Sweet sorghum hybrids F1 in productivity can surpass the parental forms on 50-60%. Thus the breeding process is aimed to develop first generation hybrids with a strong potential of productivity and quality of green mass and silage. The purpose of the work is to study heritability and heterosis of the quantitative traits of sweet sorghum hybrids F1 obtained on a sterile basis. The study was conducted in 2013-2015 on the lines with cytoplasmic male sterility (‘A-63’, ‘Knyazhna’, ‘APV-1115), the varieties (‘Listvenit’, ‘Severnoe 44’, ‘Zernogradskoe 454’, ‘Stavropolskoe 36’, ‘Galiya’ and ‘Larets’) and the hybrids. The inheritance of green mass productivity and absolutely dry matter, the length of a vegetation period, plant height and leaf formation (foliage), protein content in dry matter of the hybrids occurred according to the type of dominance and overdominance. It has been determined that while choosing the parental forms for hybridization it’s essential to select the forms with differences in the vegetation period of 4-6 days to avoid the dominance of late maturity. The height pollinator increase results in the hybrid height increase and large heterosis. It’s necessary to select the parental forms with maximum foliage to improve leaf formation in the hybrids.

Введение. Сахарное сорго (Sorghum bicolor) используется на зеленый корм, сено, выпас, силос, сенаж, брикеты, травяную муку [1, 2]. В соке этой культуры имеются сахароза, глюкоза, фруктоза, аминокислоты, витамины и микроэлементы [4], что делает его пригодным для производства сиропа на пищевые цели, для получения этанола, биопластиков, химикатов и др. Стебли растений содержат 14-18 % и более сахара [3]. Проведенные в США исследования [17] показали содержание глюкозы в стеблях сорго от 0,6 до 12 %, в листьях-от 0,3 до 1,7 %, сахарозы в стеблях-от 0,3 до 17 % и листьяхот 0 до 3,1 %. Оптимальным является сбор урожая при физиологической зрелости зерна [5]. Ряд авторов считают, что количество и качество сахара в соке в значительной степени определяют сроки сева, состав почвы, густота растений и количество азотных удобрений, применяемых при выращивании сорго [6-8]. Повышение содержания сахара при гетерозисе растений больше у родительских форм с отдаленными генетическими различиями [9, 10, 11]. Значения истинного гетерозиса определяют по среднему или лучшему показателю родительских форм [12]. У растений сахарного сорго увеличивается высота, диаметр стебля [13], размер метелки, масса 1000 зерен [14]. T.W. Pfeffer, M.I. Bitzer, I.I. Toy, I.F. Pedersen [15] считают, что мужская стерильность может влиять на распределение фотосинтеза между частями растений, создавая потенциал для увеличения содержания сахара в стеблях за счет исключения семян как потребителя света и питательных веществ. Удаление метелок после цветения снижает содержание крахмала и фенольных соединений в соке [16]. Цель исследований-изучение в конкурсном сортоиспытании фенологических, морфологических, урожайных показателей, содержания сахаров в соке стеблей стерильных линий, новых сортов и гибридов сорго. Условия, материалы и методы исследования. В 2016-2018 гг. на опытном поле ФГБНУ «Северо-Кавказский ФНАЦ» (г. Михайловск Ставропольского края) методами полевых и лабораторных опытов провели изучение 12 вариантов конкурсного испытания сахарного сорго.

