Influence of seed pre-treatments on seed germination and early seedling developments of jujube (Ziziphus jujuba Mill.)

The Chinese jujube (Ziziphus jujuba Mill.) is among one of the oldest cultivated and utilized species in the fruit domestication history of China (7000 years). The Chinese jujube is still an underutilized fruit grown in the natural flora of Turkey. Until recently, the Chinese jujube was propagated primarily by root suckers, but more farmers in China now are carrying out grafting or budding onto seedling rootstocks to maintain the benefits of elite cultivars. Even if jujube seeds are viable, they are not able to germinate readily due to its hard and thick woody endocarp seed coat and dormancy. Thus, best conditions for seed germination that will yield in viable and well-developed seedling should be determined. This study was conducted to do so. In this research, the effects of various pre-treatments on jujube seeds native to the Mediterranean region of Turkey were studied to find out the best treatment for seed germination and early seedling development by means of plant heights, numbers of developed leaves, stem diameter and chlorophyll index values. Seeds, prior to sowing, were treated as follows: 1) control (C); 2) water treatment for 24 h (W+24 h); 3) hot water at 45°C for 1/2 h (HW+1/2 h); 4) acid treatment (A) for 30 min (1/2 h) then in water for 24 h (H₂SO₄+24 h W) (A); 5) scarification (S); 6) dehulled seeds (D); 7) dehulled damage membrane (DD). Pre-treated seeds were seeded in 70% peat + 15% perlite + 15% vermiculite (v:v:v) media that were kept in an acclimatization room at 70-75% relative humidity and 25°C temperature. Results indicated that the highest germination rate was obtained by treatment D (dehulled seeds; 63.33%) and followed by treatment S (scarification; 50.00%). The lowest germination was obtained from C (control; 3.33%). The other measurements on plant heights, numbers of developed leaves, stem diameter and chlorophyll index values were also found to be correspondingly higher in treatments D and S.