Abstract

LOZANO-CONTRERAS, Mónica Guadalupe; RIVAS-PANTOJA, F  and  CASTILLO-HUCHIM, J. E. Growth of Brachiaria brizantha seedlings in response to the application of mycorrhizal fungi and diazotrophic bacteria. Pastos y Forrajes [online]. 2013, vol.36, n.2, pp.227-232. ISSN 0864-0394.

A study was conducted to evaluate the growth of seedlings of Insurgente pasture (Brachiaria brizantha), treated with mycorrhizal fungi and pseudomonads as simple or associated inocula. Under net house conditions the following treatments were evaluated: T1: Glomus mosseae strain 1; T2: G. mosseae strain 2; T3: G. mosseae strain 3; T4: Gigaspora albida strain 4; T5: Gigaspora sp. strain 5; T6: Glomus coremioides strain 6; T7: Rhizophagus intraradices strain INIFAP; T8: bacterial Pseudomonas sp. 2709 INIFAP; T9: mixture of T7 and T8; T10: mixture of T1 to T7; T11: mixture of T1 to T8; T12: control without inoculation and T13: control without inoculation, fertilized with the formula 120-80-00 of NPK. The quantified variables were: total (aerial and root) biomass production per plant (g DM/plant), root volume (cm³/plant), absolute leaf emergence rate (number of leaves week^-1), absolute growth rate in height (cm week^-1) and root length (cm plant^-1). The evaluations were conducted since seedling emergence started until they reached 54,6 cm of average height. The design was completely randomized, with 10 repetitions per treatment. The data were subject to a variance analysis through a general linear model, with bifactorial arrangement 13 (inoculants) x 2 (soil treatments). The plants inoculated with G. mosseae strain 3 and with the mixture of mycorrhizae and Pseudomonas sp. (T11) had higher total biomass production (P<0,05), as compared with B. brizantha Insurgente plants without inoculation and with those that were not inoculated and were treated with double nitrogen-phosphorus fertilization rate. The results showed the inoculum-host specificity in plants of B. brizantha pasture cv. Insurgente and proved the benefits of facultative mutualism for the growth of this forage species.

Keywords : Brachiaria brizantha; mycorrhizae; Pseudomonas.

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