Dynamics of correlation relationship changes in new winter wheat varieties (<em>Triticum aestivum</em> L.) under the influence of environmental factors in the Southern Forest-Steppe zone of Ukraine

Purpose. To establish correlation dependence of influence of such factors as seeding rate, sowing time and seeding methods on yield indicators, as well as individual response of winter wheat varieties to them in case of the ecological system of seed production, that would allow to form elements of intensive varietal technology and obtain the genetically determined productivity potential of the variety in the future. Methods. Weight measuring was used to determine seed yield; the reliability of the experiment results was identified by statistical evaluation, analysis of variance and regression procedure. Results. During the period of investigation, the weather conditions differed significantly both for the temperature regime and the amount of precipitation, but the stability of grain and seed yield over years was the main requirement to varieties, that allowed to study the intergenotypic correlation relationships of crop yield indices and the dynamics of their changes under the effect of ecological factors. In the course of investigation, winter wheat yield indices were fixed annually from 684 plots, which were grouped and analyzed for factors of influence in order to ensure the complete certainty. Conclusions. Variants of investigation were defined for the certified seed yield and environmental factors (sowing time and seeding method, seeding rate), that had strong positive correlation relationships. Seeding rate and seeding method had the greatest impact on 1000 kernel weight. For tille­ring coefficient, varieties depending on the variant of the investigation had a negative close correlation relationship, which was greatly affected by seeding rate. For correlation relationships, winter wheat varieties ‘Bohdana’ and ‘Slavna’ appeared to be the most stable, ‘Chorniava’ and ‘Astarta’ were the most plastic.