Prospects for the use of sweet sorghum in bioenergy

Sweet sorghum breeding programs aimed at bioenergy production pursue the goals to increase the sugar content of plant stems and improve biomass productivity. The purpose of the current work was to study the influence of origin, weather conditions, and key agronomic traits on ‘sugar percentage in stem juice’ and to identify promising varieties for use as a source of bioethanol. Sorghum breeding work was conducted in the ARC “Donskoy” in the Rostov region from 2015 to 2024. There have been used 200 sweet sorghum samples of various ecological and geographical origins and 20 competitively tested varieties. The trials were conducted in accordance with the Methodology for the State Variety Testing of Agricultural Crops. According to correlation and regression analysis, the sugar percentage in stem juice has a strong negative correlation with the amount of precipitation during the vegetation period (r = -0.9667 ± 0.09) and a moderate positive correlation with the sum of active temperatures over the same period (r = 0.5256 ± 0.3). When the HTC value increases, the proportion of samples with very low values increases, the proportion of samples with high values decreases, and those with very high values reaches zero. The highest average group values have been observed in the samples from Bulgaria, Australia, Argentina, Mozambique, Hungary, Germany, and Yugoslavia (VIR data) with 18-20%. There have been identified the varieties RS-124/19, DK-3868, SK-44/1634, and KL-388 with a high sugar percentage in stem juice (over 15.0%) and green mass productivity at or above the standard (34-35 t/ha), which can be recommended for obtaining sugary substances, as well as for use in bioenergy.

1. Boiko V.S., Timokhin A.Yu., Volodin A.B., Nizhel'skii T.N. Potentsial pro-duktivnosti sorgo sakharnogo v yuzhnoi lesostepi Zapadnoi Sibiri [Productivity potential of sweet sorghum in the southern forest-steppe of Western Siberia]// Kormoproizvodstvo. 2022. № 4. S. 29-33

2. Kibal'nik O.P., Kameneva O.B., Larina T.V., Semin D.S., Efremova I.G. Izuchenie fraktsionnogo sostava sakharov v soke steblya sakharnogo sorgo v zasushlivykh usloviyakh Rossii [The study of the fractional composition of sugars in sweet sorghum stem juice under arid conditions in Russia ] // Journal of Agriculture and Environment. 2022. № 1(21). DOI: 10.23649/jae.2022.1.21.15

3. Kibal'nik O.P., Partoev K., Sattorov B.N., Kubarev E.N. Ekologicheskoe ispytanie sortov sakharnogo sorgo v zasushlivykh usloviyakh Rossii i Tadzhikistana [Ecological testing of sweet sorghum varieties under arid conditions in Russia and Tajikistan ]// Ag-rarnaya Rossiya. 2024. № 9. S. 23-26. DOI: 10.30906/1999-5636-2024-9-23-26

4. Kovtunova N.A., Kovtunov V.V. Ispol'zovanie sorgo sakharnogo v kachestve istochnika pitatel'nykh veshchestv dlya cheloveka (obzor literatury) [The use of sweet sorghum as a source of nutrients for humans (a literature review)] // Zernovoe khozyaistvo Rossii. 2019. №(3). S. 3-9. DOI: 10.31367/2079-8725-2019-63-3-3-9

5. Rimareva L.V., Serba E.M., Overchenko M.B., Ignatova N.I., Pavlova A.A., Pogorzhel'skaya N.S. Kompleksnoe ispol'zovanie soka steblei sakharnogo sorgo dlya polu-cheniya etanola i kormovoi belkovo-aminokislotnoi dobavki [Integrated use of sweet sorghum stem juice to produce ethanol and a protein-amino acid feed additive] // Pishchevaya promyshlennost'. 2021. № 5. S. 56-61. DOI: 10.52653/PPI.2021.5.5.013

6. Calviño M, Messing J. Sweet sorghum as a model system for bioenergy crops. Curr Opin Biotechnol. 2012. №23(3). Pp. 323-9. DOI: 10.1016/j.copbio.2011.12.002

7. Kasegn M.M., Simachew A., Redda Y.T. Evaluation of sugar content and bioeth-anol production of Ethiopian local varieties “Nech Tinkish” and “Hawaye” sweet sorghum (Sor-ghum bicolor (L.)). Biotechnol Environ/ 2024. №1, 2. DOI: 10.1186/s44314-024-00001-6

8. Ritter K.B., Jordan D.R., Chapman S.C., Godwin I.D., Mace E.S., McIntyre C.L. Identification of QTL for sugarrelated traits in a sweet x grain sorghum (Sorghum bicolor L. Moench) recombinant inbred population // Molecular Breeding. 2008. №22(3). Pp. 367-384. DOI: 10.1007/s11032-008-9182-6

9. Sun W., He Z., Liu B., Ma D., Si R., Li R., Wang S., Malekian A. Changes in Photosynthetic Efficiency, Biomass, and Sugar Content of Sweet Sorghum Under Different Wa-ter and Salt Conditions in Arid Region of Northwest China // Agriculture. 2024. №14. P. 2321. DOI: 10.3390/agriculture141223

10. Tovignan T.K., Adoukonou Sagbadja H., Diatta C., Clément Vidal A., Soutiras A., Cisse N., Luquet D. Terminal drought efect on sugar partitioning and metabolism is modulated by leaf stay-green and panicle size in the stem of sweet sorghum (Sorghum bicolor L. Moench) // CABI Agric Biosci. 2020. № 1.P.4. DOI: 10.1186/s43170-020-00003-w