Commercial Sugarcane Research Articles

Heat Tolerance in Sugarcane: Optimum Temperature and Phenological Stage to Determination of Thermotolerance as Selection Criteria

Heat stress is the major abiotic stressor in agriculture which reduces crop productivity and yield. Six sugarcane (Sacharum officinarum L.) genotypes were studied to investigate the impact of three temperature levels at four phenological stages on tissue electrolyte production and the feasibility of using the cell thermostability method (CTM) for the identification and selection of heat tolerant sugarcane genotypes. The cell membrane thermostability was quantified by measuring relative cell injury percentage with a modification in the temperature treatment on four phenological stages in a field experiment. Our results suggest that heat tolerance based on cell membrane thermostability can be improved using the existing genetic variability available within the commercial or experimental sugarcane germplasm. We conclude that the cell membrane thermostability test can be a useful screening procedure for selecting sugarcane genotypes that tolerate high temperature stress. The test can be used in conjunction with a temperature trait of 60 °C during the maturity stage. This procedure predicts the ability of sugarcane genotypes to maintain yield and juice quality under stressful field conditions.

Colonial legacies and contemporary commercial farming outcomes: sugarcane in Eastern Uganda

This article explores the impact of nineteenth-century colonial activities of cash crop farming which altered existing forms of land use from subsistence to capitalist commercial farming. Such modifications had long-term implications for postcolonial development paths by producing and reproducing structures that skew the benefits of commercial farming towards the capitalist agenda at the expense of the welfare of the local population. The article builds on the debates over colonial legacies of agrarian transformation using commercial sugarcane farming in eastern Uganda. Using youth surveys, qualitative tools and document reviews, the authors argue that the detrimental effects of sugarcane farming are a recurrence of capitalism rooted in colonial imperialist policies in Uganda. Through its processes of accumulation by dispossession, colonial-era capitalist systems continue to operate through land seizure for sugarcane farming at the expense of food crops, precipitating food insecurity. It has also pushed the indigenous population into a very vulnerable situation, offering poorly remunerated and extremely exploitative jobs in sugarcane farming. The authors argue that the broader historical context of colonialism is relevant in explaining the contemporary dynamics associated with activities such as commercial farming in postcolonial societies.

Survey of Sugarcane Mosaic Virus disease by using principle components analysis on four ages and its effects on characteristics of two sugarcane varieties on two seasons

Sugarcane mosaic virus(SCMV) is one among many viruses that infects sugarcane; causes yield loss and becomes serious disease on sugarcane plantations. This research aimed to survey it on commercial sugarcane varieties G.T. 54-9 in 19 locations of Esna district Luxor governorate during 2018/19 on 4 ages and effect of infection with virus on growth, juice quality and yield components of two sugarcane varieties viz., G. T. 54-9 and G. 2017-57 at El-Mattana Research Station, Luxor Governorate during 2018/19 and 2019/20 seasons. Mosaic symptomatic plants were observed in nineteen production areas, with incidences ranging from 0 to 93.33%. The spatial pattern and geographical distribution of disease incidence suggested that infected seed cane was the main source to spread of the disease. Surveyed results revealed that disease incidence was varied between surveyed locations. Plant cane was lower than first and second ratoons in all fields. Locations i.e. El-trakee (Awladhamid) (EN4), Elfarsea (30-115 El-motawlelgrby) (EN7), El-Dkera (Mohamed Hassan) (EN18) and El-Adima (Abd-elrahman) (EN19 were free infection from such disease. The results revealed that a significant reduction in number of millable cane/m2, stalk diameter (cm.), stalk length (cm.) and number of internodes/plant in G. T. 54-9 and G. 2017-57 varieties due to virus infection. On the other hand, infection of two tested sugarcane varieties with SCMV caused significant reduction in juice extraction (kg), brix (TSS) %, purity%, pol% and sugar recovery%. It significantly increased of sucrose% and reducing sugars% in two tested varieties in two tested seasons also infection with virus caused significant decreased in cane yield (tons/fed.) and sugar yield (tons/fed.)

