Ripening Of Sugarcane Research Articles

Bioestimulante para maturação de cana-de-açúcar em lavouras fertirrigadas por gotejamento

ABSTRACT In irrigated fields, sugarcane’s vegetative growth and carbohydrate consumption during ripening require ripener management options to improve crop yield. The hypothesis is that ripeners, together with nutrients, biostimulants, and amino acids, improve physiological responses that favor the quality of the raw material and increase the sucrose content. Consequently, the study aimed to evaluate the agro-industrial response of a fertigated sugarcane crop to ripening agents. The treatments consisted of applying chemical ripener (CR), nutritional ripener (NR), and a joint application of NR+CR, besides control with four replicates. Agro-industrial attributes (total soluble solids, apparent sucrose (AS), reducing sugars (RS), total recoverable sugar (TRS), purity, fiber, sucrose in the stalk (SS) were evaluated at 0 (before application), 12, 19, 36, and 60 days after application (DAA). The time modified the technological attributes of sugarcane under ripener application. The highest apparent sucrose and total soluble solids values were obtained with NR+CR compared to the control. The NR and NR+CR treatments presented the highest TRS contents (150 kg Mg-1) at 36 DAA. Furthermore, the NR+CR treatment increased fiber content but did not compromise the quality of the raw material, and it showed high contents of SS and purity percentage, as well as low contents of RS. The chemical and nutritional ripeners efficiently promoted sugarcane ripening in areas without drying off before harvest. NR application at the end of the cycle can potentially increase sugar yield.

Residue Content of Sugarcane Ripener Active Ingredients and Its Effect on Ratoon’s Growth in North Sumatera

Residue Content of Sugarcane Ripener Active Ingredients and Its Effect on Ratoon’s Growth in North Sumatera

Endocrine, immune and renal toxicity in male largemouth bass after chronic exposure to glyphosate and Rodeo®.

Glyphosate is the most used herbicide worldwide, with no historical comparison. It is used for genetically modified crops, and particularly in Florida, it is used as a sugar cane ripener. An aquatic formulation (Rodeo®) is used to treat aquatic weeds in waterbodies and drainage canals. Because of its extended use, glyphosate can run off or be sprayed directly into waterbodies, and chronically expose aquatic wildlife. Exposure in animal models has been associated with kidney and liver damage and glyphosate has been suggested as an endocrine disruptor. We exposed adult male largemouth bass for 21 days to two doses of glyphosate and Rodeo® (chemically equivalent concentration of glyphosate) at 0.5 mg L-1 and 10 mg L-1 and to a clean water control (n=4 fish/tank in quadruplicate). Concentrations during the experiment were corroborated with UHPLC-MS/MS. Total RNA was isolated from the trunk kidney and head kidney. RNA-seq was performed for the high doses compared to controls. Transcripts were analyzed with fish and mammalian pathway analyses software. Transcripts mapped to Zebrafish metabolic pathways using PaintOmics showed steroid hormone biosynthesis in the trunk kidney as the most significantly enriched pathway. Steroid hormones were measured in plasma by UHPLC-MS/MS. Total androgens were significantly reduced at 0.5 mg L-1 of glyphosate and at equivalent concentrations in Rodeo® compared to controls. 11-ketotestosterone and estrone concentrations were significantly reduced in all doses. A gene involved in the conversion of testosterone to 11-ketotestosterone was down-regulated by glyphosate. Using the mammalian pathway analysis algorithm, cellular processes associated with T-cell activation/development and intracellular pH were significantly enriched in the trunk kidney by glyphosate and Rodeo® exposure. Endocrine disruption was corroborated at the hormone and gene expression levels. Rodeo® and glyphosate share gene expression pathways, however, Rodeo® had more pronounced effects in largemouth bass.

