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In sugarcane cultivation, agricultural mechanization causes soil compaction, with a consequent decrease in the yield and longevity of the sugarcane fields. Mechanized harvesting operations can promote soil compaction during the first plant cycle. The aim of this study was to identify the critical mechanized harvesting operation for soil compaction through the analysis of the field soil mechanical resistance to penetration, modelling the spatial distribution and quantifying the effects on the yield of the subsequent crop cycle. The study was conducted in an area covered by Latossolo Vermelho in the Brazilian Cerrado, and the experiment used a randomized block design with seven plots and three replicates. The plots were constructed based on the operating conditions of the following machinery: a track harvester; a tractor and three-axis trailer set; a combination of the track harvester, tractor and three-axis trailer; and maintenance, fire and convoy trucks. In addition, manual harvesting was evaluated as a reference for the soil structure and production potential. The pressures exerted on the soil by the machinery were estimated using Tyres-Tracks and Soil Compaction (TASC), and the impacts of the traffic were evaluated in two evaluation regions: the traffic lane and the planting row. The soil resistance to penetration (SRP) was measured with an automatic penetrometer. The measurements were recorded perpendicular to the traffic lane every 0.08 m at a horizontal distance of 1.52 m up to a depth of 0.50 m, with the water content in the soil profile close to the field capacity. Maps of the spatial variabilities in the SRP in the traffic lane and in the planting row were estimated via ordinary kriging and indicator kriging, respectively. The dissipation of the stresses exerted at the soil-wheel interface was confirmed by the spatial variability maps; these maps showed the high predictive capacity of the TASC tool. The fire truck generated the largest increase in the soil compaction in the traffic lane. Based on the analysis of the percentage of the affected soil profile area, the tractor and trailer dissipated the load to the restrictive values of the SRP both at depth and near the planting row. Consequently, a reduction in soil volume was observed but was not the physical limiting factor for crop development, and greater yield losses occurred in the subsequent cycle. For this reason, transportation operations (the tractor and trailer set) were considered the critical sugarcane harvesting operations; moreover, due to the combination of the track harvester, tractor and three-axis trailer, 60 % of the impacted area exhibited mechanical resistance to penetration exceeding 2.5 MPa and likely restricting the root development. In addition, support truck traffic could damage the soil structure. Thus, the machine traffic in sugarcane areas could exacerbate productivity losses caused by the soil compaction.

The identification of promising commercial varieties for irrigated crops in semiarid conditions based on characters of interest to sugarcane agro-industries is important, considering the search for high sugarcane yields to obtain sustainable crops. Thus, the objective of this work was to evaluate production components of agroindustrial interest of different sugarcane varieties grown under subsurface drip irrigation in the Semiarid region of Brazil, during two crop cycles. A randomized block experimental design was used, in an 8×2 factorial arrangement (varieties and cycles) with three replications. The sugarcane juice quality, sugar yield, and culm yield were evaluated in each cycle. Gross sugar percentage, sugarcane culm yield, juice apparent sucrose content, and juice purity were affected by the crop cycles. Soluble solids content presented strong significant correlation with most variables of agroindustrial interest. The path coefficient analysis showed that juice apparent sucrose content was the explanatory character with higher direct effect on soluble solids and that this variable presented high indirect effects on most explanatory variables. The sugarcane varieties RB72454 and Q124 are recommended for production managements with drip irrigation under semiarid conditions. Soluble solids content can be used as an alternative for direct selection of varieties with higher sugar yields in different cycles.

The identification of promising commercial varieties for irrigated crops in semiarid conditions based on characters of interest to sugarcane agro-industries is important, considering the search for high sugarcane yields to obtain sustainable crops. Thus, the objective of this work was to evaluate production components of agroindustrial interest of different sugarcane varieties grown under subsurface drip irrigation in the Semiarid region of Brazil, during two crop cycles. A randomized block experimental design was used, in an 8×2 factorial arrangement (varieties and cycles) with three replications. The sugarcane juice quality, sugar yield, and culm yield were evaluated in each cycle. Gross sugar percentage, sugarcane culm yield, juice apparent sucrose content, and juice purity were affected by the crop cycles. Soluble solids content presented strong significant correlation with most variables of agroindustrial interest. The path coefficient analysis showed that juice apparent sucrose content was the explanatory character with higher direct effect on soluble solids and that this variable presented high indirect effects on most explanatory variables. The sugarcane varieties RB72454 and Q124 are recommended for production managements with drip irrigation under semiarid conditions. Soluble solids content can be used as an alternative for direct selection of varieties with higher sugar yields in different cycles. [ABSTRACT FROM AUTHOR]

Sugarcane (Saccharum sp.) is potential as a biofuel and biomaterial source for its high cellulose content. Cellulose is the main constituent of the plant cell wall, as a linear chain arranged in a polysaccharide bundle, called cellulose microfibril. A gene named COBRA has been revealed to play role in the orientation of microfibril and cellulose crystallization. The COBRA gene in the Saccharum spp is under-explored. Therefore, the in silico study was conducted to explore the COBRA gene in Saccharum sp. By comparative genomics methods, the COBRA genes from Arabidopsis sp. (AtCOBLs) were compared to the Saccharum sp. (SoCOBLs). The conserved domain was then identified and the cluster system was constructed under a phylogenetic tree. Furthermore, each SoCOBLs protein was modelled to analyze its structure. According to the analysis, eleven of Saccharum sp. genomic scaffolds were successfully identified. Moreover, conserved domain identification resulted in nine SoCOBLs proteins. The phylogenetic tree showed two main clusters: I and II, differentiating those COBLs families based on the protein sequence, domain motif and amino acid properties. It leads to the variation of SoCOBLs protein structure as the results of the amino acid properties. Overall, the COBRA gene has been identified genomically in Saccharum sp. Yet, the function and tissue-specific expression are still unclear. It was predicted to act as the regulator of microfibril orientation and the cellulose synthesis process. Hence, further analyses by in vitro and in vivo are indispensable.

Sugarcane brown rust, caused by Puccinia melanocephala, is a severe foliar disease that occurs in almost all countries where sugarcane is grown. The main control strategy is the use of resistant cultivars. The aim of this work was to identify molecular markers linked to genomic regions associated with a novel brown rust resistance source in sugarcane. An F1 progeny of 300 clones was obtained from a cross between TUC 00–36 and RA 87–3, highly susceptible and highly resistant to brown rust, respectively. A total of 60 F1 clones with extreme phenotype, either highly susceptible or highly resistant to brown rust, were selected. This "pooled tail" population was tested for reactions to brown rust under natural infection in the field during two crop seasons and under artificial infection in the greenhouse. Whole‐genome profiling was performed by DArT‐seq technology. Phenotypic data under both conditions and 23,299 single‐nucleotide polymorphisms (SNPs) obtained from genotyping were analysed to identify markers linked to the resistance trait. Single mapping analyses and subsequent multiple regression showed that 34 SNP markers were significantly linked to resistance alleles. These SNPs jointly explained 69% and 66% of the total phenotypic variation (R2) observed for field and controlled conditions, respectively. The mapping of the 34 SNP sequences revealed that 19 markers aligned to the sugarcane genome, whereas 12 markers aligned to the sorghum genome, all grouped on chromosome 5 with some functional annotations related to vegetal defence response. These marker loci could contribute to the development of molecular tools for molecular marker‐assisted breeding. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanical harvesting operations of sugarcane are the main cause of soil compaction. • The tractor and trailer set is the critical operation. • A 47 % decrease in sugarcane yield was observed with mechanized operations. In sugarcane cultivation, agricultural mechanization causes soil compaction, with a consequent decrease in the yield and longevity of the sugarcane fields. Mechanized harvesting operations can promote soil compaction during the first plant cycle. The aim of this study was to identify the critical mechanized harvesting operation for soil compaction through the analysis of the field soil mechanical resistance to penetration, modelling the spatial distribution and quantifying the effects on the yield of the subsequent crop cycle. The study was conducted in an area covered by Latossolo Vermelho in the Brazilian Cerrado, and the experiment used a randomized block design with seven plots and three replicates. The plots were constructed based on the operating conditions of the following machinery: a track harvester; a tractor and three-axis trailer set; a combination of the track harvester, tractor and three-axis trailer; and maintenance, fire and convoy trucks. In addition, manual harvesting was evaluated as a reference for the soil structure and production potential. The pressures exerted on the soil by the machinery were estimated using Tyres-Tracks and Soil Compaction (TASC), and the impacts of the traffic were evaluated in two evaluation regions: the traffic lane and the planting row. The soil resistance to penetration (SRP) was measured with an automatic penetrometer. The measurements were recorded perpendicular to the traffic lane every 0.08 m at a horizontal distance of 1.52 m up to a depth of 0.50 m, with the water content in the soil profile close to the field capacity. Maps of the spatial variabilities in the SRP in the traffic lane and in the planting row were estimated via ordinary kriging and indicator kriging, respectively. The dissipation of the stresses exerted at the soil-wheel interface was confirmed by the spatial variability maps; these maps showed the high predictive capacity of the TASC tool. The fire truck generated the largest increase in the soil compaction in the traffic lane. Based on the analysis of the percentage of the affected soil profile area, the tractor and trailer dissipated the load to the restrictive values of the SRP both at depth and near the planting row. Consequently, a reduction in soil volume was observed but was not the physical limiting factor for crop development, and greater yield losses occurred in the subsequent cycle. For this reason, transportation operations (the tractor and trailer set) were considered the critical sugarcane harvesting operations; moreover, due to the combination of the track harvester, tractor and three-axis trailer, 60 % of the impacted area exhibited mechanical resistance to penetration exceeding 2.5 MPa and likely restricting the root development. In addition, support truck traffic could damage the soil structure. Thus, the machine traffic in sugarcane areas could exacerbate productivity losses caused by the soil compaction. [ABSTRACT FROM AUTHOR]

The sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) is a major pest of sugarcane (Saccharum sp.) (Glumiflorae: Poaceae) in Brazil and has been controlled efficiently with the parasitoid Cotesia flavipes (Cameron) (Hymenoptera: Braconidae). Addition of a silicon source to the soil induces resistance to insect pests in the host plant and can be integrated with other pest-management tactics such as biological control. This study evaluated the effects of silicon on the tritrophic interactions among sugarcane, D. saccharalis, and its natural enemy C. flavipes. Sugarcane varieties (one resistant and one susceptible to the sugarcane borer) cultivated with or without silicon constituted the four treatments. IACSP 96–2042 (susceptible variety) benefited from silicate addition as the length of tunnels bored by D. saccharalis was reduced by 43%. Tunnel length in the resistant variety (IACSP 96–3060) did not change with silicon application. The fresh mass and larval body size of the sugarcane borer were not affected by the treatments. Parasitism by C. flavipes on the sugarcane borer and the morphometric parameters of this parasitoid were not affected by silicon addition, nor were cane yield and quality parameters of the two sugarcane varieties. Treatment with silicon in the management of D. saccharalis was compatible with the parasitoid C. flavipes. This study constitutes the first field evaluation of the performance of C. flavipes combined with the effect of silicon as a resistance factor in D. saccharalis control in sugarcane. [ABSTRACT FROM AUTHOR]

Soil chiseling conducted only in the planting row is a minimal-disturbance soil management practice used for soil preparation in sugarcane plantations. However, the impacts of this practice on soil physical quality need to be evaluated through agricultural experimentation. The objective of this study was to evaluate the physical quality of an Ultisol submitted to chiseling as part of sugarcane management. The treatments consisted of soil chiseling only in the planting row (CPR) and chiseling in the total area of the soil (CTA). After soil preparation, the planting rows that were submitted to chiseling had better soil physical quality than did the area between the rows that did not receive chiseling in site preparation due to greater pore volume and lower PR and BD. However, the beneficial effect of chiseling did not persist due to subsequent soil reconsolidation, and disappeared soon after the planting of sugarcane, and remained this way up to the post-harvest period wherein the areas within (CPR) and between (CTA) the planting rows had equal soil physical quality. Because of this, the yield of stalks between the two treatments were similar, with an average yield of 110 t ha−1. [ABSTRACT FROM AUTHOR]

Endophytic bacteria with multifunctional characteristics can benefit plants through different mechanisms, as well as promoting growth in an efficient, low-cost and ecofriendly way. This study analyzed the potential of the multifunctional endophytic isolate Acinetobacter lwoffii Bac109 in promoting the early in vitro growth of sugarcane seedlings. The Bac109 strain showed potential to solubilize phosphate in a solid medium (solubilization index: 3.73). In addition, the bacterium was an efficient biocontrol agent against the phytopathogenic fungi Rhizoctonia sp., Fusarium oxysporum, Phoma sp. and Bipolaris papendorfii, showing a performance equal to or better than the commercial antifungal hygromycin B. An in vitroassay confirmed the biofilm production, which increased in the presence of sugarcane root extract. Additionally, A. lwoffiiBac109 showed a strong adhesion to the sugarcane roots. The inoculation of this bacterium in micropropagated sugarcane seedlings increased the shoot length (35 %) and regulated the nonphotochemical energy dissipation after 28 days of cultivation. At the end of the experiment, the bacterium showed a great potential for survival, with 5.72 × 107 CFU mL-1 recovered from the substrate, what is crucial for plant interaction. The results showed the potential of the biotechnology application for A. lwoffii Bac109 by evaluating multifunctional traits of plant growth promotion and by specific interactions with sugarcane, which may help to improve micropropagation protocols for this crop.

The present study aimed to evaluate the influence of Gluconacetobacter diazotrophicus (PAL5), Herbaspirillum seropedicae (HRC54) and Herbaspirillum rubrisubalbicans (HCC103) on seedling vigor, plant-crop productivity and potential to control the sugarcane Ratoon Stunting Disease (RSD) caused by Leifsonia xyli subsp. xyli (Lxx). Micropropagated seedlings (variety Co 421) were inoculated with endophytic diazotrophic bacteria and transplanted to the nursery. Lxx was inoculated in seedlings 80 days before field planting (seven months) by pruning the basal leaves with scissors pre-immersed in contaminated sap. To estimate diazotrophic bacteria's population density, shoot and root samples of seedlings transplanted to the nursery were collected at 42 and 86 days after inoculation. Agronomic characteristics of sugarcane plants were evaluated at harvest (16 months). In general, there was a population reduction of the bacterial endophytes after 86 days, compared to 42 days after inoculation. G. diazotrophicus provided greater gains in tons of cane per hectare (TCH) (68.6%) and tons of Brix per hectare (59.1%) than the other treatments. Plants inoculated with diazotrophic bacteria and challenged with the pathogen (Lxx) showed a high incidence of Lxx seropositive in the stalks. However, an increase in yield of 18.83 and 19.09 TCH was noticed, respectively, related to control and Lxx inoculated treatment in the first harvest (or growing season). The treatment with H. rubrisubalbicans alone showed a low incidence of Lxx and positive agronomic yield performance, suggesting some effect on the xylem pathogen colonization for the variety Co 421. [ABSTRACT FROM AUTHOR]

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ABSTRACT Little is known about the interaction between the inoculation of diazotrophic bacteria, the variety, and the substrate used in inoculated sugarcane seedling production. Bearing this in mind, the aim of this study was to evaluate the effects of diazotrophic bacteria inoculation, four sugarcane varieties and four different substrates on the growth and nitrogen accumulation of sugarcane seedlings. Parameters related to sprouting, height, and root growth, as well as nitrogen accumulation, were evaluated. The results indicate that inoculating sugarcane seedlings belonging to the following varieties: RB867515, RB92579, RB966928 and RB975932 with bacteria may increase sprouting speed index, height, root length, fresh and dry matter weight, as well as nitrogen accumulation, which has resulted in a more uniform stem diameter. However, the responses to inoculation differ from variety to variety and are also dependent on the substrate used with better results observed in the commercial substrate and the substrate mixtures containing a higher proportion of organic compost. Understanding the interaction between the variety and the substrate with the bacterial inoculation is essential to the success of the production of inoculated sugarcane seedlings.

