Comparison of seed priming techniques with regards to germination and growth of watermelon seedlings in laboratory condition

Abstract

Seeds of watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai, cv. Crimson Sweet] were used to investigate the effects of different priming techniques on seed germination and early seedling growth. The seeds were soaked in solutions of 0.2% gibberellin (50 mg L^–1 gibberellic acid), 0.2% cytokinin (90 mg L^–1 kinetin), 0.2% potassium nitrate (2 g L^–1 KNO₃), 0.2% calcium nitrate [2 g L^–1 Ca(NO₃)₂] or water (hydropriming) for 6 h at 25°C. After drying, five replicates of 25 seeds were distributed in plastic boxes with blotter paper and kept into a seed germinator at 26°C for 12 days. The different priming treatments significantly affect the measurements of the seed germination and growth of watermelon seedlings. The germination of watermelon seeds ranged from 0 to 100%, and was significantly greater when seeds were subjected to priming with GA,sub>3, KNO₃, Ca(NO₃)₂ and water (control), and lower under cytokinin (CK) priming. The seed priming with 0.2% solution of CK resulted in 100% of abnormal seedlings, and therefore should not be used by watermelon growers. Seed priming with GA₃, KNO₃, Ca(NO₃)₂ and water (hydropriming) increased the shoot length, whereas GA₃, Ca(NO₃)₂ and water priming improved the radicle length, as well as shoot dry matter watermelon seedlings. The KNO₃ and water priming increased the root dry matter of watermelon seedlings. Seed priming with KNO₃ and Ca(NO₃)₂ improved the germination rate and seedling vigor index. The results of this study show that seed priming with GA₃, KNO₃, Ca(NO₃)₂ and water (hydropriming) may be useful tools due to their positive effects on germination percentage and growth characteristics of watermelon seedlings.

Keywords: Citrullus lanatus, cytokinin, gibberellin, hydropriming