Phenotypic diversity and selection of promising accessions of Cucurbita spp. from Peruvian germplasm

Abstract

The genus Cucurbita spp. is native to the Americas, and Peru is one of its main centers of diversity. This crop represents a strategic resource for food security due to its adaptability and nutritional value. The objective of this study was to evaluate phenotypic diversity and select promising accessions of Cucurbita spp. conserved in the INIA Germplasm Bank (Peru). A total of 107 accessions were characterized using agromorphological descriptors (18 qualitative and 15 quantitative). Genetic variability parameters, correlation analysis, and multivariate analysis were estimated. Fruit size-related traits, including fruit length, width, and weight, exhibited high broad-sense heritability (H2 > 60%), suggesting high potential for selection. Correlation analysis revealed significant positive associations between fruit size and seed traits, and negative associations with total soluble solids, suggesting a trade-off between fruit size and sugar concentration. Likewise, the earlier-maturing accessions tended to produce larger fruits and seeds. Principal component analysis (PCA) explained 65.9% of the total variation, indicating that diversity is determined by characteristics related to fruit size, internal structure, and seed traits. Cluster analysis classified the accessions into four phenotypically distinct clusters. A multi-criteria index allowed for the selection of promising accessions in different species, notably PER1011008, PER1003595, and PER1010999 in C. ficifolia; PER1010939, PER1003572, and PER1010934 in C. maxima; PER1003584, PER1010957, and PER1010973 in C. moschata; and PER1010982, PER1010985, and PER1010987 in C. pepo. These results highlight the high value of Peruvian Cucurbita germplasm as a source of genetic diversity and as a basis for the targeted selection of ideotypes with potential in plant breeding programs focused on productivity, quality, and diversification of uses.