Comprehensive quality assessment of 296 sweetpotato core germplasm in China: A quantitative and qualitative analysis

Abstract

The potential for improving sweetpotato quality remains underutilized due to a lack of comprehensive quality data on germplasm resources. This study evaluated 296 core germplasms, revealing significant phenotypic diversity across 24 quality traits in both stem tips and roots. Landraces had higher sugar content in roots, while wild relatives showed increased total flavonoid and phenol contents. Accessions with red-orange flesh were rich in sugars and carotenoids, whereas those with purple flesh had higher dry matter, flavonoids, and phenols. The accessions were classified into three clusters: high sugars and carotenoids, high phenolic compounds, and high starch. A comprehensive quality scoring model identified SP286 and SP192 as superior for stem tips and roots, respectively. Near-infrared spectroscopy, combined with a random forest algorithm, enabled rapid screening of superior germplasm, achieving prediction accuracies of 97 % for stem tips and 98 % for roots. These findings offer valuable resources and high-throughput models for enhancing sweetpotato quality.

Keywords: High-throughput screening; Near-infrared spectroscopy; Phenotypic diversity; Quality evaluation; Random Forest algorithm; Sweetpotato germplasm.

Fig. 1

Distribution map of 296 sweetpotato core germplasm sources.

Fig. 2

Flowchart for comprehensive quantitative and qualitative analysis of 296 core sweetpotato accessions. Note: The subscript S and R represents the trait of the stem tips and roots, respectively. DM: dry matter; CL: cellulose; CP: crude protein; SS: soluble sugar; CGA: chlorogenic acid; TAC: total anthocyanin content; TFC: total flavonoid content; TPC: total phenol content; TS: total starch; AL: amylose; AP: amylopectin; RAA: ratio of amylose to amylopectin; RS: reducing sugar; SC: sucrose; FT: fructose; GC: glucose; MT: maltose; TCC: total carotenoid content; NIRS: near-infrared spectroscopy; RF: random forest.

Fig. 3

Variations in 24 quality components among 296 sweetpotato core germplasm sources. (a-b) 8 stem tip quality traits. (c-f) 16 root quality traits. Note: The two indicators on the left of each subplot correspond to the left axis, while the two indicators on the right correspond to the right axis. The subscript S and R represents the trait of the stem tips and roots, respectively. DM: dry matter; CL: cellulose; CP: crude protein; SS: soluble sugar; CGA: chlorogenic acid; TAC: total anthocyanin content; TFC: total flavonoid content; TPC: total phenol content; TS: total starch; AL: amylose; AP: amylopectin; RAA: ratio of amylose to amylopectin; RS: reducing sugar; SC: sucrose; FT: fructose; GC: glucose; MT: maltose; TCC: total carotenoid content.

Fig. 4

Correlation analysis between 24 quality traits. Note: The subscript S and R represents the trait of the stem tips and roots, respectively. DM: dry matter; CL: cellulose; CP: crude protein; SS: soluble sugar; CGA: chlorogenic acid; TAC: total anthocyanin content; TFC: total flavonoid content; TPC: total phenol content; TS: total starch; AL: amylose; AP: amylopectin; RAA: ratio of amylose to amylopectin; RS: reducing sugar; SC: sucrose; FT: fructose; GC: glucose; MT: maltose; TCC: total carotenoid content.

Fig. 5

Comparative analysis of 24 quality components of six different sweetpotato flesh colors. (a) 8 stem tip quality traits. (b) 16 root quality traits. Note: The subscript S and R represents the trait of the stem tips and roots, respectively. DM: dry matter; CL: cellulose; CP: crude protein; SS: soluble sugar; CGA: chlorogenic acid; TAC: total anthocyanin content; TFC: total flavonoid content; TPC: total phenol content; TS: total starch; AL: amylose; AP: amylopectin; RAA: ratio of amylose to amylopectin; RS: reducing sugar; SC: sucrose; FT: fructose; GC: glucose; MT: maltose; TCC: total carotenoid content.

Fig. 6

Comprehensive quality analysis of 296 sweetpotato core germplasm resources. (a) Hierarchical clustering analysis. (b) Biplot from principal component analysis of the 24 quality characteristics of 296 sweetpotato accessions. (c) Comprehensive quality scores of 296 sweetpotato accessions across three dimensions. (d) Frequency distribution of comprehensive quality scores for stem tips and roots. Note: The subscript S and R represents the trait of the stem tips and roots, respectively. DM: dry matter; CL: cellulose; CP: crude protein; SS: soluble sugar; CGA: chlorogenic acid; TAC: total anthocyanin content; TFC: total flavonoid content; TPC: total phenol content; TS: total starch; AL: amylose; AP: amylopectin; RAA: ratio of amylose to amylopectin; RS: reducing sugar; SC: sucrose; FT: fructose; GC: glucose; MT: maltose; TCC: total carotenoid content.

Fig. 7

Near infrared spectra of stem tips and roots and their rapid screening qualitative models. (a-b) Original spectra of freeze-dried and hot-air-dried for stem tips and roots. (c-d) PCA scores of freeze-dried and hot-air-dried for stem tips and roots. (e-f) Classification model performance of screening superior germplasm for stem tips and roots utilization. Min: minimum; Max: maximum; SD: standard deviation; FV: feature variable.