppress such weeds as foxtail, smooth and common marigold, common ragweed, common brambles, etc. The main root exudate, sorgoleon, has a toxicity comparable to mine with concentrations of some herbicides. Sorghum-Sudanese hybrids can be sown after any early-harvested crops, but in weed-free fields. The best are winter and spring cereals.
The purpose of this work: to characterize the new sorghum-Sudanese hybrid Dobrynya, created as a result of heterosis selection, according to the main morphological, biological, economically valuable indicators.

Materials and methods
The experimental plot was located in the ARC "Donskoy" (predecessor -winter wheat); soil -ordinary carbonate chernozem, with a humus content of 3.2% in the arable layer. In terms of fertility and physical and chemical properties, the soil of the experimental plot is favorable for growing sorghum.
Meteorological conditions during the years of research (2019-2022) varied significantly, which made it possible to study the yield, quality of green mass and disease resistance of the hybrid under contrasting conditions. So, high air temperature in May and good soil moisture in 2019, 2021 contributed to the friendly and rapid germination of seeds, and in 2020 and 2022, on the contrary, low temperatures led to a delay in germination. No precipitation in June 2019, 2020, 2022 and the average daily air temperature higher than the long-term average data by 2.6...4.7°С or 12.6...22.9% led to a reduction in the period of "sprouts-heading" and, consequently, a decrease in the yield of green mass for the first cut. In general, over the years of research, the average air temperature during the growing season was above the long-term average. The largest amount of precipitation for the period "May -September" was noted in 2021 (273 mi at a norm of 268 mm). The HTC values indicate an average drought -in 2019 (0.70), 2020 (0.68), 2022 (0.52) and insufficient moisture -in 2021 (0.82) (Fig. 1).
А.  Work on the creation of a hybrid was carried out from 2016 to 2020 at ARC "Donskoy", in 2021-2022 -it passed the state test on variety plots, since 2023 -it has been approved for cultivation in the Central Black Earth, North Caucasus and Lower Volga regions Russia.

B.
Sowing was carried out at the optimal time -May 3 ... 10 with a seeding rate of 1.6 million viable seeds per 1 ha. Sowing method -ordinary. The location of plots in the experiment is systematic. The content of the main nutrients was determined in the laboratory of biochemical evaluation of plants according to generally accepted methods.

