Objective A model to comprehensively evaluate the nutritional quality of 14 Azolla germplasms was established to screen high-quality accessions resources with high protein content, rich amino acids, and balanced functional components.

Method Twenty-four contents of protein, essential amino acids, non-essential amino acids, and functional ingredients were selected as indicators to compare the nutritional quality of 14 Azolla accessions selected from the 620 Azolla germplasm resources maintained at the National Azolla Germplasm Resource Nursery (Fuzhou). A model was constructed using the principal component analysis (PCA) and validated by the membership function method (MFM) for comprehensive evaluation of the various germplasms.

Result The quality indices varied significantly among the germplasms. Accession No. 3001 was significantly higher than 1001, 4018, 4018 and 7001 in the contents of protein, isoleucine, leucine, phenylalanine, threonine, valine, alanine, glycine, histidine, proline, serine, and tyrosine; accession No. PCGL was significantly higher than 387, 4018, 4087, and 7001 in the contents of lysine and aspartic acid; accession No. 500 was significantly higher than all other 12 tested accessions except 7001 in the contents of total flavonoids and rutin; accession No. 4058 was significantly higher than 1001, 1020, 387, 4018, 4087, 7001, MH-2, and MH3-1 in the contents of methionine and arginine; and accession No. 2002 was significantly higher than 1001, 387, 4058, 4087, 7001, CTGQ, NH-2, and NH3-1 in the contents of polysaccharides and anthraquinones. In PCA, accession No. 3001 scored the highest at 3.84, and No. 7001 the lowest at −4.29; and in MFM, it also ranked the highest at 0.71, and 7001 the lowest at 0.17. The ranking of the 14 tested Azolla accessions based on MFM for nutritional quality was as follows: 3001 > PCGL > 500 > 4058 > 2002 > CTGQ > MH3-1 > 1020 > 1001 > MH2 > 4087 > 387 > 4018 > 7001. The constructed evaluation model satisfactorily differentiated the nutritional quality of the 14 varieties of Azolla plants, and Accession No. 3001 was identified the best.

Conclusion It applied indicators that covered 4 essential categories of nutrients which identified Accessions No. 3001, PCGL, 500, 4058, and 2002 to be the superior varieties. In addition, the model showed Accession No. 3001 with high protein content, abundant amino acids, and balanced functional components to be of choice as a plant-based quality protein forage and of value for the breeding and broadening utilization of the germplasms.