## 3 Results  
### Morphological Parameters and Chemical Parameters  
The fruit morphology of 75 peppers is shown in supplemental Table S1 and Figure S1. Genotypes of 75 accessions of pepper were classified into _C. annuum_ (67), _C. bacatum_ (1), _C. chintense_ (4), and _C. frutescens_ (3). It was found that _C. annuum_ has the greatest variation in fruit morphology, followed by _C. chintense_, especially fruit shape and length, while _C. frutescens_ were mostly one type of fruit shape among the collected accessions (Supplemental Table S1). The fruit shapes across the four species were short horn (54), long finger (5), lantern (5), short finger (4), long cone (3), elongate (3) and long horn (1) (Supplemental Table S1). The range of fruit color varied from dark green (46) to olivine (12), orange (6), red (5), purple-black (5), and brown (1). Furthermore, the fruit weight, length, and diameter were also found to be significant variables, depending on the species. Individual fruit weight ranged from 0.64 g (S71, _C. annuum_) to 34.13 g (S46, _C. annuum_), with a mean of 2.99 g (Supplemental Tables S1 and S2). The fruit length ranged from 1.58 cm (S50, _C. annuum_) to 15.37 cm (S59, _C. annuum_), with a mean of 5.07 cm. The fruit diameter ranged from 0.52 cm (S43, _C. annuum_) to 4.35 cm (S46, _C. annuum_), with a mean of 1.09 cm. The coefficients of variation of fruit weight, length, and diameter were 153.21%, 39.90%, and 76.73%, respectively (Supplemental Table S2). Fruit weight, length, and diameter of the _C. frutescens_ accessions were 1.13-3.08 g, 3.32-5.12 cm, and 0.78-4.32 cm, respectively, those of _C. chintense_ were 6.12-7.67 g, 2.67-6.48 cm, and 2.19-3.40 cm, respectively, and those of _C. annuum_ were 0.64-34.13 g, 1.58-15.37 cm, and 0.52-3.95 cm, respectively (Supplemental Table S1). The results of significant analysis showed that there was no significant difference in fruit length among three pepper species (\(p\) > 0.05). However, the fruit weight of _C. chinese_ was significantly higher than that of _C. frutescens_ (\(p\) < 0.05), and the _C. annuum_ was not significantly different from that of _C. chinese_ and _C. frutescens_ (\(p\) > 0.05). Meanwhile, the diameter of _C. annuum_ was significantly lower than that of _C. chinese_ and _C. frutescens_ (\(p\) < 0.05), and there was no significant difference between _C. frutescens_ and _C. chinese_ (\(p\) > 0.05) (Supplemental Table S3). Chemical compositions of the 75 genotypes peppers were summarized in Table 1. Among them, the total phenol concentration of S24 (_C. chintense_) was the highest (12.13 mg/g), while that of S61 (_C. frutescens_) was the lowest (1.89 mg/g). The soluble sugar concentration of all 75 accessions ranged from 5.45 mg/g (S25, _C. annuum_) to 62.40 mg/g (S59, _C. annuum_). The total soluble solid concentration ranged from 0.25 \({}^{\circ}\)Brix (S42, _C. frutescens_) to 1.34 \({}^{\circ}\)Brix (S68, _C. annuum_). The tittrable acid ranged from 0.14% (S59, _C. annuum_) to 0.63% (S60, _C. annuum_), while the total soluble protein concentration ranged from 0.41 mg/g (S22, _C. annuum_) to 10.62 mg/g (S25, _C. annuum_). The coefficients of variation of total phenol, total soluble sugar, total soluble solids, tittrable acid, and total soluble protein were 12.13%, 62.40%, 1.34%, 0.63%, and 76.73%, respectively (Supplemental Table S2). There was no significantly difference in tittrable acidity among the three pepper species (\(p>0.05\)). The total soluble sugar and total soluble solids of _C. frutescens_ were significantly lower than the values of _C. chinese_ and _C. annuum_ (\(p<0.05\)), and there was no significant difference between _C. annuum_s and _C. chinese_ (\(p>0.05\)). Moreover, the phenol content of _C. chinese_ was significantly lower than that of _C. frutescens_ and _C. annuum_ (\(p<0.05\)), and there was no significant difference between _C. annuum_s and _C. frutescens_ (\(p>0.05\)). Finally, the total soluble protein of _C. chinese_ was significantly lower than that of _C. annuum_ (\(p<0.05\)), and the _C.