Databasing Molecular Identities of Sugarcane (Saccharum spp.) Clones Constructed with Microsatellite (SSR) DNA Markers

This paper reports the development of the first SSR marker-based sugarcane (Saccharum spp.) molecular identity database in the world. Since 2005, 1,025 sugarcane clones were genotyped, including 811 Louisiana, 45 Florida, 39 Texas, 130 foreign, and eight consultant/seed company clones. Genotyping was done on a fluorescence-capillary electrophoresis detection platform involving 21 highly polymorphic SSR markers that could potentially amplify 144 distinctive DNA fragments. Genotyping data were processed with the GeneMapper? software to reveal electrophoregrams that were manually checked against the 144 fragments. The presence (A) or absence (C) of these 144 fragments in any sugarcane clone was recorded in an affixed sequence order as a DNAMAN? file to represent its molecular identity being achieved into a local molecular identity database. The molecular identity database has been updated annually by continued genotyping of newly assigned sugarcane clones. The database provides molecular descriptions for new cultivar registration articles, enables sugarcane breeders to identify mis-labeled sugarcane clones in crossing programs and determine the paternity of cross progeny, and ensures the desired cultivars are grown in farmers’ fields.

Radiation-induced in vitro mutagenesis system for salt tolerance and other agronomic characters in sugarcane(Saccharum officinarum L.)

Gamma ray-induced in vitro mutagenesis and selection for salt(NaC l) tolerance were investigated in sugarcane(Saccharum officinarum L.). Embryogenic callus cultures were irradiated(10 to 80 Gy) and subjected to in vitro selection by exposure of irradiated callus to NaC l(0, 50, 100,150, 200, and 250 mmol L-1). Increasing NaC l concentrations resulted in growth reduction and increased membrane damage. Salt-selected callus lines were characterized by the accumulation of proline, glycine betaine, and Na+and K+concentration. Higher accumulation of proline and glycine betaine was observed in NaC l stressed callus irradiated at 20 Gy. Na+concentration increased and K+concentration decreased with increasing salt level. Irradiated callus showed50–60% regeneration under NaC l stress, and in vitro-regenerated plants were acclimatized in the greenhouse, with 80–85% survival. A total of 138 irradiated and salt-selected selections were grown to maturity and their agronomic performance was evaluated under normal and saline conditions. Of these, 18 mutant clones were characterized for different agro-morphological characters and some of the mutant clones exhibited improved sugar yield with increased Brix%,number of millable canes, and yield. The result suggest that radiation-induced mutagenesis offers an effective way to enhance genetic variation in sugarcane.

Gamma Irradiation of Embryogenic Callus Cultures and In vitro Selection for Salt Tolerance in Sugarcane (Saccharum officinarum L.)

Radiation induced mutagenesis followed by in vitro selection was employed for salt tolerance in popular Indian sugarcane （Saccharum officinarum L.） cv. CoC-671. Embryogenic calli were gamma irradiated and exposed to different levels of NaCl （42.8, 85.6, 128.3, 171.1,213.9, 256.7, 299.5, or 342.2 mM）. The relative growth rate （RGR） decreased progressively with increasing salt stress and was the least with a salt stress of 256.7 mM （0.25±0.009）, almost 10 fold lesser than the control. The RGR was significantly lower in 85.6 mM and higher salt stressed calli than the control. The survival percent also decreased, with an increase in NaCl concentration. In case of 10 and 20 Gy irradiated calli, regeneration was observed up to 85.6 mM NaCl selection, medium, whereas, higher treatments （128.3 mM and beyond） exhibited browning initially. However, in the subsequent subcultures, regeneration was obtained in the case of 10 and 20 Gy irradiated calli on 128.3 and 171.1 mM NaCl selections. Higher dose of gamma irradiation （40 Gy） also showed regeneration, but only with 85.6 mM NaCI selection. The unirradiated calli regenerated the highest number of plantlets followed by 10 and 20 Gy irradiated calli on salt selection. A total of 147 plantlets were selected from different salt levels. The salt selected plants are being tested for their field performance.