Soil Chemical Properties and Agronomic Response of Sugarcane (Saccharum officinarum L.) Due to Long Term of No-Tillage Practice and Bagasse Mulch Application

Intensive tillage will continuously reduce soil quality, characterized by decreased soil C-organic. Low soil C-organic indicates the disturbance of soil fertility. More conservative soil management experiments have been done for seven years to restore the soil quality for sugarcane (Saccharum officinarum L.) productivity. This research aimed to study the effect of the tillage system, bagasse mulch, and their interactions on soil chemical properties and sugarcane agronomic response. The research was conducted on a Split Plot of five groups. The main plot was the tillage system consisting of intensive tillage and no-tillage, while the subplot was the bagasse mulch consisting of bagasse mulch and no-bagasse mulch. This study found that in sugarcane cultivation, no-tillage system was beneficial for soil P-available, sugarcane length, and sugarcane ripening; bagasse mulch was beneficial for soil C-organic and also soil P-available. The no-tillage system to increase P-available can be combined with bagasse mulch or no-bagasse mulch, but the no-tillage system combined with no-bagasse mulch increases the percentage of gap in sugarcane cultivation.

Glyphosate applied at a hormetic dose improves ripening without impairing sugarcane productivity and ratoon sprouting

The management of sugarcane ripening is essential to ensuring the supply of high-quality raw material for the sugar-alcohol industry; chemical ripeners are frequently used to accelerate sucrose accumulation in the stalks during harvesting. The potential ripening effect of a low dose of glyphosate was evaluated in sugarcane, along with its impact on productivity and sprouting in the next crop cycle. A field experiment was conducted in 2015 and 2016 using a randomized block design with eight replicates in a split-plot scheme, with the following treatments: (1) control with only water application, (2) glyphosate at a low dose of 1.8 g a.e. ha−1 (corresponding to 0.005 L ha−1 of the commercial product (cp)), and (3) glyphosate at the commercially recommended dose for a ripener at 180 g a.e. ha−1 (corresponding to 0.50 L ha−1 of the cp) applied at 60, 45, 30, and 15 days before harvest (DBH). The harvest was performed on May 25, 2016 (0 DBH), and a total of five periods were evaluated. This study showed that the application of a hormetic dose of glyphosate to stimulate sugarcane ripening is promising, despite the limited duration of the effect. The application of the hormetic dose (1.8 g a.e. ha−1) at 30 DBH improved the technological quality of sugarcane in terms of Brix% juice, pol% cane, purity% juice, moisture% cane, reducing sugars, total reducing sugars, and total recoverable sugar. Additionally, it increased pol productivity, and did not affect ratoon sprouting in the subsequent cycle. Thus, this study provides a strategy for ripening management with a low environmental impact for sugarcane producers through a low (hormetic) dose of glyphosate.

Effect of subdoses of sugarcane ripeners on lettuce physiology in a drift scenario.

In order to understand the physiological effects of ripeners in sensitive crops, the objective of this work was to evaluate the effect of subdoses of the ripeners glyphosate, trinexapac-ethyl and sulfometuron methyl commonly used in sugarcane, in the growth of lettuce cultivar 'Lucy Brown' and 'Vanda'. To address the effects of the products in the lettuce physiology, analyses of fresh weight, dry weight, number of leaves, chlorophyll content, quantum efficiency of photosystem II, lipid peroxidation (MDA), hydrogen peroxide (H2O2), glutathione reductase (GR), guaiacol peroxidase (GPOX) were performed. We observed that among the products tested, glyphosate had minor impact on plant growth, compared to trinexapac-ethyl and sulfometuron methyl. All products induced a decrease in chlorophyll content for both cultivars. Chlorophyll A fluorescence suffered a major reduction with trinexapac-ethyl and sulfometuron methyl in 'Vanda' and no differences were observed for 'Lucy Brown'. MDA content and enzyme quantification varied by cultivar and the sugarcane ripener tested. By disturbing chlorophyll content and quantum efficiency of photosystem II, through these sugarcane ripeners did not have direct mode of action affecting photosystem II, they can cause some level of damage and activate different mechanisms and at different times, in response to stress. In this sense, it is possible to observe that reduced doses of glyphosate, trinexapac ethyl, and sulfometuron methyl affect the development of lettuce at different levels and trigger an oxidative response that was cultivar dependent.

