ABSTRACT The demand for the increased productivity of sugarcane crops has required changes in its production chain, such as the use of pre-sprouted seedlings (PSS) of sugarcane into the chain. In this system, the inoculation of beneficial microorganisms, such as plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF), can improve seedling development. The objective was to evaluate the beneficial effect of PGPB and AMF inoculation on sugarcane PSS production system. Experiments were carried out in greenhouse using a commercial substrate with different levels of fertilization to evaluate the plant biomass and nutritional status. The bacteria strains are able to produce indole acetic acid and to amplify the nifH gene. The coinoculation of strains IAC-BeCa-095 with AMF (Glomus macrocarpum and Glomus etunicatum) improved the plant shoot biomass (25%) on the fertilized substrate. The strains IAC-BeCa-088 (Burkholderia caribensis), IAC-RBca5 (Pseudomonas sp.) and IAC-RBca10 (Bacillus sp.) without AMF and fertilization improved the shoot biomass by up to 35%. Coinoculation with strain IAC-BeCa-095 (Kosakonia radicincitans) and AMF improved the shoot and root biomass by up to 27 and 75%, respectively, in the conventionally fertilized substrate, demonstrating a synergistic effect of these microorganism consortia. The use of beneficial microorganisms may be a viable practice in the production of PSS sugarcane. Moreover, this study is the first to demonstrate the synergistic effect of endophytic bacteria (K. radicincitans) or rhizobacteria (Bacillus sp.) with AMF and Pseudomonas sp. or B. caribensis, without AMF inoculum on the production of sugarcane PSS to improve plant growth and plant nutrition.

ABSTRACT The pre-sprouted sugarcane plantlets (PSP) system aims the production of healthy and vigorous plants in reduced time, reducing the number of stalks needed for planting. Irrigation is used in all PSP system stages and water management plays an important role. Stage 1 acclimation follows the budding stage and lasts for approximately 21 days. At this stage the plantlets are grown within an agricultural greenhouse to improve initial development. The objectives of this trial were: to identify the irrigation management which results in highest plantlet growth; to evaluate if responses to irrigation management depends on the cultivar; to evaluate water consumption and water use efficiency at early stage under PSP system; and to assess the water management effect on substrate water matrix potential and stomatal conductance in the cultivar IACSP95-5000. The experimental design was a split-plot randomized block design with four replications. Treatments applied in the plots were different irrigation depths based on daily reference evapotranspiration (ETo): 96, 80, 64 and 48%, estimated by Penman–Monteith method. In the subplots, there were sugarcane cultivars IAC91-1099, IACSP95-5000 and IACSP97-4039. Irrigation management based on 80% ETo resulted in higher growth, dry mass accumulation and greater leaf area. Water use efficiency was not influenced by irrigation management. IAC91-1099 presented higher overall growth, leaf area and dry mass accumulation. Water consumption was cultivar-dependent in irrigation managements using 80 and 96% of ETo. Water use efficiency was higher in IAC91-1099 and lower in IACSP95-5000. Lower substrate water matrix potential reduced leaves stomatal conductance, impairing IACSP95-5000 plantlet growth.

O objetivo deste trabalho foi avaliar as famílias e destacar as progênies superiores de cana-de-açúcar oriundas de 38 cruzamentos biparentais para os seguintes atributos: tonelada de colmos por hectare (TCH), toneladas de biomassa por hectare (TBIOH), brix (% caldo da cana), teor de fibra, pureza, pol e açúcar total recuperável (ATR). Os dados foram analisados via modelos mistos REML/BLUP, em que o REML (Máxima Verossimilhança Restrita) permitiu estimar parâmetros genéticos e BLUP (Melhor Predição Linear Não Viciada) permitiu predizer os valores aditivos e genotípicos. A melhor família para os atributos TCH e TBIOH foi a 41, cujos parentais são as cultivares IACSP022019 x CTC9. Na seleção individual para TCH, a planta de n. 3 do bloco 2, do cruzamento 78 foi a que apresentou o melhor resultado. Para TBIOH, a planta n. 33, do bloco 1, da família 41 foi superior. As famílias 40, 41, 43, 68, 69, 79, 91, 92 e 147 foram superiores para as variáveis brix, pol, pureza e ATR, enquanto que as famílias 85, 147, 148, 149, 161, 163, 177, 178, 179 e 183 foram superiores para fibra. A família 147, cujos parentais são IACSP042286 x IACSP963055, mostrou três progênies entre as dez melhores tanto para brix quanto para fibra, o que identifica essa combinação como potencial fonte de progênies para produção de bioenergia.