Polynomial regression analysis is a powerful statistical tool used to describe non-linear relationships. The goodness-of-fit of this model is assessed by evaluating the coefficient of determination (R2). An R2 value closer to 1 is indicative of a strong correlation between the two under consideration. While polynomial regression analysis has been widely used in studies of plant stress responses to stress, to the best of our knowledge, this represents the first report on the application of this method to study the response of sugarcane plants to salt stress in Temporary Immersion Bioreactors (TIBs). In this context, sugarcane plants were exposed to salt stress while undergoing multiplication in TIBs. At the end of the multiplication cycle, the levels of biochemical metabolites (i.e. chlorophylls, carotenoids, phenolics and aldehydes) were evaluated. Polynomial regression analysis was subsequently used to elucidate the relationships between shoots multiplied under high salt stress conditions and consequent metabolite levels. The results indicated that the levels of chlorophyll a had a strong positive relationship (in mathematical terms) with shoot multiplication rate (R2 = 0.7063) with a corresponding high determination coefficient. In contrast, shoot multiplication rate was decreased in response to increased levels of carotenoids, soluble phenolics in shoots, and other aldehydes. Changes in levels of chlorophyll b, cell wall-linked phenolics, soluble phenolics excreted to the culture medium and malondialdehyde did not seem to (mathematically) influence sugarcane shoot multiplication in TIBs under salinity stress. The results from the present investigation provides evidence for the application of polynomial regression analysis as a tool to elucidate relationships between plant metabolites as markers for stress and shoot multiplication (as an indicator of growth) in in vitro systems. It is recommended that this statistical tool would be useful in an overall in vitro screening approach to investigate the stress response of other plant species in similar systems. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the chemical and physical/hydraulic properties of sugarcane bagasse and filter cake substrates in different compositions and proportions with sand and subsoil, as well as their use in the development of pre-sprouted seedlings (PSS) of sugarcane. The treatments were set up in a 5 × 5 factorial completely randomized design, with five proportions [(0, 0.25, 0.5, 0.75 and 1.00, on a volumetric basis (v/v)] of bagasse or cake in five compositions with sand or subsoil [Bagasse (Sand), Bagasse (Subsoil), Bagasse (Cake), Cake (Subsoil) and Cake (Sand)], totaling 25 treatments with three replications. As a reference to the formulated substrates, we used the commercial substrate Trimix®. The chemical (pH and electrical conductivity) and physical (density, total porosity, aeration space, water holding capacity and particle size) properties were evaluated for the substrate characterization and the agronomic and productive variables for the characterization of PSS growth. The by-products, namely filter cake and sugarcane bagasse, recommended in the production of substrates can be used in the production of pre-sprouted seedlings of sugarcane from individualized buds. Equivalent volumetric proportions of cake and bagasse at 50% of each promoted growth and biomass production of pre-sprouted seedlings of sugarcane. [ABSTRACT FROM AUTHOR]

Aims: We examined the influence of inoculation with five species/strains of diazotrophic bacteria on the modulation of two enzymes involved in the assimilation of N and on the soluble N fractions in the sugarcane varieties RB867515 (adapted for low fertility soils) and IACSP95-5000 (adapted for medium to high fertility soils) under high- (3 mM) and low (0.3 mM)-N conditions in hydroponic cultivation for 59 days. Methods: The sugarcane plants were produced in three steps to obtain the hydroponic cultivation: the supply of 3 mM N for 30 days (first harvest), N depletion for 72 h (second harvest), and cultivation in high- and low-N conditions over 26 days (final harvest). Inoculation was performed by immersion of the minisetts in a diluted solution of five diazotrophic bacteria. After the final harvest, plants were divided into roots and shoots to assess their dry weight and N, P, and K accumulation. Results: The variety played an important role in the interaction with diazotrophs, each showing distinct behavior in the activity of their N-assimilation enzymes. The nitrate reductase activity (NRa—EC 1.7.1.1) was increased in var. RB867515 by 26% in the shoots and by 48% in the roots after 72 h under N depletion, while var. IACSP95-5000 showed a reduced enzymatic activity in the roots (by 62%) but not in the shoots. Under high-N conditions, the inoculated IACSP95-5000 plants showed 31% higher glutamine synthetase activity (GSa—EC 6.31.2) compared with 19% in RB867515. Under low-N conditions, the GSas were 21% and 16% higher in the inoculated RB867515 and IACSP95-5000 plants, respectively, compared with that of the control. The content of nitrogen in the form of nitrate (N-nitrate) confirmed these varietal differences, but the soluble sugar content did not. Conclusions: The varieties utilized N sources differently, and inoculation modified the activity of two N-assimilation enzymes as well as the biomass accumulation, with the highest improvement seen in the low fertility-adapted variety RB867515; it showed a greater response to inoculation compared with that of the high fertility-adapted variety IACSP95-5000, with an increase in biomass and nutrient accumulation (N, P, K), especially when cultivated under low-N conditions. This suggests that the best response to inoculation with diazotrophs will be achieved using low fertility-adapted sugarcane varieties under low-N conditions. [ABSTRACT FROM AUTHOR]

In a site with a Cfa-type climate in southern Brazil, the water requirements and restrictions for the cultivation of sugar cane (Saccharum spp.), in plant and soca (second cut) were characterized. Water availability was calculated based on the daily water balance and evapotranspiration was estimated using the Penman-Monteith method. The thermal and water requirements of sugarcane were calculated taking as reference the agroecological zoning in the state of Paraná, Brazil. Water requirement index did not show limiting factors for the development of the crop both in plant and soca. Water deficit was the most important agroclimatic risk factor. In Paranavaí-PR, Brazil, sugarcane is a safe crop, with possibilities of saving water in the development stage (phase II), with frequent additional irrigation needs of 508.8 mm/crop cycle for plant and 486.5 mm/sugarcane cycle for soca. [ABSTRACT FROM AUTHOR]

N fertilizers make the total cost of production of biofuels, sugar and bioelectricity expensive in the sugar-energy industry. Microbes could replace N fertilizers in the nutritional management of sugarcane crop by capturing N2 from the atmosphere. We accordingly conducted this scientific study to investigate the response of sugarcane crop to Azospirillum brasilense. We tested the strain Az-V5 at the doses of 0, 50, 100, 200 and 400 mL ha−1, by spraying it into the planting furrow, 7, 14 and 21 days after crop planting into 20-l pots filled with sieved Rhodic Hapludox, with a loamy texture. In order to examine biologically modulated morphological changes in the host plant material, namely sugarcane variety 'RB86-7515,' we harvested and then assessed 90-day-old plants for plant height, stalk diameter, number of tillers, number of leaves, leaf area, tiller length, dry matter of shoots and root dry matter. Sugarcane plants treated with the bioagent 14 and 21 days after crop planting had lower mean values of plant height, number of leaves, leaf area, dry matter of shoots and root dry matter. Therefore, applying A. brasilense into the planting furrow, instead of spraying it on sugarcane leaves, could protect it for a longer period from biotic and abiotic factors influencing cell viability, root colonization and ultimately symbiosis. The conclusion is, therefore, application of A. brasilense into planting furrow is the best environmentally friendly and low-cost strategy to promote growth and development in sugarcane plants at the beginning of their life cycle. [ABSTRACT FROM AUTHOR]

The present study aimed to select efficient arbuscular mycorrhizal fungi (AMF) for sugarcane growth and P nutrition in four soils that spontaneously contained dark septate endophytes (DSE). The effect of nine AMF isolates was evaluated individually in sugarcane presprouted seedlings (SP81-3250) grown under greenhouse conditions for a 120-day period. The isolates that stimulated plant growth in the soils with low P availability were Acaulospora colombiana (ACOL), Claroideoglomus etunicatum (CETU), Gigaspora margarita (GMAR), Rhizophagus clarus (RCLA) and Scutellospora calospora (SCAL). Compared to the Yellow Argisol, which had the highest P level, the Red-Yellow Argisol, with an intermediate P content, increased plant height. Compared to the other treatments, inoculation with ACOL, RCLA, and SCAL resulted in higher foliar P content in plants grown in soils with high to intermediate P levels. Root colonization by AMF and DSE was verified in the plants, with the coexistence of both fungal groups in the same plant and/or root fragment. However, AMF colonization was low compared to DSE colonization. The cooccurrence of DSE and AMF was higher in the plants inoculated with ACOL, RCLA, SCAL, and Dentiscutata heterogama. ACOL, CETU, GMAR, RCLA, and SCAL are AMF isolates that have the potential to establish a mycorrhizal inoculant for sugarcane that would be effective in several soils. [ABSTRACT FROM AUTHOR]

