Sugarcane (Saccharum spp. hybrid) is the world's most important sugar crop, where promoting tillering can enhance its yields. Fructose 1,6-bisphosphatase (FBPase), a key rate-limiting enzyme in plant photosynthesis, has been shown to promote branching or tillering in plants. However, systematic in-depth functional studies of the FBP gene family in sugarcane remain limited to date. Here, a total of 66 FBP gene family members were identified and analyzed using bioinformatics approaches across the genomes of three Saccharum species: Saccharum spontaneum, Saccharum hybrid R570, and Saccharum hybrid ZZ1. The FBP gene family was divided into three subgroups, with each subgroup exhibiting a consistent pattern in the distribution of conserved motifs and gene structure. Promoter cis-acting element analysis suggested that these elements are mainly predicted to be associated with light responses, regulation by plant hormones, adaptation to environmental stresses, and the control of plant growth and developmental processes. Based on RNA-Seq data, the FBP genes show distinct spatiotemporal expression patterns at different growth stages, in various tissues, as well as in response to hormones in sugarcane. Subsequently, the ScFBP3 gene was cloned, and transgenic Arabidopsis lines overexpressing ScFBP3 were generated. Compared with wild-type Arabidopsis plants, the ScFBP3 overexpression lines exhibited significantly higher sugar contents, increased sucrose accumulation, and more branches. Transcriptomic analysis combined with KEGG pathway annotation revealed that the differentially expressed genes in ScFBP3-overexpressing Arabidopsis plants were predominantly enriched in the starch and sucrose metabolism pathway. This finding suggests the conserved function of FBP gene in regulating branching by modulating sucrose metabolism, providing a reference for exploring the mechanism of carbon metabolism regulating tillering in sugarcane.

Abstract Modern sugarcane cultivars are allo‐autopolyploids and aneuploids, which pose great challenges for research and breeding to meet global demand. Recent breakthroughs in gene‐editing technologies offer the potential to expedite the development of high‐yield stress‐resilient sugarcane, a vegetatively propagated crop. However, the limited valuable targets, coupled with complex transgenic methodologies for verifying gene function, hamper this progress. Protoplasts enable rapid gene introduction and function validation, yet an efficient protoplast expression system for elite sugarcane cultivars is currently lacking. Here, we developed a protoplast isolation and transfection method using tissue‐cultured GT42, a primary sugarcane cultivar in China, yielding 1.41 × 10 7 protoplasts/g fresh weight with 78.74% viability and 39.01% transfection efficiency. This system proved effective for various assays, including GCaMP6‐based calcium imaging. Using this system, we showed that abscisic acid biosynthesis gene ScNCED3 acts as an early drought signal, positively regulated by ScPYL4‐12, ScOST1‐12 and ScMPK6‐11, whereas salicylic acid (SA) enhances ScPR1 expression. Notably, the ScNPRs exhibited opposite functionalities compared to those in Arabidopsis , with ScNPR1 negatively and ScNPR3/4 positively activating ScPR1 expression upon SA treatment. Together, we established an efficient protoplast expression system using GT42 sugarcane culm, providing a valuable tool for studying sugarcane gene function under stress.

Ubiquitination modification is a core regulatory mechanism of plant growth, development and stress response. The CHY zinc finger domain-containing RING-type E3 ubiquitin ligase (RZFP) subfamily plays a unique role in plant signal integration, but its systematic research in sugarcane remains unreported. Tillering is a key agronomic trait determining sugarcane yield, while its molecular regulatory mechanism is yet to be fully elucidated. This study aimed to systematically characterize the RZFP gene family in sugarcane and explore its association with tillering regulation. A total of 47 ShRZFP genes were identified from the sugarcane XTT22 genome. Phylogenetic analysis divided ShRZFP proteins into 3 groups with independent expansion characteristics; segmental duplication was the main driver of family expansion, dominated by purifying selection during evolution. ShRZFP proteins harbored 2–10 conserved motifs, with consistent gene structures within the same evolutionary branch. Light-responsive elements were the most abundant cis-acting elements in ShRZFP promoters. Weighted Gene Co-expression Network Analysis (WGCNA) screened 6 candidate tillering-related ShRZFP genes enriched in the yellow module, whose co-expressed genes were significantly enriched in the photosynthesis pathway. Upstream transcriptional regulatory network prediction revealed that candidate ShRZFP genes may be regulated by transcription factors (TFs) including WRKY, AP2/ERF, TCP and DBB. qRT-PCR validation showed these 6 candidate ShRZFP genes were significantly responsive to key tillering-related phytohormones, suggesting their putative involvement in the negative regulation of sugarcane tillering. This study is the first systematic analysis of the ShRZFP gene family in sugarcane, which fills the research gap of this gene family in sugarcane, and provides valuable candidate genes and a preliminary theoretical basis for molecular improvement of sugarcane tillering traits.