The objective of this study was to assess families and highlight the superior progenies of sugarcane originating from 38 biparental crosses for the following attributes: tons of cane per hectare (TCH), tons of biomass per hectare (TBIOH), brix (% cane juice), fiber content, purity, pol and total recoverable sugar (TRS). The data were analyzed by mixed model REML / BLUP in the REML (Restricted Maximum Likelihood) allowed us to estimate genetic parameters and BLUP (best linear unbiased prediction) to predict the additive and genotypic values. The best family for the attributes TCH and TBIOH was 41, whose parents are cultivars IACSP022019 x CTC9. In individual selection for TCH, the plant number 3 of Block 2, the crossing 78, showed the best results. To TBIOH the plant number 33, Block 1, family 41, showed the best results. Families 40, 41, 43, 68, 69, 79, 91, 92 and147, were higher for the variables brix, pol, purity, and ATR, where as 85 families, 147, 148, 149, 161, 163, 177, 178, 179, and 183 were higher for fiber. The family 147 whose parents are IACSP042286 x IACSP963055, showed three progenies ranked among the top ten for both brix, and for fiber, which identifies the combination as a potential source of progenies for bioenergy production.

Sugarcane (Saccharum spp.) is an efficient and sustainable alternative for energy generation compared to non-renewable sources. Currently, during the mechanized harvest process, the straw left in the field can be used in part for the second generation ethanol and increasing the electric energy production. Thus, this study aimed to provide information on the potential for residual biomass cultivars of sugarcane cropping system. This study provides the following information: yield of straw, depending on the calculated leaf area index and the number of tillers per linear meter; primary energy production of several sugarcane genotypes; contribution of dry tops and leaves; biomass yield; and evaluation of fiber, cellulose, hemicellulose and lignin. Preliminary results obtained by researchers of the State of São Paulo, Brazil, and reCviews related studies are presented. The results suggest that the production of sugarcane straw content varies according to the cultivars; the greater mass of sugarcane straw is in the top leaves and that the potential for the crude energy production of sugarcane per area unit can be increased using fiber-rich species or species that produce more straw. The straw indexes was shown to be a good indicator and allow the estimation of straw volumes generated in a sugarcane crop. The cellulose, hemicellulose and lignin composition in sugarcane is distinct among varieties. Therefore, it is possible to develop distinct biomass materials for energy production and for the development of sugarcane mills using biochemical processes and thermal routes.

Frequentemente a existência de variabilidade espacial do solo não é considerada, contudo, a uniformidade raramente existe e não pode ser pressuposta sem uma adequada averiguação. O objetivo do trabalho foi utilizar a geoestatística para verificar a variabilidade espacial do solo na área experimental localizada em Ribeirão Preto (SP), sob cultivo da variedade de cana-de-açúcar IAC SP 93-3046. Amostras a cada 10 m, totalizando 97 pontos georreferenciados, foram realizadas para análise química do solo, resistência do solo à penetração e dados biométricos das plantas de cana-de-açúcar incluindo número de perfilhos, diâmetro de colmos, massa de colmos, estimativa de produtividade (TCHe) e densidade de raízes. Utilizou-se a análise geoestatística através de semivariogramas, interpolação dos dados por krigagem e construção de mapas de isolinhas. Os resultados evidenciaram dependência espacial para a maioria dos atributos do solo. As manchas na área com menor resistência do solo à penetração e densidade do solo também foram as de maior número de perfilhos e de maior desenvolvimento da raiz da cana-de-açúcar. Para os atributos químicos do solo, houve dependência espacial mostrando maior concentração de nutrientes do solo no centro da área. A amostragem permitiu boa representatividade da dependência espacial do solo e das plantas sendo descartada a hipótese de aleatoriedade para disposição de parcelas nesta área.

