Electron beam (e-beam) irradiation is an emerging physical mutagenesis technique for sugarcane improvement. However, the functional mechanisms underlying dose-dependent physio-biochemical responses remain poorly understood. The effects of e-beam irradiation at different dose levels, such as 0, 20, 40, 60, 80, and 100 Gy on three sugarcane genotypes, i.e., GT11-2320, GT11-2142, and GT16-1232, were assessed. Different physio-biochemical parameters, i.e., protein content, superoxide dismutase, peroxidase, catalase, malondialdehyde, soluble sugars, proline, free amino acids, and photosynthetic pigments, were measured at specific time intervals across 102 samples. Two-way ANOVA analysis indicated that the irradiation dose significantly affected eight of nine parameters, with malondialdehyde (F = 10.91, P < 0.001) and chlorophyll content (F = 6.70, P < 0.001) showing the strongest dose responses. Genotype significantly influenced protein (F = 19.98, P < 0.001), peroxidase (F = 28.74, P < 0.001), proline (F = 4.90, P = 0.010), and amino acid content (F = 3.99, P = 0.022), respectively. Catalase activity was the single parameter exhibiting a significant genotype × dose interaction (F = 2.60, P = 0.009), indicating differential catalase regulation among genotypes. High-dose treatments (60–100 Gy) enhanced malondialdehyde content (45.4

Abstract Transcriptional regulation of the high-affinity K+ (HAK) transporter gene is an important mechanism of plant response to low potassium stress. Cloning and analysis of the promoter of potassium transporter gene is not only helpful to its expression pattern and regulation mechanism but also important to improve the potassium absorption efficiency in sugarcane. The potassium transporter gene ScHAK10 is highly expressed and induced by low potassium stress in sugarcane，but the functions of its promoter is still unclear. In the present article, the 1918 bp promoter region of the ScHAK10 gene (pScHAK10) was cloned by genomic walking technique. Computational analysis affirmed the existence of abiotic stress-responsive cis and core cis-elements, such as TATA box, CAAT box, phytohormone responsive, stress response and light response motifs. GUS histochemical staining of transgenic Arabidopsis thaliana seedlings showed that the leaf, corolla, and root tip were deeply stained, and paraffin sections of root tip tissue showed GUS staining in ductal tissue of A. thaliana shallowly stained. The 5′-terminal deletion of the promoter was cloned, and the lengths of 1918 (full), 1623 (Q1), 1332 (Q2), 957 (Q3), 576 (Q4), and 357 bp (Q5) were cloned into the GUS reporter vector for A. thaliana transient transformation. The transgenic plants generated through a single event exhibited a promising expression of the GUS reporter protein, which was treated with salt, low potassium, IAA and cold stress conditions. The results showed that the promoter activity correlates with the promoter fragment's length, and the long promoter fragment exhibits higher training. The Q5 was the least active and could not drive GUS expression. Under abiotic stress, the expression of GUS enzyme activity varies among different promoter fragments. Under low potassium and high salt stress, Q3 and Q4 showed the highest promoter activity. The Q1 and Q4 led the highest promoter activity during IAA and cold stress. These findings help to understand the molecular mechanism of ScHAK10 expression regulation and provide a theoretical basis for improving potassium uptake efficiency and breeding potassium-efficient varieties in sugarcane.

Biochar has the potential to become a more promising carbon source with a broad range of applications in soil agroecosystems. The depletion of soil minerals is a big problem due to soil erosion and leaching of nutrients. Biochar is a soil conditioner used in crop production to improve soil profile, increase fertilizer use efficiency, plant growth and development, carbon sequestration, and reduce greenhouse gas emissions. It is persistent in the environment and retains water, nutrients, and contaminants. It can also be applied in environmental rehabilitation for remediating contaminated soil. Applied biochar significantly enhanced the nutrients in the rhizospheric soil and reduced the bioavailability and uptake of heavy metals. The enhancement of soil nutrient values was the major functional mechanism for enhancing plant protection and production. Overall, the results of this mini-review are significant because they provide the strategies and technological direction for using biochar in sustainable agricultural systems.

