## 5 Conclusions  
Examination of phenotypic diversity of pea genotypes of different origins indicated considerable variation for a range of traits. The broad-sense heritability estimates were moderate to high for all examined traits, indicating the major influence of genetic factors. Inconsistent heritability between years and between sites for certain traits indicated their higher sensitivity to environmental conditions. Based on this work, it could be concluded that selection of traits with high and consistent heritability would be most valuable to breeders, including stable traits that effect seed weight per plant such as pod length and thousand seed weight. Moderate, consistent heritability with a long-lasting effect on seed weight per plant was observed for the number of seeds per plant, so direct selection of this trait could also be effective. Breeding for increased seed protein content is hampered by the negative correlation between protein content and yield. Therefore, increasing protein production can be done by increasing the area under protein crops or by improving protein quality over protein content, given that difference in protein content can be the result of many different environmental factors. The seed yield is a less challenging breeding target than protein content; therefore, high yields have been achieved among some of the cultivated accessions. Given the lack of the strong influence of GxE, confirmed by positive correlations between two years, this gene pool provides numerous possibilities as a starting point for future pea varieties adaptable to different agroclimatic conditions. Traits such as the number of grains per pod, plant height, pod length, thousand seed weight, seed yield, and protein content showed highly significant variations among the tested groups of genotypes. Knowledge of these variations could be used in further plant selection programs. Given the proven and evident differences between the analyzed genotypes based on type and use, and their great adaptability to tested conditions, it can be concluded that pea is a very adaptable plant species with untapped production potential. The results of this study should contribute to a better knowledge of variability and seed yield stability of pea genotypes used in Europe for future production and breeding. Obtained phenotypic results could improve pea breeding by developing new cultivars carrying favorable traits to attain more sustainable production and higher yields. In conclusion, this work should promote the broader use of pea as a grain legume within diverse agricultural systems to provide multiple beneficial advantages, in line with the principles of sustainability. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/plants11101321/s1](https://www.mdpi.com/article/10.3390/plants11101321/s1)]([https://www.mdpi.com/article/10.3390/plants11101321/s1](https://www.mdpi.com/article/10.3390/plants11101321/s1)), Table S1: Meteorological conditions in Novi Sad, Serbia during the vegetation seasons of pea in 2019 and 2020, and long-term average. Table S2: Meteorological conditions in Kessenich, Belgium during the vegetation seasons of pea in 2019 and 2020, and long-term average. Table S3: Pearson's correlation coefficient @for analyzed traits between two years (2019 and 2020). Table S4: The list of pea genotypes analyzed in the study. Conceptualization and methodology, M.C. and D.Z. ; software, A.U., M.C., and L.S. ; validation, R.G. ; formal analysis, E.S.-C., D.L., and L.S. ; investigation, A.U., D.Z., and M.C. ; writing--original draft preparation, A.U. ; writing--review and editing, M.C., R.G., and L.S. ; supervision, M.C. and D.Z. All authors have read and agreed to the published version of the manuscript. This project has received funding from the European Union's Horizon 2020 Program for Research and Innovation under grant agreement no.