GRAIN YIELD AND ITS STRUCTURE COMPONENTS IN NEW COMPETITIVE, ADAPTIVE, AND PLASTIC GENOTYPES OF SOFT WINTER WHEAT

The objective of the study is to create new competitive, flexible genotypes of soft winter wheat adaptable to cultivation in the North Caucasus, Lower Volga and Central Black Earth regions of Russia. Grain yield and elements of its structure were studied in new competitive genotypes of soft winter wheat at the North Caucasus Federal Scientific Center. The genotypes were created based on modern methods of classical, haploid, marker and ecological selection using complex stepwise hybridization and continuous, targeted, individual selection throughout all stages of the selection process according to the developed model economically valuable traits of varietal types of varying intensity. These genotypes are: selection number (synonym) 1506/16; 1450/20; 1463/20; 1466/20. The highest yield on average over 3 years (2023–2025) was achieved by genotype 1848/19 – 9.43 t/ha, exceeding the Grom standard by 1.49 t/ha. The yield of the studied genotypes varied depending on the year conditions: 2023 was moderate with Ij = –0.09 at an average yield of 8.78 t/ha; 2024 was rather unfavorable with Ij = –1.02 at an average yield of 7.74 t/ha; 2025 was favorable with Ij = 1.11 at an average yield of 10.14 t/ha. The variation coefficients showed that genotypes 1466/20 and 1450/20 had low variability (V < 10 %); below average (V = 10–20 %) – 1463/20, Grom, 1249/20, 1659/19, 1506/16; average (V > 20 %) – 1848/19. The variation of the linear regression coefficient in the years of the study was 0.17–1.80, indicating different responses of genotypes to changes in environmental conditions. The following genotypes were characterized by high responsiveness with a wide reaction norm: 1848/19 (bi = 1.80); 1506/16 (bi = 1.54); 1659/19 (bi = 1.37); 1249/20 (bi = 1.13). The standard variety Grom and the following new genotypes were characterized by high stability: 1659/19, 1249/20, 1848/19 (S2d = 0.004–0.013). Grain yield correlates positively with the number of productive stems per plant (r = 0.53 ± 0.25), the number of spikelets (r = 0.62 ± 0.20) and grains per ear (r = 0.56 ± 0.24), and the weight of grains per ear (r = 0.74 ± 0.16). An important indicator of the comprehensive performance of an agrocenosis is the cenosis capacity. The standard cenosis capacity is only 28,000 grains/m2. New genotypes with a high cenosis capacity, 1.5 times higher than the standard, include: 1249/20 (46,000 grains/m2), 1450/20 (44,000 grains/m2), 1848/19 (42,000 grains/m2), and 1506/16 (42,000 grains/m2).