AbstractPlant cellulose synthase is one of the important glycosyltransferases, which catalyzes the synthesis of the paracrystalline of H-bonded-β-(1,4)-glucose chains. This study isolated the cellulose synthase 3 (Ces3) sequence from sugarcane (Saccharum officinarum L.) leaves. SoCes3 (GenBank accession No. MG324347) has a full-length cDNA sequence of 3625 bp. It contains an open reading frame (3225 bp), encoding 1074 amino acids with a molecular weight of about 120.89 kDa and isoelectric point of 6.26. SoCes3 protein showed high activity with other plant cellulose synthases. The recombinant protein contains plant cellulose synthase (Ces) protein conservative domains. In subcellular localization experiments, the fusion protein of SoCes3 with green fluorescent protein (GFP) was specifically localized in the cell membrane. The gene expression of SoCes3 was found in the leaf, leaf sheath, and internodes of the sugarcane stem. The highest expression level was found in the internode, especially with the highest expression level in the 5th internode and lowest in the leaves, and the gene expression level of SoCes3 was upregulated by PP333 and not in gibberellic acid-treated plants. It was conducted in tobacco plants to understand the biotechnological potential of SoCes3. The contents of cellulose and lignin were increased in SoCes3-overexpressing tobacco. Transcriptomic analysis showed that the transgenic tobacco induced different genes associated with different biological regulatory processes. Differentially expressed genes (DEGs) mediated plant hormone signal transduction, starch and sucrose metabolism signaling pathways were widely induced and mostly upregulated. The transcription levels in SoCes3-overexpressing transgenic lines were higher than wild-type. Graphical Abstract

探讨不同甘蔗品种单芽段种茎在生产应用中的产量潜能,为甘蔗精量和高效率种植技术推广及应用提供科学依据.在宾阳县邹圩镇甘蔗"双高"基地,设置桂糖42号单芽段(A1)、桂糖42号双芽段(A2)、桂糖44号单芽段(B1)、桂糖44号双芽段(B2)、桂糖49号单芽段(C1)、桂糖49号双芽段(C2)、桂糖55号单芽段(D1)和桂糖55号双芽段(D2)共8个处理,分别调查新植蔗和宿根蔗的农艺、产量及品质性状.结果表明:甘蔗单芽段种茎处理的新植蔗在出苗率、分蘖发生率、分蘖率和单位面积有效茎数上表现出高于双芽段种茎处理,均达到0.01极显著差异水平,且在桂糖44号中表现最为明显,分别提高20.30％、17.74％、58.26％、15.49％;在宿根蔗表现上,单芽段种茎处理的发株数、发株率、单位面积有效茎数、产量和产糖量高于双芽段种茎处理,桂糖44号单芽段种茎处理的宿根蔗比双芽段种茎处理分别提高15865株/hm2、12.64％、15.39％、13.59％、13.12％.本试验研究结果为甘蔗单芽段种茎技术在生产中推广应用提供科学参考.

甘蔗新品种桂柳05136是柳城县甘蔗研究中心以美国运河点(CP81/1254)为母本、新台糖22号为父本进行杂交选育而成,2014年通过省级品种审定和国家级品种鉴定,正式命名为桂柳05136.该品种高产、高糖,综合抗性强,适应性广,是目前全国主要蔗区替代原当家品种新台糖22号最好的品种之一.应该根据其种性要求配套相应的栽培技术,才能充分发挥桂柳05136的单位面积蔗茎产量及其含糖量的丰产潜能.

为全面地了解2021年广西蔗区糖料蔗生产情况,采用面上调查、数据收集和实地调查相结合的方法,调查了蔗区的种植面积及植期、品种结构、甘蔗苗情、病虫害发生情况等.调查发现:2021年广西蔗区整体苗情较好,有足够的苗数;南宁市蔗区甘蔗种植面积有一定程度减少(-5.81％),其他蔗区基本保持稳定;螟害枯心苗率整体较低,但宿根蔗螟害防治仍然是难题;宿根蔗黑穗病问题严峻,需加强关注并做好防控;机械化收获仍处于较低水平;蔗农种植新品种意愿强烈,蔗区的品种类型进一步多元化.建议加强甘蔗生产全程机械化的研发和推广力度,以及抗黑穗病优良新品种选育及配套技术的推广应用.