Genetic analysis for brix weight per stool and its component traits in sugarcane (Saccharum officinarum)

Brix weight per stool (BW) of sugarcane is a complex trait, which is the final product of a combination of many components. Diallel cross experiments were conducted during a period of two years for BW and its five component traits, in- cluding stalk diameter (SD), stalk length (SL), stalk number (SN), stalk weight (SW), and brix scale (BS) of sugarcane. Phenotypic data of all the six traits were analyzed by mixed linear model and their phenotype variances were portioned into additive (A), dominance (D), additive×environment interaction (AE) and dominance×environment interaction (DE) effects, and the correlations of A, D, AE and DE effects between BW and its components were estimated. Conditional analysis was employed to investigate the contribution of the components traits to the variances of A, D, AE and DE effects of BW. It was observed that the heritabilities of BW were significantly attributed to A, D and DE by 23.9%, 30.9% and 28.5%, respectively. The variance of A effect for BW was significantly affected by SL, SN and BS by 25.3%, 93.7% and 17.4%, respectively. The variances of D and DE effects for BW were also significantly influenced by all the five components by 5.1%～85.5%. These determinants might be helpful in sugarcane breeding and provide valuable information for multiple-trait improvement of BW.

Optimizing Row Spacing to Ameliorate the Productivity of Spring Sugarcane (Saccharum officinarum L.)

One of the main reasons behind reduced cane yield is pathetic method of planting. Planting method and row spacing are the most important yield contributing factors in sugarcane. A field experiment was carried out in order to determine quality and yield of sugarcane in various spatial arrangements. Treatments are 180 cm spaced trenches with triple row strips;180 cm spaced trenches with alternate row strips;120 cm spaced trenches with double row strips and 60 cm spaced furrow with single row. Perusal of data revealed that 3.6%, 13.4%, 15%, 15.3% more cane diameter (cm), cane length (cm), stripped cane yield (t·haˉ1), sugar yield (t·haˉ1) were obtained from 180 cm spaced trenches with triple row strips as compared to conventional planting method i.e. 60 cm spaced furrows. While the number of millable canes mˉ2, polarity %, cane juice purity %, cane juice %, commercial cane sugar % and cane sugar recovery % remained non-significant by different planting techniques.

Optimization of protoplast isolation,transformation and its application in sugarcane (Saccharum spontaneum L.)

Sugarcane is a prominent source of sugar and ethanol production.Genetic analysis for trait improvement of sugarcane is greatly hindered by its complex genome,long breeding cycle,and recalcitrance to genetic transformation.The protoplast-based transient transformation system is a versatile and convenient tool for in vivo functional gene analysis;however,quick and effective transformation systems are still lacking for sugarcane.Here,we developed an efficient protoplast-based transformation system by optimizing conditions of protoplasts isolation and PEG-mediated transformation in S.spontaneum.The yield of viable protoplasts was approximately 1.26×107 per gram of leaf material,and the transformation efficiency of 80.19%could be achieved under the optimized condition.Furthermore,using this approach,the nuclear localization of an ABI5-like bZIPs transcription factor was validated,and the promoter activity of several putative DNase I hypersensitive sites(DHSs)was assessed.The results indicated this system can be conveniently applied to protein subcellular localization and promoter activity assays.A highly efficient S.spontaneum mesophyll cell protoplast isolation and transient transformation method was developed,and it shall be suitable for in vivo functional gene analysis in sugarcane.

Integrated Nutrient Management Improves Productivity and Quality of Sugarcane(Saccharum Officinarum L.)

