Strategy to improve peanut development by application of biostimulant and inoculant under drought stress.

FURLAN, A., BIANUCCI, E.; SEQUEIRA, M.; GIORDANO, W.; CASTRO, S.

Lima

Congreso; XXVIII Reunión Latinoamericana de Rhizobiología; 2017

The symbiotic interaction between legumes and nitrogen-fixing bacteria is often affected by abiotic stresses, within which drought is of concern. Drought-stressed plants have an impaired growth and nodulation, accumulate osmoprotectants such as proline and show oxidative stress symptoms. Therefore, many efforts have been devoted to contribute to the improvement of inoculation practices and crop protection by biostimulant application. Thus, the objective of this work was to analyze the effect of the joint application of seed biostimulant and inoculant on growth and nodulation of peanut exposed to drought stress, evaluating the role of the aminoacid proline in the redox metabolism. The biostimulant used was a complex mixture of organic substances and micronutrients, including molybdenum and cobalt; the inoculants were two reference strains, Bradyrhizobium sp. SEMIA6144 and Bradyrhizobium sp. C-145; and the peanut cultivar Granoleico, the most used in Argentina. The results showed that the application of the biostimulant along with the inoculation improved plant growth upon exposure to drought, since promoted the development of an extended radical system that would be beneficial in the stress situation by increasing the exploration surface of water sources. The strain Bradyrhizobium sp. C-145 was more efficient in the nodulation process than Bradyrhizobium sp. SEMIA6144 and its efficiency was increased when the biostimulant was added. Drought stress induced oxidative damage in peanut plants, although those inoculated with Bradyrhizobium sp. C-145 and treated with the biostimulant did not present alterations. The biostimulant induced the higher production of proline, which would protect peanut plants from the oxidative stress generated upon drought stress in the peanut cultivar. Thus, the use of the Bradyrhizobium sp. C-145 strain along with the biostimulant is recommended for peanut cultivation in arid regions. Financed by SECYT-UNRC; FONCYT.