The aims of the present research were to study selection samples of cocksfoot in the conditions of the middle taiga zone of the Komi Republic with the ecological adaptability parameters, calculated on the basis of green mass yield, with a subsequent selection of the most promising forms for further breeding. The experimental part of the work was carried out in the breeding nurseries laid on the experimental fields of the A.V. Zhuravsky Institute of Agrobiotechnologies FRC Komi SC UB RAS (Syktyvkar) in 2019-2021. We studied 7 cross-pollinated lines from wild-growing populations from the Komi Republic (BN-184, BN-185, BN-186, BN-188), Norway (BN-1817) and Finland (BN-1816) which were given breeding numbers (BNs). Since there were no locally recognized varieties during the study period, BN-1810 was taken as a control. Agroclimatic conditions during the years of research varied. By the environmental conditions’ index, 2020 saw favorable growing conditions (Ij = +14.2) and 2019 – relatively unfavorable (Ij = -18.4). The average yield of green mass of cocksfoot ranged within 22.6-30.3 t/ha in 2019-2021. BN-188 demonstrated the highest result (30.3 t/ha). Almost any breeding number showed a high ecological adaptability: the plasticity coefficient varied within 0.91-1.09. BN-1810, BN-185, BN-184, BN-1816 turned out to be highly adaptive and flexible (bi=1.00-1.09, Si2=0.25-0.75). BN-188 (125.5 %) and BN-185 (115.2 %) were marked through the highest stability level of variety. These numbers also were first by the stability index (0.50 and 0.47, respectively). Four of the studied breeding numbers had the adaptability coefficient of 1.03-1.12 with the highest value of BN-188. The greatest genetic flexibility between genotype and environmental factors was noted for BN-188 (18.1), as well as for BN-185 (17.5), BN-1810 (17.5) and BN-1816 (17.6). BN-185 (Sc=6.9) and BN-188 (Sc=6.4) are classified as having the highest breeding value. In total, according to the set of adaptability parameters, the breeding numbers BN-188 and BN-185 were recognized as highly promising forms by the breeding value (Sc = 6.4 and 6.9, respectively), stable productivity, and homeostatic index (Hom. = 1.4).