The present study aimed to select efficient arbuscular mycorrhizal fungi (AMF) for sugarcane growth and P nutrition in four soils that spontaneously contained dark septate endophytes (DSE). The effect of nine AMF isolates was evaluated individually in sugarcane presprouted seedlings (SP81-3250) grown under greenhouse conditions for a 120-day period. The isolates that stimulated plant growth in the soils with low P availability were Acaulospora colombiana (ACOL), Claroideoglomus etunicatum (CETU), Gigaspora margarita (GMAR), Rhizophagus clarus (RCLA) and Scutellospora calospora (SCAL). Compared to the Yellow Argisol, which had the highest P level, the Red-Yellow Argisol, with an intermediate P content, increased plant height. Compared to the other treatments, inoculation with ACOL, RCLA, and SCAL resulted in higher foliar P content in plants grown in soils with high to intermediate P levels. Root colonization by AMF and DSE was verified in the plants, with the coexistence of both fungal groups in the same plant and/or root fragment. However, AMF colonization was low compared to DSE colonization. The cooccurrence of DSE and AMF was higher in the plants inoculated with ACOL, RCLA, SCAL, and Dentiscutata heterogama. ACOL, CETU, GMAR, RCLA, and SCAL are AMF isolates that have the potential to establish a mycorrhizal inoculant for sugarcane that would be effective in several soils.

Few studies have evaluated endophytic bacteria in relation to plant growth promotion, nitrogen uptake and biological control. The aim of this study was to molecularly and physiologically characterize thirteen endophytic bacteria strains, evaluate their biological control properties and their ability to promote plant growth and plant N nutrition. All the strains produced indole acetic acid and promoted increase of plant biomass, N accumulative amount and N-use efficiency index. None of the strains carries the nifH gene. Four strains stimulated plant nitrate reductase activity, four solubilized phosphate, nine produced siderophores and none produced HCN. Seven strains inhibited Bipolaris sacchari growth and one was antagonistic to Ceratocystis paradoxa. The pathogens were inhibited by the production of diffusible and volatile metabolites by the bacterial strains. Moreover, this is the first study to demonstrate the effect of Delftia acidovorans on sugarcane plant growth, nitrogen metabolism improvement and antagonism to B. sacchari. The most efficient strains in promoting plant growth and exhibiting antagonistic activities towards fungal pathogens were Herbaspirillum frinsingense (IAC-BECa-152) and three Pantoea dispersa strains (IAC-BECa-128, IAC-BECa-129, and IAC-BECa-132). These bacteria show potential to be used as inoculants for sustainable agricultural management, mainly at the seedling production phase. [ABSTRACT FROM AUTHOR]

Highlights • Sprouting of sugarcane can be enhanced by inoculation with diazotrophs. • Nutrient cycling is dependent on sugarcane variety and strain used. • Root architecture is modified by the inoculation influencing nutrient acquisition. • Inoculation did not increase the proportion of atmospheric nitrogen uptake over the first 60 days. Abstract Renovation of Brazilian sugarcane plantations using the pre-sprouted seedling technique (PSS) was undertaken to increase sanitation and productivity while reducing the cost of sugarcane planting. The objective of this study was to evaluate growth, nutrient acquisition, and contribution of biological nitrogen fixation (BNF) in two sugarcane cultivars RB867515 and IACSP95-5000, inoculated with five strains/species of diazotrophic bacteria, applied together and individually, for 60 days during growth. The cultivars were grown in a greenhouse in boxes filled with a sterile substrate followed by growth in tubes filled with a commercial substrate in the second phase; finally the plants were transferred to pots containing soil enriched with 15N and grown outdoors. The treatments used were control (no inoculation); mixed inoculation with the five strains, Gluconacetobacter diazotrophicus (PAL5T), Herbaspirillum rubrisubalbicans (HCC103), Herbaspirillum seropedicae (HRC54), Nitrospirillum amazonense (CBAmC) and Paraburkholderia tropica (PPe4T); and individual inoculation with each strain. Increases of up to 50% in the root dry mass was observed following mixed inoculation of the seedlings in the germination phase, with a significant increase in root initiation, volume, and area, especially of the fine roots. Inoculation of seedlings of both cultivars led to increased biomass in tubes of non-sterile substrate. In soil, a higher nitrogen accumulation was also observed in the cvar. IACSP95-5000 in all treatments except plants inoculated with N. amazonense. For the cvar. RB867515 shoots, the opposite was observed were the highest N accumulation was observed for N. amazonense , H. seropedicae followed by the mixture. In this experiment using soil labelled with 15N there was a response on N uptake caused by all bacteria used in one cvar but only by 2 of the 5 strains in other cvar. Using the 15N enrichment of the plants the results showed that the control and inoculated plants all derived 60–70% of N from the atmosphere, and inoculation had no effect on BNF contribution. For P and K levels, RB867515 showed no effect of inoculation, but the other cvar. did respond to inoculation. [ABSTRACT FROM AUTHOR]

Beneficial plant–microbe interactions lead to physiological and biochemical changes that may result in plant-growth promotion. This study evaluated the effect of the interaction between sugarcane and endophytic bacterial strains on plant physiological and biochemical responses under two levels of nitrogen (N) fertilization. Six strains of endophytic bacteria, previously selected as plant growth-promoting bacteria (PGPB), were used to inoculate sugarcane mini stalks, with and without N fertilization. After 45 days, biomass production; shoot nutrient concentrations; foliar polyamine and free amino acid profiles; activities of nitrate reductase and glutamine synthase; and the relative transcript levels of the GS1, GS2, and SHR5 genes in sugarcane leaves were determined. All six endophytic strains promoted sugarcane growth, increasing shoot and root biomass, plant nutritional status, and the use efficiency of most nutrients. The inoculation-induced changes at the biochemical level altered the foliar free amino acid and polyamine profiles, mainly regarding the relative concentrations of citrulline, putrescine, glycine, alanine, glutamate, glutamine, proline, and aspartate. The transcription of GS1, GS2, and SHR5 was higher in the N fertilized seedlings, and almost not altered by endophytic bacterial strains. The endophytic strains promoted sugarcane seedlings growth mainly by improving nutrient efficiency. This improvement could not be explained by their ability to induce the production of amino acid and polyamine composts, or GS1, GS2, and SHR5, showing that complex interactions may be associated with enhancement of the sugarcane seedlings’ performance by endophytic bacteria. The strains demonstrated biotechnological potential for sugarcane seedling production.

The aim of this paper was to determine growth indicators in a 48-clone sugar cane population, with promising phenotypical features for forage production. The following indicators were assessed: leaf area (A), leaf area index (LA1); leaf area ratio (LAR); specific leaf area (SLA); leaf weight ratio (LWR); crop growth rate (CGR); net assimilation rate (NAR); relative growth rate in weight (RGR); biomass production speed (G); leaf area duration (LAD); and biomass duration (Z), monthly (187 - 370 days). The minimum, the mean, the maximum values, and the population variance were determined for all cutting ages and the variables assessed. The results achieved have provided quantitative values that can be used as reference for selection and assessment of forage genotypes for ruminant nutrition.

Dark septate endophytes (DSEs) constitute a polyphyletic group within the Ascomycota, with global distribution and a wide range of host plant species. The present study evaluated the diversity of DSE in sugarcane roots of the varieties RB867515, RB966928, and RB92579, and four varieties of not commercialized energy cane. A total of 16 DSE strains were isolated, mostly from the varieties RB966928 and RB867515, with six and five isolates, respectively. Just one of the four energy cane varieties had fungi with DSE appearance. The analyses of the DNA sequences from the internal transcribed spacer (ITS) and the large subunit (LSU), in association with the micromorphology of the isolates, allowed the differentiation of the 16 isolates in at least five species, within the families Periconiaceae, Pleosporaceae, Lentitheciaceae, Vibrisseaceae, and Apiosporaceae and the orders Pleosporales, Helotiales, and Xylariales. The order Pleosporales represented 80% of the isolates, and the species Periconia macrospinosa, with six isolates, accounted for the highest isolation frequency. The results confirm the natural occurrence of the DSE symbiosis in sugarcane varieties and the generalist character of these fungi as some of the detected species have already been reported associated with other host plants, ecosystems, and regions of the world.