CHARACTERIZATION AND IN SILICO ANALYSES OF RTCS GENE FROM SUGARCANE ENCODING LOB PROTEIN FAMILY OF TRANSCRIPTION FACTORS: A KEY REGULATOR OF SHOOT-BORNE ROOT INITIATION

RTCS (Rootless concerning Crown and Seminal roots) is a member of the plant-specific LATERAL ORGAN BOUNDARIES (LOB) domain (LBD) protein family of transcription factors. The RTCS gene has been identified as a key regulator of shoot borne root initiation in maize. In this study an attempt has been made to characterize RTCS from a wild related genus of sugarcane Erianthus arundinaceus and compared to the RTCS gene isolated from commercial sugarcane hybrid genotypes. The candidate gene has been successfully isolated from two genotypes of E. arundinaceus (SES 288 and IND 04- 1335: EaRTCS) and two commercial sugarcane hybrid genotypes (Co 775 and Co 86032: ShRTCS). The isolated RTCS full length gene showed significant variation between EaRTCS and ShRTCS at the DNA and protein level. The RTCS amino acid sequence of all the four genotypes indicated the presence of the characteristic structural features of LBD proteins such as a C-motif, LOB domain sequence and leucine zipper-like dimerization domain. Prediction and analysis of secondary structure of RTCS protein in SES 288 and IND 04-1335 showed the presence of 65% alpha helix, 1% β strand and 38% disorder, while sugarcane commercial genotypes showed 58 % alpha helix, 1% β strand and 47% disorder. Both the sequences of EaRTCS and ShRTCS was found to be closely related to Zea mays RTCS.

EVALUATION OF INTRA-SPECIFIC HYBRIDS OF SACCHARUM OFFICINARUM FOR YIELD, QUALITY AND INCIDENCE OF YELLOW LEAF DISEASE

Improvement of parental clones of Saccharum officinarum L. through repeated cycles of intra-specific hybridization and selection was undertaken at ICAR-Sugarcane Breeding Institute (SBI), Coimbatore during 1987 to 1996. Thirty one clones selected from six polycrosses involving 13 parental clones of S. officinarum constituted cycle 1 (C1) population. Intermating among fourteen C1 clones followed by selection resulted in identification of 33 clones in cycle 2 (C2) population. Fourteen clones selected in C2 and C1 were inter-crossed. From the progenies, 50 clones were selected to constitute cycle 3 (C3) population. As the original parental clones of S. officinarum had low number of millable canes (NMC) and poor cane yield, in each cycle of selection emphasis was given to select progenies with high NMC, single cane weight and cane yield. The C1, C2 and C3 population, totalling 114 (designated as population-improved S. officinarum clones or PIO clones) were evaluated at ICAR-SBI Research Centre, Agali during 2015-16 and 2016-17 for NMC, single cane weight, cane yield per plot, brix%, sucrose% in juice and resistance to yellow leaf disease (YLD). Generation-wise improvement in the targeted traits was estimated. Significant improvement in NMC /ha (37.18 per cent), single cane weight (16.67 per cent) and cane yield (61.51 per cent) was achieved in two cycles of selection. Ten YLD-free improved clones with acceptable agronomic traits were identified for further use. They are: PIO 94-847, PIO 94-875, PIO 99-633, PIO 00-513, PIO 00-547, PIO 00-638, PIO 00-757, PIO 00-769, PIO 00-772 and PIO 00-840. These improved PIO clones would serve as new parental gene pool in the interspecific hybridization programmes and for diversifying the genetic base of commercial sugarcane varieties.

Soil moisture deficit induced changes in antioxidative defense mechanism of sugarcane (Saccharum officinarum) varieties differing in maturity

A split plot experiment was conducted at Regional Research Station, CCS HAU, Uchani, Karnal during 2014–15 and 2015–16 to investigate the effect of different soil moisture regimes on antioxidative defense mechanism of sugarcane (Saccharum officinarum L.) varieties. The experiment consisted of three moisture regimes based on available soil moisture i.e. irrigation at 50% ASM, 40% ASM and 30% ASM in main plot and four commercial sugarcane varieties, i.e. CoS 767, CoH 128, CoJ 64 and Co 0238 in sub plot with three replications. The observations recorded on antioxidative defense system have suggested possible key characteristics of drought tolerance. Low ASM levels induced the antioxidative defense system by increasing ROS and the specific activities of antioxidative enzymes, viz. peroxidase, catalase and ascorbate peroxidase. Specific activity of these enzymes increased in varieties Co 0238 and CoS 767 at 60 and 90 DAP. Severe stress of 30% ASM levels also resulted in a sharp rise in total ascorbic acid content (9.36 to 13.14 mg/g), total soluble proteins (from 9.6 to 13.77 mg/g), and the increase was more in varieties Co 0238 and CoS 767. A gradual decrease was observed in all the parameters after stress revival (120 DAP). ASM levels 30% and 40% significantly reduced K+ content in leaves (2.93 to 1.83%) as compared to 50% ASM level. So, it might be concluded from this study that biochemical traits had a significant varietal variation, indicating that these parameters could be used as screening criteria for selecting the tolerant and sensitive cultivars exposed to water limiting stress.

