The effect of seed priming and culture medium type on germination characteristics and quality of tomato seedlings (Lycopersicon esculentum)

Extended Abstract Introduction: Today, seed priming is widely used to improve seed germination in a wide range of plant species. As a result of seed pre-treatment, several molecular and biochemical changes occur, including increased macromolecule synthesis, enzyme activity and formation of different metabolites. Enzymatic and metabolic activities, synthesis of proteins in quantitative and qualitative terms, and respiratory activities and, the formation of ATP for the synthesis of macromolecules, membranes, and materials required for the cell wall are increased during and after seed preparation. The aim of this study was to investigate the effect of seed priming using some hormonal and nutritional treatments as well as the type of culture medium on germination characteristics and quality of Karun tomato seedlings. Materials and Methods: Two separate experiments were performed in two laboratory and pot stages in a completely randomized design with three replications. In the first experiment, the treatment used included seed priming at six levels (distilled water, 0.2 mM salicylic acid, 0.2 mM putrescine, 1.5% humic acid, 0.03% zinc sulfate, and 0.2 mM potassium nitrate). In the second experiment, the treatments used included the culture media type at six levels (coco peat, perlite, peat moss, 50% cocopeat + 50% perlite, 50% coco peat + 50% peat moss and 50% perlite + 50% peat-moss). Results: Analysis of variance showed that the effect of different levels of seed priming on seed germination percentage and root length was significant. The highest germination percentage was obtained six days after cultivation in salicylic acid treatment and was equal to 97.1%. The highest shoot dry weight in peat moss treatment was 1.7 g and the lowest shoot dry weight in perlite treatment was 0.3 g. The use of peat moss treatment in comparison with coco peat increased seedling length by 31.3%. Conclusion: Application of 0.2 mM salicylic acid, putrescine and humic acid improved seed germination compared with zinc sulfate and potassium nitrate. Also, application of peat moss and combined peat moss treatments in comparison with coco peat and perlite, increased the dry weight of roots and shoots of the plant as well as increasing the absorption of various elements.   Highlights: 1- Germination percentage and rate of tomato var. Karun significantly increased by salicylic acid and putrescine application (Karun cultivar) 2- Peat mass is the best culture medium for the commercial production of tomato seedlings var. Karun