Results and discussion
Sorghum-Sudanese hybrid Dobrynya belongs to the group of grassy sorghum. The main morphological features of the hybrid in comparison with parental forms are given in table 1. The hybrid Dobrynya differs from the standard Dense-leaved in the nature of the core of the stem (in the new hybrid it is juicy, in the standard it is intermediate), the color of seedlings and spikelet scales when ripe, higher leafiness and protrusion of the stem. The duration of the period "shoots-heading" in a hybrid on average for 2019-2022 was 55 days (mid-season), which is 5 days less than the standard. According to the length of the second part of the growing season (1-2 cuts), the hybrid is at the standard level (54 days). Thus, the first mowing of the green mass of the Dobrynya hybrid can be obtained by the end of June -early July, and the second mowing -in the 2-3 decades of August. In conditions of warm autumn, it is possible to receive the third mowing -in the middle of October -October. The hybrid is tall: in the heading phase -211 cm, in the phase of full grain ripeness -246 cm, which is 21 and 26 cm higher than the standard, respectively.
A comparative analysis of the hybrid and parental forms reveals the nature of the inheritance of the main quantitative traits in the F1 hybrid. So, according to the number of leaves and the duration of the period "1-2 mowing", there is an incomplete dominance of a larger value (hp=0.8 and 0.5); according to foliage, panicle length and leaf length, plant height and the duration of the period "shoots -1 cut" -overdominance (hp≥1) (table 2). Almost all of the presented indicators revealed the presence of hypothetical and true heterosis. The Dobrynya hybrid surpasses the Bushy-leaved standard in all respects, except for the length of the stem and the duration of the shoot-out period (Гconc.=-5,7 and -8,3% respectively).
The data obtained are consistent with the studies of a number of scientists, according to which F1 sorghum hybrids, due to the effect of heterosis, surpass parental forms in plant height, leafiness (leaf size and number), and stem diameter [4,[13][14]. This explains their superiority in the yield of leaf-stem mass. Productivity is a decisive indicator of the value of varieties, lines, samples, hybrids of agricultural crops. However, for the development of fodder production and animal husbandry, it is important not only the amount of feed, but also its quality [15,16]. The new sorghum-Sudanese hybrid is characterized by a high yield of green mass -63 t/ha (in total for 2 cuttings) and dry matter -13.0 t/ha, which is higher than the standard by 28.6 and 31.3%, respectively (Table 3). In terms of quality, the new hybrid is not inferior to the standard. In addition, it is distinguished by juiciness with a sugar content of 6 ... 7%, which indicates good milk-producing properties of the feed. The nutritional value of dry matter is determined by its qualitative composition, and protein is of the greatest value. The maximum protein content in the dry matter of green mass is observed in the heading phase. Then its amount gradually decreases, which is consistent with the research of scientists [3,4]. In terms of the content of crude protein and the collection of digestible protein, the Dobrynya hybrid is significantly superior to the Gustolistny hybrid by 1.1% and 0.24 t/ha. The content of exchangeable energy serves as the main characteristic of the energy nutritional value of the feed. The calculation of the content of exchangeable energy in the crop (for cattle) indicated the superiority of the new hybrid over the standard by 3 mJ/ha or 31.9%.
Obtaining high and stable yields of any agricultural crop can be prevented by diseases that can significantly reduce the productivity and quality of forage. Therefore, when creating varieties of resistance to major diseases and pests of this crop, special attention is paid. In sorghum crops, these are loose smut and bacteriosis. According to the results of evaluation under natural conditions, the new sorghum-Sudanese hybrid Dobrynya is distinguished by high or practical resistance to these pathogens (Table 4). In the laboratory of physiological assessment, it was established that the Dobrynya hybrid belongs to group I of cold resistance, that is, it is highly cold-resistant.
When seeding a new hybrid Dobrynya, it is necessary to take into account the basic requirements: in the hybridization area, the maternal and paternal forms are sown simultaneously with a row ratio of 10:2, 12:4, 24:6. Before flowering and ripening, varietal and species weeding is carried out. The maternal form reproduces in isolated areas by seeding a sterile line with a fixative of sterility, the paternal form -by re-seeding in compliance with spatial isolation. Sowing is carried out in isolated areas with spatial isolation from other varieties and types of sorghum for 1000 m; do not propagate after predecessors: sorghum-Sudanese hybrids, Sudanese grass, grain sorghum.
The best predecessors in the cultivation of the hybrid are early ripening crops (legumes, winter and spring crops). The method of soil cultivation after ear predecessors is semifallow cultivation (stubble peeling to a depth of 5-7 cm, plowing to a depth of 25-28 cm). Pre-sowing tillage includes early spring harrowing and 2-3 cultivations. Before sowing, the seeds must be treated (Vincite, Vincit forte (1-1.2 kg/t)). Sowing is carried out with a seeding rate of 1.5-2.0 million grains per hectare. After sowing, it is necessary to carry out rolling, as weeds appear, male-row cultivation.
The sorghum-Sudanese hybrid has been included in the State Register of Breeding Achievements of the Russian Federation since 2023 and is recommended for use for green fodder and silage in the Central Black Earth, North Caucasus and Lower Volga regions of Russia.

Conclusions
The new sorghum-Sudanese hybrid Dobrynya is characterized by a high yield of green mass -63 t/ha (in total for 2 cuttings) and dry matter -13.0 t/ha, which is higher than the Gustolistny standard by 28.6 and 31.3%, respectively. In terms of the content of crude protein and the collection of digestible protein, as well as the collection of metabolic energy in the crop, the Dobrynya hybrid significantly outperforms the Gustolistny hybrid by 1.1%, 0.24 t/ha and 3 mJ/ha. Among the advantages of the hybrid, one should single out good foliage (39-41%), succulence, cold resistance, resistance to loose smut and bacteriosis.