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Brown rust is an important disease that can affect the production of sugarcane in susceptible varieties. Reaction to brown rust has influenced the improvement programs in the process of clonal selection. Bru1 is one of the main resistance genes for brown rust. Therefore, the knowledge of the reaction to brown rust in the genotypes most used as parents in hybridizations would avoid crosses between susceptible genotypes. In this sense, the objectives of this work were to evaluate the reaction to brown rust in the field and the pattern of disease evolution; and the presence of the Bru1 gene in sugarcane parents of the RIDESA genetic improvement program. The experiment was carried out at the Paranavai experimental station, where 64 genotypes were planted in a randomized block design with three replications. The severity of brown rust in the field under natural infection conditions and the presence of the Bru1 gene were evaluated. Of the 63 genotypes evaluated, 38 were classified as resistant, 13 as intermediate and 12 as susceptible. Lower values of severity of brown rust were observed in intermediate genotypes with a slow evolution of the disease when compared with susceptible parents, indicating a quantitative resistance. Bru1 was detected in 58.7% of the evaluated genotypes. The frequency of Bru1 increased from 0% in the genotypes used as parents in the 1970s to 20, 64.71 and 76% in the 1980, 1990 and 2000s, respectively.

Orange rust (OR) and brown rust (BR) are among the most important diseases of sugarcane. The objective of this work was to evaluate the efficiency of fungicides in the control of both rusts. Two experiments, one for each rust, were conducted in the state of Parana, Brazil, in plant cane and in ratoon. A randomized block design with 8 treatments and three replications was used. The treatments were: control (T1), pyraclostrobin (T2), pyraclostrobin + epoxiconazole (T3), azoxystrobin + cyproconazole (T4), azoxystrobin + tebuconazole (T5), trifloxystrobin + tebuconazole (T6), azoxystrobin + benzovindiflupyr (T7) and pyraclostrobin + fluxapyroxad (T8). The cultivars RB72454 and RB835486 were used for their susceptibility to OR and BR, respectively. Four applications of fungicides were carried out in plant cane and also in ratoon, in a 30-day intervals. With the severity data over time, the relative area under the disease progress curve (rAUDPC) was calculated. After harvest, yield (tons of cane per hectare-TCH), yield recovery compared to the control (YR) (%), pol% cane (PC) and tons of pol per hectare (TPH) were obtained. From rAUDPC results, treatments T3, T4, T5, and T7 were the most efficient for the control of OR and treatments T2, T3, T4, T5, T7 and T8 were the most efficient for controlling BR. Yield was affected by treatments only in ratoon in both experiments. The YR ranged from 18.5% to 31.1% and from 16.1% to 37.7% to OR and BR, respectively. There were no differences between treatments for PC in both experiments and TPH was influenced by treatments in ratoon in the BR experiment.

This study's objectives were to compare the occurrence of brown rust and smut in conventional and energy cane families and clones in field conditions and to understand how the new hybridizations could contribute to increasing the allele frequency of resistance against the main crop diseases in breeding populations. Disease occurrence was evaluated in two selection stages. Of the 2.400 clones constituting the material for selection in the first stage, 88 clones (« 4% of the total) were selected for the second stage. Considering the overall performance of the clones without symptoms of either disease in the evaluated families that would be possibly selected in the second stage, the percentage was at least 28% lower in the families selected for high biomass (37.33%) than of the selected conventional (57.14%) and intermediate biomass (66.67%) families. In the intermediate biomass and high biomass sugarcane families, brown rust and smut rates were higher in the first stage. In the second stage, brown rust incidence was higher in high biomass families. However, at the end of both selection phases, intermediate biomass and high biomass sugarcane clones without simultaneous brown rust and smut symptoms could be selected.

Cold stress reduces crop yields and quality, limiting agricultural expansion. The objective of this study was to evaluate cold tolerance in sugarcane (Saccharum spp.) progenies based on physiological and biometric characteristics under natural cold stress. The experiment was carried out at a station of the Temperate Climate Research Center, of the Brazilian Agricultural Research Corporation (Embrapa), in Pelotas, Rio Grande do Sul, where 21 full-sib sugarcane progenies were evaluated in an incomplete block design with six replications. Physiological and biometric characteristics were measured after frost events to determine cold tolerance. The components of variance, genetic parameters and correlations were estimated using mixed models (REML/BLUP). The meteorological data recorded on-site showed the occurrence of 13 frost events (0 °C) and a minimum temperature of − 2.9 °C. Genetic variability for cold tolerance was detected between and within progenies. Narrow-sense heritability was moderate for chlorophyll content (0.23), leaf damage (0.26), stalk damage (0.19) and total soluble solids content (0.44), while heritability at the progeny level was high for all traits (> 0.57). The genotypic values for cold tolerance and yield potential were highest in the progenies RB996962 × RB016916, RB016916 × RB996962, RB867515 × RB92579 and RB106802 × RB036088.

