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The variables related to the agro-industrial quality in sugarcane considered as main tools are being used by producers to choose the varieties to be planted. In general, cultivars that present a better industrial yield for the manufacture of sugar and alcohol have great importance promoting crop sustainability. In this research, the objective was to evaluate the industrial quality of four sugarcane varieties during plant-cane, first and second ratoon crops. The experimental design was a randomized block, with four treatments and five replications. The varieties studied were RB867515, RB92579, SP813250 and VAT90212. In first and second ratoon cycles, the industrial quality of the four varieties was evaluated by determining the fiber content, apparent sucrose (Pol), purity, soluble solids (Brix) and total recoverable sugars (TRS). The results showed that varieties RB867515, RB92579, SP813250 and VAT90212 were similar for agro-industrial quality. In first ratoon crop, only fiber was same between varieties. The RB867515 evidenced larger soluble solids and recoverable sugars. In second ratoon crop, the RB92579 evidenced larger apparent sucrose (Pol) and soluble solids (Brix) and total recoverable sugars (TRS).

Diversidade de novas bactérias isoladas de nódulos de Recife, PE, Brazil; 3 Embrapa Semiárido, BR 428, Km 152, Petrolina, PE, Brazil, A B S T R A C TThis study aims to evaluate the phenotypical characteristics of bacterial isolates from mulungu (Erythrina velutina Willd.) nodules and determinate their Box-PCR fingerprinting. All bacteria were evaluated by the following phenotypic characteristics: growth rate, pH change, colony color and mucus production. The bacterial isolates able to re-nodulate the original host were also evaluated regarding its tolerance to increased salinity and different incubation temperatures, ability to growth using different carbon sources, intrinsic antibiotic resistance and "in vitro" auxin biosynthesis. The molecular fingerprints were set up using the Box-PCR technique and the isolates were clustered by their profiles. Among the 22 bacterial isolates obtained, eight were able to re-nodulate the original host. Among the nodule inducing isolates, some were tolerant to 1% of NaCl and 39° C and all of them metabolized the maltose, fructose, glucose, sucrose and arabinose, were resistant to rifampicin and produced auxin. The bacteria showed low genetic similarity among them and reference strains, which indicates the great genetic variability of the isolates. The results of this work are the first reports about the bacterial isolates able to nodulate this species. A more deep study of these bacteria may reveal the existence of isolates tolerant to environmental stresses and suitable as a future mulungu inoculant.Keywords: Biological nitrogen fixation, inoculant, rhizobia, tree legumes. R E S U M OO objetivo desse estudo foi avaliar as características fenotípicas dos isolados de nódulos de mulungu (Erythrina velutina Willd.) e determinar seu fingerprinting molecular por meio de Box-PCR. Todas as bactérias foram avaliadas pelas seguintes características fenotípicas: tempo de crescimento, alteração de pH, cor da colónia e produção de muco. As bactérias isoladas hábeis em renodular o hospedeiro original também foram avaliadas em relação à tolerância ao aumento da salinidade e da temperatura de incubação, capacidade de crescimento utilizando diferentes fontes de carbono, resistência intrínseca aos antibióticos e biossíntese de auxina "in vitro". O fingerprint molecular foi estabelecido usando a técnica Box-PCR e os isolados foram agrupados pelos perfis obtidos. Dos 22 isolados obtidos, oito foram hábeis em renodular o hospedeiro original. Entre eles, alguns foram tolerantes a 1% de NaCl e a 39° C e todos metabolizaram as fontes maltose, frutose, glicose, sacarose e arabinose, resistiram à rifampicina e produziram auxina. As bactérias isoladas mostraram baixa similaridade genética entre elas e as estirpes de referência, o que indica a grande variabilidade genética dos isolados. Os resultados deste trabalho constituem o primeiro relato sobre bactérias capazes de nodular esta espécie. O estudo mais aprofundado destas bactérias poderá revelar a existência de isolados tolerantes a stresses ambienta...

Erythrina velutina (“mulungu”) is a legume tree from Caatinga that associates with rhizobia but the diversity and symbiotic ability of “mulungu” rhizobia are poorly understood. The aim of this study was to characterize “mulungu” rhizobia from Caatinga. Bacteria were obteined from Serra Talhada and Caruaru in Caatinga under natural regeneration. The bacteria were evaluated to the amplification of nifH and nodC and to metabolic characteristics. Ten selected bacteria identified by 16S rRNA sequences. They were tested in vitro to NaCl and temperature tolerance, auxin production and calcium phosphate solubilization. The symbiotic ability were assessed in an greenhouse experiment. A total of 32 bacteria were obtained and 17 amplified both symbiotic genes. The bacteria showed a high variable metabolic profile. Bradyrhizobium (6), Rhizobium (3) and Paraburkholderia (1) were identified, differing from their geographic origin. The isolates grew up to 45 °C to 0.51 mol L−1 of NaCl. Bacteria which produced more auxin in the medium with l-tryptophan and two Rhizobium and one Bradyrhizobium were phosphate solubilizers. All bacteria nodulated and ESA 90 (Rhizobium sp.) plus ESA 96 (Paraburkholderia sp.) were more efficient symbiotically. Diverse and efficient rhizobia inhabit the soils of Caatinga dry forests, with the bacterial differentiation by the sampling sites.

Tropical dry forests have high diversity and plant abundance of potentially biologically nitrogen fixing (BNF) legume species, attributed to the ecological advantage of fixation. However, there are few estimates of N quantities annually fixed, hindering the understanding of factors that control BNF, like low phosphorus availability. The quantities of N fixed in three dry forest (caatinga) fragments of the semiarid Brazilian northeastern region with different legume plant proportions were determined and seedlings of Mimosa tenuiflora were grown with phosphorous fertilized soil from the fragments to verify if lack of fixation was due to the absence of rhizobia populations or P deficiency. The vegetation of all areas was dominated by legume plants, mainly potentially nodulating ones, despite the relatively high soil N availability. M. tenuiflora was the most abundant nodulating legume in all fragments, with annual leaf productions from 800 to 1400 kg ha-1. BNF amounts were low (1.4, 18 and 3.6 kg ha-1 year-1 in the mature caatinga of Petrolina and in the mature and regenerating caatingas of São João, respectively) considering the high proportions of potentially nodulating plants (33, 61 and 82% of total plant basal area), because 80, 10 and 70% of these plants were not fixing Electronic supplementary material The online version of this article (