Sugarcane is one of the major important sugar yielding crops in Bangladesh.As an exhaustive crop,sugarcane removes a huge amount of plant nutrients from the soil.However,the combined use of organic and inorganic fertilizers can be a good approach to deal with nutrient depletion and promote sustainable crop production as well as improve soil health.Therefore,an attempt was made to identify the most fruitful and profitable integrated nutrient management on the aspects of growth,yield and quality of sugarcane in two consecutive growing seasons.Seven treatments:T_(1)=Control,T_(2)=165:55:120:30:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(3)=Poultry Litter(PL)at 5 t ha^(−1)+95:51:87:9:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(4)=Cow Dung(CD)at 15 t ha^(−1)+36:52:60:17:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(5)=Press Mud(PM)at 15 t ha^(−1)+10:50:43:0:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(6)=Mustard Oil Cake(MOC)at 0.5 t ha^(−1)+140:54:115:25:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1)and T_(7)=GM(Green Manure)at 5 t ha^(−1)+140:53:100:28:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1)were used in this experiment.Two years data showed that treatment T_(3)produced the maximum amount of tillers,total dry matter yield,millable sugarcane,cane yield and sugar yield,followed by the T_(4)treatment.The highest stalk heights were recorded in the T_(3)treatment,which was statistically similar to all other treatments except T_(1)and T_(2).The juice quality parameters viz.,brix and pol in cane were found significant in treatment T_(3)while the highest purity was obtained in the T_(7)treatment.All the data of Jaggery(goor)quality parameters,the highest sucrose content,color transmittance,Jaggery(goor)recovery and the lowest ash content of Jaggery(goor)were observed in the T_(3)treatment,which was statistically similar to the T_(4)treatment in both seasons.The highest cost of production was obtained from the T_(6)treatment while the highest gross return,net return and BCR were recorded in the T_(3)treatment.No significant changes were found in one cycle of sugarcane in initial and post-harvest soil characteristics viz.,pH,organic carbon,total N,and available P,K and S contents due to integrated use of different fertilizer packages.From the experimental findings,it was concluded that treatment T_(3)followed by T_(4)treatment would be the better productive and profitable integrated nutrient management technology for ensuring higher yields and quality of sugarcane without soil fertility degradation in the High Ganges River Floodplain soils.

Heritability and Correlation among Sugarcane (Saccharum spp.) Yield and Some Agronomic and Sugar Quality Traits in Ethiopia

To assess broad sense heritability and phenotypic and genetic correlations among sugarcane yield components, an experiment was conducted at Wonji and Metehara Sugar Estates of Sugar Corporation of Ethiopia during 2012/2013. High broad sense heritability (h2) was detected for stalk diameter (0.730), single cane weight (0.672), millable cane number (0.624), stalk height (0.624) and pol % (0.608), indicating that these traits could be selected for easily. Expected genetic gain of the yield components was moderate to high. All traits had low to high genetic correlations (rg = -0.005 to 0.884) with cane yield and (rg = 0.027 to 0.999) with sugar yield. On average genetic correlations were higher than phenotypic correlations. High Genotypic Coefficient of Variation (GCV), broad sense heritability and expected genetic advance were recorded for stalk diameter, single cane weight and millable cane number. A selection strategy based on these traits could lead to improvement in cane and sugar yield.

Economic Assessment of Sugarcane (Saccharum officinarum L.) through Intercropping

Sugarcane has pronounced importance to provide sugar for more than half of the global population. World population is enhancing day-by-day and production land is in the worst situation. The cultivated land is diminishing rapidly due to urbanization, road construction, and land deterioration. This crisis demands alternate research to raise crop productivity and maximize the economic returns per unit land for feeding the gigantic population. Sugarcane is a long duration crop and gave late net economic return. Intercropping in sugarcane received much attention and need to properly manage for getting higher net return from same unit area. It is becoming popular among farming community due to resourcefully utilization of land. Intercropping has the potential to inspire the farmers to get maximum economic return per acre per annum. For intercropping, wheat, gram, soybean, and potato were used as an intercrop in September-sown sugarcane. Triple row strip planting geometry of sugarcane with four intercropped (SC + Wheat, SC + Gram, SC + Soybean, and SC + Potato) and check with sole SC was used. Sugarcane was planted during September 2011- 12 and 2012-13 at research area University College of Agriculture, University of Sargodha, Pakistan. Randomized complete block design with three replications were used. Results showed that number of millable cane, cane diameter;unstripped and stripped cane yield and crop growth rate was significantly higher in sole sugarcane when compared with different intercrop in 2011-12 while trend was same in 2012-13. Cane diameter and un-stripped cane yield were statistically at par of intercrops SC + Soybean and SC + Potato while stripped cane yield of Sole SC and SC + Potato was statistically at par in 2012-13. In both the year of study, intercrops gave higher land equivalent ratio and net return over sole sugarcane planted while sole sugarcane gave maximum benefit cost ratio compared with other intercrops.