Drought, heat, and salinity, as well as pests, are stressing agents, which have impressively declined the productivity and quality of sugarcane crop in harsh environments. Our study aimed to examine the effect of various chemical ripeners as alternatives to enhancing the reactiveness of the enzymatic antioxidant system of sugarcane crop. The field experiment consisted of spraying the ingredients, ethephon, ethyl-trinexapac, glyphosate, carboxylic compounds (MTD) and methyl-sulfumeturon on the Brazilian commercial varieties, SP80-1842 and SP80-3280, before flowering stage. The enzymatic assay comprised the monitoring of the rate of degradation of free radical by ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) in the extract from leaves of 11-month-old plants. Spraying glyphosate at 0.15 L ha−1 with MTD at 1.00 L ha−1 provided the highest activity of CAT, 0.65 µmol H2O2 min−1 mg−1 protein, in variety SP80-1842 Spraying glyphosate at 0.15 L ha−1 with ethephon at 0.33 L ha−1 caused the highest activity of APX, 1.70 nmol ascorbate min−1 mg−1 protein, in variety SP80-3280. The conclusion is, therefore, that mixtures of glyphosate with the insecticide/acaricide, MTD, and with the synthetic ethylene-releasing product, ethephon could help sugarcane crop grow adequately under uncontrollable or unpredictable agroecosystems like marginal lands.

RESUMO A cana-de-açúcar é uma cultura de grande destaque na economia, em razão da produção de açúcar, etanol e energia. Tecnologias que possam contribuir para o aumento da produtividade e qualidade da cultura com mínimos danos ao meio ambiente são necessárias. Objetivou-se avaliar a produção de ácido indol acético de cinco estirpes de bactérias diazotróficas e o efeito da inoculação delas na brotação de duas variedades de cana-de-açúcar, RB867515 e IACSP95-5000. A produção de auxina foi determinada pelo teste colorimétrico, usando o reagente de Salkowski. Para avaliar a germinação, foi conduzido um experimento em casa de vegetação, utilizando-se delineamento experimental em blocos ao acaso com quatro repetições e sete tratamentos: controle não inoculado; inoculação mista com as cinco estirpes e inoculação individual com Gluconacetobacter diazotrophicus (Gd) estirpe BR11281T(PAL-5T), Herbaspirillum seropedicae (Hs - BR11335 = HRC54), Herbaspirillum rubrisubalbicans (Hr - BR11504 = HCC103), Burkholderia tropica (Bt - BR11366T = PPe 8 T) e Azospirillum amazonense (Aa - BR11145 = CBAMc). As bactérias mais eficientes na produção de auxina foram Hs e Hr, declinando 48 h após o crescimento. Hr, Aa e Bt aumentaram o índice de velocidade de germinação e o número de brotações nas duas variedades. Na var. RB867515, a velocidade de germinação ainda foi positivamente influenciada pela inoculação mista, sendo o mesmo observado pela inoculação de Gd na var. IACSP95-5000.

The evaluation of performance stability and high yields is essential for yield trials in different environments. This study was carried out to identifysugarcane genotypesthat have both a high mean cane yield, mesured in tons of cane per hectare (TCH), and stability across seven different environments, using 11 non-parametric statistical methods: Si(1), Si(2), Si(3), Si(6), NPI(1), NPI(2), NPI(3), NPI(4), RS, TOP and DE. The data came from acane yield of 20 genotypes, as measured at seven locations over three crop-years in the sugarcane regional trials of the Instituto Nacional de Investigaciones Agrícolas (INIA) of Venezuela. The genotypes V99-213, V99-236 and V00-50 showed promising yields and stability according to all of the non-parametric statistics. The TCH presented a positive association with the TOP, NPI(2), NPI(3) and Si(6) statistics. The analysis distinguished two groups of statistics using a principal component analysis (PCA). The first group (G1) was composed of the TOP, NPI(4), NPI(2), NPI(3), Si(3) and Si(6) statistics, which were located under the concept of dynamic or agronomic stability because they are associated with yield. The other group (G2) was composed of the NPI(1), Si(1), Si(2), DE and RS statistics, which fell within the static or biological stability concept.

The aim of this study was to assess the efficiency of the simulated individual BLUP (BLUPIS) method in selecting genotypes within full-sib families of sugarcane in ratoon stage, through comparison with selection using the individual BLUP method. The optimal number of genotypes to be selected in the best families were established for mean stems mass, total soluble solids assay (BRIX), ton of stalks per hectare, and BRIX tons per hectare traits. Seventeen full-sib families were assessed in the Centre for Experimentation in Sugarcane, located in Oratórios, MG, Brazil. Mixed model methodology was used to predict the genotypic effects of each family and the genotypic values of each individual within family. BLUPIS method is efficient for individual selection. The optimal number of genotypes to be selected in the best family for obtaining higher efficiency of the BLUPIS method is 100 in the majority of cases.

The sugarcane is one of the main crops produced in Brazil and is cultivated since the colonial Brazil Times. Soil management in the culture of sugarcane has undergone changes over time, applying new techniques of management and conservation of soil, taking advantage of systematic way the waste from the manufacture of alcohol and sugar, minimizing damage to environment. This aimed to evaluate the chemical attributes of the soil cultivated with sugarcane certified organic with and without soil disturbance, organic certification, conventional with and without straw burning and a remaining area of Cerrado in Goiatuba, Goiás, Brazil. Soil samples were collected in September 2009 in the depths of 0-10 cm and 10-20 cm for chemical analysis. The results were analyzed descriptively by estimating the mean, standard error of the mean and also by means of multivariate analysis, estimating the Euclidean average distance between the treatments with complete connection. There forming groups among the organic cultivation without soil disturbance and the remaining area of Cerrado in the depth 0-10 cm indicating proximity between the evaluated attributes. The organic cultivation without soil disturbance presents phosphorus and potassium far superior to other managements. The results underscore the importance of greater supply of organic waste for improved chemical attributes and maintenance of soil quality. [ABSTRACT FROM AUTHOR]

This work aims to know thiamine response as a growth promoter in sugarcane varieties. A completely randomized experimental was installed and designed in a double factorial scheme at 3x4 levels, in which the first factor consists of a variety of sugarcane: RB86-7515; RB96-6928 and CTC-4; the second factor was thiamine doses in five levels: zero mg L-1; 100 mg L-1; 200 mg L-1; 400 mg L-1 and 800 mgL-1; fifteen treatments were made with five replications, 75 plots in total. Forty five days after planting the following variables were determined: ESI - emergence speed index; ALA - average leaf area; APL - aerial part length; DMAP - dry mass of aerial part; DMR - dry mass of root; XD - leaf xylem vessel diameter and PD - leaf phloem vessel diameter. It is recommended doses of 400 mg L-1 Thiamine use as a promoter of growth in varieties RB86-7515; RB96-9628 and CTC-4 of sugarcane. Emergence speed index and diameter of xylem vases of leafs in CTC-4 varieties showed a negative response to Thiamine use. However, since the work was conducted only once, more studies are needed to prove the results. [ABSTRACT FROM AUTHOR]

