Nadia Massa
University of Piemonte Orientale, Italy
Title: Application of soil microorganisms for the improvement of bean seed yield and quality in conditions of reduced fertilization
Biography
Biography: Nadia Massa
Abstract
Legumes, like common bean, have the capacity to form symbiotic associations both with ancient arbuscular mycorrhizal fungi (AMF) and recent Rhizobium bacteria. Phaseolus vulgaris cv. Billò is an important and valuable crop widely cultivated in western Piedmont (Northern Italy). AMF are known to improve plant nutrition, in particular phosphorus acquisition, and hence fruit or seed quality. Rhizobium leguminosarum is a gram-negative bacterium, symbiont of various species of Fabaceae that is able to fix atmospheric nitrogen.
In this study, 15 different Rhizobium strains were isolated either from root nodules or soil, and characterized by a molecular and a biochemical point of view (phosphate solubilization, siderophore and IAA production, intrinsic antibiotic resistance). Among them, one strain was selected for a field trial. The aim of this work was to check, in field conditions, the possibility to improve bean seed yield and quality by means of inoculation with AMF and/or rhizobia under conditions of low fertilization. At harvesting, yield (pod and seed number and weight) and seed quality parameters (starch, protein, fiber and metal contents) were evaluated. Nodulation and mycorrhizal colonization of roots were assessed.
Yield parameters and fiber content were not influenced by the inoculation of microorganisms nor by the reduced fertilization, whilst protein concentration was significantly higher in the seeds of Rhizobium-inoculated plants in combination or not with AMF. Starch concentration significantly increased in the seeds of plants inoculated with rhizobia alone. Mg, K and Zn concentrations were positively affected by AMF, while Mn concentration was higher in the presence of Rhizobia. Ca and Fe levels did not show differences between the treatments.
In conclusion, an environment-friendly practice like low chemical fertilization can be associated to inoculation with soil microorganisms in order to improve bean seed quality, which can be differently affected by different combinations of inoculated microorganisms.