Molecular Markers Associated with Starch Content and Implications for Sugarcane Introgression Breeding Using Saccharum spontaneum

Introgression with Saceharum spontaneum intended to broaden the genetic base of sugarcane resulted in an increase in desirable genes for broader adapt ability as well as undesirable genes for high starch content. Markers could provide a quick and efficient method of screening parental genotypes for low starch. The objectives of this study were to identify potential markers associated with starch in S. spontaneum population and evaluate their potential for screening for starch content. Data for starch content and （simple sequence repeats） SSR markers were collected from 51 S. spontaneum clones grown in replicated pots. The mixed procedure of statistical analysis system （SAS） was used to determine markers significantly associated with starch. Thirty-nine out of 357 polymorphic markers were significantly （P 〈 0.05） associated with starch content. Eighteen were positively associated and 21 were negatively associated. The presence of a positive marker produced 39% more starch than absence while the absence of a negative marker produced 57% more starch than presence. Selecting parents using negative markers may be more efficient than selecting using positive markers.

In Vitro Regeneration of Commercial Sugarcane （Saccharum spp.） Cultivars in Nigeria

The effect of different concentrations of 6-benzylaminopurine （BA） with or without 0.2 mg/L NAA on in vitro regeneration of sugarcane （Saccharum spp.） cultivars SP726180, B47419, M1176/77 and M2119/88 were evaluated. Leaf base explants were cultured on Murashige and Skoog （MS） basal medium supplemented with 3.0 mg/L 2,4-dichlorophenoxyacetic acid （2,4-D） for 4 weeks. Thereafter, induction of somatic embryogenesis was observed following the transfer of resulting calli to 2,4-D-free medium for another 4 weeks. Regeneration was achieved by transfer of the embryogenic calli to regeneration media fortified with different concentrations of BA ＋ tt-naphthylacetic acid （NAA）. The number, length and vigor of shoots produced in all the genotypes were highest on media supplemented with 1.0 and 1.5 mg/L BA with and without 0.2 mg/L NAA. Among the genotypes tested, B47419 and M1176/77 recorded highest number of shoots, while maximum shoot length and crop vigor was obtained with M1176/77. Induction of callus with 3.0 mg/L 2,4-D and its subsequent incubation on 2,4-D-free media, followed by regeneration on media supplemented with 1.0 or 1.5 mg/L BA with 0.2 mg/L NAA was found to be efficient for in vitro regeneration of the sugarcane genotypes used in this study. This protocol could be applied for micropropagation of other elite genotypes.

Intergeneric chromosome-specific painting reveals differential chromosomal transmission from Tripidium arundinaceum in sugarcane progeny

Sugarcane has recently attracted increasing attention for its potential as a source of sugar and bioethanol,so increasing its yield is essential to ensure the sugar security and bioenergy production.Intergeneric hybridization is a highly efficient method to produce new genetic variants of crop plants,particularly those species with high ploidy such as sugarcane(Saccharum spp.).Tripidium arundinaceum exhibits many desirable agronomic traits,and has been widely studied to produce hybrids with improved stress tolerance and other characteristics in sugarcane breeding.However,the genetic relationship between T.arundinaceum and Saccharum species,and the individual T.arundinaceum chromosomal compositions in sugarcane hybrids are still elusive.Here we used whole-genome single-nucleotide polymorphisms(SNPs)to ascertain the phylogenetic relationships between these species and found that T.arundinaceum is more closely related to Saccharum than Sorghum,in contrast to the previous narrow genetic analyses using chloroplast DNA.Additionally,oligonucleotide(oligo)-based chromosome-specific painting derived from Saccharum officinarum was able to distinctly identify the chromosomes of T.arundinaceum.We developed the oligo-genomic in situ hybridization(GISH)system for the first time,to unveil the novel chromosome translocations and the transmission of individual T.arundinaceum chromosomes in sugarcane progeny.Notably,we discovered that the chromosomal transmission of T.arundinaceum exhibited several different inheritance modes,including n,2n,and over 2n in the BC1 progenies.Such inheritance patterns may have resulted from first division restitution(FDR)or FDR+nondisjunction of a chromosome with the sister chromatids in the second meiosis division/second division restitution(FDR+NSC/SDR)model during meiosis.These results will be of substantial benefit for the further selection of T.arundinaceum chromosomes for sugarcane genetic improvement.