Assessment of Gene Flow to Wild Relatives and Nutritional Composition of Sugarcane in Brazil.

The commercial release of genetically modified organisms (GMO) requires a prior environmental and human/animal health risk assessment. In Brazil, the National Biotechnology Technical Commission (CTNBio) requires a survey of the area of natural occurrence of wild relatives of the GMO in the Brazilian ecosystems to evaluate the possibility of introgressive hybridization between sexually compatible species. Modern sugarcane cultivars, the focus of this study, derive from a series of hybridization and backcrossing events among Saccharum species. The so-called “Saccharum broad sense” group includes around 40 species from a few genera, including Erianthus, found in various tropical regions, particularly South-Eastern Asia. In Brazil, three native species, originally considered to belong to Erianthus, were reclassified as S. angustifolium (Nees) Trin., S. asperum (Nees) Steud., and S. villosum Steud., based on inflorescence morphology. Thus, we have investigated the potential occurrence of gene flow among the Brazilian Saccharum native species and commercial hybrids as a requisite for GMO commercial release. A comprehensive survey was carried out to map the occurrence of the three native Saccharum species in Brazil, concluding that they are sympatric with sugarcane cultivation only from around 14°S southwards, which precludes most Northeastern sugarcane-producing states from undergoing introgression. Based on phenology, we concluded that the Brazilian Saccharum species are unable to outcross naturally with commercial sugarcane since the overlap between the flowering periods of sugarcane and the native species is limited. A phylogenomic reconstruction based on the full plastid genome sequence showed that the three native Saccharum species are the taxa closest to sugarcane in Brazil, being closer than introduced Erianthus or Miscanthus. A 2-year study on eight nutritional composition traits of the 20 main sugarcane cultivars cultivated in Brazil was carried out in six environments. The minimum and maximum values obtained were, in percent: moisture (62.6–82.5); sucrose (9.65–21.76); crude fiber (8.06–21.03); FDN (7.20–20.68); FDA (4.55–16.90); lipids (0.06–1.59); ash (0.08–2.67); and crude protein (0.18–1.18). Besides a considerable amount of genetic variation and plastic responses, many instances of genotype-by-environment interaction were detected.

Temporal and varietal variation in sugarcane post-harvest residue biomass yields and chemical composition

Sugarcane is the world’s largest biomass crop. Extraneous leaf material, also known as post-harvest crop residue, represents a significant resource for use as a biomass feedstock by bioenergy industries. Information on temporal and varietal variation in sugarcane post-harvest crop residue is limited. Therefore, residue collected every two weeks during two harvest seasons from three commercial sugarcane varieties were analyzed for biomass quantity and quality. Residue biomass yields exceeded 3.5 t ha−1 y−1. When averaged over the two years and across the three varieties utilized, lignin, cellulose, hemicellulose, and ash content of residue were 4.7, 36.0, 31.5, and 0.7 %, respectively. Variety affected biomass, lignin, cellulose, hemicellulose, and ash yield, indicating there is some genetic variation in residue. Variability in lignin concentration was greatest; but, the overall concentrations in sugarcane residue were low. Both yield and quality changes over time within a season were consistent with the three varieties investigated in this study. Thus, harvest scheduling for sugarcane can be focused on varieties with the greatest sucrose concentration knowing that residue quality is stable across varieties.

