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.

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.

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.

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.

Application of AHP and DTOPSIS in Sugarcane Breeding

The weights of ten important traits of sugarcane, including the number of hair groups, plant height, defoliation capability, stalk diameter, ratooning property, stalk number of disease resistance, cane yield, sucrose content and sugar yield, were distributed with the Analytic Hierarchy Process （AHP） method. Ten Yuetang series of sugarcane lines were evaluated by Dynamic Technique for Order Preference by Similarity to Ideal Solution （DTOPSIS）. AHP results indicated that the weights of ten traits were 0. 013 4, 0.022 7, O. 030 2, 0.040 8, 0.065 3, 0.088 1, 0.116 2, 0. 160 6, 0.198 4 and 0.264 5, respectively, with random consistency ratio C.R. =0.098 1 〈0.1, suggesting that the distribution of the weights of evaluation indicators was reasonable. Comprehensive evaluation of 10 sugarcane lines by DTOPSLS method combining with the conclusion of AHP showed that the comprehensive performances of Yuetang 03-393 and Yuetang 03-373 were much better than other sugarcane lines, with relative approach degree Ci ranking the first and second, respectively, which was basically consistent with the practical survey, suggesting that Yuetang 03-393 and Yuetang 03-373 were suitable for large-scale popularization. The above results confirmed the feasibility of applying AHP and DTOPSIS in comprehensive evaluation of new crop varieties and provided reference for the breeding of new sugarcane lines.

Application of ^15N Stable Isotope Labeling Technology in Sugarcane Nitrogen Research

Nitrogen is one of the essential nutrient elements for plant growth,which plays an important role in the growth and development of sugarcane. The whole growth cycle of sugarcane needs a large amount of nitrogen. Increasing the application of nitrogen can improve the yield of sugarcane,but it will also cause environmental pollution. Therefore,how to control or reduce the application of nitrogen fertilizer while continuously increasing sugarcane yield,reduce the increase of sugarcane production cost and environmental pollution caused by excessive application of nitrogen fertilizer has become an important scientific problem faced by sugarcane industry in China.^15N stable isotope labeling technology has been applied to many crops as a nitrogen research tool. In order to better understand the demand of nitrogen fertilizer in soil-cane system,this paper reviewed nitrogen allocation in plants,nitrogen loss,nitrogen recycling and endogenous nitrogen fixation of sugarcane based on^15N stable isotope labeling technology used in the nitrogen uptake and utilization,providing a theoretical basis for the improvement of sugarcane nitrogen use efficiency and the efficient nitrogen fertilizer management of sugarcane.

Nutrients of Topsoil for Sugarcane Planting in Xinping County of Yunnan Province

To provide reference for fertilizer application of sugarcane planting in Xinping County,this paper analyzed nutrient content of topsoil according to the nutrient indicators established in the Second Soil Census. The results show that 51. 76% soil in sugarcane planting area of Xinping County is faintly acid,50. 88% soil has relatively low organic matter,45. 88% soil lacks alkali-hydrolyzable nitrogen( N),26. 47% soil lacks phosphorus( P),50. 29% soil lacks potassium( K),37. 14% soil lacks sulfur( S),12. 86% soil lacks magnesium( Mg),10% soil lacks manganese( Mn),and 31. 43% soil lacks zinc( Zn). In the sugarcane production,it is required to pay attention to increase of application of organic fertilizer,to foster soil fertility,supplement boron fertilizer,to keep balance of soil nutrients.

Past and recent advances in sugarcane cytogenetics

The Saccharum genus comprises species with large and variable chromosome numbers, leading to challenges in genomic studies and breeding improvement. Cytogenetics, including classical and molecular approaches, has played a central role in deciphering the genome structure, classification, and evolution of the genus Saccharum. The application of fluorescence in situ hybridization using oligonucleotide probes significantly improved our understanding of the complex genomes of Saccharum species. This paper reviews the application and progress of cytogenetic techniques in Saccharum. Future applications of cytogenetics are discussed, as they could benefit both genomic studies and breeding of sugarcane as well as other plants with complex genomes.

Overexpression of a sugarcane ScCaM gene negatively regulates salinity and drought stress responses in transgenic Arabidopsis thaliana

Calmodulin(CaM)proteins play a key role in signal transduction under various stresses.In the present study,the effects of a sugarcane ScCaM gene(NCBI accession number:GQ246454)on drought and salt stress tolerance in transgenic Arabidopsis thaliana and Escherichia coli cells were evaluated.The results demonstrated a significant negative role of ScCaM in the drought and salt stress tolerance of transgenic lines of A.thaliana,as indicated by the phenotypes.In addition,the expression of AtP5CS and AtRD29A,two genes tightly related to stress resistance,was significantly lower in the overexpression lines than in the wild type.The growth of E.coli BL21 cells expressing ScCaM showed weaker tolerance under mannitol and NaCl stress.Taken together,this study revealed that the ScCaM gene plays a negative regulatory role in both mannitol and NaCl stresses,and it possibly exerts protective mechanisms common in both prokaryotes and eukaryotes under stress conditions.

