# Construction and Evaluation of Pepper Core Collection Based on Phenotypic Traits and SSR Markers
## 3 Results
### Determination of Intragroup Sampling Ratio Method and Construction of Core Collection  
The RPR is notably higher for square root and logarithmic samples compared to simple and diverse samples when the overall sample size is 20% or more. The CR shows similar trends. The CVR exceeds 100%, following the order: diversity retention > square root retention > logarithmic retention > simple retention. The Hi varies irregularly; however, between 15% and 25% overall sample size, the Hi is highest for square root samples compared to logarithmic and diversity samples. When the sample size is above 5%, the Hi consistently exceeds 0.9 (Table 4). Thus, the square root ratio method is most effective for intra-group sample retention.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Overall** & & & \multicolumn{3}{c}{**Intragroup Retention Ratio Method**} \\
**Sample** & **Gemplasm Category** & **Simple** & **Logarithmic** & **Square Root** & **Diversity** \\
**Ratio** & & **Retention** & **Sample** & **Sample** & **Sample** \\ \hline \hline \multirow{8}{*}{5\%} & var. _fasciudatum_ [PERSON] & 1 & 2 & 2 & 2 \\  & var. _grossum_ [PERSON] & 1 & 2 & 2 & 2 \\  & var. _crasil\%_ & 1 & 1 & 1 & 1 \\  & var. _conoides_ [PERSON] & 1 & 2 & 2 & 2 \\  & var. _longum_ [PERSON] & 6 & 3 & 4 & 2 \\  & Number of pre-selected core & 10 & 10 & 11 & 9 \\  & germplasm & & & & \\ \hline \hline \multirow{8}{*}{10\%} & var. _fasciudatum_ [PERSON] & 1 & 3 & 3 & 4 \\  & var. _grossum_ [PERSON] & 2 & 4 & 3 & 4 \\  & var. _crasil\%_ & 1 & 2 & 2 & 2 \\  & var. _conoides_ [PERSON] & 2 & 3 & 3 & 4 \\  & var. _longum_ [PERSON] & 12 & 6 & 8 & 4 \\  & Number of pre-selected core & 18 & 18 & 19 & 18 \\  & germplasm & & & & \\ \hline \hline \multirow{8}{*}{15\%} & var. _fasciudatum_ [PERSON] & 2 & 4 & 4 & 5 \\  & var. _grossum_ [PERSON] & 3 & 5 & 4 & 5 \\  & var. _crasil\%_ & 1 & 2 & 2 & 3 \\  & var. _conoides_ [PERSON] & 2 & 5 & 4 & 6 \\  & var. _longum_ [PERSON] & 18 & 9 & 11 & 6 \\  & Number of pre-selected core & & & & \\  & germplasm & & & & \\ \hline \hline \multirow{8}{*}{20\%} & var. _fasciudatum_ [PERSON] & 2 & 6 & 5 & 7 \\  & var. _grossum_ [PERSON] & 4 & 7 & 6 & 7 \\  & var. _crasil\%_ & 1 & 3 & 3 & 3 \\  & var. _conoides_ [PERSON] & 3 & 6 & 5 & 8 \\  & var. _longum_ [PERSON] & 24 & 12 & 15 & 8 \\  & Number of pre-selected core & & & & \\  & germplasm & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 4: Accessions of selected germplasm from each group to corresponding pre-core germplasm under different sampling strategies.  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Intragroup** & **Overall** & & **Ratio of** & & **Change Rate** & \\
**Retention** & **Sample** & **Phenotypic** & **Coincidence** & **of** & **Genetic** \\
**Ratio** & **Retention** & **Retention** & **Rate of** & **Coefficient** & **Diversity** \\
**Method** & **Ratio** & **Retention** & **Range (CR)** & **of Variation** & **Index (Hi)** \\  & & **Ratio** & **(RPR)** & **CVR** & \\ \hline \hline \multirow{8}{*}{Diversity retention sample} & 5\% & 67.68\% & 72.43\% & 196.68\% & 0.8121 \\  & 10\% & 87.88\% & 82.99\% & 197.19\% & 0.9291 \\ \cline{1-1}  & 15\% & 90.91\% & 85.07\% & 197.92\% & 0.9316 \\ \cline{1-1}  & 20\% & 92.93\% & 85.07\% & 198.26\% & 0.9257 \\ \cline{1-1}  & 25\% & 92.93\% & 85.07\% & 201.20\% & 0.9217 \\ \cline{1-1}  & 30\% & 94.95\% & 89.24\% & 204.81\% & 0.9286 \\ \hline \hline original sample & 100\% & 100\% & 100\% & 100\% & 0.7954 \\ \hline \hline \end{tabular}
\end{table}
Table 3: _Cont._In summary, using a 25% overall sample size with the square root ratio method is optimal for retaining the phenotypic core germplasm. As a result, a core collection of 41 germplasms was selected (Table S3), comprising 6 accessions of var. _fuscicultatum_, 7 accessions of var. _grossum_, 3 accessions of var. _cerasiforme_, 6 accessions of var. _conoides_, and 19 accessions of var. _longum_.