Creation of adaptive winter wheat source material in the southern steppe using geographically distant ecotypes

Aim. To establish the nature of the influence of the duration of the term “spring regrowth–flowering” on grain yield in varieties of the southern steppe ecotype and lines of soft winter wheat created using late-ripening samples of the Western European ecotype. Methods. Field studies were conducted at the Institute of Climate-Oriented Agriculture of the NAAS (2018–2024, Kherson, 46°38′24″ N 32°36′52″ E and Odessa 2023–2024, 46°29′08.3″ N 30°44′36.6″ E). The object of the research was varieties of soft winter wheat of the southern steppe ecotype and lines obtained using samples of the Western European ecotype. Results. The extension of the duration of the “growth–flowering” period in newly created lines stimulated an increase in grain yield. The highest grain yield was recorded in lines with a duration of the “growth–flowering” period of 54–56 days. Their grain yield was 9.85–10.35 t/ha with irrigation. However, without irrigation, the grain yield in these lines sharply decreased by 40–75 %. Conclusions. The directions of breeding soft winter wheat in the conditions of the Arid Steppe can be radically opposite depending on the technological support. High drought resistance of genotypes and heat resistance are ensured by a shortened period of “spring regrowth–flowering”, early maturity. Selection of varieties of the intensive type for conditions of optimal moisture supply should use as starting material genotypes with an extended duration of the period of vegetation.