Assessment of Physico-Chemical and Microbial Quality of Sugarcane Juice Sold by Street Vendors in Three Regions of Bangladesh

Sugar cane juice is a popular refreshing drink in most part of Bangladesh. It has great taste and health benefits;also it is available most of the public places at reasonable prices which consumed by road side customers including general public, shopping personals, tourists, students. In our country, street vendors crushing sugarcane between roller crusher and sold without any heat treatment or preservative, also served with or without added ice and lemon juice. The study aimed to identify and compare the physico-chemical and microbial quality of sugarcane juice. The chemical qualities of juices including moisture, PH, ash, total soluble solid, total sugar, reducing sugar and titrable acidity were found slightly different in Mymensingh, Gazipur and Narayangonj areas. The highest and lowest value of moisture, ash, PH, total soluble solids, total sugar, reducing sugar and titrable acidity were found in 84.33% - 79.26% (Gazipur-Mymensingh), 0.57% - 0.04% (Mymensingh-Gazipur), 5.9 - 2.9 (Gazipur-Narayangonj), 17.48% - 4.98% (Mymensingh-Narayangonj), 21.9% - 6.56% (Mymensingh-Gazipur), 3.7 - 2.1 (Gazipur-Mymensingh) and 0.523% - 0.007% (Narayangonj-Gazipur) respectively. For microbiological analysis, the total viable count of sugar cane juice in Mymensingh, Gazipur and Narayangonj were ranged from 0.6 × 105 - 43.6 × 105 cfu/ml, 4.6 × 105 - 21.6 × 105 cfu/ml and 3.6 × 105 - 36.6 × 105 cfu/ml respectively, where the permitted value is 1.0 × 104 cfu/ml, whereas the total coliform count was ranged from 0.4 × 105 - 6.4 × 105 cfu/ml, 0.6 × 105 - 8.4 × 105 cfu/ml and 0.00 - 8.4 × 105 cfu/ml, where the permitted value is 100 cfu/ml and total fungal count was ranged from 5.5 × 105 - 56.5 × 105 cfu/ml, 21.5 × 105 - 54.5 × 105 cfu/ml and 32.5 × 105 - 68.5 × 105 cfu/ml, where the permitted value is 1000 cfu/ml. According to the Gulf standard, the microbiological parameters of all the collected sugar cane juice were out of the permitted standards, so that a serious health outbreak can be caused anytime.

A growth-regulating factor 7(GRF7)-mediated gene regulatory network promotes leaf growth and expansion in sugarcane

Knowledge of the function of growth-regulating factors(GRFs)in sugarcane(Saccharum officinarum and S.spontaneum)growth and development could assist breeders in selecting desirable plant architectures.However,limited information about GRFs is available in Saccharum due to their polyploidy.In this study,22 GRFs were identified in the two species and their conserved domains,gene structures,chromosome location,and synteny were characterized.GRF7 expression varied among tissues and responded to diurnal rhythm.SsGRF7-YFP was localized preferentially in the nucleus and appears to act as a transcriptional cofactor.SsGRF7 positively regulated the size and length of rice leaves,possibly by regulating cell size and plant hormones.Of seven potential transcription factors binding to the SsGRF7 promoter in S.spontaneum,four showed positive expression patterns,and two showed negative expression patterns relative to SsGRF7.

Chemically Modified Sugarcane Bagasse for Innovative Bio-Composites. Part One: Production and Physico-Mechanical Properties

Sugarcane bagasse is an agro-waste that could replace timber resources for the production of bio-composites.Composite boards such as particleboard offer an issue for the use and recycling of poor quality timber,and these engineered products can overcome some solid wood limitations such as heterogeneity and dimension.Bagasse offers an alternative to wood chips for particleboard production but present some disadvantages as well,such as poor physico-mechanical properties.To address these issues,bagassefibers were treated with an innovative natural resin formulated with tannin and furfural.Impregnated particles with different concentrations of resin(5%,10%,and 15%m/m)were exposed to temperatures of 40℃,60℃,80℃,and 100℃ for resin curing.Various types of tannin-based adhesives,including tannin formaldehyde,tannin/formaldehyde-furfural,and tannin hex-amine,were utilized for bonding the treated bagasse particles.The resultant panels were assessed for their physical and mechanical properties and compared to those produced using Melamine-Urea-Formaldehyde(MUF)adhe-sive.The density of the panels varied from 650 to 730 kg/m^(3) depending on the resin concentration.The values for both modulus of elasticity and modulus of rupture increased as the resin concentration increased.The internal bonding values exhibited an increase with resin concentration up to a critical point,after which a decreasing trend was observed.The water absorption and thickness swelling were significantly reduced with an increase in resin concentration.However,the panels produced using MUF adhesive yielded the most favorable physico-mechanical properties.Additionally,the panels made with tannin-based adhesives met the minimum requirements specified in the standard EN 312(specifications for uncoated resin-bonded particleboards)for application in dry condi-tions.The analysis of formaldehyde emissions indicated that panels produced with tannin-based adhesives exhib-ited significantly lower emissions compared to those made with MUF.The tannin/furfural resin showed great potential for improving the quality of bagasse particleboard using tannin-based adhesives.