Biomass is a promising renewable alternative to decarbonize and to secure energy production on small islands, as most insular power generation systems rely heavily on imported fossil fuels. Feedstock procurement is a key aspect of bioenergy chain sustainability, and local resources as well as imported biomass can be considered if the electricity generated presents environmental benefits. We used Life Cycle Assessment (LCA) to evaluate the environmental impacts of 1 kWh of electricity produced in Guadeloupe from the combustion of locally grown energy cane and imported wood pellets. The energy cane agricultural supply was simulated using a bio-economic model to elaborate and analyze five scenarios involving different biomass mixes and geographical areas of production. Our results show that electricity produced from energy cane reduced the impacts of ABIOTIC DEPLETION, ACIDIFICATION and PHOTOCHEMICAL OXIDATION by 29% compared with pellet-based electricity. The environmental impacts of the energy cane cultivation stage varied by a factor of 1.5–3.7 among regional areas of cultivation because of differences in yields, soil emissions and land conversion for energy crop farming. The substitution of 5% of fossil energy by biomass in the island electricity mix can reduce GLOBAL WARMING and ABIOTIC DEPLETION impact by 4.5%. However, this change requires 3.5 to 5.2 times higher LAND OCCUPATION per unit of energy produced. Given the limited land availability on small islands, this latter point confirms that the combination of locally grown energy crops with imported biomass will be a suitable strategy to develop sustainable bioenergy for small islands. [ABSTRACT FROM AUTHOR]

This study aimed to verify the technological feasibility, chemical quality and sensory acceptance of alcoholic fermented beverage obtained from sugarcane juice. A completely randomized design was applied. Sugar and alcohol content, phenolic (HPLC-MS) and volatile (GS-MS) compounds, pH, density, dry matter and acidity of the fermented beverage of sugarcane were quantified, as well as the acceptance of the product was carried out. The complete fermentation of sugarcane lasted 7 days, and it was obtained an alcohol content of 8.0% v/v. Titrable acidity of the beverage was of 67.31 meq L, pH 4.03, soluble solids of 5 °Brix, reducing sugar of 0.07 g glucose 100 g, density of 0.991 g cm, reduced dry matter of 14.15 g L, sulfates lower than 0.7 g KSO L. Various phenolic compounds, among which, gallic acid (10.97%), catechin (1.73%), chlorogenic acid (3.52%), caffeic acid (1.49%), vanillic acid (0.28%), p-coumaric acid (0.24%), ferulic acid (6.63%), m-coumaric acid (0.36%), and o-coumaric acid (0.04%). Amongst aromatic compounds, were found mainly esters with fruity aromas (ethyl ester hexanoic acid and ethyl ester octanoic acid). The sugarcane juice can be commercialized as an alternative wine, as it presented adequate features to an alcoholic fermented beverage and was sensory accepted by consumers. [ABSTRACT FROM AUTHOR]

There is a great demand of salt-tolerant sugarcane planting material in Cuba. Temporary immersion bioreactors (TIB) are effective to significantly increase sugarcane in vitro shoot proliferation rate from 1:4 in conventional containers to about 1:35. Sugarcane micropropagation in TIBs under NaCl stress may help screen mutants with salinity tolerance. We developed the experiment shown here to identify a NaCl concentration able to stress shoot in TIBs. At 30 days of culture initiation with different NaCl levels (0 - 200 mM), explant multiplication rate, shoot cluster fresh mass, and levels of aldehydes, chlorophylls, carotenoids and phenolics were determined in the plant material. Content of soluble phenolics in the culture medium was also evaluated. Addition of NaCl decreased shoot multiplication rate and fresh mass. Other statistically significant differences were recorded but the most important were noted in the increased contents of carotenoids, malondialdehyde, other aldehydes and soluble phenolics in the plants, and in the soluble phenolics in the culture medium. This research may be useful for future experiments of in vitro selection of new sugarcane genetic materials with NaCl tolerance. Fifty percent of multiplication rate was reduced with 89 mM NaCl which can be used to stress shoots during micropropagation in TIBs and eventually detect mutants with salt tolerance.

In the south-central region of Brazil, there is a trend toward reducing the sugarcane inter-harvest period and increasing traffic of heavy harvesting machinery on soil with high water content, which may intensify the compaction process. In this study, we assessed the structural changes of a distroferric Red Latosol (Oxisol) by monitoring soil water content as a function of the Least Limiting Water Range (LLWR) and quantified its effects on the crop yield and industrial quality of the first ratoon crop of sugarcane cultivars with different maturation cycles. Three cultivars (RB 83-5054, RB 84-5210 and RB 86-7515) were subjected to four levels of soil compaction brought about by a differing number of passes of a farm tractor (T0 = soil not trafficked, T2 = 2 passes, T10 = 10 passes, and T20 = 20 passes of the tractor in the same place) in a 3 × 4 factorial arrangement with three replications. The deleterious effects on the soil structure from the farm machinery traffic were limited to the surface layer (0-10 cm) of the inter-row area of the ratoon crop. The LLWR dropped to nearly zero after 20 tractor passes between the cane rows. We detected differences among the cultivars studied; cultivar RB 86-7515 stood out for its industrial processing quality, regardless of the level of soil compaction. Monitoring of soil moisture in the crop showed exposure to water stress conditions, although soil compaction did not affect the production variables of the sugarcane cultivars. We thus conclude that the absence of traffic on the plant row maintained suitable soil conditions for plant development and may have offset the harmful effects of soil compaction shown by the high values for bulk density between the rows of the sugarcane cultivars.

The sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments) with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha-1 N and absolute control (no inoculation and no N fertilizer). The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha-1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by inoculation, indicating that the benefits of the inoculant in sugarcane may have resulted from plant growth promotion.

Understanding how host-crop genotypes affect the life history of insect pests is important for developing and using varietal resistance as a pest control measure. Here we determined how wild and cultivated sugarcane genotypes affect key life-history traits and the demographic performance of the root spittlebug, Mahanarva fimbriolata (Stål; Hemiptera: Cercopidae), a major pest of sugarcane, which produces most of the world’s sugar and bioethanol. In the greenhouse, plants of four sugarcane genotypes (two wild and two cultivated) were infested with newlyecloded spittlebug nymphs. A longitudinal life-table experiment was conducted recording developmental time, survival, reproductive output, and longevity of the released spittlebug nymphs. One of the promising sugarcane genotypes was the accession IM76-229 (Saccharum robustum Brandes & Jesw. ex Grassl), which allowed only 20% of nymph survival to adulthood and reduced the spittlebug longevity by 10 d. Such effects on these life-history traits led to a negative intrinsic rate of population growth (rm = −0.002) of the insects, indicating that the test population would eventually go extinct on this sugarcane genotype. An opposite trend (i.e., population growth) was obtained for the insects raised on Saccharum spp. (SP81-3250 and SP80-1816 cultivars) and Erianthus arundinaceus (Retz) Jeswiet (Kawandang genotype). These results show that S. robustum IM76-229 genotype has resistance traits that drastically reduce spittlebug population growth and indicate that it can be used in breeding programs aiming to develop sugarcane cultivars with resistance to spittlebugs. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effect of lindane-degrading yeast on the growth and lindane uptake by Saccharum sp., in doped garden soils. The rhizosphere of Saccharum plant was amended with yeast Candida VITJzN04 by root-inoculation. The bio-augment yeast was applied in two different forms viz., planktonic form and cells immobilized on sugarcane-bagasse, in the pot experiments. Garden soils (lindane∼100 mg/kg) exposed to various treatments were monitored for a period of 30 days, for residual lindane by gas-chromatography analysis. The lindane-removal rates in soil were expressed in terms of half-life period and were recorded as 13.3 days (yeast), 43.3 days ( Saccharum ), 9.8 days (free yeast-plant) and 7.1 days (immobilized yeast-plant). Additionally, Candida sp., was also identified as a plant growth promoting yeast due to its ability to produce growth hormone and solubilize insoluble phosphates in the soil for better uptake by the plant species. Bio-stimulation of the soil with yeast immobilized on sugarcane bagasse further enhanced the total yeast activity in the soil which in turn had a positive influence on lindane-removal. Combined treatment with bagasse immobilized yeast and plant showed the best lindane degradation. Results suggested that the synergistic activity of plant and yeast resulted in fast and efficient degradation of lindane. Thus, it can be concluded that Saccharum plant in combination with Candida VITJzN04 is an effective alternative for the conventional remediation strategies. [ABSTRACT FROM AUTHOR]