Establishment and Application of Identification Methods for Resistance to Sugarcane White Leaf Disease(SCWL)

[Objectives]This study was conducted to establish simple, efficient, stable, standardized and practical identification methods for sugarcane resistance to white leaf disease(SCWL), and promote the breeding for sugarcane resistance to SCWL. [Methods]The identification technology of sugarcane resistance to SCWL was systematically studied and explored from the aspects of sugarcane material treatment and planting, inoculation liquid preparation, inoculation method, disease investigation, grading standard formulation, etc., and two sets of simple, efficient, stable, standardized and practical accurate identification methods for sugarcane resistance to SCWL were created for the first time, namely, the seed cane coating inoculation method and the stem-cutting inoculation method at the growth stage. The seed cane coating inoculation method includes the steps of directly screening SCWL phytoplasma, extracting juice from cane and adding 10 times of sterile water to prepare an inoculation liquid, spraying seed cane on plastic film to keep moisture, planting the inoculated materials in barrels in an insect-proof greenhouse for cultivation, investigating the incidence rate 30 d after inoculation, and evaluating the disease resistance according to the 1-5 level standard. The method of stem-cutting inoculation includes the steps of directly screening sugarcane stems carrying SCWL phytoplasma and adding 10 times of sterile water to prepare an inoculation liquid, cultivating the identification materials in an insect-proof greenhouse, dropping 100 μl of the inoculation liquid into each root incision with a pipette gun at the age of 6 months, investigating the incidence rate 20 d after planting, and evaluating the disease resistance according to the 1-5 level standard. [Results] The two methods are similar to the natural transmission method. After inoculation, SCML occurred significantly, with high sensitivity and good reproducibility. The results of resistance identification were consistent with those of natural disease in the field. Through the two inoculation methods and field natural disease investigation, the resistance of 10 main cultivars to SCML was identified, which was true and reliable. [Conclusions] This study can provide standard varieties for identification of SCML resistance in the future.

Climate Impact on the Productivity of Sugarcane Varieties in Ferke1 Industrial Plantations

This study assesses the climate impact on the productivity of five sugarcane varieties (R579, SP711406, M2593/92, M1400/86, and SP701006) in the industrial plantations of Ferké 1 sugar complex. It is a contribution to research efforts aimed at increasing the productivity of sugarcane varieties in the sugar fields. Also to support agricultural development and guarantee the income of planters. The sugarcane production data are from 2013 to 2017. Climatological data are measured and calculated continuously daily at the production site. In addition, the CMIP-5 (Coupled Model Intercomparison Project) climate database at 1º × 1º horizontal resolution was used for the predictability of crop yields of the 5 sugarcane varieties in the near future (2021-2050) and far future (2056-2075) to improve the quality of climate services to producers. The statistical methodological approach by multiple linear regression associated with the significativity test shows important and significant coefficients of determination (R2 > 0.90) between the yields of sugarcane varieties with certain climatic parameters such as minimum and maximum temperatures, insolation, global solar radiation, and potential evapotranspiration. The impact of rainfall has not been directly evaluated because the linear models do not explicitly show sensitivities to this parameter and the total water requirements for the plot are completely assured by irrigation. The future climate projections analyzed only from extreme thermal parameters (Tmax and Tmin) highlight their strong sensitivities with yields from an idealized model. In this model, we have assumed that the water supply needed by sugarcane is always met by irrigation on different plots. Moreover, linear models do not evolve fast enough in time and changes due to external environmental constraints are not too important at the plot scale. The projected thermic parameters can thus constitute a limiting factor for the producibility of sugarcane varieties either by excess or by default. In addition, the linear models used allowed us to observe the behavior of yields with respect to observed past climatic conditions. However, for future yields, there is no way to know if these regressions have the ability to predict them since they are based on projected weather conditions (i.e. CMIP5 data) marked by uncertainties. Additionally, none of the regression equations have been tested against independent observations.

Effectiveness of Rice Husk and Sugarcane Bagasse Ashes Blended Cement in Improving Properties of Concrete

This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m3) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO2 which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)2 crystals, converting it into CaH2O4Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.