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Arid conditions in Central Ciscaucasia caused a shortage of green fodder for animal husbandry. In the current circumstances, new sorghum-sudan hybrids creation and introduction into production are of great importance. The aim of the research is twofold: to assess green mass, hay and grain productivity and quality; to determine the main biomorphological characteristics and level of heterosis of the new sorghum-sudan hybrid ‘Gvardeets’. The experiments were carried out in competitive and environmental testing. In the Novgorod Oblast, the new hybrid provided 43.0 t/ha of green mass; the same indicator in the Altai FASC comprised 42.1 t/ha exceeding standard hybrid ‘Navigator’ by 2.6 and 0.9 t/ha, respectively. The data were obtained in a competitive test by methods of field and laboratory experiments, as well as environmental testing in various regions of Russia. On average for 2015–2020, in the conditions of the Stavropol Territory, the new hybrid provided 53.87 t/ha of green and 11.55 t/ha of dry matter exceeding standard hybrid ‘Navigator’ by 5.03 and 1.26 t/ha or 10.3 and 12.2%, respectively. ‘Gvardeets’ is a mid-ripening hybrid. The first mowing can be carried out in the booting phase or at the end of June/first half of July, the second one – in the second half of August. Furthermore, in moderately warm and humid summers, it is possible to obtain the third mowing in late September/early October. The new hybrid ‘Gvardeets’ has a high rate of initial plants growth on the 30th day of vegetation (80 cm), as well as a high content of leaves in the green mass (34.7 %). The content of protein in dry matter is 11.8 %, fat – 1.9 %, fiber – 30.9%, ash – 6.3 %. One kilogram of new combination feed contains 0.67 feed units, 70 g of digestible protein, 31.9 g of sugar, 81.2 mg of carotene. The provision of one feed unit with digestible protein is 123 g. There is 8.59 MJ/kg of exchange energy, which is better than that of the standard hybrid ‘Navigator’. The stems of ‘Gvardeets’ plants have a juicy core; plants are resistant to drought, lodging, pests and diseases. The parental forms of the hybrid (‘Zersta 90C’ x ‘Sputnitsa’) are distinguished by a high combinational ability and provide a level of true heterosis of the yield of green mass in the amount of 20.81 t/ha (62.9%). The new sorghum-sudan hybrid ‘Gvardeets’ has been included in the State Register of Breeding Achievements of the Russian Federation since 2021 in the North Caucasus, Lower Volga, Central Black Earth and West Siberian regions.

Creation and introduction of new hybrids of sugar sorghum adaptive to arid conditions allow stabilizing and increasing the productivity of forage mass over the years, which is of current importance. The aim of the research was to clarify the scheme and methods of selection of the initial material, assess the level of true heterosis, quantitative traits of green mass yield and plant height in the best obtained hybrids of sugar sorghum. The research was carried out according to the methods of laboratory and field experiments. The scheme of the breeding process included nurseries of source material and breeding nurseries, as well as creation of self-pollinated and sterile lines, hybridization, assessment of samples for CMS, combining ability, and testing new hybrids by saturating crosses and topcross. According to this scheme, sterile lines ‘A-63’, ‘Knyazhna’, ‘Zersta 38A’ were created. By methods of multiple and individual selection with subsequent inbreeding from hybrid populations, fertile paternal forms ‘Stavropolskoe 36’, ‘Galia’ and ‘Larets’ were created. Also, obtained on their basis hybrids ‘Silosnoe 88’ (standard), ‘Alga’, ‘Kalaus’, ‘Yarik’ served as the object of research. On average for 2016–2019, the most significant plant height under the conditions of the “North-Caucasus Federal Agrarian Research Center” was found in late-ripening combinations ‘Yarik’ (301.4 cm) and ‘Kalaus’ (289.0 cm). The level of true heterosis of this trait was 41.7 % and 31.6 %, respectively. In the studied hybrids, the pollination period of the parental forms coincides, the heterosis of the thickness of the stems is observed. The significant leafiness of the plants is also found to be in the late-ripening forms (15.7–16.0 %). The maximum yield of green mass was obtained from hybrids ‘Yarik’ (102.0 t/ha) and ‘Kalaus’ (86.7 t/ha). The level of true heterosis of the studied trait in these combinations was 67.9 t/ha and 47.0 t/ha, respectively, or 66.5 % and 54.2 %. The combination of other genetic plasmas provided a lower level of true heterosis. The late-ripening hybrids ‘Yarik’ and ‘Kalaus’ have significantly higher sugar content in the juice of the stems (12.89–14.03 %) compared with the mid-ripening ‘Silosnoe 88’ (8.9 %) and the medium-late ‘Alga’ (11.14 %).