Combined evaluation of agronomic and quality traits to explore heat germplasm in celery (Apium graveolens L.).

• The genetic diversity of celery germplasms was evaluated based on agronomic traits, quality traits and heat tolerance. • Apigenin and cellulose were the main contributors to the variation of quality traits. • The comprehensive evaluation value of celery after heat stress had a highly significant positive correlation with the heat damage index. • The heat resistance of celery was related to its hollow/solid and color. Existing celery germplasm resources must be evaluated prior to celery biological research and application of germplasm resources. In this study, 14 agronomic and quality traits, and heat-resistance of 50 celery cultivars were analyzed. The results showed that the coefficients of variation of the 14 traits ranged from 1.73% to 64.69%, 50 samples of celery could be divided into 5 groups by cluster analysis. The primary sources of variation in agronomic traits were petiole color, hollow/solid, and yield per plant, and the primary sources of variation of quality traits were apigenin and cellulose. The photosynthetic parameters and heat damage index was investigated, and the correlation between celery germplasm resources and heat-resistance was analyzed. The result showed that heat-resistance was correlated with its hollow/solid and color. This study analyzed the genetic diversity of celery germplasm resources, screened heat-resistant and heat-sensitive varieties, and performed an association analysis with the germplasm resources, which laid the foundation for the subsequent selection of heat-resistant celery varieties. [ABSTRACT FROM AUTHOR]