Chronic exposure to glyphosate in Florida manatee

Florida manatees depend on freshwater environments as a source of drinking water and as warm-water refuges. These freshwater environments are in direct contact with human activities where glyphosate-based herbicides are being used. Glyphosate is the most used herbicide worldwide and it is intensively used in Florida as a sugarcane ripener and to control invasive aquatic plants. The objective of the present study was to determine the concentration of glyphosate and its breakdown product, aminomethylphosphonic acid (AMPA), in Florida manatee plasma and assess their exposure to manatees seeking a warm-water refuge in Crystal River (west central Florida), and in South Florida. We analyzed glyphosate’s and AMPA’s concentrations in Florida manatee plasma (n = 105) collected during 2009–2019 using HPLC-MS/MS. We sampled eight Florida water bodies between 2019 and 2020, three times a year: before, during and after the sugarcane harvest using grab samples and molecular imprinted passive Polar Organic Chemical Integrative Samplers (MIP-POCIS). Glyphosate was present in 55.8% of the sampled Florida manatees’ plasma. The concentration of glyphosate has significantly increased in Florida manatee samples from 2009 until 2019. Glyphosate and AMPA were ubiquitous in water bodies. The concentration of glyphosate and AMPA was higher in South Florida than in Crystal River, particularly before and during the sugarcane harvest when Florida manatees depend on warm water refuges. Based on our results, Florida manatees were chronically exposed to glyphosate and AMPA, during and beyond the glyphosate applications to sugarcane, possibly associated with multiple uses of glyphosate-based herbicides for other crops or to control aquatic weeds. This chronic exposure in Florida water bodies may have consequences for Florida manatees’ immune and renal systems which may further be compounded by other environmental exposures such as red tide or cold stress.

Identification of proteins and metabolic networks associated with sucrose accumulation in sugarcane (Saccharum spp. interspecific hybrids)

ABSTRACT The rate of improvement of sugar content in sugarcane remains low for decades worldwide. Our previous transcriptome studies provided an atlas of sucrose accumulation-related gene expression, but little is known about the proteins involved. Here, we conducted a proteomic analysis of experimentally altered sucrose accumulation in sugarcane. Analysis of stem proteomes of sugarcane ripener ethephon treated high- and low-sugar genotypes had identified 2983 proteins of which 139 were significantly differentially expressed (DEPs). These DEPs were found to be associated with sugar metabolism-related processes with 25 of them may have a regulatory role in sucrose accumulation. The key proteins identified include UDP-glucose 6-dehydrogenase associated with amino sugar and nucleotide sugar metabolism; those involved in carbon fixation; and fructokinase, β-D-glucosidase, and α-glucan phosphorylase involved in starch and sucrose metabolism. Distinct genotype- and ethephon-dependent DEP expression was evident providing new insights into one of the most intractable sugarcane traits to breeding.

Modeling of Sugarcane Felling Information System Using the Use Case Driven Object Method

Use case driven object is a method for controlling object-oriented modeling based on functions or operations in the system (use case). Sistem Informasi Tebang Angkut Tebu (SITAT) is an operational information system for cutting and transporting sugarcane in a sugar factory. The system was made to improve the method of managing sugarcane plantations, analysis of sugarcane ripening, the process of cutting sugarcane, and the weighing process. Referring to the use case driven object method, this object-based system modeling discussion on SITAT will focus on the stages of designing use case diagrams, use case descriptions, robustness diagrams, and sequence diagrams. The implementation of use case driven method is expected to reduce bad factors, optimize existing resources, improve services to farmers, sugarcane owners or other stakeholders, which will lead to increase efficiency and effectiveness in all processes related to sugarcane transport management.

Effects of meteorological variables on sugarcane ripening in the Cauca river valley, Colombia

ABSTRACT Sugarcane ripening is conditioned by the interaction between biological factors of the crop and climate. This study aimed to evaluate the effects of some meteorological variables on the sucrose content, during the ripening period, in the Cauca river valley (Colombia). The evaluations were conducted at seven locations, during four periods, being each one a three-month period. The meteorological variables of maximum, mean and minimum air temperature, diurnal vapor pressure deficit and precipitation were evaluated with respect to the sucrose variable (% cane). The results showed that a low precipitation and a high vapor pressure deficit increased the sucrose content in the stems. High minimum temperatures during the maturation stage decreased the sucrose levels, although their effect was less noticeable than previously mentioned. The meteorological conditions in the different localities caused substantial differences in the sucrose concentration of the stems, especially during the beginning of the maturation phase. However, these differences were reduced by the age of the crop and by the periods of rainfall or drought occurrence.