Orange rust, caused by the fungus Puccinia kuehnii, is an important disease of sugarcane (Saccharum sp.). A molecular marker (G1) was developed to identify the resistance of sugarcane to orange rust. The aim of the present study was to validate the molecular marker G1 in the detection of resistance to orange rust in Brazilian sugarcane genotypes. 80 genotypes were analyzed by PCR, being classified according to the presence or absence of the marker. For field evaluation of orange rust resistance, a randomized block experiment was conducted, with the same 80 genotypes using four replications. Artificial inoculation was performed in the leaf whorl, with an evaluation made at 30 days after inoculation, using a scale from zero (without symptoms) to four (more than five pustules with sporulation), in which cultivars with an average score between zero and two were classified as resistant, and a score greater than two, susceptible. Of the 17 genotypes classified as resistant through the field test, 9 did not present the respective band. Of the 63 susceptible genotypes, 27 had the band relative to the molecular marker G1. The selection accuracy of G1 marker (the efficiency of predicting resistant phenotype) was 22.86%. The Phi correlation coefficient (ϕ) was calculated, through which it was observed that the variables are independent, with no statistically significant correlation between them. The results indicate that the G1 marker had a low efficiency to predict the resistance to orange rust in clones under selection in a Brazilian breeding program and Brazilian commercial cultivars of sugarcane.

Made available in DSpace on 2022-05-01T15:13:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 The use of single-bud sugarcane propagules brings a challenge concerning the initial sprouting, as the physiological ages of buds affect their outgrowth. This work is addressed to stimulate the sugarcane buds sprouting in a nature-friendly way using microalgae biomass. A metabolomics approach, connecting physiological and phenotypic changes, was adopted to identify the microalgae effect on sugarcane sprouting. For that, initially the changes in propagules metabolites according to their size and bud position in culm were determined. Then, single-bud propagules from apical, medial and basal segments of culms from cv. RB036152 were immersed in a solution containing microalgae biomass. Budding percentage, sprouts size and changes in sprouts and propagules metabolites—free amino acids; total soluble, reducing and non-reducing sugars; phenolic compounds; polyamines—putrescine, spermine, spermidine; tryptophan, 5-hydroxytryptamine (serotonin) and tryptamine—were determined. Data indicated that bud outgrowth is accompanied by the increase in its amino acids and non-reducing sugars accumulation at the early stages of budding. The propagules immersion in the suspension of green microalgae Asterarcys quadricellulare (CCAP 294/1) biomass improved bud sprouting percentage and promoted remarkable sprouts growth, increasing spermidine and reducing putrescine content in sprouts, thus indicating the polyamines as the key compounds of nitrogen metabolism related to sugarcane sprouting and sprouts growth, a pathway that was triggered by microalgae biomass. Departamento de Fitotecnia e Fitossanidade Universidade Federal do Paraná, Paraná Departamento de Química Instituto de Biociências Universidade Estadual Paulista Júlio de Mesquita Filho, São Paulo Departamento de Química Instituto de Biociências Universidade Estadual Paulista Júlio de Mesquita Filho, São Paulo

Functional genomics along with genetic transformation and plant regeneration are used to identify genes of interest, comprising essential tools to obtain plants with desired characteristics. In this study, we described an organogenesis and a genetic transformation protocol for Populus tremula x Populus alba clone 717-1B4 using roots. In the organogenesis experiments the PGRs zeatin, BA and kinetin at different concentrations were evaluated. The effect of explant age was evaluated and at 30 days “old” roots (6 months old) showed a higher regeneration rate when compared to “young” roots (2 months old). In the genetic transformation experiments kanamycin concentration, the use of sonication (SAAT), co-cultivation period and explant age were evaluated. Sonication positively affected transformation, while co-cultivation time did not interfere. Regarding explant age, no statistical differences were observed. Quantitative real-time PCR (qPCR) data showed that among the six transgenic plants evaluated, two presented two copies and the others only one copy of the gene. In this study, efficient protocols of organogenesis and genetic transformation for poplar roots are presented with a transformation efficiency of 58%.

