Soaking time in sulfuric acid to overcome sweet potato seeds dormancy

Abstract

To increase genetic variability, sweet potato needs to be sexually propagated in breeding programs. However, its seeds have a hard and thick integument, requiring some dormancy breaking method. Chemical treatment of seeds allows greater efficiency of the relationship between seeds obtained in crosses and those that germinate, providing genotypes to be tested for their potential, aiming at developing a new commercial cultivar. Thus, the objective of this study was to identify the effects of immersion times of seeds in sulfuric acid (98%) on the germination and initial growth of sweet potato seedlings. The seeds were immersed for five different times: 0 (control), 20, 40, 60, and 80 min. The experiment was carried out in a completely randomized design with ten repetitions consisting of 25 seeds each experimental plot. The germination percentage, germination speed index (GSI), dry mass of whole seedlings, and length of the largest root and shoot of the seedlings were evaluated. The germination percentage and GSI increased with immersion time until 53.30 min, with maximum estimated values of 85.39 and 25.10%, respectively. For the parameters dry mass of whole seedlings, length of the largest root, and shoot length, increases were observed up to 55.00, 37.63, and 44.44 min, respectively. In conclusion, the immersion of sweet potato seeds in sulfuric acid (98%) for 53 min is ideal for breaking dormancy and providing better conditions for the initial development of seedlings.