Ethylene-mediated improvement in sucrose accumulation in ripening sugarcane involves increased sink strength

BackgroundSugarcane is a major crop producing about 80% of sugar globally. Increasing sugar content is a top priority for sugarcane breeding programs worldwide, however, the progress is extremely slow. Owing to its commercial significance, the physiology of sucrose accumulation has been studied extensively but it did not lead to any significant practical outcomes. Recent molecular studies are beginning to recognize genes and gene networks associated with this phenomenon. To further advance our molecular understanding of sucrose accumulation, we altered sucrose content of sugarcane genotypes with inherently large variation for sucrose accumulation using a sugarcane ripener, ethylene, and studied their transcriptomes to identify genes associated with the phenomenon.ResultsSucrose content variation in the experimental genotypes was substantial, with the top-performing clone producing almost 60% more sucrose than the poorest performer. Ethylene treatment increased stem sucrose content but that occurred only in low-sugar genotype. Transcriptomic analyses have identified about 160,000 unigenes of which 86,000 annotated genes were classified into functional groups associated with carbohydrate metabolism, signaling, localization, transport, hydrolysis, growth, catalytic activity, membrane and storage, suggesting the structural and functional specification, including sucrose accumulation, occurring in maturing internodes. About 25,000 genes were differentially expressed between all genotypes and treatments combined. Genotype had a dominant effect on differential gene expression than ethylene treatment. Sucrose and starch metabolism genes were more responsive to ethylene treatment in low-sugar genotype. Ethylene caused differential gene expression of many stress-related transcription factors, carbohydrate metabolism, hormone metabolism and epigenetic modification. Ethylene-induced expression of ethylene-responsive transcription factors, cytosolic acid- and cell wall-bound invertases, and ATPase was more pronounced in low- than in high-sugar genotype, suggesting an ethylene-stimulated sink activity and consequent increased sucrose accumulation in low-sugar genotype.ConclusionEthylene-induced sucrose accumulation is more pronounced in low-sugar sugarcane genotype, and this is possibly achieved by the preferential activation of genes such as invertases that increase sink strength in the stem. The relatively high enrichment of differentially expressed genes associated with hormone metabolism and signaling and stress suggests a strong hormonal regulation of source-sink activity, growth and sucrose accumulation in sugarcane.

Ethylene-induced transcriptional and hormonal responses at the onset of sugarcane ripening

The effects of ethephon as a sugarcane ripener are attributed to ethylene. However, the role of this phytohormone at the molecular level is unknown. We performed a transcriptome analysis combined with the evaluation of sucrose metabolism and hormone profiling of sugarcane plants sprayed with ethephon or aminoethoxyvinylglycine (AVG), an ethylene inhibitor, at the onset of ripening. The differential response between ethephon and AVG on sucrose level and sucrose synthase activity in internodes indicates ethylene as a potential regulator of sink strength. The correlation between hormone levels and transcriptional changes suggests ethylene as a trigger of multiple hormone signal cascades, with approximately 18% of differentially expressed genes involved in hormone biosynthesis, metabolism, signalling, and response. A defence response elicited in leaves favoured salicylic acid over the ethylene/jasmonic acid pathway, while the upper internode was prone to respond to ethylene with strong stimuli on ethylene biosynthesis and signalling genes. Besides, ethylene acted synergistically with abscisic acid, another ripening factor, and antagonistically with gibberellin and auxin. We identified potential ethylene target genes and characterized the hormonal status during ripening, providing insights into the action of ethylene at the site of sucrose accumulation. A molecular model of ethylene interplay with other hormones is proposed.