Tests to evaluate competition between plants, in general do not consider the soil spatial variability, nevertheless, the uniformity rarely is present and can not be assumed without verification. The aim of this work was to apply geostatistics to verify the spatial variability of the soil in an experimental field near Ribeirão Preto, SP, with sugarcane variety IACSP93-3046. Ninety seven geo-referenced samples, placed at distances of 10 m, were collected for soil chemical analysis, soil resistance to penetration and biometric evaluation of the sugar cane plant included number of tillers, stalk diameter, stalk height, estimated productivity (TSSe) and root density. Geostatistics has been applied by means of semivariogram, data interpolation via kriging and iso-line maps creation. The results have shown soil spatial dependence for most of the evaluated attributes. The spots, within the area, with low resistance to penetration and low soil density have shown the largest number of tillers and the largest root development of sugar cane. For soil chemical attributes, there was spatial dependence showing higher concentration of nutrients in the central area. The sampling allowed a good representativity of the spatial dependence of soil and plants, making it possible to eliminate the randomness hypothesis for the placement of the plots in this area.

Embora haja homogeneidade nas características morfológicas na classe dos Latossolos, existe grande diversidade química na subsuperfície. Trabalhos indicam que a produção agrícola apresenta correlação significativa com atributos químicos de subsuperfície, que são mais estáveis que na camada arável, sujeita a alterações decorrentes da exploração agrícola. Pelo exposto, o presente estudo avaliou os efeitos dos atributos químicos de subsuperfície de Latossolos da região Centro-Sul do Brasil na produtividade agrícola dos três primeiros cortes de clones de cana-de-açúcar e da variedade RB72454. Utilizaram-se os dados de produtividade agrícola correspondentes ao período de 1993 a 1998. Os solos foram caracterizados sob o ponto de vista granulométrico e químico na profundidade entre 0,8 e 1,0 m e foram feitos estudos de correlação entre tais atributos e as médias de produtividade agrícola diária durante o ciclo dos clones de cada ensaio e da variedade RB72454 e análise de regressão múltipla, com as variáveis selecionadas pelo procedimento "stepwise" em função do R². As características químicas de subsuperfície dos Latossolos influenciaram na produtividade agrícola da cana-de-açúcar, principalmente no 3º corte. Para as médias dos clones, o modelo de produtividade do 3º corte em função de saturação por bases e fósforo, mostra R² = 0,31, ou seja, que 31% da variação de TCH dia-1 pode ser explicada por esses dois atributos. No caso da variedade RB72454, essa mesma variação no 3º corte é explicada em 47% pelos atributos soma de bases e teores de cálcio e matéria orgânica. As variações de produtividade de 1º e 2º cortes foram melhor explicadas pelo pHágua.

In spite of the great homogeneity found in the morphological characteristics of Oxisols, there is great chemical diversity in subsurface layers of these soils. Studies indicate that crop yield presents significant correlation with the chemical attributes of the subsurface, which, are more stable than attributes found in the plough layer, subject to greater alterations as a consequence of agricultural exploration. This work evaluated the effects of subsurface chemical attributes of Oxisols of the South Central region of Brazil, on the yield of sugarcane clones and of variety RB72454, during the first, second and third cropping cycles. Productivity data were obtained between 1993 and 1998. Soils were characterized in terms of their mechanical analysis and chemical traits at 0.8 to 1.0 m; correlation studies between these attributes and mean daily productivity as well as multiple regression analysis were also carried out; variables were selected based on their R² values by means of the stepwise procedure. The subsurface chemical traits of the Oxisols influenced sugarcane productivity, especially the 3rd harvest; the clone productivity model for the 3rd harvest as a function of base saturation and phosphorus content presented R² = 0.31, i.e., 31% of the variation in sugarcane yield (t ha-1 day-1) can be explained by these two attributes. For variety RB72454, 47% of that variation is explained by the sum of bases and contents of calcium and organic matter. Variations on productivity at 1st and 2nd harvests can be better explained by pHwater.