Dormancy behaviour and effectiveness of dormancy breaking methods in cucumber seeds (Cucumis sativus)

This study aimed to examine the dormancy behaviour and effectiveness of various dormancy breaking treatments on cucumber seeds. Freshly harvested cucumber seeds of varieties CU-1047 and CU-1051 were extracted, dried and stored for eight weeks at ambient temperature. The stored seed lots were tested for seed germination once a week and hormone analysis (ABA, GA, zeatin and kinetin) every two weeks. In a second experiment, dormancy breaking methods using dry heat treatment (DHT) at 36, 50 or 80°C for various lengths of time. Chemical treatments were also tested, with a 24-hour soaking time using GA3, KNO3 or ultra-fine bubble (UFB) water. The results showed that the dormancy persistence in both varieties was three weeks after the seeds were harvested, by which time germination reached more than 85%. The decrease in ABA content during the storage period correlated with an increase in seed germination. The most effective methods of breaking dormancy were dry heat at 80°C for 24 hours (highest germination: 62%) and a DHT chamber (59%) compared with control (1%). An alternative method was soaking the seeds in 1% KNO3 followed by drying to the initial moisture content (55% germination). UFB water was not effective in breaking the dormancy of cucumber seeds.