Growth Effect of Isolates on Tomato in Greenhouse Production.

<b>Background and Objective:</b> Greenhouse tomato production faces various challenges, including soilborne diseases and nutrient limitations, which can impact plant growth and yield. Beneficial rhizobacteria, particularly <i>Pseudomonas</i> spp., have emerged as promising biological solutions for enhancing plant growth and resilience. This study investigates the growth-promoting effects of different <i>Pseudomonas</i> isolates taken from greenhouse soil in Kazakhstan on tomato (<i>Solanum lycopersicum</i> L.) under controlled conditions. <b>Materials and Methods:</b> Soil samples were collected from inside (No. 1) and outside (No. 2) of the greenhouse in the Turkestan Region. <i>Pseudomonas</i> isolates were obtained on selective <i>Pseudomonas</i> Agar medium. Four isolates (P1-1, P1-2, P1-3 and P1-4) were selected for further analysis. To evaluate their effects on plant growth, tomato seeds were inoculated with <i>Pseudomonas</i> suspensions at concentrations of 10⁴, 10⁶ and 10⁸ CFU/mL and incubated on Kovrovtsev's medium at 30°C for 14 days. Statistical analysis, including regression analysis, were performed using Excel software at 95% confidence level. <b>Results:</b> The highest root elongation and maximum germination rate were observed at 1×10⁶ and 1×10⁸ CFU/mL, respectively, suggesting these concentrations may be optimal for plant growth. Growth parameters exhibit a positive correlation with isolate concentration, but with varying degrees of response strength. <b>Conclusion:</b> The findings highlight the potential of <i>Pseudomonas</i> isolates as bioinoculants for sustainable greenhouse tomato cultivation, offering an eco-friendly alternative to chemical fertilizers and growth stimulants. Further research is needed to optimize application methods and assess the long-term effects on crop productivity and soil health.