Assessment of inland valley soils for sugarcane (Saccharum officinarum L.) production in some floodplains in central Nigeria

Abstract Sugarcane is an energy crop with great economic potentials. Information on soil evaluation for sugarcane in central Nigeria is very scanty. This study was carried out to evaluate the suitability of some soils of the floodplains in central Nigeria for sugarcane cultivation. A semi-detailed soil survey was carried out on 18,500 hectares of land straddling the floodplains of Rivers Niger and Benue in Korton-Karfe Local Government Area of Kogi State. Land resource survey was carried out using a 500 m×500 m grid pattern. Identified soil types were further examined with standard soil profiles. Samples were collected from the soil genetic horizons as well as surface (0–30 cm) soils at selected sampling points for fertility analysis. Parametric and non-parametric suitability evaluation methods were used to relate land qualities with land use requirements for commercial sugarcane cultivation. Relationships between evaluation methods were assessed using Spearman’s rank correlation coefficients. Nine soil mapping units were identified in the study areas which were mainly Inceptisols (55.4%) and Alfisols (22.5%) which correlates with Fluvisols (40.4%), Cambisols (15.1%) and Lixisols (22.5%) in the World Reference Base (WRB) classification system. The evaluation methods used revealed that 0%, 4.95%, 49.48%, 23.55% of the soils were highly suitable (S1), moderately suitable (S2), marginally suitable (S3) and not suitable (N) for sugarcane cultivation, respectively. Potentially, 0%, 9.52%, 44.91% and 23.55% of the soils were found to be highly suitable (S1), moderately suitable (S2), marginally suitable (S3) and not suitable (N) for sugarcane cultivation, respectively. The soils were strongly limited by low soil nutrient availability, soil acidity and flood hazard. Soil management practices such as application of organic manures, fertiliser and liming could be adopted to ameliorate the soil acidity and supply deficient nutrients while land development strategies such as drainage, flood control and possibly sub-soiling would mitigate other major limitations to sugarcane cultivation.

Molecular detection of sugarcane striate virus and sugarcane white streak virus and their prevalence in the Miami World Collection of sugarcane and related grasses

AbstractViruses in the genus Mastrevirus (family Geminiviridae), including those infecting sugarcane, have natural geographical ranges almost exclusively restricted to Africa and the Indian Ocean islands off the African coast. Only sugarcane white streak virus (SWSV) in Barbados and sugarcane striate virus (SStrV) in Florida and Guadeloupe are known to infect a few sugarcane varieties in the Western Hemisphere. In this study, PCR assays were developed to detect these two viruses in sugarcane. Five hundred and seventy‐one DNA samples from Saccharum species and interspecific hybrids from the Miami World Collection of sugarcane and related grasses were tested for the presence of SStrV and SWSV by PCR. No variety was found infected by SWSV but SStrV was detected in 19 varieties. PCR data were confirmed by sequencing amplified fragments (248 bp). These fragments shared 93%–100% nucleotide identity with SStrV sequences from the GenBank database. SStrV isolates were distributed in six phylogenetic groups, including the four strains of the virus. Most varieties infected by SStrV originated from Asia, thus confirming a previous hypothesis stating that this virus originated from this continent. Absence of SStrV in commercial sugarcane in Florida also suggested that this virus has not been spread in this location, while infected plants have been present for several decades.

Spatial variation of soil carbon stability in sugarcane crops, central-south of Brazil

The decay constant (k) of soil organic carbon can be used in the decision making of soil management practices and it is an indicative of the spatial variability of soil carbon stability, which depends on the interactions of physical, chemical and biological factors within agroecossystem. The aim of this work was to determine the spatial variability structure of soil carbon losses, expressed by the factor k, and its relationship with the soil attributes in sugarcane crops, in the central-south region of Brazil. The experiments were carried out in areas of commercial sugarcane plantations, in the cities of Motuca (MOT), Guariba (GUA) and Pradópolis - SP (PAD), in the State of São Paulo, and Aparecida do Taboado (APT), in Mato Grosso do Sul. The measurements of soil CO2 emission (FCO2) were recorded in the areas of study by the LI-COR system (LI-8100). The multivariate approach indicated that the two principal components (PC1 and PC2) explained around 55% to 68% of the total variability contained in the dataset in the areas studied, respectively. The soil physical attributes showed discriminatory power within PC1 and indicated a contrast between air-filled pore space and soil water content. In PC2, the chemical attributes indicated a joint action of the cations exchange capacity and available phosphorous content. PAD and APT areas presented negative and significant spatial patterns between factor k and PC1. For the spatial patterns between k and PC2 in GUA and APT, values with negative and significant correlations occurred. The results indicate that the soil carbon accumulation potential presented high spatial variability on a small scale; thus, in the same area, there were changes in the spatial patterns of factor k, presenting regions with potential accumulations or sources of carbon in the system of cultivation of raw cane, being able to be carried out the specific management in the same productive area.

