Observing Sucrose Accumulation With Sentinel-1 Backscatter

In this study the impact of sucrose accumulation in Sentinel-1 backscatter observations is presented and compared to Planet optical observations. Sugarcane yield data from a sugarcane plantation in Xinavane, Mozambique are used for this study. The database contains sugarcane yield of 387 fields over two seasons (2018-2019 and 2019-2020). The relation between sugarcane yield and Sentinel-1 VV and VH backscatter observation is analyzed by using the Normalized Difference Vegetation Index (NDVI) data as derived from Planet Scope optical imagery as a benchmark. The different satellite observations were compared over time to sugarcane yield to understand how the relation between the observations and yield evolves during the growing season. A negative correlation between yield and Cross Ratio (CR) from Sentinel-1 backscatter was found while a positive correlation between yield and Planet NDVI was observed. An additional modeling study on the dielectric properties of the crop revealed how the CR could be affected by sucrose accumulation during the growing season and supported the opposite correlations. The results shows CR contains information on sucrose content in the sugarcane plant. This sets a basis for further development of sucrose monitoring and prediction using a combination of radar and optical imagery.

Insights into the Bacterial and Nitric Oxide-Induced Salt Tolerance in Sugarcane and Their Growth-Promoting Abilities

Soil salinity causes severe environmental stress that affects agriculture production and food security throughout the world. Salt-tolerant plant-growth-promoting rhizobacteria (PGPR) and nitric oxide (NO), a distinctive signaling molecule, can synergistically assist in the alleviation of abiotic stresses and plant growth promotion, but the mechanism by which this happens is still not well known. In the present study, in a potential salt-tolerant rhizobacteria strain, ASN-1, growth up to 15% NaCl concentration was achieved with sugarcane rhizosphere soil. Based on 16S-rRNA gene sequencing analysis, the strain ASN-1 was identified as a Bacillus xiamenensis. Strain ASN-1 exhibits multiple plant-growth-promoting attributes, such as the production of indole-3-acetic acid, 1-aminocyclopropane-1-carboxylate deaminase, siderophores, HCN, ammonia, and exopolysaccharides as well as solubilized phosphate solubilization. Biofilm formation showed that NO enhanced the biofilm and root colonization capacity of the PGPR strain ASN-1 with host plants, evidenced by scanning electron microscopy. The greenhouse study showed that, among the different treatments, the combined application of PGPR and sodium nitroprusside (SNP) as an NO donor significantly (p ≤ 0.05) enhanced sugarcane plant growth by maintaining the relative water content, electrolyte leakage, gas exchange parameters, osmolytes, and Na+/K+ ratio. Furthermore, PGPR and SNP fertilization reduced the salinity-induced oxidative stress in plants by modulating the antioxidant enzyme activities and stress-related gene expression. Thus, it is believed that the acquisition of advanced information about the synergistic effect of salt-tolerant PGPR and NO fertilization will reduce the use of harmful chemicals and aid in eco-friendly sustainable agricultural production under salt stress conditions.

Silicon Changes C:N:P Stoichiometry and Favors Pre-Sprouted Seedling Growth, Yield and the Technological Quality of Sugarcane.

The importance of silicon (Si) in sugarcane is well known, but its effects on changing C:N:P stoichiometry enough to increase pre-sprouted seedling (PSS) and sugarcane development in the field remains unknown. To that end, the present study aimed to assess whether Si fertigation favors its absorption enough to change elemental stoichiometry (C:N:P), physiological attributes and PSS growth, as well as the growth, stem yield and juice quality of sugarcane. Two field experiments were conducted in the PSS formation stage and another in the sugarcane plant development phase. Experiment 1 was carried out in a greenhouse with PSSs under two treatments: in the absence and presence of Si (2 mmol L−1) fertigation. Experiment 2 was performed in the field in red-yellow argisol with the sugarcane plant undergoing the following treatments: absence of Si (No Si); Si supplied by fertigation during the PSS formation and sugarcane plant development phases (Si–C); and Si supplied during the PSS formation and sugarcane plant development phases (Si–M+C). The following were assessed in experiment I: growth, leaf green color index (GCI), chlorophyll fluorescence, C, N, P, and Si content, and C:Si, C:N and C:P stoichiometric ratios. In experiment II, the same stoichiometric ratios were assessed, as well as sugarcane growth, stem yield and juice quality. Si reduced the C:Si, C:N and C:P stoichiometric ratios in PSS. The C:Si ratio in the leaves and stems declined with the supply of Si, while the C:N and C:P ratio in the leaves and stem was higher in plants that received Si in the Si-M+C treatment. Applying Si fertigation in PSS formation to promote changes in C:N:P stoichiometry favored photosynthetic efficiency and growth. The Si–M+C treatment stood out, since it also caused enough C:N:P stoichiometric changes to increase sugarcane growth, yield and juice quality.