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There is a great demand of salt-tolerant sugarcane planting material in Cuba. Temporary immersion bioreactors (TIB) are effective to significantly increase sugarcane in vitro shoot proliferation rate from 1:4 in conventional containers to about 1:35. Sugarcane micropropagation in TIBs under NaCl stress may help screen mutants with salinity tolerance. We developed the experiment shown here to identify a NaCl concentration able to stress shoot in TIBs. At 30 days of culture initiation with different NaCl levels (0 - 200 mM), explant multiplication rate, shoot cluster fresh mass, and levels of aldehydes, chlorophylls, carotenoids and phenolics were determined in the plant material. Content of soluble phenolics in the culture medium was also evaluated. Addition of NaCl decreased shoot multiplication rate and fresh mass. Other statistically significant differences were recorded but the most important were noted in the increased contents of carotenoids, malondialdehyde, other aldehydes and soluble phenolics in the plants, and in the soluble phenolics in the culture medium. This research may be useful for future experiments of in vitro selection of new sugarcane genetic materials with NaCl tolerance. Fifty percent of multiplication rate was reduced with 89 mM NaCl which can be used to stress shoots during micropropagation in TIBs and eventually detect mutants with salt tolerance. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the microbial soil cultivated with sugar cane certified organic with and without soil disturbance, organic certification, with and without conventional burning and a remaining area of Cerrado in Goiatuba, Goiás. We conducted a soil collected in March (rainy season) and another in September 2009 (dry season) at a depth of 00-10 cm and 10-20 cm for microbiological analysis. The data of microbiology and soil were analyzed descriptively through the estimation of the mean and standard deviation and also by multivariate analysis, estimating the average Euclidean distance between treatments, with complete linkage. There are training groups between organic management without soil disturbance and the remaining area of Cerrado indicating proximity between attributes. The area under conventional conditions with burns presents the highest values of respiration and metabolic quotient indicating stress solo. O organic management system without tilling the soil shows levels of microbial biomass nitrogen higher than the other managements and the remaining area of Cerrado. Objetivou-se avaliar os atributos microbiológicos do solo cultivado com cana-de-açúcar orgânica certificada com e sem revolvimento do solo, orgânica em certificação, convencional com e sem queima da palha e uma área remanescente de Cerrado no município de Goiatuba, Goiás. Foi realizada uma coleta de solo em março (período chuvoso) e outra em setembro de 2009 (período de estiagem) nas profundidades de 0-10 cm e de 10-20 cm para análise microbiológica. Os dados de microbiologia do solo foram analisados de forma descritiva por meio da estimação da média e erro padrão da média e também por meio da análise multivariada, estimando-se a distância Euclidiana média entre os tratamentos, com ligação completa. Há formação de grupos entre o manejo orgânico sem revolvimento do solo e a área remanescente de Cerrado indicando proximidade entre os atributos avaliados. A área com manejo convencional com queima apresenta os valores mais altos de respiração e quociente metabólico indicando estresse do sistema solo. O manejo orgânico sem revolvimento do solo apresenta níveis de nitrogênio da biomassa microbiana mais elevados que os demais manejos e a área remanescente de Cerrado.

La roya marrón de la caña de azúcar, causada por Puccinia melanocephala, es una enfermedad foliar de preocupación en casi todos los países donde se cultiva la caña de azúcar. Los programas de mejoramiento del cultivo se encuentran en la búsqueda de fuentes de resistencia de la planta al patógeno.

A cana-de-açúcar apresenta ampla área cultivada no estado de São Paulo. Em decorrência das precipitações desuniformes e heterogêneas ao longo do ano, torna-se importante o estudo de irrigação para definir quando e o quanto irrigar. A definição da quantidade de água adequada nas diferentes fases de desenvolvimento favorece o desenvolvimento morfo-fisológico. O objetivo do presente trabalho foi avaliar parâmetros morfogênicos de cana-de-açúcar RB 86 7515 irrigada durante o desenvolvimento inicial. O experimento conduziu-se em vasos no campus II da Universidade do Oeste Paulista, durante o estágio inicial de desenvolvimento da cana-de-açúcar. Os tratamentos foram baseados em diferentes lâminas de irrigação (50, 75, 100, 125 e 150% da evapotranspiração da cultura – ETc). As lâminas de irrigação foram calculadas pelo método de Penmam Monteith recomendado pela FAO. O delineamento experimental se deu em blocos ao acaso sendo 5 lâminas de irrigação e 5 blocos. Avaliou-se a altura quinzenal das plantas, número de folhas quinzenal, concentração da prolina, massa seca da parte, matéria seca e volume de raiz, comprimento de raiz e eficiência do uso da água. Os parâmetros avaliados foram submetidos ao Teste F e posteriormente ao Teste de Scott-Knott ao nível de probabilidade 5% para comparação de médias. Para os parâmetros biométricos não houve diferença entre as médias obtidas. A lâmina de 50% foi a que apresentou maior eficiência do uso da água pela evapotranspiração da cultura. A cana-de-açúcar obteve as maiores concentrações de prolina nas folhas frescas quando se encontra no estado de disponibilidade que a planta necessita para a fase de desenvolvimento inicial (100% ETc) assim quando se tem o estresse hídrico por déficit (50% ETc) e por excesso (150% ETc).

La búsqueda de alternativas de producción y consumo energético permite una nueva perspectiva para la industria de los combustibles biológicos como el bioetanol, tema central del presente trabajo, ya que sus ventajas competitivas frente a otras fuentes primarias de energía constituye una alternativa energética que permite superar los problemas generados por los métodos tradicionales de producción y consumo. A partir de la evaluación de la industria del bioetanol desde un análisis global, como el que se plantea en la mezcla de marketing, se expone qué tan atractiva o competitiva puede llegar a ser esta industria en la actualidad. Es sin duda de gran importancia señalar el reto que enfrenta la sociedad actual al intentar mantener un elevado nivel de vida sin que éste represente un peligro contra el medio ambiente o el bienestar humano. El principal desafío se centra en encontrar alternativas ecológicas y económicas que permitan cubrir las necesidades de energía, mediante el uso eficiente de fuentes alternativas y, a su vez, reducir la extrema dependencia y vulnerabilidad frente a los combustibles fósiles.The search for alternative energy production and supply, allow a new perspective on the biofuels industry as bioethanol, the focus of this work, as an alternative energy that enables to overcome the disadvantages generated by the traditional methods of production and consumption, by generating competitive advantages over other primary energy sources. The evaluation of the bioethanol industry from a global analysis such as that posed by the Marketing Mix, and exposed how attractive or competitive can become your industry today. It is certainly of great importance to note the challenge facing today’s society while trying to maintain a high standard of living without this represents a danger to the environment or to human welfare. The main challenge lies in finding alternatives that allow ecological and economic energy needs through the efficient use of alternative sources, and in turn, reduce extreme dependence and vulnerability to fossil fuels.

Transposable elements (TEs) account for a large portion of plant genomes, particularly in grasses, in which they correspond to 50%-80% of the genomic content. TEs have recently been shown to be a source of new genes and new regulatory networks. The most striking contribution of TEs is referred as “molecular domestication”, by which the element coding sequence loses its movement capacity and acquires cellular function. Recently, domesticated transposases known as mustang and derived from the Mutator element have been described in sugarcane. In order to improve our understanding of the function of these proteins, we identified mustang genes from Sorghum bicolor and Zea mays and performed a phenetic analysis to assess the diversity and evolutionary history of this gene family. This analysis identified orthologous groups and showed that mustang genes are highly conserved in grass genomes. We also explored the transcriptional activity of sugarcane mustang genes in heterologous and homologous systems. These genes were found to be ubiquitously transcribed, with shoot apical meristem having the highest expression levels, and were downregulated by phytohormones. Together, these findings suggest the possible involvement of mustang proteins in the maintenance of hormonal homeostasis.