Effectiveness of Rice Husk and Sugarcane Bagasse Ashes Blended Cement in Improving Properties of Concrete

This paper emphasized the use of rice husk ash (RHA) and sugarcane bagasse ash (SBA) in improving concrete properties, and also their combined effects on workability, compressive strength, flexural strength, permeability and water absorption capacity. Thus, in this study, the water-to-cement ratio was kept constant (0.45), the binder materials content for conventional mix was kept constant at (350 kg/m3) and the partial replacement of cement with RHASBA used was 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The maximum compressive strength was noted at a 5% replacement level of cement with RHASBA. The Results showed that the optimum replacement of cement with RHASBA in concrete was 5%, which was found to increase the compressive strength by 15%, flexural strength by 3.4%, lowered permeability by 50%, lowered sorptivity by 11.34% as compared with control concrete at 90 days of curing time. The micro-structural test results further established that RHA and SBA have a high content of SiO2 which enables them to be more reactive in concrete and also revealed that the presence of RHASBA depletes Ca(OH)2 crystals, converting it into CaH2O4Si (C-S-H gel) leading to the strengthening of bond within the concrete matrix.

Influence of Climate on Sugarcane Yield in Côte d’Ivoire: Case of the Ferkessédougou Region

This study aims to understand the current climatic trends and explain the possible losses of agricultural yields. To achieve this objective, this work characterized the evolution of extreme temperature indices in the sugar complexes of Ferké 1 and Ferké 2, two stations located in the northern part of C?te d'Ivoire. The onset and cessation dates of the rainy season and the length of the rainy season were investigated. The agricultural and climatic data were obtained from each sugar complex. The period of study ranges from 2002 to 2019 in Ferké 1 and Ferké 2. The results show significant upward trends in extreme temperature indices. The analysis of sugarcane yield associated with the different climatic parameters shows no significant results in general. However, on the Ferkessédougou sugar complexes, the results highlight that maximum and minimum temperatures could be the variables that influence most yield production. The maximum temperature with coefficients of 1.60 and 0.77 at Ferké 1 and Ferké 2 respectively seems to contribute to an increase in yield while the minimum temperature with coefficients of -0.98 and -0.22 at Ferké 1 and Ferké 2 respectively could lead to a loss in yield. The results obtained with the Single Linear Regression (SLR) and the Multiple Linear Regression (MLR) models also highlight the strong influence of minimum and maximum temperatures.

Effect of biochar on the metabolome of soybean seedlings

The use of biochar can have several effects on plant germination,depending on raw material,preparation method and application dose.However,the molecular mechanisms that lead to those results have yet to be elucidated.The aim of this research was to improve the understanding of these mechanisms by characterizing the metabolic effects of sugarcane bagasse biochar on soybean germination.Three types of biochars were prepared by pyrolysis at 300℃(SCB300),400℃(SCB400)and 600℃(SCB600).Then,each one was mixed into sand at 1%,3%,5%(w/w)dose,respectively.The experiment was performed in 8 days of incubation,when the number of germinated seeds and the average radicle length were determined.To evaluate the metabolome,the dry biomass(DB)was subjected to extraction with a mixture of methanol-d4 and D2O(1:1 v/v).The extracts were submitted to metabolomics analysis by Proton Nuclear Magnetic Resonance.The Relative Germination,Relative Average Radicle Growth and Germination Index increased in all treatments compared to control.On the other hand,the DB increased in all treatments,except for SCB300,at doses of 1%and 3%w/w.Seven metabolites(alanine,asparagine,acetic acid,citric acid,glycerol,fatty acids and sucrose)were identified and quantified in DB extracts as the most influential finding for the separation of treatments.Taken together,these results strongly suggested that biochars accelerated the catabolism of triacylglycerols to sucrose and induced a slight osmotic stress.

Comparative Preliminary Evaluation of Agronomic and Quality Traits of New"Zhongtang"Superior Lines

[Objectives]Sugarcane is the most significant sugar cash crop in the tropical and subtropical regions of China.However,it is notable for its narrow genetic basis,limited trait improvement,weak adaptability of varieties,and poor planting efficiency.In order to accelerate the process of sugarcane variety replacement and expand the basis of genetic variation,interspecific hybridization and multiple mutagenesis are the most effective methods for obtaining new sugarcane varieties.The evaluation and identification of phenotypic traits of germplasm represents a significant analytical method.The"Zhongtang"series of sugarcane varieties is distinguished by its high yield and high sugar content.New sugarcane germplasms with excellent agronomic and quality traits can be identified and developed as breeding parents and new breeding lines through comprehensive evaluation of the existing germplasm.[Methods]A total of 181 new lines were selected through genetic origin and orientation,and evaluated and appraised for growth,yield,and economic characteristics.The data on 6 important agronomic and quality traits,including tillering,initial plant height,plant height,stem diameter,number of effective stems,and brix at maturity,were used to discover superior lines.These traits were evaluated during the two production seasons of the participant lines.[Results]A comprehensive evaluation of seedling growth traits and economic traits at maturity of the experimental lines identified 30 excellent new germplasms of sugarcane.Among the selected lines,1501 and 1701 exhibited superior agronomic and quality traits,rendering them suitable as parental lines for sugarcane breeding or breeding as new varieties.[Conclusions]The exemplary results obtained in this study provide a solid foundation for the improvement of sugarcane germplasm,with the goal of enhancing quality and efficiency.These findings are of great scientific and practical significance to the study of sugarcane yield and sugar-related genes,as well as the exploration of the evaluation and utilization of sugarcane germplasm resources.

