Effect of Rhizobium Inoculation on Tomato (Solanum lycopersicum L.) Yield in Protected Crops

Beatriz Toledo Cabrera

doi:10.3390/iecag2021-09993

Abstract

The insufficient availability of nutrients in the soil and the non-use of biofertilizers as a strategy in the tomato nutrition process are factors that limit the yield of this crop. The objective of this research was to evaluate the effect of different Rhizobium strains on the yield of the Aegean hybrid tomato variety. The inoculation of the microorganisms was carried out at the time of sowing and transplantation, in a proportion of 10% with respect to the volume of the root ball. The experimental design was in randomized blocks, with four treatments and with four replications for each treatment: an uninoculated control and three levels of the inoculation factor with the strains of Rhizobium, Rhizobium etli CE-3, Rhizobium leguminosarum SCR; Rhizobium leguminosarum Semia-4088. The sampling was carried out in a zig zag pattern throughout the field and the following variables were evaluated: dry mass by plant organs, foliar NPK, growth indicators, productive indicators, crop yield, and economic evaluation. The results achieved showed a positive effect on the indicators evaluated in the plants inoculated with the Rhizobium strains with respect to the control without inoculation. With the inoculation of the Rhizobium etli CE-3 strain, the best results were obtained regarding tomato yield.

Highlights

The tomato (Solanum lycopersicum L.) is one of the most important and most demanded horticultural crops in the world due to its excellent nutritional properties and its role in the eating habits of a large part of the population, both for fresh consumption and industrial processing; its performance is limited by different factors, the most important being the inadequate use of chemical fertilizers and the insufficient availability of nutrients in the soil, mainly nitrogen, affecting the growth and production of this crop.Among the factors that influence the decrease in tomato crop production, the inappropriate use of chemical fertilizers is the one that most affects the growing deterioration of biodiversity and the microbial balance of the soil, whose damages are sometimes observed in the long term [1]
Among the described biochemical mechanisms exerted by (PGPR) that have beneficial effects on plants is the biological fixation of atmospheric nitrogen (FBN), carried out by symbiotic rhizobacteria such as Rhizobium sp. or other free-living species, such as Azotobacter sp. and Azospirillum sp., that have been used extensively as biofertilizers to improve the availability of nitrogen in vegetables such as tomato (Solanum lycopersicum L.), onion (Allium cepa L.), and lettuce (Lactuca sativa L.) [3–5]
The evaluated variables showed a greater increase in the average height and thickness of the plants inoculated with R. etli CE-3 and Rl-SCR compared to the other strain and the control treatment, at 25 and 75, there were no significant differences between the treatments or in the thickness of the stem during the first evaluation

Summary

Introduction

Among the factors that influence the decrease in tomato crop production, the inappropriate use of chemical fertilizers is the one that most affects the growing deterioration of biodiversity and the microbial balance of the soil, whose damages are sometimes observed in the long term [1] For this reason, it is currently necessary, as one of the most valuable elements to consider, to promote sustainable agriculture from the use of biofertilizers, which allows for the reduction of the use of chemical fertilizers and improve the absorption and availability of nutrients in the soil. Other mechanisms that promote plant growth include the solubilization of phosphorus (P), as well as the synthesis of phytohormones, vitamins, and enzymes, which reduce the incidence of diseases and pathogens and provide greater tolerance to abiotic stress, as well as the increased absorption of water and nutrients [2,6]

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Conclusion