Author(s)

Carlos Augusto Rocha de Moraes Rego^1*, Bruna Penha Costa¹, Marinez Carpiski Sampaio¹, Marcos Massuo Kashiwaqui¹, João Henrique Silva Caetano¹, Vandeir Francisco Guimarães¹, Juan López de Herrera², Pablo Wenderson Ribeiro Coutinho¹, Cláudio Yuji Tsutsumi¹, Maria Soraia Fortado Vera Cruz¹, Thatiane Nepomuceno Alves¹, Shirlene Souza Oliveira¹, Ana Carolina Pinguelli Ristau¹, Hannah Braz¹

¹Center of Agrarian Sciences, State University of Western Paraná, Marechal Candido Rondon, Brazil.
²University School of Agricultural Technical Engineering, Polytechnic University of Madrid, Madrid, Spain.

The objective of this work was to verify the responses in agronomic and physiological characters of lettuce seedlings when submitted to different doses of humic acids and the presence or absence of inoculation of the bacterium Azospirillum brasilense. The experiment was carried out at the Protected Cultivation Station and Biological Control Teacher Mário César Lopes, belonging to the Experimental Stations Nucleus of the State University of the West of Paraná. The experimental design was a randomized block design, in a 5 × 2 factorial scheme, with four repetitions, totaling 40 plots. The first factor consisted of five solutions containing humic acid (100%, 75%, 50%, 25% and 0%) and the second factor was the presence or absence of the diazotrophic bacterium Azospirillum brasilense obtained by commercial product. Germination tests were carried out in addition to the determination of agronomic characters such as the number of fully expanded leaves, plant height, stem diameter, main root length, shoot dry mass, root dry mass, total dry mass, and Dickson quality index. The association of diazotrophic bacteria and humic acids did not influence the emergency rate, mean emergence time, mean speed of emergency, emergence speed index, plant height, and root length of lettuce seedlings. The dilutions of humic acids, regardless of inoculation with bacteria diazotrophic favored the development of the number of leaves, stem diameter and Dickson quality index. Inoculation of lettuce seeds with diazotrophic bacteria associated with the addition of humic acids, favored the development of the dry mass of root and total dry matter.

Azospirillum brasilense, Humic Substances, Lactuca sativa L., Productive Characteristics

Rocha de Moraes Rego, C. , Costa, B. , Sampaio, M. , Kashiwaqui, M. , Silva Caetano, J. , Guimarães, V. , López de Herrera, J. , Ribeiro Coutinho, P. , Tsutsumi, C. , Vera Cruz, M. , Alves, T. , Oliveira, S. , Pinguelli Ristau, A. and Braz, H. (2018) Production of Lettuce Seedlings with Association of Diazotrophic Bacteria and Humic Acids. American Journal of Plant Sciences, 9, 946-957. doi: 10.4236/ajps.2018.95072.