Elite Bradyrhizobium strains boost biological nitrogen fixation and peanut yield in tropical drylands.

Peanut (Arachis hypogaea L.) is an important crop for the family-based systems in the tropics, mainly in Brazil. In the Brazilian drylands, peanuts are cropped in low technological systems, and cheap and efficient technologies are needed to improve crop yield and sustainability. Despite this importance, few data are available on selecting efficient peanut rhizobia in experiments under different edaphoclimatic conditions. This work evaluated the agronomic efficiency and the biological nitrogen fixation (BNF) by two elite Bradyrhizobium strains under four different fields in the Brazilian semiarid region. We compared a new efficient strain Bradyrhizobium sp. ESA 123 with the reference strain B. elkanii SEMIA 6144, currently used in peanut rhizobial inoculants in Brazil. Besides the inoculated treatments, two uninoculated controls were assessed (with and without 80 kg ha-1 of N-urea). The BNF was estimated by the δ15N approach in three out of four field assays. BNF contribution was improved by inoculation of both Bradyrhizobium strains, ranging from 42 to 51% in Petrolina and 43 to 60% in Nossa Senhora da Glória. Peanuts' yields benefited from the inoculation of both strains and N fertilization in all four assays. Nevertheless, the results showed the efficiency of both strains under different edaphoclimatic conditions, indicating the native strain ESA 123 as a potential bacterium for recommendation as inoculants for peanuts in Brazil, mainly in drylands.

Chemical Composition of Essential Oil of Leaves from Lippia schaueriana Mart. Collected in the Caatinga Area.

Lippia schaueriana Mart. (Verbenaceae) is an endemic species of Caatinga with a restricted distribution to the states of Bahia and Pernambuco, which presents itself as a potential source of raw material for extraction of essential oil and exploitation by the chemical and pharmaceutical industries. Considering that there are no reports in the literature of research carried out with this species, this paper aimed to establish-for the first time-the chemical composition of its essential oil. The essential oil of the dry leaves at room temperature was obtained by hydrodistillation after 3 h of extraction and the phytochemical analyzes were done by gas chromatography coupled to mass spectrometry (GC/MS). The main compounds found in the oil of leaves were piperitone oxide (51.25%), caryophyllene (17.76%), limonene (8.06%), spathulenol (6.63%), and piperitone (2.90%). The piperitone oxide is a compound described in the literature that shows antinociceptive, cardiovascular, analgesic, and relaxing activities, as well as fungicidal and insecticidal effect, which gives it an interesting potential for the alternative control of agricultural pests.