Sugarcane (Saccharum officinarum L.) grows under different weather conditions directly affecting crop maturation. Raw material quality predicting models are important tools in sugarcane crop management; the goal of these models is to provide productivity estimates during harvesting, increasing the efficiency of strategical and administrative decisions. The objective of this work was developing a model to predict Total Recoverable Sugars (TRS) during harvesting, using data related to production factors such as soil water storage and negative degree-days. The database of a sugar mill for the crop seasons 1999/2000, 2000/2001 and 2001/2002 was analyzed, and statistical models were tested to estimate raw material. The maturity model for a one-year old sugarcane proved to be significant, with a coefficient of determination (R 2 ) of 0.7049*. No differences were detected between measured and estimated data in the simulation (P < 0.05). Key words: sucrose, predicting, quality, mathematical model, climatology ESTIMATIVA DA MATURAÇÃO DA CANA-DE-AÇÚCAR POR MEIO DE PARÂMETROS EDAFOCLIMÁTICOSRESUMO: A cultura da cana-de-açúcar (Saccharum officinarum L.) é submetida durante o seu desenvolvimento a diferentes condições ambientais que afetam diretamente a maturação. Modelos de previsão da qualidade da matéria-prima são ferramentas importantes no gerenciamento da lavoura canavieira, pois permitem estimativas de rendimento ao longo da safra, o que aumenta a eficácia das decisões gerenciais e estratégicas. O objetivo deste trabalho foi desenvolver um modelo capaz de obter estimativas de Açúcar Total Recuperável (ATR), utilizando dados referentes aos fatores de produção como armazenamento de água no solo e graus-dias negativos. Para o teste dos modelos estatísticos de estimativa da qualidade da matéria-prima foi utilizado o banco de dados de uma usina açucareira com produções das safras 1999/2000, 2000/2001 e 2001/ 2002. O modelo de maturação para cana de ano mostrou-se significativo, com um coeficiente de determinação R 2 = 0,7049*. Na simulação não houve diferença entre os dados medidos e estimados (P < 0,05).

Ao amigo e orientador Prof. Dr. Edgar Gomes Ferreira de Beauclair pelo incentivo e orientação ao longo desses anos. Ao Prof. Dr. Valter Barbieri pelas sugestões. À Usina Açucareira Bortolo Carolo na pessoa de seus diretores Marcelo Carolo e Badri Kazan, por incentivarem e fornecerem as informações fundamentais para a elaboração deste trabalho. Ao amigo M.S. Luis Fernando Sanglade Marchiori pelo incentivo e a todos os funcionários da Fazenda Experimental Areão-ESALQ/USP. Ao Dr. Orivaldo Brunini pesquisador do IAC, pelo fornecimento dos dados climáticos. À CAPES pelo auxílio da bolsa de estudo. A todos os amigos da cidade de Piracicaba onde nasci e adoro tanto e a cidade de Ubatuba onde busco inspiração para continuar caminhando. vi SUMÁRIO Página

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.

Sugarcane (Saccharum spp.) grows in different weather and management conditions which directly affect crop maturation. These conditions lead to the necessity of quantifying crop response to different stimuli for planning purposes. Forecast models for the quality of raw material are important tools in sugarcane farming, especially the forecast curve of sucrose accumulation in shoots. The goal of these models is to supply yield estimates during the crop cycle, aiming to characterize alternatives and to increase the efficacy for management and strategic decisions. The objective of this project was to develop empiric models capable of obtaining estimates of total recoverable sugar (TRS), for the varieties RB72454, SP81-3250 and SP80-1842 during the crop cycle, using reference data as the production factors. Sugarcane harvest results obtained in Piracicaba, State of São Paulo, Brazil were analyzed using the following parameters: maturation, stand age, type of soil, variety, flowering and management for the crops in the years 1998/99, 1999/00, 2000/01, 2001/02 and 2002/03. Models developed for these years were used to estimate TRS from the 2003/04 cropping season. All the forecast models for ratoon crops were significant indicating that they are an excellent tool to optimize agricultural planning. Key words: climatology, crop models, productivity, regression, sucrose MODELO FISIOLÓGICO PARA A ESTIMATIVA DA MATURAÇÃO EM CANA-DE-AÇÚCARRESUMO: A cultura da cana-de-açúcar (Saccharum spp.) é submetida a diferentes condições ambientais e de manejo durante o seu desenvolvimento, o que afeta diretamente a maturação. Assim, surge a necessidade de se quantificar as respostas da cultura aos diferentes estímulos para fins de planejamento. Modelos de previsão da qualidade da matéria-prima tornam-se ferramentas importantes na lavoura canavieira, em especial a previsão da curva de acúmulo de sacarose nos colmos, objetivando suprir estimativas de rendimento ao longo da safra, visando à caracterização das alternativas de manejo, aumentando a eficácia das decisões gerenciais e estratégicas. Desenvolveram-se modelos empíricos capazes de obter estimativas de ATR -Açúcar Total Recuperável nas variedades RB72454, SP81-3250 e SP80-1842 ao longo da safra, utilizando dados referentes aos fatores de produção. Foram analisados os resultados de colheita realizados no município de Piracicaba -SP, dos anos safras