Logistic regression analysis is a technique that may aid genetic breeding programs in the selection of clones, especially in the early stages where experimental accuracy is low. This research aimed to identify the most important agronomic traits for energy cane clonal selection, and to verify the efficiency of the logistic model in predicting the genotypes to be selected. Evaluations were carried out on 220 clones in the first ratoon. The data were subjected to binary logistic regression analysis. Stalk number per meter was the most important trait in the selection of energy cane clones. In addition, plants with lower grade for smut incidence had a greater chance of being selected. The predictive capacities of the qualitative and quantitative models were 94% and 88%, respectively. The use of a qualitative model proved to be effective at predicting the number of energy cane genotypes to be selected and could be used as a selection strategy. RESUMO: A análise de regressão logística é uma técnica que pode auxiliar programas de melhoramento genético na seleção de clones, especialmente nos estágios iniciais, em que a precisão experimental é baixa. Este trabalho teve como objetivo identificar os principais caracteres agronômicos para a seleção clonal de cana energia e verificar a eficiência do modelo logístico na predição dos genótipos a serem selecionados. As avaliações foram realizadas em 220 clones na primeira soca. Os dados foram submetidos à análise de regressão logística binária. O número de colmos por metro foi um caractere de maior importância na seleção de clones de cana energia. Além disso, os clones com nota menor para incidência de carvão tiveram maior chance de serem selecionados. As capacidades preditivas dos modelos qualitativos e quantitativos foram de 94% e 88%, respectivamente. O uso de um modelo qualitativo mostrou-se eficaz na previsão do número de genótipos de cana energia a serem selecionados e pode ser usado como estratégia de seleção.

In response to the new requirements of the sugar-energy sector, sugarcane breeding programs are addressing the selection of clones for different purposes, e.g., sucrose production, ethanol production for first-generation (1G) and second-generation (2G) biofuels. Consequently, agronomic variables such as fiber content, sucrose content and biomass yield, become more relevant in the selection process, for underlying the definition of conventional, high biomass and multipurpose ideotypes. The relation between fiber and sucrose contents and biomass quantity should be used to differentiate thee different clone types: conventional clones, with high sucrose content and high biomass; high biomass, with high fiber content and high biomass; or multipurpose, with high fiber and sucrose contents and high biomass. In view of the difficulty of selecting different ideotypes from the same population, the objective of this study was to develop a method of selecting sugarcane clones for the different purposes. A population with 220 clones derived from crosses involving parents of different Saccharum species were subjected to the new methodology of clone selection with a fuzzy controller programmed to classify experimental clones in three ideotypes. Apart from the selection involving real data, the fuzzy controller was tested on 26 simulated populations. The controller proved to be efficient in the classification and selection of clones from the three ideotypes with real and simulated data.

Cultivar RB036091 is an early-maturing sugarcane with a long period of industrial suitability; in the Central South region of Brazil, harvest is recommended between April and August, and the cultivar is indicated for planting on moderate to highly fertile soils. It is widely adaptable and has a high sugar yield and stability of agricultural yield.

The purpose of this study was to select cold-tolerant sugarcane families and clones. Evaluations were carried out during three selection phases in the municipality of Pelotas, state of Rio Grande do Sul, Brazil. The experiments were arranged in an incomplete block design, with initially 4,452 seedlings of 53 full-sib families. Aside from the traits soluble solids content (BRX), tons of stalks per hectare (TSH) and tons of brixper hectare (TBH), the survival of the apical bud (ABS) was evaluated in the first selection stage (T1) of the breeding program. At the end of three selection phases, 15 clones of 14 of the 53 families evaluated in the first phase (T1) were selected for the experimental phase. Of these, the clones RS/PR126066, RS/PR126044, RS/PR126052, RS/PR126007 and RS/PR126033, had a good performance for apical bud survival in the first selection phase. RESUMO: O objetivo desse trabalho foi selecionar famílias e clones de cana-de-açúcar tolerantes ao estresse por frio. As avaliações ocorreram durante três fases de seleção no município de Pelotas, no estado do Rio Grande do Sul, Brasil. Os experimentos foram conduzidos no delineamento de blocos incompletos, sendo inicialmente composto por 4.452 seedlings oriundos de 53 famílias de irmãos completos. Além dos caracteres teor de sólidos solúveis (BRIX), tonelada de colmos por hectare (TCH) e tonelada de brix por hectare (TBH), foi avaliada a sobrevivência do meristema apical (GEM) na primeira fase de seleção (T1) do programa de melhoramento genético. Ao final de três fases de seleção, 15 clones pertencentes a 14 das 53 famílias avaliadas na primeira fase (T1) foram selecionados para a fase de experimentação, destes, destacam-se: RS/PR126066, RS/PR126044, RS/PR126052, RS/PR126007 e RS/PR126033, pois além de apresentar desempenho satisfatório para os caracteres TCH e TBH, foram avaliados com notas máximas (N4 e N5) para sobrevivência de gema apical no primeiro ciclo de seleção.

