Seed dormancy mechanism and dormancy-breaking methods in wild raspberry (Rubus fraxinifolius Poir.)

Abstract

Raspberries are subtropical plants that contain high levels of vitamin C, antibacterial and anti-inflammatory. They can potentially be developed as horticultural and medicinal plants. Dormancy is a challenge in the cultivation of raspberries (Rubus fraxinifolius Poir.). This study was conducted as two separate experiments. The first experiment aimed to identify the dormancy mechanism of R. fraxinifolius seed. In a two-factor factorial design, the first factor was seed storage, as unstored and three-month-stored, and the second factor was chemical-immersed treatment consisting of control, H2SO4, acetone, GA3, KNO3, H 2SO4-GA3, acetone-GA3, H2SO4-KNO3, acetone-KNO3. The second experiment was aimed at determining dormancy-breaking methods for R. fraxinifolius seeds. In main plots were filter paper and cocopeat germination substrates. The subplots included control, immersed with distilled water, H2SO4, ultrafine bubble water, and temperature treatment at −80 °C, 50 °C, and 70 °C. The germination of unstored and three-month-stored seeds increased after H2SO4 treatment (36 to 82% and 82 to 94%, respectively). Seed germination increased after three months of storage. There was an increase in cytokinin hormone levels along with germination enhancement. The seeds went into physical dormancy because their seed coat was hard, and they went into physiological dormancy because of low cytokinin concentration. Stratification at 50 °C increased germination (78.5 to 93.0%), reduced dormancy intensity (15 to 6.5%), and increased the percentage of the speed of germination (1.99 to 3.12 %NS.day-1) on filter paper substrate.