Journal of Hunan Ecological Science

【Objective】In cucumber (Cucumis sativus L. ) breeding, both bitterness and hollow heart are important factors affecting commercial quality. This study focuses on developing molecular markers for the key genes regulating bitterness and hollow heart, on which two precise and efficient molecular breed- ing technology systems are established. 【Method】Firstly, the new Bt allele bt-2 which not causing bitter- ness under adverse conditions, and its related molecular markers were combined with Bi gene molecular markers for the prospective selection of cucumbers. Secondly, molecular markers were developed using SNP28756924 on the CsALMT2 gene, which leading to 14. 27% of the hollow fruit traits in 750 cucum- ber resequencing resources. KASP genotyping and field phenotype validation were then conducted. 【Re- sult】The high-throughput screening of molecular markers for bitter leaves and non-bitter fruits in cucum- bers has significantly improved the breeding efficiency of bitter-free cucumber strains, with a selection ac- curacy rate of 96. 87% . The verification results of the non-hollow molecular marker in the fruit are accu- rate, indicating that this marker can assist in the selection of hollow traits in cucumber fruit during the seedling stage. 【Conclusion】Two high-throughput molecular breeding systems were created for cucumber with bitter leaves and non-bitter fruits, and non-hollow fruits. Compared to traditional methods of detecting bitterness and hollowness, these two systems have the advantages of high accuracy, convenience, and high- throughput screening, accelerating the breeding process of bitter-free and non-hollow cucumbers.

cucumber; bitter leaves and non-bitter fruit; non-hollow fruit; molecular marker; high- throughput molecular breeding