Continuous Sugarcane Planting Negatively Impacts Soil Microbial Community Structure, Soil Fertility, and Sugarcane Agronomic Parameters

Continuous planting has a negative impact on sugarcane plant growth and reduces global sugarcane crop production, including in China. The response of soil bacteria, fungal, and arbuscular mycorrhizae (AM) fungal communities to continuous sugarcane cultivation has not been thoroughly documented. Using MiSeq sequencing technology, we analyzed soil samples from sugarcane fields with 1, 10, and 30 years of continuous cropping to see how monoculture time affected sugarcane yield, its rhizosphere soil characteristics and microbiota. The results showed that continuous sugarcane planting reduced sugarcane quality and yield. Continuous sugarcane planting for 30 years resulted in soil acidification, as well as C/N, alkali hydrolyzable nitrogen, organic matter, and total sulfur content significantly lower than in newly planted fields. Continuous sugarcane planting affected soil bacterial, fungal, and AM fungal communities, according to PCoA and ANOSIM analysis. Redundancy analysis (RDA) results showed that bacterial, fungal, and AM fungal community composition were strongly associated with soil properties and attributes, e.g., soil AN, OM, and TS were critical environmental factors in transforming the bacterial community. The LEfSe analysis revealed bacterial families (e.g., Gaiellaceae, Pseudomonadaceae, Micromonosporaceae, Nitrosomonadaceae, and Methyloligellaceae) were more prevalent in the newly planted field than in continuously cultivated fields (10 and 30 years), whereas Sphingomonadaceae, Coleofasciculaceae, and Oxyphotobacteria were depleted. Concerning fungal families, the newly planted field was more dominated than the continuously planted field (30 years) with Mrakiaceae and Ceratocystidaceae, whereas Piskurozymaceae, Trimorphomycetaceae, Lachnocladiaceae, and Stigmatodisc were significantly enriched in the continuously planted fields (10 and 30 years). Regarding AMF families, Diversisporaceae was considerably depleted in continuously planted fields (10 and 30 years) compared to the newly planted field. These changes in microbial composition may ultimately lead to a decrease in sugarcane yield and quality in the monoculture system, which provides a theoretical basis for the obstruction mechanism of the continuous sugarcane planting system. However, continuous planting obstacles remain uncertain and further need to be coupled with root exudates, soil metabolomics, proteomics, nematodes, and other exploratory methods.

Sugarcane-Legume Intercropping Can Enrich the Soil Microbiome and Plant Growth

Soil microbes have a direct impact on plant metabolism and health. The current study investigates the comparative rhizobiome between sugarcane monoculture and sugarcane–soybean intercropping. A greenhouse experiment was performed with two treatments: (1) sugarcane monoculture and (2) sugarcane–soybean intercropped. We used a high-throughput sequencing (HTS) platform to analyze the microbial community. We used the 16S rRNA gene and internal transcribed spacer region primers to identify the microbial diversity. HTS results revealed that a total of 2,979 and 124 bacterial and fungal operational taxonomic units (OTUs) were observed, respectively. Microbial diversity results concluded that the intercropping system has a beneficial impact on soil microbes. The highest numbers of bacterial and fungal OTUs were found in the intercropping system, and these results also collaborated with quantitative PCR results. Additionally, intercropped sugarcane plants showed a higher weight of above- and below-ground parts than the monoculture. Soil chemical analysis results also complemented that the intercropping system nourished organic carbon, total nitrogen, and soil enzyme activities. Correlation analysis of the diversity index and abundance concluded that soil nutrient content positively influenced the microbial abundance that improves plant growth. The present study frames out the profound insights of microbial community interaction under the sugarcane–soybean intercropping system. This information could help improve or increase the sugarcane crop production without causing any negative impact on sugarcane plant growth and development.