Chemical ripening of sugarcane with trinexapac-ethyl (Moddus®) — Mode of action and comparative efficacy

Chemical ripeners cause growth suppression, thus increasing sucrose accumulation in sugarcane by lowering the growth sink demand for sucrose. Trinexapac-ethyl (Moddus®), the most recent chemical to be introduced as a ripener with a hormonal mechanism, inhibits production of the plant hormone gibberellic acid, which leads to restriction of internode elongation. This study reports novel findings on a dual mode of action, by which Moddus® affects growth processes in both the stalk and leaf canopy above a certain concentration, and how this influences ripening efficacy. In addition the efficacy of Moddus® is compared to Ethephon®, the other ripener with a hormonal mechanism. An irrigated field trial was planted to variety N32 at the South African Sugarcane Research Institute’s research station in Pongola, South Africa. The plant and subsequent three ratoons were used as experimental crops and harvested in April of each year. Replicated treatment plots consisted of 6 cane rows, 16m long and spaced 1.4m apart. Treatments comprised an unsprayed control, Ethephon® applied according to standard practise, and Moddus® applied at three dosages. Products were applied with CO2-pressurised equipment and a hand-held overhead spray boom. Measurements on the stalks (length, individual internode elongation and juice quality) and leaves (green and dead leaf mass per stalk) were conducted at intervals until harvest. At harvest the cane and sugar yield was determined for each treatment. A novel finding was that Moddus®, above a certain concentration, ripened the crop through a dual mode of action involving restriction of both internode elongation and leaf growth. Characterisation of effects on individual internode elongation and mass of the green leaf canopy, coupled to yield data, provided insights to be considered in future when attempting to explain varietal differences in response to Moddus®. The easy-to-measure plant processes identified in this study as sensitive indicators of ripening efficacy might enable initial pot-based screening of large numbers of varieties for responsiveness to Moddus®, before embarking on more time-consuming and expensive field-based testing. The data acquired in this study could also be used in attempts to simulate Moddus®-induced ripening with mechanistic sugarcane crop models.

Photosynthetic and antioxidant responses to drought during sugarcane ripening

Water deficit is an important exogenous factor that enhances the influx of sucrose into sugarcane (Saccharum spp.) stem internodes during ripening, when photosynthetic ability in supplying sinks is essential. The aim of this study was to test the hypothesis that drought tolerance in sugarcane is associated with an effective antioxidant protection during the ripening phase that might maintain a favorable redox balance in chloroplasts and protect photosynthesis under drought conditions. Two commercial sugarcane varieties, IACSP94-2094 (tolerant) and IACSP96-2042 (sensitive), with contrasting behavior under water deficit, were subjected to water withholding during the ripening stage. Our results revealed that the tolerant variety was less affected by water deficit, maintaining photosynthesis for a longer period and showing a faster recovery after rehydration as compared to the sensitive one. As consequence, the tolerant variety faced lesser excess of light energy at PSII. The maintenance of photosynthesis under water deficit and its fast recovery after rehydration resulted in the lower leaf H2O2 concentration and favorable redox status in the drought-tolerant genotype, which was associated with stimulation of superoxide dismutase during ripening. Our results also revealed that ferric superoxide dismutase isoforms were strongly enhanced under drought conditions, playing an important role in chloroplast redox homeostasis.

Modeling sugarcane ripening as a function of accumulated rainfall in Southern Brazil.

The effect of weather variables on sugarcane ripening is a process still not completely understood, despite its huge impact on the quality of raw material for the sugar energy industry. The aim of the present study was to evaluate the influence of weather variables on sugarcane ripening in southern Brazil, propose empirical models for estimating total recoverable sugar (TRS) content, and evaluate the performance of these models with experimental and commercial independent data from different regions. A field experiment was carried out in Piracicaba, in the state of São Paulo, Brazil, considering eight sugarcane cultivars planted monthly, from March to October 2002. In 2003, at the harvest, 12 months later, samples were collected to evaluate TRS (kg t(-1)). TRS and weather variables (air temperature, solar radiation, relative humidity, and rainfall) were analyzed using descriptive and multivariate statistical analysis to understand their interactions. From these correlations, variables were selected to generate empirical models for estimating TRS, according to the cultivar groups and their ripening characteristics (early, mid, and late). These models were evaluated by residual analysis and regression analysis with independent experimental data from two other locations in the same years and with independent commercial data from six different locations from 2005 to 2010. The best performances were found with exponential models which considered cumulative rainfall during the 120 days before harvest as an independent variable (R (2) adj ranging from 0.92 to 0.95). Independent evaluations revealed that our models were capable of estimating TRS with reasonable to high precision (R (2) adj ranging from 0.66 to 0.99) and accuracy (D index ranging from 0.90 to 0.99), and with low mean absolute percentage errors (MAPE ≤ 5 %), even in regions with different climatic conditions.

