Abstract:

Lettuce is an annual vegetable crop with an edible leaf and widely grown and consumed around the world. It is consumed in all seasons of the year because it can be grown in the open fields and greenhouses. However, to meet the fresh lettuce demand of the increasing world population, it has brought along the use of excessive synthetic fertilizers, which cause environmental pollution and are harmful to human health. Nowadays, by developing environmentally friendly agricultural techniques, alternative applications have gained momentum in order to minimize the use of chemical fertilizers. In our study, 13 strains of PGPR (Bacillus Subtilis RC631, RC67, RC11, B. megaterium RC34, RC33, B. pumilus RC356, Pseudomonas fluoresence RC77e, RC86, RC9, P. putida biotype B RC14, Pantoea agglomerans RC36, RC16 and Rodococcus erythropolis RC49) were used. Bacterial strains in groups of 5 (B1, B2, B3, B4, B5) were applied to lettuce seeds in 5 different combinations and their effects on seedling growth were investigated. The study was carried out in ESOGU Faculty of Agriculture, Department of Horticulture, and the “Sürpriz” curly leaf salad variety was used as plant material. PGPR applications significantly increased the seedling's leaf fresh weight, root length and fresh weight and root collar diameter compared to control applications, it was statistically determined that there is no effect on leaf number and dry weight and root dry weight. As a result, it was found that the use of a mixture of different PGPR strains as a biofertilizer had significant effects on the development of lettuce seedlings, it was concluded that the research should be done more comprehensively with different plant species, different application forms and doses.

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