Study of Yield Components and Assessment of Their Stability in Local Field Pea Varieties Grown in Northeastern and Central Southern Bulgaria

Field pea (Pisum sativum L.) is an important legume crop whose productivity is strongly influenced by environmental conditions, making the evaluation of genotype performance and stability essential for breeding and sustainable cultivation. The aim of the present study was to evaluate local field pea varieties grown under the climatic conditions of Northeastern and Central Southern Bulgaria with respect to yield-related traits and to assess the effects of genotype, environment, and genotype × environment interaction on trait expression and stability. Field experiments were conducted during 2024 and 2025 at two locations (Ruse and Sadovo) using four local field pea cultivars arranged in a randomized complete block design with three replications. Plant height, number of primary branches, number of productive pods per plant, number of seeds per pod, number of seeds per plant, and seed weight per plant were recorded. The data were analyzed using multifactor analysis of variance (ANOVA), Tukey's HSD test, and stability statistics including Shukla's stability variances, Wricke's ecovalence, and Kang's rank-sum criterion. The results demonstrated significant effects of genotype, year, and their interactions on most of the evaluated traits, indicating a substantial influence of environmental conditions on yield formation. In general, higher values for several productivity-related traits were observed under the conditions of the Sadovo environment. The cultivar Ruse 1 exhibited the highest stability for the traits number of seeds per plant and seed weight per plant and achieved favorable rankings according to Kang's stability criterion, whereas Mir showed superior performance for several yield-related characteristics. The obtained results provide useful information for the evaluation of local field pea germplasm and may support breeding programs and the selection of genotypes adapted to different environmental conditions in Bulgaria.