Insufficient water is a leading environmental problem that affects overall crop development, productivity, and sometimes total crop failure. It brings a number of morpho-physiological and cellular disturbances. The purpose of this study was carried out to assess the effects of photosynthetic pigments and antioxidative enzyme activities of Saccharum spontaneum cv. GX83-10 plants during mild to severe water stress conditions. After 90 days of bud setts germination, S. spontaneum plants were sustained up to 15 days of withdrawing water. Our results indicated that the stressed plants were negatively affected, such as growth, biomass, photosynthetic loss, and significant reduction in photosynthetic CO2 assimilation rate. Severe water stress enhanced the level of osmolytes, i.e., proline, soluble protein, soluble sugar, and malondialdehyde, as well as catalase, peroxidase, and superoxide dismutase enzyme activities. Antioxidative enzyme activities in S. spontaneum plant leaves were improved and enhanced the metabolism of superoxide, leading to enhanced water stress tolerance efficiency. The present findings may help in better understanding of S. spontaneum antioxidative defense systems in drought-stressed conditions.

为探讨单芽段机械作业、双芽段种茎人工直接补种作业对甘蔗品种桂糖49号宿根蔗农艺性状及产量的影响,为宿根蔗机械化补种作业的进一步利用提供科学依据,该研究分别采用桂辐98-296和桂糖49号单芽段机械补种、双芽段种茎手工补种桂糖49号的宿根蔗,调查不同补种方式的农艺性状、产量、产糖量及各指标间的相关性.试验结果表明,桂辐98-296单芽段、双芽段种茎直接补种的蔗株成茎率高,且其茎径无明显差异,有效茎数比对照增加约22.1％.桂辐98-296生长速度快,其补种蔗株7月和11月株高与桂糖49号宿根蔗无明显差别,且病害发生率低于桂糖49号,结果补种处理的平均甘蔗产量和产糖量分别比对照显著增加31.91％和31.71％.桂糖49号单芽段和双芽段直接补种桂糖49号宿根蔗的处理与对照相比,甘蔗产量和产糖量等各项指标均未达到显著差异.可见,桂辐98-296种茎单芽段机械化与双芽段种茎人工直接补种桂糖49号宿根蔗能有效改善群体结构,显著提高单产和产糖量,有效解决缺株断垄导致产量下降的问题,延长了宿根年限.同时,利用单芽段进行机械补种作业获得了成功,有助于提高劳动生产率及降低补种生产成本.

Drought is the abiotic factor that adversely affects plant growth, development survival, and crop productivity, posing a substantial threat to sustainable agriculture worldwide, especially in warm and dry areas. However, the extent of damage depends upon the crop growth stage, severity and frequency of the stress. In general, the reproductive growth phase is more sensitive to stresses causing a substantial loss in crop productivity. Saccharum spontaneum (L.) is the most variable wild relative of sugarcane with potential for use in sugarcane crop improvement programs. In the present study addresses the transcriptomic analysis of drought stress imposed by polyethylene glycol-6000 (PED-6000; w/v- 25%) on the root tip tissues of S. spontaneum GX83-10. The analysis of microarrays of drought-stressed roots was performed at 0 (CK), 2 (T2), 4 (T4), 8 (T8) and 24 h (T24). The analyzed data were compared with the gene function annotations of four major databases, such as Nr, KOG/COG, Swiss-Prot, and KEGG, and a total of 62,988 single-gene information was obtained. The differently expressed genes of 56237 (T4), 59319 (T8), and 58583 (T24), among which CK obtained the most significant number of expressed genes (35920) as compared to T24, with a total of 53683 trend genes. Gene ontology (GO) and KEGG analysis were performed on the 6 important trends, and a total of 598 significant GO IDs and 42 significantly enriched metabolic pathways. Furthermore, these findings also aid in the selection of novel genes and promoters that can be used to potentially produce crop plants with enhanced stress resistance efficiency for sustainable agriculture.

