O.A. Posylaeva, V.V. Kirichenko
Рlant Production Institute nd. a. V. Ya. Yuryev of NAAS
Summary. By means of the modified thermotest the experiment for determination of heat resistance of modern soybean varieties for selection of valuable forms as a parent material for breeding on this sign was carried out. The method provided for the processing of seeds by high temperatures (+60 °C) during 40 minutes, after it the germinating capacity, length and weight of 5-day seedlings with reference to the parameters established during sprouting of not processed seeds were determined. 83 samples of soybean of the Ukrainian and foreign selection of three groups of ripeness with various genetic plasma served as a material. Seeds were grown up in breeding crop rotation in the Рlant Production Institute nd. a. V. Ya. Yuryev of NAAS under conditions of the Eastern part of forest-steppe of Ukraine in 2011-2013. The variability of heat stability of varieties in different reproduction years was established. When using the seeds collected in more droughty and hot year the indicators, characterizing heat stability of soybean varieties, were higher, than at a reproduction of the seeds which were grown up in years with the smaller sum of temperatures and the best providing with moisture. It were selected 14 modern heat-resistant soybean varieties of three groups of ripeness which could be used in breeding programs on heat tolerance increase (Ksenya, Versia, UIR 21752, Labrador, NM 4961, Sonyachna, Veras, Arkadia Odesska, Hybrid ASS 21, Emerson, Bajka, Feya, Valentina, Annushka). For correct thermodiagnostics and distribution of soybean samples the heat-resistant variety Ksenya (UKR), middle resistant variety N 0300 (CAN) and unstable variety Karikachi (JPN) could be recommended as variety-classifiers.
Keywords: soybean, heat tolerance, heat stability, depression of growth processes, soy breeding, heat-resistant varieties, variety-classifiers.