Analysis of Occurrence and Mixed Infection of Sugarcane Bacilliform Virus Disease in Hainan Sugarcane-growing Area

[Objectives]The paper was to explore the occurrence and mixed infection of sugarcane bacilliform virus disease in Hainan sugarcane-growing area.[Methods]A total of 348 sugarcane leaf samples were collected from 7 sugarcane-growing areas in Hainan Province.Molecular detection of sugarcane bacilliform virus(SCBV)was carried out by PCR using specific primers.[Results]SCBV was detected in 244 out of 348 sugarcane samples,with an average detection rate of 70.11%.The highest detection rate was 76.66%in the Danzhou sugarcane-growing area,while the lowest was 57.14%in the Baisha sugarcane-growing area.The SCBV-positive samples were subjected to testing for SCYLV,SCSMV,SrMV,and SCMV,respectively.The results indicated that 106 out of 244 positive samples exhibited a single infection with SCBV,while 138 samples exhibited mixed infections with SCBV and other sugarcane viruses.The proportion of mixed infections among the SCBV-positive samples was as high as 56.56%.Among the various types of mixed infections,two-virus and three-virus mixed infections were the most prevalent.[Conclusions]SCBV has emerged as a significant threat to the secure production of sugarcane in the Hainan sugarcane-growing region.It presents an explosive infection in the Hainan sugarcane-growing region and frequently combines with other sugarcane viruses to infect sugarcane.The findings of this study will provide a theoretical foundation for the prevention and control of sugarcane bacilliform virus disease.

Sugarcane leaves-derived polyphenols alleviate metabolic syndrome and modulate gut microbiota of ob/ob mice

Sugarcane leaves-derived polyphenols(SLP)have been demonstrated to have diverse health-promoting benefits,but the mechanism of action has not been fully elucidated.This study aimed to investigate the anti-metabolic disease effects of SLP and the underlying mechanisms in mice.In the current study,we prepared the SLP mainly consisting of three flavonoid glycosides,three phenol derivatives,and two lignans including one new compound,and further demonstrated that SLP reduced body weight gain and fat accumulation,improved glucose and lipid metabolism disorders,ameliorated hepatic steatosis,and regulated short-chain fatty acids(SCFAs)production and secondary bile acids metabolism in ob/ob mice.Notably,SLP largely altered the gut microbiota composition,especially enriching the commensal bacteria Akkermansia muciniphila and Bacteroides acidifaciens.Oral gavage with the above two strains ameliorated metabolic syndrome(MetS),regulated secondary bile acid metabolism,and increased the production of SCFAs in high-fat diet(HFD)-induced obese mice.These results demonstrated that SLP could be used as a prebiotic to attenuate MetS via regulating gut microbiota composition and further activating the secondary bile acids-mediated gut-adipose axis.