Brazil is the world's third largest beer consumer and currently imports all of its hops for the brewing industry. Such a fact justifies the selection of hop genotypes adapted for cultivation locally, which requires high quality seeds and efficient sex determination of the seedlings. The objectives of this study were to develop a methodology to assess hop seed quality and to efficiently determine hop seedling sex through the use of male-specific molecular markers. Freshly harvested hop seeds were germinated with and without pre-chilling (3-5 ° C) for 3, 6 and 12 weeks and then germinated at 20 or 25 ° C in the presence or absence of light, evaluating germination percentage and germination speed index. F1 progenies were obtained from after seed germination in a greenhouse and seedlings sex was determined using male-specific molecular markers. The best conditions for physiological quality assessment of hop seeds used in the present study were pre-chilling for 12 weeks, followed by germination at 25 ° C, and normal seedling counts at 7 and 15 days. The progeny submitted to molecular marker sexing was composed of 61.3% female plants. The established methodologies presented here can be considered efficient and may contribute to expedite hops breeding programs.

The sugarcane cultivar RB036066 is medium-maturing and has a long period of industrial suitability; in the South-Central region, harvest is recommended between June and September, and it is indicated for planting on medium to highly fertile soils. The cultivar is widely adaptable and has high sugar yield and stability of agricultural production.

Os objetivos deste estudo foram avaliar a reação de 28 cultivares de cana-de-açúcar à ferrugem alaranjada, em campo, estabelecendo uma época de avaliação adequada para os programas de melhoramento e determinar os períodos de incubação e latência, incidência e severidade na cultivar padrão suscetível, em casa-de-vegetação. No campo, a severidade foi avaliada em cana-planta (dez meses) e em cana-soca (três, cinco, sete e nove meses). A partir destes dados, calculou-se a área abaixo da curva de progresso da doença (AACPD). Para estabelecer a época de avaliação adequada, calculou-se a correlação de Pearson entre os resíduos das datas com os da AACPD. Em casa-de-vegetação, inoculou-se a cultivar RB72454 e avaliou-se incidência e severidade. Das cultivares avaliadas, 14 foram suscetíveis à ferrugem alaranjada, sendo discriminadas em quatro grupos de suscetibilidade. A avaliação em maio (cana-soca, aos nove meses), foi a que mais se correlacionou com a AACPD, sendo a época adequada para avaliar a reação de cultivares à doença, no norte do Estado do Paraná. O período de incubação e latência na cultivar padrão suscetível foi de sete e dez dias, respectivamente. A cultivar RB72454 é a única altamente suscetível à ferrugem alaranjada e as demais avaliadas apresentam menores graus de suscetibilidade.

The sugarcane cultivar RB036088 is late-maturing, harvested from September to November in south-central Brazil, and is recommended for soils with medium to high fertility. It stands out with continuously high sugar yield over the harvests, longevity of the ratoon plants, high tillering capacity and can be harvested mechanically.

