Comprehensive Evaluation of Nutritional Quality Diversity in Cottonseeds from 259 Upland Cotton Germplasms

Abstract

Cottonseeds, rich in high-quality protein and fatty acids, represent a vital plant-derived feedstuff and edible oil resource. To systematically investigate genetic variation patterns in nutritional quality and screen superior germplasm, this study analyzed 26 nutritional quality traits and 8 fiber traits across 259 upland cotton (Gossypium hirsutum L.) accessions using multivariate statistical approaches. Results revealed significant genetic diversity in cottonseed nutritional profiles, with coefficients of variation ranging from 3.42% to 26.37%. Moreover, with advancements in breeding periods, the contents of protein, amino acids, and the proportion of unsaturated fatty acids (UFAs) increased, while oil content and C16:0 levels decreased. Correlation analyses identified significant positive associations (p < 0.05) between proteins, amino acids, UFAs, and most fiber traits, except for seed index (SI), fiber micronaire (FM), and fiber elongation (FE). Through a principal component analysis-fuzzy membership function (PCA-FMF) model, 13 elite accessions (F > 0.75) with high protein content, high UFA proportion, and excellent fiber quality were identified. These findings provide both data-driven foundations and practical germplasm resources for value-added utilization of cottonseed and coordinated breeding for dual-quality traits of nutrition and fiber.

Keywords: Gossypium hirsutum L.; comprehensive evaluation; cottonseed; fiber quality; nutritional quality.

Figure 1

Descriptive analysis of nutritional quality of 259 upland cotton accessions. Frequency distribution of protein content (A) and oil content (B) in cottonseeds. Correlation analysis of protein content and oil content in cottonseeds (C). Multiple comparisons of amino acid content (D), fatty acid proportion (E), and proportion of saturated and unsaturated fatty acids (F) in cottonseeds. Different lowercase letters indicate significant differences at the p < 0.05 level. EAAs: Essential amino acids, NAAs: non-essential amino acids, Asp: Aspartic Acid, Thr: Threonine, Ser: Serine, Glu: Glutamic Acid, Gly: Glycine, Ala: Alanine, Val: Valine, Met: Methionine, Ile: Isoleucine, Leu: Leucine, Tyr: Tyrosine, Phe: Phenylalanine, Lys: Lysine, His: Histidine, Arg: Arginine, Pro: Proline, PRO: Protein, C14:0: Myristic Acid, C16:0: Palmitic Acid, C16:1: Palmitoleic Acid, C18:0: Stearic Acid, C18:1: Oleic Acid, C18:2: Linoleic Acid, C18:3: α-Linolenic Acid, C20:0: Arachidic Acid, UFA: Unsaturated fatty acids, SFAs: Saturated fatty acids.

Figure 2

Analysis of nutritional quality differences in 259 upland cotton accessions by geographical sources and breeding period. Multiple comparisons of protein content and oil content in cottonseeds from different geographical origins (A) and different breeding periods (B). Heatmap of 26 cottonseed nutritional quality traits by geographical origins (C) and breeding period (D). Red indicates high content; blue indicates low content. Intensity reflects magnitude. Different lowercase letters indicate significant differences at the p < 0.05 level. YZR: Yangtze River Basin, YZR: Yellow River Basin, NER: northern extra-early-maturing cotton region, NIR: northwest inland region, LAN: landraces, FOR: foreign.

Figure 3

Correlation analysis of 26 nutritional quality traits and 8 fiber traits. The upper part of the heatmap shows correlation visualization (circular color blocks + significance markers), while the lower part presents the corresponding correlation coefficient values (*: p < 0.05, **: p < 0.01). Negative correlations are denoted in blue, positive correlations in red, with color intensity and circle size proportional to the strength of the correlation coefficient.

Figure 4

Comprehensive evaluation of 259 cotton germplasms. PCA (A) and cluster analysis (B) of 26 cottonseed nutritional quality traits and 8 fiber traits. (C) Comparative analysis of all traits across four groups of accessions. (D) Frequency distribution of comprehensive evaluation F values.