Productivity of Zea mays L., in drought stress, inoculated with Bradyrhizobium sp. and Trichoderma harzianum

Abstract

A field experiment was developed under agricultural drought stress conditions to evaluate agroproductive variables of Zea mays L., to which inocula of Bradyrhizobium sp. and Trichoderma harzianum were applied. The inocula preparation and the inoculation of the plants were carried out according to recognized rules. A randomized block experimental design with seven treatments was used: 1) Bradyrhizobium sp. (Ho13), when seed germinates; 2) Trichoderma, when seed germinates (Trichoderma); 3) Bradyrhizobium sp. + Trichoderma, when seed germinates (Ho13 + Trichoderma); 4) Bradyrhizobium sp., when seed germinates+ Trichoderma at 15 d of sowing (Ho13 + Trich.15 d); 5) Trichoderma, when seed germinates + Bradyrhizobium sp. at 15 d of sowing (Trich. + Ho13.15d); 6) absolute control and 7) control fertilized with 150 kg N / ha and three replications. ANOVA analysis was performed. The differences between means were determined by LSD of Fisher. The values with digit count were transformed by √x. and the percentage data by 2arcosen√P. The dry weight of the aerial part, the efficiency index of the inoculation on the basis of the DWAP, stem length, the dry weight of corncob, the grain yield, the efficiency index of the inoculation on the basis of grain yield and the weight of 1000 grains (P1000G) were evaluated. The state of the agricultural drought was determined. In the weight of the corncob, the treatments inoculated when germinating the seed with Trichoderma (120.30 g) and Ho13 + Trichoderma (118.25 g), as well as with Trichoderma when germinating the seed + Ho13 at 15 d of sowing (119.90 g) (Trich. + Ho1315d) were superior to the rest of the treatments. The grain yield in the treatment inoculated with Ho13 (1.49 t/ha) and in the treatment inoculated with Trich. + Ho13.15d. (1.58 t/ha) exceeded the rest, except for the fertilized control. It is concluded that, in general, the productivity of the crop was increased when inoculated with the simple application of Bradyrhizobium sp. (Ho13) as combined with Trichoderma harzianum. The variables with the best response to the treatments inoculated were: dry weight of the corncob, stem length and grain yield. It was also observed that the fertilized treatment was inferior to the treatments inoculated in dry weight of the corncob and
weight of 1000 G. The treatments with higher results in the studied variables were Ho13 and Trichoderma + Ho13.15 d., recommended to apply in agricultural practice.
Key words: Bradyrhizobium, Trichoderma, agricultural drought, corn