Production and characterization of a new distillate obtained from fermentation of wet processing coffee by-products.

Coffee is one of the most important commodities worldwide. The industrial processing of coffee cherries generates a considerable volume of by-products such as wastewater, coffee pulp, mucilage, and husk. These by-products have sugars and nutrients that can be converted into value-added products via microbial action. In this study, for the first time, we evaluated the potential of coffee pulp and coffee wastewater as substrate for alcoholic fermentation produce a distilled beverage. The must composed by dry or wet coffee pulp and coffee wastewater added of commercial sucrose or sugarcane molasses was fermented by S. cerevisiae. After a screening step, a larger fermentation was carried out with the wet pulp added of sucrose due to its higher alcoholic fermentation efficiency. The distilled beverage contained 38% (v/v) ethanol and 0.2g/L of acetic acid. The contaminants furfural, hydroxymethylfurfural and ethyl carbamate were below detection level. Among the 48 volatile compounds detected, the majority (21) were ethyl esters usually associated with floral and sweet aromas. Ethyl decanoate (996.88µg/L) and ethyl dodecanoate (1088.09µg/L) were the most abundant esters. Coffee spirit presented taste acceptance of 80% and sugarcane spirit, 70%. The tasters indicated an aroma acceptance of 86% for the coffee spirit and 78% for the sugarcane spirit. The results of this work demonstrate the potential for using coffee by-products to produce a good quality distilled beverage. Considering our results, especially sensorial analysis, we can infer that the produced coffee beverage represents a new alternative for adding value to the coffee production chain.

Genetic Variability and Heritability among Sugarcane Genotypes at Early Stage of the Advanced Selection for some Agronomic Traits in Ferké, Northern Ivory Coast

Selection in sugarcane from true seed was recently implemented in Ivory Coast with the aim to increase the genetic variability of crop material used and, therefore, improve significantly sugar yields with a positive impact on the competitiveness of the Ivorian sugar industry. The objective of study was to determine the best performing cane genotypes among 29 clones tested under sprinkler irrigation, in comparison with a check variety (R579). It was carried out on R3-002 commercial sugarcane plantation of Ferké 2 sugar estate, in northern Ivory Coast. The experimental design used was a randomized complete block with 30 cane genotypes in three replications. Each plot comprised two dual rows of five meters with 0.5 and 1.90 m of inter-row spacing, i.e. 19 m² per plot and about 600 m² for the whole experiment. Based on sugar yields, four promising genotypes namely RCI12/15, RCI12/19, RCI13/121 and RCI13/136 were equivalent to the check variety which performed 15.6 t/ha. They are due to undergo the advanced selection stage during the 2020-21 cropping season for three more years for determining the first new sugarcane varieties of RCI origin to be tested commercially in Ferké sugar estates. Their yield performances ranged from 12.8 to 13.8 t sugar/ha, i.e. from 134.0 to 144.8 t cane/ha compared to 161.3 t/ha for the control variety. Although a relatively high level of stem-borer infestation rate recorded, with 15.6% on average (almost three times the tolerable threshold value of 5%), reasonable values of sucrose percent obtained with the promising genotypes, ranged from 12.7 to 13.9% over both crop cycles, compared with 13.6% for the check. Higher heritability values ranging from 61 to 80.5% were observed in traits like sugar yield, sucrose content (62.6%), recoverable sucrose (60.6%), fiber content (72%), stem-borer infestation rate (80.5%), number of internodes/stalk (67.7%), and flowering rate (79.6%). In contrast, lower and moderate values of heritability were observed for Pol juice (59.8%), juice purity (50.5%), cane yield (53%), millable stalk number/ha (29.5%), single stalk weight (36.7%), single stalk height (45%), and single stalk diameter (38.7%).