This study aimed to evaluate the effect of the availability of sugar cane residues on the epigeic invertebrate fauna. The evaluations were made after cane sugar harvest f, considering three levels of residues: 0% (total removal of residues from the soil surface), 50% (removal of half of the waste in the plots, the dry mass of 7.6 Mg ha-1) and 100% (keeping track of residues produced, dry mass of 16.9 Mg ha-1). A fragment of native vegetation in the region, located close to the sugar cane crop, was evaluated for comparison. The experimental plots were arranged in a randomized block design with eight replications. Each plot consisted of five rows 20 m long, were installed two pitfalls to capture the invertebrate fauna, representing sixteen traps in each treatment, totaling forty-eight throughout the experiment. The organisms were extracted manually and identified at major taxonomic groups. The highest diversity and groups richness of epigeic invertebrate fauna were observed in the cane sugar crop with the maintenance of the surface residues (100 and 50%). Moreover, complete removal of residues from the soil surface promoted a significant reduction of the soil invertebrates organisms. Soil samples were collected for evaluation of chemical attributes. The organisms of epigeic invertebrate fauna showed sensitive in detecting changes in systems, depending on the maintenance of plant residues of sugar cane.O presente estudo teve como objetivo avaliar o efeito da disponibilidade de resíduos de cana-de-açúcar sobre a fauna invertebrada epigéica. As avaliações foram realizadas após a colheita da cana-de-açúcar, considerando três níveis de resíduos: 0 % (retirada total de resíduos da superfície do solo), 50 % (retirada da metade dos resíduos nas parcelas, massa seca de 7,6 Mg ha-1) e 100 % (manutenção completa dos resíduos produzidos, massa seca de 16,9 Mg ha-1). As parcelas experimentais foram dispostas num delineamento em blocos casualizados, com oito repetições. Cada parcela foi constituída por cinco linhas de 20 m de comprimento, onde foram instaladas duas armadilhas de queda “pitfall” para captura da fauna invertebrada, representando dezesseis armadilhas em cada tratamento, totalizando quarenta e oito em todo o experimento. Um fragmento de vegetação nativa da região, localizado próximo ao cultivo da cana-de-açúcar, foi avaliado para comparação. Os organismos foram extraídos manualmente e identificados em nível de grandes grupos taxonômicos. A maior diversidade e riqueza de grupos da fauna invertebrada epigéica foram observadas na cultura da cana-de-açúcar com a manutenção dos resíduos na superfície (100 e 50%). Por outro lado, a retirada completa dos resíduos da superfície do solo promoveu uma significativa redução dos organismos de invertebrados do solo. Amostras de solos foram coletadas para avaliação de atributos químicos. Os organismos da fauna invertebrada epigéica mostraram-se sensíveis indicadores em discriminar alterações nos sistemas, em função da manutenção de resíduos vegetais da cana-de-açúcar.

To identify genes that are up and down-regulated by water deficit in sugarcane we used the macroarray methodology and the expression level of 3 575 independent sugarcane cDNAs was measured by hybridization with RNA extracted from plants submitted to mild, moderate and severe water deficit. We identified approximately 1 670 differentially expressed genes from which 62 % were up-regulated by different stress-conditions, whereas many repressed genes were exclusive for each time-point. Analysis of similarity showed that approximately 24 % of the differentially expressed genes shared homology with proteins involved in different processes such as signal transduction, hormone metabolism, photosynthesis, transcription and stress response. Transcripts with no known function accounted for approximately 39 % and those without similarity represented 36 % of the sequences. Five genes analyzed by RT-PCR confirmed the macroarray results.

A aplicação de vinhaça na cana-de-açúcar, complementada com adubação nitrogenada e manutenção da palhada na superfície do solo, melhoram as propriedades físicas, químicas e biológicas do solo, podendo resultar em aumento da produtividade da cultura. O objetivo deste estudo foi avaliar o efeito residual de adubação na cana-planta e a adubação da cana-soca, com e sem aplicação de vinhaça, sob diferentes sistemas de colheita no município de Conceição da Barra - ES. O experimento foi conduzido no período de 2005 a 2007, num Argissolo Amarelo em Tabuleiros Costeiros. Utilizou-se o delineamento de blocos ao acaso com quatro repetições, no esquema fatorial 2 x 7, com parcelas subdivididas, sendo dois tratamentos cana crua e cana queimada e sete subtratamentos com diferentes doses de N associadas a doses de K2O na forma de cloreto de K e vinhaça. Os tratamentos foram: testemunha (T1); vinhaça (T2); vinhaça + 80 kg de N incorporado (T3); vinhaça + 80 kg de N em cobertura (T4); vinhaça + 40 kg de N em cobertura (T5); K2O + 80 kg de N incorporado (T6); e K2O + 80 kg de N em cobertura (T7). Não houve efeito residual de adubação na produtividade de colmos na cana-planta. A cana crua apresentou produtividade superior à da cana queimada na cana-soca. Nesta, a fertilização com vinhaça complementada com N incorporado ou em cobertura e a adubação com 120 kg de K2O na forma de KCl + 80 kg de N incorporados ao solo proporcionaram produtividade superior à dos demais tratamentos. Não foi verificada diferença na produtividade de colmos entre as doses de 40 e 80 kg ha-1 de N, aplicadas em cobertura na cana-soca. A extração e retorno de nutrientes ocorreu de forma similar entre cana-planta e cana-soca.The application of vinasse supplemented with nitrogen fertilizer to sugarcane with stubble maintained on the soil surface improves the physical, chemical and biological soil properties and may result in increased crop yield. The aim of this study was to evaluate residual effects of fertilization on cane plant, as wellas the effect of vinasse application to ratoon cane under different management systems in Conceição da Barra, state of Espírito Santo. The experiment was carried out from 2005 to 2007, on an Ultisol on the Coastal Plains, in a randomized block, 2 x 7 factorial design with four replications with split plots. The two treatments consisted of green cane and burnt cane and the seven subtreatments of different N and K2O doses as potassium chloride and vinasse, as follows: control (T1), vinasse (T2), vinasse + 80 kg of incorporated N (T3), vinasse + 80 kg of N (T4), vinasse + 40 kg of sidedressed N (T5), K2O + 80 kg of incorporated N (T6), K2O + 80 kg of sidedressed N (T7). No residual effect of fertilization on sugarcane yield was observed. The yield of green cane was higher than that of the burnt ratoon cane. For ratoon cane, fertilization with vinasse supplemented with incorporated or sidedressed N and fertilization with 120 kg K2O in the form of KCl + incorporated 80 kg N achieved best results. No difference in the stalk yield was observed between doses of 40 and 80 kg ha-1 sidedressed N applied to ratoon cane. Nutrient extraction and return were similar for cane plant and ratoon cane.

A redução do período de entressafra canavieiro pode levar à disseminação da compactação do solo, em decorrência da colheita mecanizada da cana-de-açúcar na estação chuvosa. Dessa forma, faz-se necessário definir estratégias que visem a minimizar a esse processo. O presente estudo objetivou modelar o processo de compressão do solo com base na pressão crítica. Avaliou também os efeitos da colheita mecanizada da cana-de-açúcar em diferentes épocas da safra em um Latossolo Vermelho-Amarelo (LVA) e em um Cambissolo Háplico (CX). Determinaram-se em amostras indeformadas a macroporosidade do solo, a pressão de preconsolidação em diferentes conteúdos de água no solo e a densidade do solo. A partir da incorporação da densidade do solo crítica na modelagem do comportamento compressivo do solo, foi possível estimar a pressão crítica. A pressão crítica superestima a capacidade de suporte de carga dos solos. A colheita mecanizada da cana-de-açúcar, realizada na zona de friabilidade do solo, não provocou compactação prejudicial à cultura. A cana-de-açúcar pode ser colhida mecanicamente sem causar a degradação estrutural no LVA e no CX, respectivamente, sob conteúdos de água de até 0,16 e 0,21 kg kg-1.The reduction of a second growing season of sugarcane can lead to spread soil compaction, due to mechanical harvesting of sugarcane in the rainy season. Thus, it is necessary to define strategies to minimize this process. This study aimed to model the compressive behavior of the soil based on the critical pressure. The effects of the mechanized harvesting of sugarcane at different times of the crop were also assessed in a Red-Yellow (LVA) and in a Haplic Cambisol (CX). Soil macroporosity, preconsolidation pressure at different soil water contents and bulk density were determined in undisturbed soil samples. With the incorporation of the critical bulk density in modeling the soil compressive behavior, it was possible to estimate the critical pressure. The critical pressure overestimates the soil bearing capacity. The mechanized harvesting of sugarcane made in the friability zone did not cause harmful compaction to the crop. The sugarcane can be harvested mechanically without causing structural degradation in the LVA and CX, respectively, at soil water contents up to 0.16 and 0.21 kg kg-1.