First report of Fusarium sacchari causing sugarcane wilt in Bangladesh

Wilt is one of the destructive fungal diseases of sugarcane (Saccharum officinarum L.) affecting sugarcane production in many sugarcane growing regions including Bangladesh. In July 2018, sugarcane plants showing wilting symptom including withered, dried leaves and shriveling stalks with brown to pinkish discoloration in internal tissues (Viswanathan, 2013) were collected from sugarcane field from Gazipur district (23°54′41″ N, 90°23′20″ E) of Bangladesh. Average disease incidence was 17% in 60 ha of sugarcane fields that were sampled for diseased plants with visible symptoms. Ten infected stalks (30cm) were collected from five severely infected fields. The stalks were surface sterilized with 70% ethanol for 1 minute followed by 0.2% sodium hypochlorite for 3 minutes and then rinsed three times with distilled water. Small pieces (2mm×2mm) of the inner discolored tissue were cut with a strile scalpel and placed on half strength Potato Dextrose Agar (PDA) medium followed by incubation for 7 days at 25 °C. A total of ten isolates were recovered from the infected sugarcane stalks and were purified by single spore culture method. Isolates produced floccose and cottony colony with white mycelia and dark violet pigmentation on the lower surface of the PDA plate. Microconidia were oval, generally, without septation measuring 5-9.6 µm length and 1.8-3.7 µm width in size (Appendix 1). Macro conidia were not found on the PDA medium. Conidiophores produced mono- or poly-phialides and conidia were arranged in a false head on conidiophore which is consistent with Fusarium sacchari (Duan et al. 2019). For molecular identification, DNA was extracted from two representative isolates BTFSS1 and BTFSS6. The internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF-1α) gene and RNA polymerase II (RPB2) genes were amplified using primers ITS1/ITS4, EF1α-F EF1α-R and 5F2/11aR, respectively (Appendix 2). Obtained ITS sequences (GenBank accession nos. MT176492.1 and MT177209.1) showed 99.8% similarity with the sequences from F. sacchari strain olowEKT1 (MK072727.1). Sequence identity of TEF-1α (GenBank accession nos. MW558264.1 and MW507839.1) was 99.36% with the sequence of F. sacchari strain FF031 (MK152501.1) and RPB2 (GenBank accession nos. MW558265.1 and MW507840.1) was 99.42% with the sequence of F. sacchari strain FF001 (MK152508.1), respectively. The isolates BTFSS1 and BTFSS6 were identified as F. sacchari based on the sequences alignment of ITS, TEF-1α and RPB2 and onolecular phylogenetic analyses by maximum likelihood tree method. To confirm the pathogen as a causal agent of wilt of sugarcane, pathogenicity tests were conducted in sugarcane plants by the plug method described by Viswanathan et al. (2011). Ten plants (variety BSRI Akh 42) were inoculated with 1 × 105 conidia mL−1 suspension of the isolate BTFSS1. A borehole was made on the third or fourth internode from the base of the sugarcane plant in where the conidial suspension was placed and the bore place was sealed with cane tissues. Control plants were inoculated with deionized distilled water. All canes were cuts longitudinally to evaluate the disease symptoms at fifteen and thirty days after inoculation. Inoculated stalks exhibited tissue discoloration that were similar to those observed in infected sugarcane field, whereas the control remained unaffected (Appendix 1). Pathogens were re-isolated from the artificially inoculated cane and characterized morphologically. Sugarcane is the second important cash crop and the only source of white sugar in Bangladesh (Rahman et al. 2016). Our report for the first time confirmed that F. sacchari is the causal pathogen of sugarcane wilt in Bangladesh. This report has significance to develop suitable management practices to control the pathogen in sugarcane field.

Analysis of Nutritional Composition of Five Growing Waxy Vegetable Varieties In West Halmahera Regency North Maluku

The wax vegetable plant (Saccharum edule) is a type of sugarcane plant, has many types and can be found in several regions in Indonesia. This study aims to determine the nutritional content of five varieties of vegetable Lilin cultivated in West Halmahera Regency North Maluku. This research is using experimental method. Using short white, long white, long white, red, short yellow and long yellow wax vegetables, which are cultivated in West Halmahera Regency, North Maluku. The variables observed included moisture content, fat content, protein content, ash and carbohydrate content. The results showed that the moisture content ranged from 87.59% - 91.76%, fat content ranged from 0.25% - 0.67%, protein content ranged from 3.19% - 4.17%, ash content ranged from 1, 40% - 1.56%, and the carbohydrate content ranges from 3.41% - 6.20%. In terms of nutritional content (fat, protein and carbohydrates), short yellow and long yellow varieties have a higher value.Keywords: Nutritional content, Candle Vegetables, West Halmahera

MANEJO E PRODUÇÃO DE PALHADA DA CANA-DE-AÇÚCAR EM UM SISTEMA IRRIGADO POR GOTEJAMENTO SUBSUPERFICIAL PARA GERAÇÃO DE BIOETANOL

