Scientific Papers Series Management, Economic Engineering in Agriculture and Rural Development Vol. 21, Issue 3, 2021 PRINT ISSN 2284-7995, E-ISSN 2285-3952 491 REACTION OF SUDAN GRASS AND SORGHUM-SUDAN HYBRIDS TO SALINITY Sergey Ivanovich KAPUSTIN 1,3 , Alexander Borisovich VOLODIN 1 , Andrey Sergeevich KAPUSTIN 2 , Olga Ivanovna VLASOVA 3 , Inna Anatolievna DONETS 3 1 North Caucasus Federal Agrarian Research Center, 49 Nikonov street, Mikhailovsk, Stavropol region, 356241, Russia, Phone: +79624512303; E-mail: sniish@mail.ru 2 North Caucasus Federal University, 1 Pushkin street, Stavropol, 355017, Russia, Phone: +78652330291; E-mail: hpplus@bk.ru 3 Stavropol State Agrarian University, 12 Zootekhnicheskiy Lane, Stavropol 355017, Russia, Phone: +78652352282; E-mail: inf@stgau.ru Corresponding author: hpplus@bk.ru Abstract According to the data obtained in 2019-2020, a noticeable decrease in seed germination to 84-94% in sterile female parent lines of Sorghum was found when the concentration of NaCl in the solution was 1.0%, and at 1.5% it decreased to 23-80%. The lowest performance (23%) was obtained in A-63 line. Paternal varieties of Sudan grass reduce germination to 68-87% with 1.0 NaCl and to 45-74% with 1.5% of salinity. The most significant seed germination of Sudan grass with 1.0% of salinity (82-87%) was found in Zemlyachka, Sputnitsa and Zlata varieties with a solution concentration of 1.5% in Zemlyachka (74%). Among the other varieties of Sudan grass, the most salt-tolerant were Alexandrina and Violeta varieties. In the Bulgarian variety SVE, when NaCl concentration in the soil solution was 1.0%, the seed germination rate was 82%, and when its concentration increased to 1.5%, it was 32%. In the obtained Sorghum-Sudan hybrids with 0.6% salt concentration, seed germination decreased to 67-96%, but most of all (96%) it was obtained in the combinations of Zersta 90C x Sputnitsa and A-63 x Nika. The highest seed germination with 1.0% – 1.5% saturation of NaCl solution was obtained in the recognized hybrids Zersta 90C x Zemlyachka, Zersta 90C x Sputnitsa, and the combination of Knyazhna x Sputnitsa. The increase in concentration of the soil solution significantly reduces the length of the shoots and roots of the seedlings to 1.6 – 3.4 cm with 1.0% NaCl con-centration and 0.7 – 2.4 cm in the variant with 1.5% of salt presence. In the Navi-gator and Gvardeets hybrids, the length of seedlings with high salt concentration (0.6-1.5%) was the highest. Key words: sterile lines, varieties of Sudan grass, Sorghum-Sudan hybrids, germination, length of seedlings INTRODUCTION The area of solonetz in the Stavropol Territory is 1.5 million hectares. The main features of these soils are high density and cloddy structure [12]. pH of chernozem and chestnut soils in the region on an area of 38-43% is 6.9-8.0. The soil salinity is one of the main negative factors that reduces the productivity of agricultural production [7]. The amount of exchangeable sodium in solonetzic soils reaches 15-20%, and in solonetz soils more than 20% of the base exchange capacity. At the same time, solonetz soils are relatively rich in nutrient elements. The cultiva-tion of salt-tolerant crops is effective on such soils [5]. Russian and foreign varieties, hybrids and sterile lines of Sweet sorghum, Sudan grass, and Sorghum-Sudan hybrids have a relatively high drought resistance (transpiration coefficient 230-300), but their cultivation in the North Caucasus is often combined with a high concentration of NaCl in the soil [4, 13]. To create salt-tolerant hybrids and varieties, special breeding programs for sorghum crops are carried out [8, 12]. The species composition, variety assortment and salinity tolerance largely determine the time of sowing and the density of Sudan grass and Sorghum- Sudan hybrids [6]. Literature sources show that the use of NH4 + increases the salt tolerance of plants by limiting the accumulation of Na + [15]. In Sweet sorghum, the concentration of Na + in the roots decreases, which ensures their low concentration in the shoots by protecting the photosynthesis structures [18, 19]. Under