Sugarcane/soybean intercropping with reduced nitrogen addition enhances residue-derived labile soil organic carbon and microbial network complexity in the soil during straw decomposition

Sugarcane/soybean intercropping with reduced nitrogen addition is an important sustainable agricultural pattern that can alter soil ecological functions,thereby affecting straw decomposition in the soil.However,the mechanisms underlying changes in soil organic carbon(SOC)composition and microbial communities during straw decomposition under long-term intercropping with reduced nitrogen addition remain unclear.In this study,we conducted an in-situ microplot incubation experiment with^(13)C-labeled soybean straw residue addition in a two-factor(cropping pattern:sugarcane monoculture(MS)and sugarcane/soybean intercropping(SB);nitrogen addition levels:reduced nitrogen addition(N1)and conventional nitrogen addition(N2))long-term experimental field plot.The results showed that the SBN1 treatment significantly increased the residual particulate organic carbon(POC)and residual microbial biomass carbon(MBC)contents during straw decomposition,and the straw carbon in soil was mainly conserved as POC.Straw addition changed the structure and reduced the diversity of the soil microbial community,but microbial diversity gradually recovered with decomposition time.During straw decomposition,the intercropping pattern significantly increased the relative abundances of Firmicutes and Ascomycota.In addition,straw addition reduced microbial network complexity in the sugarcane/soybean intercropping pattern but increased it in the sugarcane monoculture pattern.Nevertheless,microbial network complexity remained higher in the SBN1 treatment than in the MSN1 treatment.In general,the SBN1 treatment significantly increased the diversity of microbial communities and the relative abundance of microorganisms associated with organic matter decomposition,and the changes in microbial communities were mainly driven by the residual labile SOC fractions.These findings suggest that more straw carbon can be sequestered in the soil under sugarcane/soybean intercropping with reduced nitrogen addition to maintain microbial diversity and contribute to the development of sustainable agriculture.

Establishment and Application of Prevention and Control Techniques of New Sugarcane White Leaf Disease

Aiming at the basic and key technical problems in prevention and control of sugarcane white leaf disease(SCWL),this study systematically overcame key technical bottleneck of prevention and control of new SCWL after 10 years of collaborative research,and achieved several innovative achievements.SCWL phytoplasmas newly recorded in China and the new subgroup of SCWL phytoplasmas(16SrXI-D)were discovered for the first time in Yunnan,and the whole genome analysis of the epidemic subgroup was completed.The main transmission source of SCWL pathogens has been identified as infected seed canes,and Tettigoniella viridis and Clovia conifer were newly discovered as vectors for virus transmission.The disease resistance of 25 main varieties was identified,and 10 control varieties were selected.The prevention and control strategy of"emphasizing early warning,strictly carrying out quarantine,blocking the vectors and controlling residual plants"was put forward,and a comprehensive prevention technique was established through integration of various techniques,and standardized technical regulations were formulated for demonstration application.The promotion and application of these achievements have realized scientific prevention and control of SCWL,effectively curbed the spread of SCWL,and ensured the safety of sugarcane producing areas in China,achieving great economic,social and ecological benefits and providing technical support for high-quality development,loss reduction and efficiency improvement of China's sugar industry.

Evaluating Sugarcane Bagasse-Based Biochar as an Economically Viable Catalyst for Agricultural and Environmental Advancement in Brazil through Scenario-Based Economic Modeling

The increasing global demand for sustainable agricultural practices and effective waste management has highlighted the potential of biochar as a multifaceted solution. This study evaluates the economic viability of sugarcane bagasse-based biochar in Brazil, focusing on its potential to enhance agricultural productivity and contribute to environmental sustainability. While existing literature predominantly explores the production, crop yield benefits, and carbon sequestration capabilities of biochar, there is a notable gap in comprehensive economic modeling and viability analysis for the region. This paper aims to fill this gap by employing a scenario-based economic modeling approach, incorporating relevant economic models. Findings include that biochar implementation can be economically viable for medium and large sugarcane farms (20,000 - 50,000 hectares) given the availability of funding, breaking even in about 7.5 years with an internal rate of return of 18% on average. For small farms, biochar can only be viable when applied biochar to the soil, which in all scenarios is found to be the more profitable practice by a large margin. Sensitivity analyses found that generally, biochar becomes economically feasible at biochar carbon credit prices above $120 USD/tCO2e, and at sugarcane bagasse availability percentages above 60%. While the economic models are well-grounded in existing literature, the production of biochar at the studied scales is not yet widespread, especially in Brazil and uncertainties can result. Reviewing the results, the land application scenario was found to be the most viable, and large farms saw the best results, highlighting the importance of scale in biochar operations. Small and medium farms with no land application were concluded to have no or questionable viability. Overall, sugarcane bagasse-based biochar can be economically viable, under the right circumstances, for agricultural and environmental advancement in Brazil.