Influence of ohmic heating on commercial peroxidase and sugarcane juice peroxidase inactivation

Different fractions of sugarcane juice (liquid, solid and concentrated) were ohmically (75 °C and 7.8 V/cm for 25 min) treated to investigate the effect of different sample compounds on peroxidase inactivation. Moreover, commercial peroxidase solutions with and without the addition of sucrose were evaluated during ohmic (OH) and conventional heating (CH – with the same parameters of OH but without electric field application). It was observed that samples ohmically treated presented greater enzymatic inactivation (78% in the liquid fraction and 100% in the solid fraction, after 25 min of treatment) than those treated by CH (72% and 95% for liquid and solid fraction, respectively). The solid fraction was the most labile, and the liquid the most resistant fraction during both heating treatments. The concentrated fraction, which contains all isozymes, presented an intermediate inactivation rate. A zymogram showed three POD isozymes in the fresh sugarcane juice, explaining the different stabilities of the assayed fractions. Furthermore, the presence of sugar promoted a stabilizing effect on enzyme structure when exposed to the electric field, delaying its denaturation.

Genomic prediction of sugar content and cane yield in sugar cane clones in different stages of selection in a breeding program, with and without pedigree information

High cane yield and commercially extractable sucrose (CCS) content are two of the key sugarcane commercial traits selected in sugarcane breeding programs. Advancements in genomic prediction may provide opportunities to speed up gains for these traits in breeding programs by combining accurate prediction of breeding values in candidate parent clones shortening generation intervals. Selection trials in commercial breeding programs may provide training populations for developing genomic predictions. In this study, three different populations of clones in early and advanced stage selection trials in an established commercial sugarcane breeding program were used to assess genomic prediction accuracy. The clones (genotypes) were evaluated for cane yield and sugar content in field trials and genotyped using a SNP array developed for sugarcane cultivars and parents. Five models (Bayes A, Bayes B, Bayesian LASSO, Bayesian GBLUP and RKHS) were tested using pedigree and/or marker data. Prediction models that included marker information had higher prediction accuracies than models with pedigree data only. For CCS, the prediction accuracies for genotypes in advanced stage trials using DNA markers were superior compared with prediction accuracies for early-stage trials, suggesting that prior intensive selection for CCS did not diminish accuracy of genomic prediction. However, by contrast, for cane yield, the prediction accuracies were much less for the population in the advanced stages of selection. The levels of prediction accuracy obtained in most datasets (0.25–0.45) are encouraging for developing applications of genomic prediction to predict breeding values of yield and sugar content in sugarcane breeding programs.

Genotype x Environment Interactions in Sugarcane under Irrigation for Agronomic Traits at Advanced Screening Stage in Ferké, Northern Ivory Coast

Background: The selection procedure of commercial sugarcane varieties introduced in Ivory Coast involves two different stages. Four varieties pre-selected at the first stage regarding a previous trial were due to be tested at the advanced stage.
 Aims: The study aimed to determine the best performing sugarcane genotypes at the advanced selection stage under sprinkler irrigation, in comparison with to two check varieties (R579, SP70-1006).
 Methodology: The same field experiment was carried out on two different locations in Ferké 2 sugar estate of Northern Ivory Coast. The experimental design used was a randomized complete block (RCB) with six cane genotypes in four replications. Every plot consisted of five dual rows of ten meters with 0.5 and 1.90 m of inter-row spacing, i.e. 95 m² per plot and about 3000 m² for each experiment. Both experiments were conducted over two seasons (plant cane and first ratoon) as early-season crops from early November, 2017 to mid-December, 2019. Over each micro-plot, data based on different agro-morphological traits were collected at harvest from three central dual rows. 
 Results: The study showed that most relevant traits in genotype clustering were related to juice quality (recoverable sucrose, sucrose content, purity), yields and yield components (Millable stalk number/ha, stalk height, stalk diameter, internode number). Based on sugar yields, two genotypes (N47, ECU01) superior to both check varieties were found promising with, respectively, 13.7 and 13.5 t sugar/ha. Their cane yield performances gave 124 and 123 t/ha, respectively, compared to 126.8 t/ha for the best performing check.
 Conclusions: Not only sugar yield, but also flowering rate, stem borer infestation rate, stalk diameter, average stalk height and the number of tillers per hectare were found as the most relevant agronomic traits in the genetic variation of sugarcane genotypes tested. It came out also that GxE interactions were highly significant for five different traits, namely, cane and sugar yields, stalk borer infestation rate, fiber content and the average stalk height.

