Abstract: The cracking resistance of watermelon germplasm resources was identified and evaluated，to provide support for enriching elite cracking⁃resistant breeding materials of watermelon.92 watermelon germplasm accessions were used as test materials，to conduct genotypic analysis by KASP molecular marker linked to cracking⁃resistant traits.And a correlation analysis was further carried out in combination with fruit traits including pericarp hardness，pericarp thickness，fruit shape index，single fruit weight，central soluble solids content and pericarp color.The results showed that 42 watermelon germplasm accessions with cracking⁃resistant genotypes were identified via KASP genotyping.The genotype was significantly correlated with pericarp hardness，and the pericarp hardness of the cracking⁃resistant genotype（GG） was higher than that of the cracking⁃susceptible genotype（AA）.Through the combined identification of cluster analysis based on pericarp hardness and genotyping，17 germplasm accessions of small⁃fruited watermelon with medium to high pericarp hardness and cracking resistance were screened out，including HY⁃20，HY⁃25 and Siweite No. 2. 25 germplasm accessions of large⁃fruited watermelon with medium to high pericarp hardness and cracking resistance were identified，including A3，W10 and Yubao No. 1. Pericarp hardness and the KASP molecular marker for cracking resistance can be applied to the screening of cracking⁃resistant watermelon germplasm and marker⁃assisted breeding. And the screened cracking⁃resistant germplasm resources can serve as elite parental materials for the breeding of new cracking⁃resistant watermelon varieties.

Key words: Watermelon, Cracking resistance, KASP molecular marker, Genotype, Germplasm resources, Pericarp hardness, Fruit trait, Large?fruited type, Small?fruited type

摘要： 鉴定评价西瓜种质资源的耐裂性，为丰富西瓜优异耐裂育种材料提供支撑。以92份西瓜种质为材料，利用耐裂性相关KASP分子标记进行基因型分析，并结合果皮硬度、果皮厚度、果形指数、单果质量、中心可溶性固形物含量、果皮颜色等果实性状开展关联分析。结果表明，通过KASP分子标记分型共获得耐裂基因型西瓜种质42份。基因型与果皮硬度呈显著相关性，耐裂基因型（GG）果皮硬度高于不耐裂基因型（AA）。通过果皮硬度聚类分析与基因分型联合鉴定，筛选出小果型西瓜果皮中高硬度耐裂型种质17份，包含HY-20、HY-25和斯维特2号等；大果型西瓜果皮中高硬度耐裂型种质25份，包含A3、W10和豫宝1号等。果皮硬度与耐裂性KASP分子标记，可用于西瓜耐裂种质筛选和标记辅助育种，筛选获得的耐裂种质资源，可为耐裂西瓜新品种培育提供优质亲本材料。

关键词: 西瓜, 耐裂, KASP分子标记, 基因型, 种质资源, 果皮硬度, 果实性状, 大果型, 小果型