Phenotypic Variation and Classification of Melon Germplasm Resources Based on DUS Test Characteristics

Area of Science:

• Plant genetics and breeding
• Horticultural science
• Agricultural research

Background:

• Melon (Cucumis melo L.) germplasm is crucial for developing innovative seed industries and improved cultivars.
• Systematic characterization of melon accessions is needed to understand phenotypic variation, classification, and breeding potential.

Purpose of the Study:

• To systematically evaluate phenotypic variation and classification relationships among 403 melon accessions.
• To assess the breeding potential of melon germplasm resources.
• To provide a quantitative phenotypic basis for melon germplasm utilization.

Main Methods:

• Evaluation of 403 melon accessions using nine quantitative characteristics (e.g., fruit diameter, flesh thickness, soluble solids).
• Statistical analyses including coefficient of variation, Shannon-Weaver diversity index, Spearman rank correlation, principal component analysis, and hierarchical cluster analysis.
• Development of a weighted comprehensive selection index to identify superior accessions.

Main Results:

• Extensive phenotypic variation observed, with coefficients of variation from 14.0% to 57.4%. Rind thickness showed the greatest variation.
• High diversity indices (1.74–1.96) indicated substantial variation in fruit morphology, vegetative growth, and quality traits.
• Principal component analysis identified three main components explaining 65.22% of variation, representing fruit structure, vegetative growth, and quality. Cluster analysis grouped accessions into four distinct phenotypic groups.
• Accession 20225110454A identified as having superior agronomic performance based on a comprehensive selection index.

Conclusions:

• The study provides a quantitative phenotypic characterization of melon germplasm resources.
• Findings support informed decisions in melon germplasm conservation, core collection development, and parental selection for breeding programs.
• Significant phenotypic diversity and correlations among traits offer valuable insights for breeding-oriented resource utilization in melon.