This study aimed to evaluate the effect of factors that may affect the genetic transformation of cotiledonary explants of Eucalyptus saligna mediated by EHA105 strain of Agrobacterium tumefaciens. The vector pBI121 carrying gus gene under control of 35S CaMV promoter was used. The effect of the following factors was evaluated: explant pre-culture, use of different antibiotics and presence of acetosyringone (AS) in co-culture media. An antioxidant solution was also used during excision, containing ascorbic acid (250mg.L-1), citric acid (25mg.L-1) and PVP-40 (1g.L-1). Pre-culture of the explants before the co-culture with bacteria was done over a 4-day period in MS culture medium supplemented with 4.4µM BAP and 2.7ìM NAA. After theco-culture period, three concentrations of kanamycin (12.5;25 and 50mg.L-1) combined with 300mg.L-1 Augmentin® in the culture medium were tested The influence of the antibiotic was also evaluated by keeping the explants in a medium containing 50mg.L-1 Km and 300mg.L-1 Augmentin® or 500mg.L-1 cefotaxime. It was concluded that Augmentin® stimulates organogenesis, that a Km concentration of 12.5mg.L-1 allows selection of explants transformed with gus gene and, finally, the addition of AS (50ìM) to the liquid and solid co-culture media has a positive effect on gus gene expression. Moreover, the use of an antioxidant solution during cotyledon excision is dispensable and the pre-culture of the explants has no effect on bud regeneration or gus gene expression. A transformation efficiency of 1.5% was reached. RESUMO Esse trabalho teve como objetivo avaliar o efeito de vários fatores que podem afetar a transformação genética de explantes cotiledonares de Eucalyptus saligna mediante co-cultura com a cepa EHA105 de Agrobacterium tumefaciens. Foi utilizado o vector pBI121 carregando o gene repórter gus sob controle do promotor 35SCaMV. Foi estudado o efeito dos fatores a seguir: pré-cultura dos explantes, uso de diferentes antibióticos e presença de acetosiringona (AS) nos meios de co-cultura. Uma solução contendo ácido ascórbico (250mg.L-1), ácido cítrico (25mg.L-1) e PVP-40 (1g.L-1) foi utilizada no momento da excisão dos explantes. A pré-cultura dos explantes antes da co-cultura com a bactéria foi de 4 dias, em meio de cultura MS suplementado de 4,4µM BAP e 2,7ìM ANA. Após a co-cultura três concentrações de canamicina (12,5; 25 e 50mg.L-1) combinadas com 300mg.L-1 de Augmentin® no meio de cultura foram testadas. O efeito do Augmentin® (300mg.L-1) nos explantes foi comparado ao da cefotaxima (500mg.L-1), em meio contendo 50mg.L-1de Km. Foi concluído que Augmentin® estimula a organogênese, em comparação com a cefotaxima, que a concentração de 12,5mg.L-1 de Km permite a seleção de explantes transformados com o gene gus e, finalmente, a adição de AS (50ìM) aos meios de co-cultura líquido e sólido tem efeito positivo sobre a expressão do gene gus. O uso de antioxidante não é necessário e a pré-cultura dos explantes antes da inoculação com A. tumefaciens não tem efeito na regeneração de gemas nem na expressão do gene gus. A eficiência de transformação foi de 1,5%.

In the present study, the effects of two CaCl2.2H2O levels (440 and 1320 mg L-1) and two subcultures were evaluated on in vitro shoots of Lavandula angustifolia cv. Provence Blue. Ca2+ content of the apical, middle and basal portion of shoots was determined. Increasing CaCl2.2H2O level in the culture medium increased tissue Ca2+ content and decreased hyperhydricity. Shoot-tip necrosis also decreased with 1320 mg L-1 CaCl2.2H2O, but it did not occur in the second subculture. The middle and basal portion had higher Ca2+ content than apical portion. In non-hyperhydric tissues, there were smaller and more juxtaposed cells. Scanning electron microscopy of the leaves demonstrated that trichomes from in vitro leaf surface occurred in smaller quantities.

High salinity interferes in sugarcane growth and development, affecting not only crop yield but also reducing sucrose concentration in culms. Sugarcane plants submitted to salt stress can accumulate compatible solutes, such as proline, which may counteract the effects of salt accumulation in the vacuole and scavenge reactive oxygen species. The objective of this study was to evaluate the response to salt stress of sugarcane plants transformed with the Vigna aconitifolia P5CS gene, which encodes ∆1-pyrroline-5-carboxylate synthetase, under the control of a stress-induced promoter AIPC (ABA-inducible promoter complex). For this, 4-month-old clonally multiplied sugarcane plants from two transformation events were irrigated every 2 days with 1/10 Hoagland’s solution supplemented with 100, 150 and 200 NaCl, progressively, during 28 days. Transgenic lines showed increased transgene expression in 3.75-fold when compared with the control plants after 9 days of irrigation with saline water, which can explain the higher proline concentration found in these plants. At the end of the experiment (day 28), the transgenic lines accumulated up to 25 % higher amounts of proline when compared with non-transformed control plants. Stress response in transgenic plants was also accompanied by a reduction of malondialdehyde (MDA) derived from cellular lipid peroxidation in leaves, lower Na+ accumulation in leaves and maintenance of photochemical efficiency of PSII. Thus, proline contributed to the protection of the photosynthetic apparatus and the prevention of oxidative damage in transgenic sugarcane under salt stress.