Flowering is of utmost relevance for the agricultural productivity of the sugarcane bioeconomy, but data and knowledge of the genetic mechanisms underlying its photoperiodic induction are still scarce. An understanding of the molecular mechanisms that regulate the transition from vegetative to reproductive growth in sugarcane could provide better control of flowering for breeding. This study aimed to investigate the transcriptome of +1 mature leaves of a sugarcane cultivar subjected to florally inductive and non-inductive photoperiodic treatments to identify gene expression patterns and molecular regulatory modules. We identified 7,083 differentially expressed (DE) genes, of which 5,623 showed significant identity to other plant genes. Functional group analysis showed differential regulation of important metabolic pathways involved in plant development, such as plant hormones (i.e., cytokinin, gibberellin, and abscisic acid), light reactions, and photorespiration. Gene ontology enrichment analysis revealed evidence of upregulated processes and functions related to the response to abiotic stress, photoprotection, photosynthesis, light harvesting, and pigment biosynthesis, whereas important categories related to growth and vegetative development of plants, such as plant organ morphogenesis, shoot system development, macromolecule metabolic process, and lignin biosynthesis, were downregulated. Also, out of 76 sugarcane transcripts considered putative orthologs to flowering genes from other plants (such as Arabidopsis thaliana, Oryza sativa, and Sorghum bicolor), 21 transcripts were DE. Nine DE genes related to flowering and response to photoperiod were analyzed either at mature or spindle leaves at two development stages corresponding to the early stage of induction and inflorescence primordia formation. Finally, we report a set of flowering-induced long non-coding RNAs and describe their level of conservation to other crops, many of which showed expression patterns correlated against those in the functionally grouped gene network.

Flowering is essential in any breeding programme, particularly in genetic introgression programmes in which flowering synchronism is required. In this work, 16 sugarcane genotypes were evaluated using three different flowering-inductive photoperiod treatments (30 s, 45 s, and 1 min of a daily photoperiod decrease from 12 h 55 of light). Each genotype was planted in 43 L pots (equal proportion of soil, sand, and substrate) with three tillers per pot. Plants with 4 to 6 internodes were placed in a photoperiod facility with three controlled chambers, each chamber containing all 16 genotypes (one treatment per chamber). The temperature range (21˚C to 32˚C) and humidity were the same for all of the treatments. The flower induction started in September 2010 and ended in April 2011. The plant elongation and flag leaf and inflorescence emergence were recorded and the pollen viability was evaluated by using the iodine staining method. The photoperiod facility provided suitable conditions for flowering, as the plants in the three treatments successfully flowered. The genotypes in the three treatments behaved differently in relation to the date of panicle emergence, with the treatment of 45 s showing better results. The results here presented contribute to synchronise flowering for desired sugarcane crosses, particularly those from introgression programmes between commercial cultivars and species from the Saccharum complex.

Phytomass production is a result of physiological processes occurring at plant canopy level, with canopy architecture affecting the availability of solar radiation to photosynthesizing tissues. The aim of this study was to identify a possible association between light availability, canopy photosynthesis and plant growth in three sugarcane varieties under field conditions. As a hypothesis, higher canopy photosynthesis and plant growth are probably found in sugarcane varieties with higher light availability at bottom canopy positions. Measurements of diurnal course of leaf gas exchange were taken in two canopy positions of the sugarcane varieties IACSP93-2060, IACSP95-3028 and IACSP95-5000, maintaining the natural leaf inclination. All sugarcane varieties exhibited similar values of diurnal CO 2 uptake at the upper canopy position. On the other hand, the bottom canopy position had an important role on photosynthesis of IACSP95-3028 sugarcane, with slight changes in leaf inclination causing significant variation of photosynthetic active radiation at the bottom canopy positions. High light availability at the bottom canopy position of IACSP95-3028 caused increased photosynthesis and improved plant vegetative growth, given by increases in tillering, leaf area and leaf and stalk phytomass accumulation.

Although reference genes have previously been used in the expression analysis of genes involved in sugarcane flowering they had not been experimentally validated for stability and consistency of expression between different samples over a wide range of experimental conditions. Here we report the analysis of candidate reference genes in different tissue types, at different temporal time-points, in both short and long day photoperiodic treatments. The stability of the candidate reference genes in all conditions was evaluated with NormFinder, BestKeeper, and RefFinder algorithms that complement each other for a more robust analysis. As the Normfinder algorithm was more appropriate for our experimental conditions, greater emphasis was placed on Normfinder when choosing the most stable genes. UBQ1 and TUB were shown to be the most stable reference genes to use for normalizing RT-qPCR gene expression data during floral induction, whilst 25SrRNA1 and GAPDH were the least stable. Their use as a reference gene pair was validated by analyzing the expression of two differentially expressed target genes (PIL5 and LHP1). The UBQ1/TUB reference genes combination was able to reveal small significant differences in gene expression of the two target genes that were not detectable when using the least stable reference gene combination. These results can be used to inform the choice of reference genes to use in the study of the sugarcane floral induction pathway. Our work also demonstrates that both PIL5 and LHP1 are significantly up-regulated in the initial stages of photoperiodic induction of flowering in sugarcane.