Sugarcane is a cash crop that plays an integral part in the sugar industry. The Sustainable Sugarcane Initiative (SSI) has been adopted globally, ensuring enough and aiming for more yield, helping increase disease-free sugarcane cultivation. Single-bud seeds could be the best approach for sugarcane cultivation. Indole-3-butyric acid (IBA) is a rooting agent utilized significantly in seedling propagation. Greenhouse experiment results discovered the significant growth promotion in sugarcane seedlings and accumulation of plant hormones at 100 ppm IBA. Next, we performed transcriptomic analysis of sugarcane buds using RNA sequencing and compared their gene expression during root development due to affect of IBA (100 ppm). A total of 113,475 unigenes were annotated with an average length of 836 bp (N50 = 1,536). The comparative RNA-seq study between the control (CK) and IBA-treated (T) buds showed significant differentially expressed unigenes (494 upregulated and 2086 downregulated). The IBA influenced major biological processes including metabolic process, the cellular process, and single-organism process. For cellular component category, cell, cell part, organelle, membrane, and organelle part were mainly affected. In addition, catalytic activity and binding were primarily affected in the molecular function categories. Furthermore, the expression of genes related to plant hormones and signaling pathways was analyzed by qRT-PCR, which was consistent with the RNA-seq expression profile. This study provides new insights into the IBA response to the bud sprouting in sugarcane based on RNA sequencing, and generated information could help further research on breeding improvement of sugarcane.

甘蔗种业是糖料蔗生产的根基,甘蔗工厂化制种是推进甘蔗生产机械化、标准化的基础.目前,广西蔗区面临商品化供种率低、种茎质量差和种植效率低等问题,需通过产业化、标准化的技术来突破瓶颈.文章阐述了甘蔗健康种茎工厂化制种配套机械精量种植技术优势,并对其产生的效益进行投入与产出对比分析,以此确定该技术在甘蔗生产中的节本提质增效性,为推进甘蔗种业产业化、甘蔗供种标准化打下基础.

为不断完善甘蔗单芽种植技术,加快推进甘蔗良种产业化进程,有效降低生产成本,促进甘蔗产业可持续发展,本研究以桂糖49号为试验材料,研究不同种植密度对甘蔗单芽生产的影响.结果表明:随着种植密度增加,各农艺性状指标均呈现先上升后下降的趋势,T3处理(5芽/m)种植密度表现最佳,其出苗率、分蘖率和有效茎数与其他处理均达到极显著(P<0.01)差异;不同种植密度对甘蔗可溶性蛋白质、可溶性糖、丙二醛含量和脯氨酸含量未达到显著性影响;甘蔗抗倒能力强弱表现为T4>T3>T2>T5>T1>T6;不同种植密度下甘蔗品质无明显变化规律,但产量和产糖量表现出显著性差异,其中T3处理(5芽/m)可获得最佳产量(83.85 t/hm2)和产糖量(13.44 t/hm2).综合分析得出:桂糖49号甘蔗单芽适宜种植密度为5～6芽/m.该结果可为甘蔗单芽种植技术的推广提供参考依据.

Potassium ions are widely involved in a series of physiological and biochemical processes of plants, which is of great significance to plant growth. High-affinity K + ( HAK ) transporter mainly absorbed and transported potassium in plants, but there are few studies on HAK gene in sugarcane. In this study, the coding region of high-affinity K + transporter genes were cloned from sugarcane and designated as ScHAK9, ScHAK10, ScHAK11 (GenBank accession number: MG564720, MG564721, MG564722). Phylogenetic analysis results confirmed that ScHAK9 and ScHAK11 had the closest relationship with ZmHAK9 and ZmHAK11 ( Zea mays ), ScHAK10 had the closest relationship with SbHAK10 ( Sorghum bicolor ). In subcellular localization experiments, the fusion protein of ScHAK9 and ScHAK11 with green fluorescent protein was specifically localized in the cell membrane, but ScHAK10 green fluorescent protein was not detected, it was speculated to be expressed in Golgi apparatus. The gene expression level of ScHAK in different tissues of sugarcane at the growth periods was different, and the gene expression level of ScHAK genes were up-regulated by the low-potassium and salt stress. Through the functional characterization experiments of ScHAK genes in K + uptake-deficient yeasts, it was founded that ScHAK genes possessed K + transporter activity. The study indicated that ScHAK genes might mediate K + absorption through the cell membrane and might be participate in maintaining Na + /K + homeostasis in sugarcane under the adversity stress, and the development of plant organs is regulated by the potassium ions transport of ScHAK genes.