http://dx.doi.org/10.5902/1980509814572Os objetivos deste trabalho foram avaliar diferentes meios de cultura na organogênese indireta e na multiplicação in vitro de brotos de Eucalyptus benthamii x Eucalyptus dunnii. Para organogênese, explantes foliares foram excisados no sentido transversal e cultivados in vitro, sendo os seguintes fatores testados: dois meios de cultura (MS N/2 e JADS) adicionados de 0,1 μM de ANA, duas concentrações de thidiazuron (0,1 e 0,5 μM) e presença ou não de PVP-40 (250 mg L-1). Após 70 dias de cultivo foram avaliadas as porcentagens de explantes oxidados totalmente, formando calo, produzindo antocianina, formando gema, formando brotações e o número de brotações formadas por explante regenerando. No experimento de multiplicação, brotações isoladas foram cultivadas em meio MS, JADS e WPM, adicionados de 1,11 μM de BAP. Foram realizados quatro subcultivos a cada 28 dias e em cada subcultivo foram avaliados: a porcentagem de oxidação, de explantes apresentando clorose total ou parcial, massa fresca e número médio de brotos por explante. O meio de cultura MS N/2 suplementado com 0,1 μM de ANA, 0,5 μM de TDZ e PVP-40 promoveu a maior taxa de organogênese (8,3%). No meio de cultura MS com 1,11 μM de BAP, a taxa de multiplicação foi maior que nos outros meios, no primeiro e segundo subcultivos (9,28 e 9,24 por mês), não havendo diferença entre os três meios nos demais subcultivos.

Polyploid plants can exhibit transcriptional modulation in homeologous genes in response to abiotic stresses. Coffea arabica, an allotetraploid, accounts for 75 % of the world’s coffee production. Extreme temperatures, salinity and drought limit crop productivity, which includes coffee plants. Mannitol is known to be involved in abiotic stress tolerance in higher plants. This study aimed to investigate the transcriptional responses of genes involved in mannitol biosynthesis and catabolism in C. arabica leaves under water deficit, salt stress and high temperature. Mannitol concentration was significantly increased in leaves of plants under drought and salinity, but reduced by heat stress. Fructose content followed the level of mannitol only in heat-stressed plants, suggesting the partitioning of the former into other metabolites during drought and salt stress conditions. Transcripts of the key enzymes involved in mannitol biosynthesis, CaM6PR, CaPMI and CaMTD, were modulated in distinct ways depending on the abiotic stress. Our data suggest that changes in mannitol accumulation during drought and salt stress in leaves of C. arabica are due, at least in part, to the increased expression of the key genes involved in mannitol biosynthesis. In addition, the homeologs of the Coffea canephora subgenome did not present the same pattern of overall transcriptional response, indicating differential regulation of these genes by the same stimulus. In this way, this study adds new information on the differential expression of C. arabica homeologous genes under adverse environmental conditions showing that abiotic stresses can influence the homeologous gene regulation pattern, in this case, mainly on those involved in mannitol pathway.

The climatic influence in minerals content of peach palm heart (Bactris gasipaes Kunth) was studied and a quick method was assessed to determine Mg, Cl, K and S in the basal portion of peach palm heart based on multivariate predictive model using agro-meteorological data. A total of 24 samples of B. gasipaes Kunth were collected along 14 to 18 months of cultivation, growing in two types of terrain: hillside and lowland. Principal component analysis (PCA) was used to select principal components. The data were modeled using partial least squares regression (PLS). Low average relative prediction errors (4.60%) confirm the good predictability of the models. The factors that most influence the minerals content prediction model were the rain precipitation and solar radiation. The results show that predictive model can be used as rapid method to determine the mineral content in the basal portion of peach palm heart factories and may help to choose geographical regions suitable for the establishment of new peach palm plantations. The models can provide reductions of cost and time analysis to palm heart without generating laboratory effluents. This is the first time in which multivariate analysis is used to generate models to predict minerals concentration in the basal portion of peach palm hearts, quantifying numerically the intensity of climatic factors in the minerals content.

