Effect of rhizospheric microorganisms inoculum on sweet pep - per quality

The effect of the interaction among rhizospheric microorganisms and plant roots on plant physiology has been largely investigated and it is well known that they can improve plant nutrition, water efficiency, bioprotection against pathogens, and crop productivity. Several inocula composed of arbuscular mycorrhizal fungi and Plant Growth Promoting Rhizobacteria (PGPR) are commercially available. Most literature focused on the effects of commercial inocula on the productivity of maize and cereals; less abundant are studies on the quality of fruits and vegetables, such as apple, tomato, strawberry. Sweet pepper is an important horticultural crop in the world; it is as an important source of nutrients in the human diet and of antioxidant compounds, useful for prevention of health disease.We investigated the effects of a commercial rhizospheric inoculum on the productivity and on the quality of sweet pepper. Morphometric parameters, flavour profile, amount of vitamins, carotenoids and sugars were analysed in fruits. Plants of two local varieties (cv. Corno and cv. Cuneo) of sweet pepper, largely widespread in Italy, were cultivated in mesocosms. The addition to soil of a commercial inoculum containing mycorrhizal fungi and PGPR was compared to the traditional cultivation without inoculum; the yield and the quality of fruitswere analysed. Several significant effects of the inoculum in particular on fruit quality parameters were observed. The thickness of the pericarp was higher due to the inoculum in all varieties. The ascorbic acid content variation due to the inoculum was related to fruit colour (red or yellow) but not to the variety. Sugar content (wet weight) decreased in fruits of inoculated plants. The pH was also influenced by the inoculum.