## 2 Results
### Genetic Distance and Hierarchical Clustering  
This work was part of a more extensive study on genetic diversity and phenotypic variation in yield and protein content of pea accessions in Europe. After filtering, markers with a Gentrain score (Illumina quality measure) below 0.7 and a minimum allele frequency of 0.05-a total of 11,693 polymorphic markers--were left in the panel of 165 accessions used here. The genetic distance matrix was based on all the 16,693 markers and the phenotypic distance matrices were based on all the phenotypic traits measured in this study. The hierarchical grouping chart showed four groups (Figure 5). The first group (green) consists of nine genotypes, exclusively of the breeding line population type and dry type of use, originating from Serbia. The second group (red) consists of 36 genotypes, mainly of the breeding line population type and dry type of use, with some exceptions of the vegetable type. In this group, vegetable pea lines, as expected, are clustered very closely together (mainly the 00 lines, Table S4); however, a set of 00 lines shows introgression from other types of peas. A number of forage peas are also part of this genetic group (Flex, H3) The third group (blue) consists of 57 genotypes, mainly landraces, forage, wild/semi-wild population, and dry types of use. Clustering showed that some of the landraces are very closely related. The fourth group (black) consists of 63 genotypes, mostly varieties and  
Figure 4: Principal component analysis (PCA) of the broad phenotypic diversity of the investigated pea panel composed by analyzed genotypes, classified by variety type by usage. (**Left**): IFVCNS, Serbia site results; (**Right**): Agro Seed, Belgium site results. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**IFVCNS, Serbia**} & \multicolumn{3}{c}{**Agro Seed, Belgium**} \\ \hline \multirow{2}{*}{**Trait**} & \multicolumn{2}{c}{**2019**} & \multicolumn{2}{c}{**2020**} & \multicolumn{2}{c}{**2019**} & \multicolumn{2}{c}{**2020**} \\ \cline{2-9}  & \multicolumn{1}{c}{**F**} & \multicolumn{1}{c}{\(p\)**-Value**} & \multicolumn{1}{c}{**F**} & \multicolumn{1}{c}{\(p\)**-Value**} & \multicolumn{1}{c}{**F**} & \multicolumn{1}{c}{\(p\)**-Value**} \\ \hline
**GPP** & 33.171 & 0.0122 * & 53.086 & 0.0005 ** & 0.45 & 0.772 & 0.55 & 0.696 \\
**PP** & 17.281 & 0.1463 & 0.6242 & 0.6459 & 1.10 & 0.357 & 1.44 & 0.222 \\
**SPP** & 30.741 & 0.018 * & 12.562 & 0.2895 & 2.01 & 0.096 & 0.16 & 0.957 \\
**FD** & 14.681 & 0.2134 & 0.3419 & 0.8494 & 0.27 & 0.894 & 1.58 & 0.183 \\
**PH** & 79.438 & 0.000 ** & 11.588 & 0.000 * & 14.28 & 0.000 ** & 14.32 & 0.000 ** \\
**PL** & 0.6091 & 0.6566 & 17.638 & 0.1387 & 3.42 & 0.010 & 2.05 & 0.089 * \\
**PoL** & 49.446 & 0.0009 ** & 31.052 & 0.0171 * & 1.66 & 0.162 & 3.16 & 0.016 * \\
**TSW** & 37.281 & 0.0063 * & 3.375 & 0.0111 * & 3.85 & 0.005 ** & 2.57 & 0.040 * \\
**SWPP** & 30.949 & 0.017 * & 16.254 & 0.170 & 1.51 & 0.201 & 0.47 & 0.761 \\
**SY** & 10.22 & 0.000 ** & 4 & 0.009 * & 1.97 & 0.101 & 3.26 & 0.013 * \\
**PC** & 4.87 & 0.001 ** & 9.62 & 0.000 ** & 2.50 & 0.045 & 6.1 & 0.000 ** \\ \hline \hline \end{tabular}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{GPP—grains per pod; PPP—pods per plant; SPP—seeds per plant; FD—flowering duration; PH—plant height; PL—plot lodging; PoL—pod length; TSW—thousand seed weight; SWPP—seed weight per plant; SY—seed yield; PC—protein content. Significant at \(p\leq 0.05\) (\(\tau\)), \(p\leq 0.01\) (**).  
\end{table} 
Table 5: Analysis of variance for data collected on pea genotypes tested on both sites. dry types of use. This group consists of modern dry varieties, which are related and grouped together. A Mantel test was performed to test the correlations between the genetic distance matrix and the phenotypic distance matrices at the two sites and years (Table 6). There were significant correlations at both sites and in both years. However, the correlations were highest for the two seasons at IFVCNS, Serbia.