The response of sugarcane (Saccharum spp.) families to the inoculation with plant growth-promoting bacteria (PGPB) may show positive or negative interaction values depending on the plant genotype, allowing the selection of responsive genotypes to the association. Based on these precepts, this study aimed to evaluate the response of 27 sugarcane families treated with two PGPB-based inoculants in two sugarcane cycles: plant-cane and first ratoon. Four months after germination, 27 families from crosses between clones of sugarcane were: (T0) not inoculated; (T1) inoculated with Triazo, which consists of a mixture of the strains Abv5, Abv6, and Abv7 of Azospirillum brasilense; and (T2) inoculated with an inoculant called Mix, which contains five strains of PGPB (Gluconacetobacter diazotrophicus Pal5, Azospirillum amazonense CBAmC, Burkholderia tropica Ppe8, Herbaspirillum rubrisubalbicans HCc103, and Herbaspirillum seropedicae HRC54). The productivity traits evaluated were the number of stalks, average height, stalk diameter, and Brix. The correlation values between the two cycles were 0.87 for the number of stalks, 0.70 for average height, 0.48 for stalk diameter, and 0.63 for Brix. Differences were observed between treatments for average height, stalk diameter, and Brix. Differences were also observed between families for all the studied traits. Brix was the only parameter that presented a significant interaction between family and inoculant. Different responses were observed between cycles for some families, showing that other factors can also influence the association.

Sugarcane is of great economic importance worldwide. Hence, there is great interest in the development of effi­cient techniques for the production of good quality, homogeneous, disease- and pest-free seedlings. One way to eliminate viruses is through meristem culture. To guarantee success during meristem culture, it is necessary to optimize the components and concentrations of the culture medium. Sucrose is an essential component in the culture medium, serving as a source of carbon and energy for the seedlings. Nitrogen, in turn, is essential in plants because it is a component of biomolecules and countless enzymes. This work evaluates the best combina­tion of nitrogen (75, 100, 125, and 150%) and sucrose (0, 20, 30, and 40 g L -1 ) concentrations in the in vitro multi­plication and development of sugarcane cultivar RB036091. The design was completely randomized, in a factorial scheme with four replicates and five explants per experimental unit. The concentration of 20 g L -1 sucrose with 100% nitrogen, from the original formulation of the MS culture medium, provided a better response in sugarcane multiplication.

At present, the sugarcane (Saccharum spp.) breeding programs from around the world have practiced early family selection, because in the early stages of breeding the evaluated characteristics have shown low heritability. This study aimed to select through restricted maximum likelihood/best linear unbiased prediction also known “mixed models” the best families among the 78 that comprise the RB05 sugarcane series, stage T1, of Programa de Melhoramento Genetico da Cana-de-acucar of the Rede Interuniversitaria para o Desenvolvimento do Setor Sucroalcoleiro, Brazil. The experiments, conducted during 2007/2008 and 2008/2009 in Paranavai, PR were implemented using an incomplete-block design with five replicates of each family. Each plot was composed of two planting rows of 5 m, spaced from each other by 1.40 m and spacing between plants was of 0.50 m, containing ten seedlings for planting row, resulting in a total of 20 individuals per replicate of each family. The characteristics evaluated were Brix (°Brix), ton of stalk per hectare (TCH) and ton of °Brix per hectare (TBH). The joint analysis obtained from these three traits in both harvests favored the selection of 35–41 families. The analysis also favored the selection of the best parents. The top five families for Brix were: F41M60, F02M77, F41M82, F61M38 and F62M35; to TCH were F66M30, F35M06, F78M45, F70M30 and F57M46 and for TBH the five elites families were F66M30, F35M06, F78M45, F70M30 and F01M39. The five best sugarcane parents for Brix were RB835486, SP91-1049, SP80-3280, RB72454 and RB925211; to TCH were IAC87-3396, RB941531, RB855511, RB915141 and RB957689, and for TBH the elite were IAC87-3396, RB855511, RB957689, RB941531 and RB855563. As each harvest season had different order of the best families, the joint analysis proved to be a primordial tool for plant breeders.