Water deficit detection in sugarcane using canopy temperature from satellite images

Water deficit (WD) is the main yield gap for sugarcane in Midwest Brazil. Thus, WD detection is essential to quantify yield losses, but field detection requires measurement of soil water content over large areas. In this study, we tested leaf temperature (TL) and land surface temperature (TS) to detect WD in a commercial sugarcane area. The area is located in the central region of Goiás State, Brazil. According to Köppen classification, the climate of the region is Aw (humid tropical, with rainy summer and dry winter). The soil is a Ferralsol (clayey texture). TL was measured by a portable infrared thermometer, and TS was obtained using a spectral image from Landsat 8. Both TL and TS measurements occurred between 28 Jan and 24 Aug 2014 (298-506 DAP). The water balance identified periods of water deficit (WD) and surplus (WS). The difference between TL Ta was greater than zero (7.11 °C) in WD periods and lower than zero (-2.18 °C) in WS periods. The difference between TS-Ta, in turn, ranged from -0.66 °C to 4.06 °C, but not following the tendency of WD or WS, which is associated with a relative error between TL and TS near 20% for some date. The TS Ta difference detected soil WD or WS when the relative error was low (362 and 410 DAP) and under higher WD (506 DAP) and WS (394 DAP). This way, TL was able to detect WD and WS along sugarcane growth, while TS showed limited application, requiring improvement based on surface properties to reduce the error in relation to TL. Furthermore, bands 10 and 11 are recommended for surface temperature estimation. Calibration uncertainty increases when the band 11 is used alone, being this band more affected by the absorption of radiation by the atmospheric water vapor, which implies larger errors related to the atmospheric profile in the acquisition of surface temperature.

Biomass Yield and Carbohydrate Composition in Sugarcane and Energy Cane Grown on Mineral Soils

A better understanding of sugarcane and energy cane (Saccharum spp.) in biomass accumulation and carbohydrate composition can improve the knowledge of crop production sustainability and optimal utilization. The objectives of this study were to identify sugar composition and concentrations of stalk juice in sugarcane and energy cane grown on two sandy soils during ripening and to determine differences between the two types of canes in nonstructural and structural carbohydrate partitioning and concentrations in dry biomass for the mature plant-cane, first-ratoon, and second-ratoon crops. A field study was conducted at two locations with mineral (sand) soils in south Florida, USA, using two commercial sugarcane cultivars of CP 78-1628 and CP 80-1743 and two energy cane genotypes (US 78-1013 and US 84-1066) to determine their biomass yields and carbohydrate composition and concentrations. Averaged across the three crops and two locations, energy cane had significantly higher biomass yield, lower nonstructural carbohydrate (reducing sugars and sucrose) concentrations, and higher concentrations of cellulose, hemicelluloses, and lignin than sugarcane. Although there were no differences between sugarcane and energy cane in total carbohydrate concentration (839 to 842 g kg−1 DW), energy cane had 80% higher cellulose, 63% higher hemicelluloses, and 76% higher lignin; 69, 64, and 56% lower sucrose, glucose, and fructose concentrations, respectively, than sugarcane, when averaged across the three crops and two locations. These results can be useful for potential use of canes for both sucrose and cellulosic ethanol production on marginal sand soils to improve sustainability and profitability in the future.

Correction to: Commercial Sugarcane Dry Cleaning Systems in Brazil: Progress and Challenges

The original version of this article was published with a wrong heading by mistake. The correct heading is Original Paper.

Optimising the number of test sites, crop-years and replications to maximize post-release testing efficiencies

The South African sugar industry develops commercial sugarcane cultivars across multiple testing sites, crop-years and replications. The extent of such parameters has not been well quantified for optimum breeding and resource allocation. The objective of this study was to identify the optimum number of testing sites, crop-years and replications needed to maximize efficiency of post-release cultivar evaluations in South Africa. Ten commercial sugarcane varieties were evaluated in randomized block designs across five regions tested over five crop cycles. The study was conducted from the main plant to third ratoon crops across the locations. The general linear model was used to estimate variance components. Genotype × location (G×L) interactions were significant (p ≤ 0.01) for cane yield (TCANE), estimated recoverable crystal content (ERC), sugar yield (TERC) and fibre (F). Tonnes of estimated recoverable crystal were highly influenced by G×L interaction, suggesting that evaluating cultivars across locations is essential. High broad sense heritability estimates were observed for TCANE (71.17%), ERC (97.11%) and F % (93.11%), implying that these traits were genetically controlled. The G×L and G×L×C variances were the largest source of variation, suggesting that the evaluation of sugarcane cultivars across locations as opposed to crop cycles would be essential.