Multivariate analysis of the temporal variability of sugarcane ripening in south-eastern Brazil

Sugarcane ripening is a process controlled by cultivar characteristics and the interaction of genotypes with local climate. The objective of this study was to characterise the temporal variation of sugarcane ripening by assessing the multivariate structure contained in sugarcane quality data, and by correlating the results with local climatic conditions. Eight sugarcane cultivars were evaluated from March to October in Piracicaba, São Paulo State, Brazil. Characteristics related to the quality of raw sugarcane juice were submitted to statistical analysis by ANOVA, hierarchical and non-hierarchical (k-means) clustering methods, and principal components, in order to classify the cultivars into groups for each month of sampling. The ANOVA showed a clear difference (P < 0.001) among harvesting months for all sugarcane quality variables, which was reinforced by the cluster analysis for the whole dataset that selected groups according to the month of harvest. By analysing the quality variables by months, patterns of similarity among sugarcane cultivars were identified, which allowed three ripening groups to be established: early, middle and late. As the harvesting season progressed, the variations within each group, as well as among groups, were explained mainly by local soil-water availability conditions. The early ripening cultivars showed polarisable sugar (Pol) values >13% in early May, whereas these values were reached by the middle cultivars in July, and the late ones in August–September. However, the differences among groups tended to decrease through the harvest season, as expressed by the Euclidean distance, which decreased from 5.62 in March to 1.82 in September, when the water deficit reached the maximum accumulated value, totalling >130 mm. The non-hierarchical analyses (k-means) and principal components methods agreed, resulting in the identification of the same three main cultivar groups. The approach proposed for cultivar classification in this study is more complete than the usual analysis of Pol variation over time, since it allowed all of the variability contained in the sugarcane quality dataset to be analysed in an integrated way, providing a better understanding of the differences observed in the ripening of different cultivars.

Climatic effects on sugarcane ripening under the influence of cultivars and crop age

The lack of information about the effects of cultivars, crop age and climate on the sugarcane (Saccharum ssp.) crop yield and quality has been the primary factor impacting the sugar-ethanol sector in Brazil. One of the processes about which we do not have a satisfactory understanding is sugarcane ripening and the effects of cultivars, crop age and climate on that. Sugarcane ripening is the process of sucrose accumulation in stalks, which is heavily influenced by several factors, mainly by climatic conditions such as air temperature and water deficits. Because it is a complex process, studies of the variables involved in sugarcane ripening can provide important information, resulting in a better use of commercial cultivars, bringing advantages to growers, processing units, breeding programs and scientific community. In this review, we discuss the available knowledge of the interaction between climate conditions and sugarcane ripening, under the influence of genotypic characteristics and crop age. In several studies, the main conclusion is that sugarcane ripening depends on a complex combination of climate variables, the genetic potential of cultivars and crop management. Soil moisture and air temperature are the primary variables involved in sugarcane ripening, and their combination stimulates the intensity of the process. In addition, the need for studies integrating the effects of climate on plant physiological processes and on the use of chemical agents to stimulate sugarcane ripening is highlighted.

Evaluation of Trinexapac-ethyl (Moddus®) as a New Chemical Ripener for the South African Sugarcane Industry