为了研究CaO型土壤调理剂施用量对酸化蔗地的调节效果及对甘蔗生长的影响,为合理使用土壤调理剂改良酸化蔗地土壤提供科学依据,在广西扶绥县常年连作的新植甘蔗地,设置CaO型土壤调理剂0(CK)、1500(A)、2250(B)和3000 kg/hm2(C)4个施用量水平,调查不同时期蔗地土壤pH和甘蔗株高、茎径及收获期产量性状.结果表明:与CK比较,A、B和C处理的蔗地土壤pH分别提高达到0.74、0.80和0.90,均达极显著差异水平;甘蔗施用CaO型土壤调理剂后,对株高、茎径有促进效应,特别是B处理在2019年7月17日、8月6日、9月18日和2020年1月12日的株高分别比对照提高了31.9、30.2、22.7和27.4 cm,达到极显著差异水平;CaO型土壤调理剂对甘蔗蔗糖分和产量具有显著的促进效果,蔗糖分可增加0.51％～0.65％(绝对值),蔗茎产量增加达7.80～9.15 t/hm2.CaO型土壤调理剂能有效提高蔗地土壤pH,促进甘蔗生长,以2250 kg/hm2施用量较适合.本研究试验结果为CaO型土壤调理剂在土壤酸化蔗区合理施用提供技术参考.

2015～2017年,基于当时广西蔗区主栽品种ROC22宿根蔗缺株断垄严重而开展了种茎直接补种宿根蔗延长年限研究,利用桂辐98-296种茎直接补种ROC22、桂糖42号、桂柳05-136宿根蔗的田间试验.根据3年的试验结果表明,桂辐98-296种茎直接补种处理蔗茎产量比对照平均增产19.39 t/hm2,增幅33.51％,种茎补种处理蔗茎蔗糖分比对照高0.04％.经济效益分析结果表明:宿根蔗因年限延长2年而年节约种植成本平均为1234.2元/hm2,种植者纯增收平均为4898.8元/hm2,制糖企业新增工业产值平均为14838.0元/hm2.综合部分制糖企业多点及其它甘蔗品种的示范表征结果,完善与提炼出具有创新性和实用性的"种茎直接补种宿根蔗延长年限栽培技术体系".对该技术在广西蔗区生产未来大面积推广应用,对蔗糖产业提质和降本增效,以及利用机械化作业以提高补种作业劳动生产率进行了展望,并提出了一定的推广建议.

[目的]研究甘蔗套种马铃薯机械化栽培对土壤微生物多样性和甘蔗养分吸收的影响,为该套种模式的推广应用提供理论依据.[方法]采用大田随机区组试验,设甘蔗单作(对照)和甘蔗套种马铃薯2种栽培模式,每种种植模式分为根际区和非根际区进行土壤采集,即甘蔗单作区的根际土、非根际土及甘蔗套种区的根际土、非根际土.利用传统测定方法和Illumina高通量测序技术分析2种栽培模式下的土壤理化性质、甘蔗养分吸收和微生物多样性的差异.[结果]与甘蔗单作相比,套种区甘蔗根际土的有机质、水解性氮、有效磷和速效钾含量分别显著提高4.93%、12.32%、6.40%和8.92%(P＜0.05,下同);非根际土的有机质、水解性氮、有效磷和速效钾含量分别显著提高10.50%、56.01%、48.31%和51.52%;套种区显著降低了土壤容重,提高了土壤含水量.套种区土壤的真菌Shannon、ACE和Chao1指数显著高于单作区,Simpson指数显著低于单作区;土壤细菌Shannon、Simpson、ACE和Chao1指数则与单作区无显著差异(P＞0.05,下同).套种提高了土壤细菌酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)和浮霉菌门(Planctomycetes)及真菌担子菌门(Basidiomycota)、毛霉菌门(Mucoromycota)和其他未知真菌类群的比例,降低了细菌变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)和杆菌属门(Patescibacteria)及真菌子囊菌门(Ascomycota)的比例.相关分析结果显示,土壤pH、速效钾、土壤容重和土壤含水量对土壤细菌及真菌群落的影响较大,其中土壤细菌群落中的拟杆菌门和厚壁菌门分别与土壤容重和土壤有效磷呈显著正相关,绿弯菌门和芽单胞菌门分别与土壤容重和土壤速效钾呈显著负相关;土壤真菌群落中的子囊菌门与土壤容重呈显著正相关,担子菌门与土壤容重呈显著负相关.套种显著降低了苗期甘蔗对磷和钾的吸收量,对生长后期甘蔗的养分吸收无显著影响.[结论]甘蔗套种马铃薯机械化栽培可有效改善土壤理化性质,改变土壤微生物群落结构,提高甘蔗产量和含糖量,增加经济效益,实现土地的用养结合,是较合理的套种模式.