Prediction of Low Heating Value of Sugar Cane Bagasse as a Fuel for Industrial Boilers in the High Relative Humidity Region: Case of Cameroon

Many attempts have been made to estimate calorific value of bagasse using mathematical equations, which were created based on data from proximate, ultimate, physical and chemical analysis. Questions have been raised on the applicability of these equations in different parts of the globe. This study was initiated to tackle these problems and also check the most suited mathematical models for the Law Heating Value of Cameroonian bagasse. Data and bagasse samples were collected at the Cameroonian sugarcane factory. The effects of cane variety, age of harvesting, source, moisture content, and sucrose on the LHV of Cameroon bagasse have been tested. It was shown that humidity does not change within a variety, but changes from the dry season to the rainy season;the sugar in the rainy season is significantly different from that collected in the dry season. Samples of the same variety have identical LHV. LHV in the dry season is significantly different from LHV in the rainy season. According to the fact that this study was done for cane with different ages of harvesting, the maturity of Cameroonian sugarcane does not affect LHV of bagasse. Tree selected models are much superior tool for the prediction of the LHV for bagasse in Cameroon compared to others. The standard deviation of these validated models is around 200 kJ/kg compared to the experimental. Thus, the models determined in foreign countries, are not necessarily applicable in predicting the LHV of bagasse in other countries with the same accuracy as that in their native country. There was linear relationship between humidity, ash and sugar content in the bagasse. It is possible to build models based on data from physical composition of bagasse using regression analysis.

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.

Effects of exogenous enzymes, Lactobacillus acidophilus or their combination on feed performance response and carcass characteristics of rabbits fed sugarcane bagasse

The aim of this study was to evaluate the effect of Lactobacillus acidophilus（LAC）, exogenous enzymes of ZAD（exogenous enzyme preparation） or their combination on feed conversion, and dressing of rabbits fed different treatments of sugarcane bagasse（SCB）. Five rations were allotted randomly to five groups of New-Zealand White（NZW） rabbits（n=10） with initial live body weight of（838±42.4） g and 5 weeks of age. Rabbits were fed on diets with different sources of fiber as follows,（i） a control diet composed of 100% berseem hay and 0% SCB,（ii） 50% berseem hay and 50% untreated SCB（USCB）,（iii） 50% berseem hay and 50% SCB treated with L. acidophilus（LAC）,（iv） 50% berseem hay and 50% SCB treated with ZAD（ZAD）, and（v） 50% berseem hay and 50% SCB treated with a combination of LAC＋ZAD（LZ）. Treatments of SCB with L. acidophilus, ZAD and LAC＋ZAD had the highest feed conversion ratio than both USCB and control. The dressing percentage of rabbits that fed the LAC and LZ diets was higher（P〈0.05） compared with that in the other groups. Performance index（PI） for LAC group was improved（P〈0.05） compared to that for the other groups; however, PI for USCB group was the lowest（P〈0.05）. It could be concluded that treating SCB with L. acidophilus, exogenous enzymes of ZAD or their combination improved feed conversion and performance with more positive effects with L. acidophilus than the other treatments.

Genetic Structure and Diversity of Parental Cultivars Involved in China Mainland Sugarcane Breeding Programs as Inferred from DNA Microsatellites

To understand genetic structure and diversity of parental cultivars involved in China Mainland sugarcane breeding programs, 92 elite parents and 4 wild relatives were genotyped with 18 microsatellite DNA markers. The genetic similarity （GS） values among the cultivars ranged from 0.346 to 0.960 with an average of 0.533. Among the introduced cultivars, India accessions had the closest genetic distance to China Mainland accessions （0.447）, while Australia accessions have the furthest distance （0.503）. A comparison of allelic diversity among geographical origins showed that there were 22 China Mainland specific alleles, of which 28% were derived from native S. spontaneaum germplasm in China. Model-based genetic structure, clustering, and principal components analyses consistently revealed there were five groups within the 96 accessions. Groups 1, 2, 4, and 5 consisted of all cultivars and group 3 only contained wild germplasm. Group 2 was characterized as the Introduction group with 46 cultivars predominantly introduced from Australia, Taiwan of China, India, and USA. Groups 1, 4, and 5 consisted of cultivars mostly originated from China Mainland, defined as the Complex group, Yacheng lines group, and F134/CP72-1210 group, respectively, upon their pedigree. By understanding the genetic relationships among the parental cultivars, breeders can gain a rational basis for expanding the gene pool and select the best parental accessions for crossing.