Manifestation of selection traits and properties of forage productivity in groups of alfalfa varieties with different resistance to viral and phytoplasma infections

The research was conducted in 2019–2023 in Belgorod region with the purpose of breeding evaluation of alfalfa cultivars with different resistance to «witches’ broom alfalfa» (WBA). Fifty-two selection samples belonging to species Medicago sativa L., M. varia Mart., M. falcata L. The soil is typical chernozem, humus content (according to Tyurin) 4.7…5.0 %, The year of sowing – 2019. Predecessor – pure fallow. Plots – two-row long 3.5 m, row spacing width – 0.3 m. Repetition – five times. Standard – variety Belgorodskaya 86, sown through 5 numbers. Seeding rate of 100 germinated seeds per 1 linear meter. It was found that the group of varietal samples (n = 10) with low resistance to WBA (variation of prevalence 24.3–34.9 %) is characterized by a greater accumulation of protein (by 44.6 g/kg, t = 8.0, p < 0.05), higher foliage (by 4.8 %, t = 3.7, p < 0.05) and height (by 25.3 cm, t = 6.2, p < 0.05), compared to the group of varieties resistant to WBA (n = 12) (prevalence variation 4.6… 9.1 %). Varieties with high resistance to WBA, belong to yellow and yellow-hybrid alfalfa varieties: Pavlovskaya 7, PO-172, Marusinskaya 425, PO-173, Sarga, PO-174, Victoria, 20–89 H, 193–95d, PO-175, SGPR-8, Vela×Sarga. Varieties with low resistance to VML belong to blue alfalfa and partially – blue-hybrid varieties: Krasnoyaruzhskaya 2, SI-139, SI-138, Plateau, Verko, Luzelle, Salsa, Kreno, Galaxi, Planet.