以甘蔗单芽种茎为材料,研究甘蔗单芽种茎包衣处理对不同保存时间和温度的影响,为甘蔗种茎包衣技术推广应用提供参考.结果表明:包衣和未包衣处理甘蔗单芽种茎,其可溶性糖、氨基酸含量均从高到低排列依次为10℃＞13 ℃＞15 ℃＞常温,同处理比较,包衣甘蔗单芽种茎可溶性糖含量均高于未包衣处理.包衣甘蔗单芽种茎在不同保存温度和保存时间下,病菌感染率明显低于未包衣处理.其中,10℃、13 ℃、15 ℃和常温保存20 d,包衣比未包衣病菌感染率分别低189％、226％、256％和191％;10 ℃、13 ℃、15 ℃和常温保存30 d,包衣比未包衣病菌感染率分别低112％、106％、174％和94％;包衣保存30 d,13 ℃低温下甘蔗单芽种茎病菌感染率最低为27.35％.综合得知,甘蔗单芽种茎包衣处理可延长保存时间至30 d左右,并以13 ℃保存温度效果最佳,其能有效延缓营养物质的下降,减少病菌对甘蔗单芽种茎的侵染,增强蔗种抗逆性,较好的保持甘蔗种茎活力.

为优化甘蔗高产高效栽培技术,以桂糖49号为试验材料,研究了促根剂处理甘蔗单芽种茎对其农艺性状、生理生化指标、品质及产量的影响.结果表明,与不包衣(CK2)相比,包衣+50mg/L促根剂(T1)、包衣+100mg/L促根剂(T2)和包衣(CK1)的甘蔗出苗率、分蘖率、株高和有效茎数显著提高,产量分别增加27.5％、9.2％和8.2％,产糖量分别增加27.4％、9.2％和8.3％;同时,促根剂可提高甘蔗生长速度,提高甘蔗叶片可溶性蛋白、可溶性糖和脯氨酸含量,对甘蔗品质略有提升,但不显著.因此,促根剂能有效促进甘蔗生长,提高甘蔗产量和产糖量,促根剂浓度100mg/L的效果最佳.

Standardized mechanical planting of single-bud seedcane sett can improve planting efficiency and reduce costs in sugarcane production and is a research focus at present. Small RNA (miRNA) is an important regulator of life activities, which regulates many plant physiological processes such as gene expression, growth, development and metabolism. In this study, miRNAs in six germinating bud samples (S, bud of single-bud sett; D1, upper bud of double-bud sett; D2, lower bud of double-bud sett; T1, upper bud of three-bud sett; T2, median bud of three-bud sett; T3, lower bud of three-bud sett) derived from sugarcane variety GT42 were analyzed. As a result, 8,055,449, 19,172,991, 8,163,579, 11,748,126, 13,547,550 and 12,861,743 clean tags were obtained respectively, and their length was ranged from 16 to 35 nt. For different bud samples, S, D1, D2, T1, T2 and T3, 174, 600, 318, 425, 466, and 317 novel miRNAs were identified respectively, and a total of 1797 miRNAs, 28,042 target genes and 53,141 target sites were obtained from them. As compared with D1, D2, T1, T2 and T3, it was found the sample S showed 219, 157, 108, 44 and 41 up-regulated miRNAs, respectively. Plant hormone signal transduction pathway was the unique pathway enriched by KEGG analysis, and the enriched gene number was 67, 48, 54, 44 and 40 in S_VS_D1, S_VS_D2, S_VS_T1, S_VS_T2 and S_VS_T3, respectively. Furthermore, a total of 19 allelic genes were co-enriched. Among them, the most abundant allelic gene was found to beIAAgene, with a total of 32 gene sequences. All the up-regulated genes were involved in eight aspects metabolic regulation in plant hormone information transduction. The results showed that plant hormone information transduction played a dominant role in the single-bud sett germinating process, which might be the main reason for promoting the early germination and growth. These results can be referred for popularization and application of standardized mechanical planting of single-bud sett in sugarcane.