Evaluation of the film coating technique on tomato seeds with plant growth promoting Rhizobacteria (PGPR)

Project no. 28501 · Status: Kapanmış (Yayın bekleniyor) · 2023

Summary

Tomatoes are widely consumed worldwide, both as fresh and processed products. However, bacterial and fungal diseases encountered during tomato cultivation can negatively impact harvest yield. The high global demand for tomatoes necessitates an increase in yield. Various methods are employed to enhance the yield of tomato seeds, spanning from the seed stage to cultivation processes and continuing post-harvest. With the widespread adoption of good agricultural practices, the use of plant growth-promoting rhizobacteria (PGPR) has become an increasingly preferred method to boost crop yield. PGPRs protect plant roots, control diseases, and promote plant growth by acting effectively in the rhizosphere region. These bacteria offer several key benefits, such as producing growth-promoting phytohormones, solubilizing bound phosphate in the soil to make it available for plants, producing siderophores and antibiotics, inhibiting ethylene synthesis in plants, and enhancing systemic resistance against pathogens.PGPRs are used in microbial seed coating applications to increase tomato seed yield and protect against plant pathogens. In microbial seed coating, the use of biopolymers to support environmentally friendly practices and the preference for PGPRs constitute an important step toward sustainability. Such applications can also contribute to efforts aimed at reducing chemical input in agriculture.In our study, four different seeds from two tomato varieties (MSC-50-ETAE, MSC-50-Zenitt, SC-2121-ETAE, SC-2121-Zenitt) were used. Various optimizations were made for seed surface sterilization, coating material, and technique. Sterilized seeds were placed in the culture liquid of B. subtilis EGE B. 10+ with PGPR characteristics, shaken in an incubator, and then transferred to a solution of 2:1 sodium alginate and pectin, followed by further shaking in an incubator. The coated seeds were removed from the solution and sprayed with CaCl2 and propylene glycol before being left to dry. The same procedures were repeated for each tomato seed variety using B. subtilis EGE B. 16+, B. subtilis EGE B. B3P5, and combinations of these bacteria. The coated seeds' monthly germination rates under standard, drought, and salinity stress conditions were analyzed, along with the number of viable cells adhering to the seeds post-coating.In the thesis study conducted, successful results were obtained in terms of viable cell counts and germination percentages using the film coating method optimized for tomato seeds. The film coating applied to tomato seeds resulted in a spore count of 108 CFU/ml. This number decreased after the first month and then stabilized at 107 CFU/ml. When comparing the germination rates of seeds coated using the optimized method with uncoated seeds, an increase of 18-25% was observed. Additionally, measurements of root, hypocotyl, and epicotyl lengths post-germination showed an average increase of 65%. Although there was no significant difference in the adherence of B. subtilis strains to tomato seeds after the coating process, the SC-2121-Zenitt variety exhibited the highest microorganism adherence, with 4x107 CFU/ml. Upon reviewing the germination data, a statistically significant difference (p>0.05) was observed in the germination rate of the treated SC-2121-Zenitt seeds and the untreated MSC-50-ETAE seeds compared to the other seeds.

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