MANEJO E PRODUÇÃO DE PALHADA DA CANA-DE-AÇÚCAR EM UM SISTEMA IRRIGADO POR GOTEJAMENTO SUBSUPERFICIAL PARA GERAÇÃO DE BIOETANOL ANDERSON RAMOS DE OLIVEIRA1, WELSON LIMA SIMÕES1 1 Embrapa Semiárido, Rodovia BR-428, Km 152, s/n, Zona Rural, CEP 56302-970, Petrolina, PE, Brasil, e-mail: [email protected], [email protected] RESUMO: Práticas agrícolas que contemplam a sustentabilidade do sistema de produção da cana-de-açúcar têm sido cada vez mais demandadas pela sociedade. A palhada disponibilizada na colheita da cana-de-açúcar, sem queima, pode ser utilizada para a cogeração de energia na forma de bioetanol. Assim, objetivou-se com este trabalho avaliar a produtividade de palhada de cana-de-açúcar e estimar o rendimento de bioetanol de segunda geração - E2G, em um sistema irrigado por gotejamento subsuperficial, sob diferentes percentuais de manutenção de palhada sobre a superfície do solo. O estudo foi desenvolvido na Usina Agrovale S.A., em Juazeiro, BA. Adotou-se o delineamento em blocos casualizados com cinco tratamentos, correspondentes aos percentuais de manutenção de palhada sobre o solo: 0, 25, 50, 75 e 100%, com quatro repetições, durante quatro ciclos de cultivo. Avaliou-se a produtividade de palhada remanescente após as colheitas e estimou-se o rendimento de bioetanol. A produtividade de palhada da cana-de-açúcar na colheita foi influenciada pela porcentagem de palhada remanescente mantida sobre o solo. A cultivar VAT90212 apresenta maior produtividade de palhada no ciclo de cana-planta. O rendimento de E2G proveniente da palhada aumenta o potencial de produtividade total de bioetanol de cana-de-açúcar por hectare. Palavras-chave: E2G, sustentabilidade, bioenergia, Semiárido. MANAGEMENT AND PRODUCTION OF SUGARCANE STRAW UNDER SUBSURFACE DRIP IRRIGATION FOR BIOETHANOL GENERATION ABSTRACT: Sustainable agricultural practices in the sugarcane production system have been increasingly demanded by society. The amount of sugarcane straw available in the harvest, without burning, can be used as energy for second-generation bioethanol production. The objectives of this work were to evaluate the productivity of sugarcane straw and to estimate the yield of second-generation bioethanol, under subsurface drip irrigation, using straw at different percentages of soil surface coverage. The study was conducted at Agrovale S.A. in Juazeiro, BA, Brazil. A randomized block design with five treatments, corresponding to the levels of straw soil surface coverage was used: 0, 25, 50, 75, and 100%, with four replications, during four crop cycles. The yield of remaining straw on the soil after the harvest was evaluated and the yield of bioethanol was estimated. The yield of sugarcane straw at harvest was influenced by the percentage of remaining straw soil surface coverage. The cultivar VAT90212 shows higher straw productivity in the sugarcane plant cycle. The yield of the second generation bioethanol from the straw increases the total productivity potential of bioethanol from sugarcane per hectare. Keywords: E2G, sustainability, bioenergy, Semi-arid.

Endophytic Bacillus Bacteria Living in Sugarcane Plant Tissues and Telchin licus licus Larvae (Drury) (Lepidoptera: Castniidae): The Symbiosis That May Open New Paths in the Biological Control

Bacteria of the genus Bacillus can colonize endophytically and benefit several crops including the control of some pest orders. In view of the benefits provided by these microorganisms and in order to find out an efficient biotechnological control for the giant borer, our interest in studying the microorganisms in symbiosis with sugarcane and the giant borer has arisen, since there is no efficient chemical or biological control method for this pest. Therefore, endophytic Bacillus strains were isolated from three sugarcane niches (apoplast fluid, central internode cylinder and roots) and also from the giant borer larvae living inside sugarcane varieties grown in the Northeast region of Brazil. The taxonomical characterization (16S rRNA) of 157 Gram-positive isolates showed that 138 strains belonged to the Bacillus genus. The most representative species were phylogenetically closely related to B. megaterium (11.5%) followed by B. safensis (10.8%), B. cereus (8.9%), B. oleronius (8.9%), B. amyloliquefaciens (7.0%), and B. pacificus (6.4%). BOX-PCR analyses showed very distinct band pattern profiles suggesting a great diversity of Bacillus species within the sugarcane niches and the digestive tract, while the B. cereus group remained very closely clustered in the dendrogram. According to XRE biomarker analysis, eleven strains (FORCN005, 007, 008, 011, 012, 014, 067, 076, 092, 093, and 135) correspond to B. thuringiensis species. Additional studies using conserved genes (glp, gmk, pta, and tpi) indicated that most of these strains were phylogenetically closely related to B. thuringiensis and may be considered different subspecies. In conclusion, this study suggests that the culturable Bacillus species are greatly diversified within the plant niches and showed Bacillus species in the digestive tract of the giant borer for the first time. These results open new perspectives to understand the role and functions played by these microorganisms in symbiosis with this pest and also the possibility of developing an efficient biological control method for the giant borer using strains identified as the B. thuringiensis species.