Although information from Brazil and Australia indicate that trinexapac-ethyl (Moddus®) is an excellent new sugarcane ripener, there is no information on the response of South African varieties to this chemical. The objective of this investigation was to establish the ripening potential of this chemical in a local variety and to compare responses with current industry standards, 2-chloroethyl phosphonic acid (Ethephon®) and fluazifop-p-butyl (Fusilade Forte®). Evaluation was conducted in an irrigated plant and first ratoon crop of variety N32 at Pongola, South Africa. The field trial was laid out as a complete randomised design with five replicates per treatment. The nine treatments comprised: (a) untreated control, (b) Ethephon® (1.5 L/ha) applied 84 days before harvest (DBH), (c) Fusilade Forte® (0.2 L/ha) applied 43 DBH, (d) Moddus® at three rates (0.8, 1 and 2 L/ha) applied 70 DBH, (e) Ethephon® (1.5 L/ha) and Fusilade Forte® (0.2 L/ha) applied in combination 84 and 43 DBH, and (f) Moddus® (0.8 and 1 L/ha) and Fusilade Forte® (0.2 L/ha) applied in combination 70 and 43 DBH. The various ripener treatments improved estimated recoverable crystal (ERC) yields in the 12-month old crops by between 1.6 and 4.9 t/ha when compared with the control. Moddus® applied at 0.8 and 1 L/ha achieved similar improvements as Fusilade Forte® and Ethephon®, but at 2 L/ha outperformed the latter two ripeners by up to 1.9 t ERC/ha. Best ERC yield responses were achieved in the three combination treatments. However, the Moddus®—Fusilade Forte® combination treatments outperformed the standard Ethephon®—Fusilade Forte® combination treatment by up to 1 t ERC/ha. These results indicate that Moddus® is an effective sugarcane ripener under South African high-potential irrigated conditions and that improved in ERC yields exceeding those obtained with current industry standards might be possible.

Fertilización nitrogenada, edad de la plantación al cosechar y la calidad de la caña de azúcar en un suelo moderadamente salino

El estudio se realizó en el campo Zapote C-D, Agro Industrial Tumán, costa norte del Perú, Departamento de Lambayeque. En este campo moderadamente salino (1,98-8,66 dSm-1) se estudiaron cinco dosis de N (180, 250, 320, 390, 460 kg ha-1de N) por edad, con cuatro repeticiones, y una parcela testigo sin aplicación de N por cada edad; y cinco edades de la plantación al momento de cosechar (12,3, 15,5, 20,0, 23,3, 26,5 meses). Se plantó el cultivar de caña de azúcar H32-8560 (caña planta). En cada cosecha, se realizó el análisis de la calidad de la caña: Sacarosa, brix, pureza, azúcares reductores, fibra y humedad. Se efectuó el Análisis de Varianza para estudiar el efecto de las dosis de N y de la edad, en la calidad. Los resultados de calidad se relacionaron (vía análisis de regresión) con la salinidad promedio de los primeros 60 cm del suelo, de cada parcela, a la plantación, con las dosis de N, y con la edad de la caña. Se encontró que las aplicaciones de N no afectaron a la calidad de la caña. La salinidad moderada del suelo antes de la plantación, no estuvo relacionada con ninguna característica de calidad de la caña. La calidad no se afectó, ni por las dosis de nitrógeno, ni por la salinidad del suelo. La calidad de la caña varió con la edad de la plantación al momento de cosechar, presentando un comportamiento similar al que hay en suelos no salinos. La falta de agua no afectó la maduración de la caña.

Herbicides as Ripeners for Sugarcane

Chemical ripening of sugarcane is an important component to profitable sugar production in the United States as well as other sugarcane industries throughout the world. Harvesting of sugarcane often begins before the sugarcane reaches the desirable maturity level. This is especially true in the Louisiana sugarcane industry where the window for harvesting is limited because of the risk of freezing temperatures encountered in a temperate climate. Research on the application of chemicals, mostly of herbicide origin, to enhance sucrose accumulation (ripening) or limit flowering to conserve stored sucrose has been conducted for more than 60 yr. The only sugarcane ripener currently registered for use in the United States is glyphosate applied before harvest. The herbicide fluazifop is used as the primary ripener of sugarcane in South Africa. The herbicides glyphosate, fluazifop, and sulfometuron-methyl and the growth regulators ethephon and trinexapac-ethyl are registered for use in Brazil. There is a continuing need to evaluate sugarcane ripeners to increase the utility of currently registered ripeners and to find additional ripeners for use by sugarcane industries. The need for alternatives to glyphosate is especially critical before a glyphosate-tolerant sugarcane can be utilized to improve control of problematic weeds.