A large and highly polyploid genome, long breeding cycles, low narrow-sense heritability of yield and its components, and persisting yield stagnation continue to challenge sugarcane variety improvement through both conventional and molecular breedings. To address this, this study developed an efficient phenotype-based concurrent multi-trait prediction framework using artificial intelligence, leveraging 2700 parent combinations and their offspring field performance data from the Sugarcane Research Institute of Guangxi Academy of Agricultural Sciences. Five machine learning paradigms were selected based on data characteristics: tree-based models (GBDT, XGBoost) for structured tabular data and nonlinear trait interactions; attention-based tabular models (TabTransformer, TabNet) for subtle cross-trait dependencies; and an MLP as a baseline. All models were optimized via 80/20 stratified train–test split, class-weighted loss, and cross-validated grid search. GBDT achieved the best overall performance with a macro F1 score of 0.7316, Hamming loss of 0.2052, and sample accuracy of 0.5630, excelling in predicting sucrose content, cane yield, and smut resistance. XGBoost performed comparably, while TabTransformer offered complementary advantages with a higher F1 score (0.6829) on overall agronomic performance. These results indicate the potential of using artificial intelligence (AI), particularly machine learning (ML), to increase the predictive power and robustness through integrated AI approaches in the future. This phenotype-based framework shows the value of ML as an efficient decision support tool that can help breeders prioritize cross combinations and optimize resource use, thereby reducing reliance on extensive field trials. While the potential of AI in accelerating variety development is evident, its routine application in real-world commercial breeding requires validation.

Poor leaf abscission in sugarcane significantly increases harvesting costs and constrains mechanized efficiency, yet its molecular basis remains poorly understood. Here, we performed an integrated hormone-targeted metabolomics and transcriptomics analysis in three sugarcane cultivars (GT47, LZ02-169, and ROC22) with contrasting abscission phenotypes. A total of 37 differentially accumulated metabolites and 3109 differentially expressed genes (DEGs) were identified. Integrated analysis revealed extensive reprogramming of phytohormone-related pathways, particularly those associated with auxin, jasmonic acid, abscisic acid (ABA), salicylic acid, gibberellin, and cytokinin. Notably, comparisons involving LZ02-169 and GT47 showed a higher enrichment of hormone-related DEGs, indicating dynamic hormonal regulation underlying phenotypic divergence. Focusing on ABA biosynthesis, two key genes, zeaxanthin epoxidase (ZEP) and β-carotene hydroxylase (BCH), were consistently upregulated in abscission-prone cultivars. Metabolomic data further supported increased accumulation of ABA precursors, including zeaxanthin, suggesting activation of the carotenoid-derived ABA biosynthetic pathway. Correlation analysis indicated a strong association between ZEP/BCH expression and ABA accumulation. Importantly, Upregulation of ZEP and BCH is associated with increased ABA accumulation in the leaf abscission zone, suggesting a potential role for this carotenoid-derived pathway in modulating cell separation during natural abscission. This coordinated transcriptional–metabolic regulation suggests that ABA is a potential key correlate of natural leaf abscission in sugarcane. Collectively, this study provides a multi-omics correlative framework linking carotenoid metabolism to hormone signaling and identifies ZEP and BCH as promising targets for improving sugarcane harvesting efficiency.

Side-deep fertilization (SDF) is widely recognized as an effective strategy for enhancing rice yield, nitrogen use efficiency (NUE), and reducing nitrogen (N) loss compared to surface fertilization in China. Nevertheless, the precise extent to which N can be reduced, and the specific improvements in yield, NUE, and profitability achievable through SDF remain unclear. To address this knowledge gap, a meta-analysis was conducted to comprehensively assess the impact of N input, application method and frequency, N fertilizer type, rice varieties, and rice production regions on yield, NUE, and profitability under SDF in China. The findings indicate that compared to surface fertilization, SDF with a 10% reduction in N input simultaneously increased rice yield, NUE, and profitability by 3.96%, 20.5%, and 11.9%, respectively. These gains were attributed to increases in effective panicles (2.65%) and grains per panicle (2.96%). Furthermore, side-deep basal fertilization, either without topdressing or in combination with panicle fertilization, emerged as a reliable strategy for achieving high yields in comparison to surface fertilization. The implementation of controlled-release N fertilizer (CRN) through SDF significantly enhanced rice yield while reducing the N application rate compared to surface fertilization. This method resulted in increased yields across various rice types, including indica hybrid rice, indica inbred rice, indica-japonica hybrid rice, and japonica hybrid rice, with the exception of japonica inbred rice, compared to surface fertilization. The advantages of SDF were particularly pronounced in regions characterized by high rainfall, elevated temperatures, and substantial N input, such as the Yangtze River Basin, where it demonstrated superior adaptability and efficacy. These findings provide valuable insights for stakeholders aiming to promote the adoption of SDF technology to achieve higher rice productivity, improved NUE, and increased profitability with reduced N input in China.

Biochar can significantly alter soil nitrogen (N) availability and nitrous oxide (N2O) emissions, but the mechanisms by which different biochar application rates affect N retention, N turnover, and N2O emissions in degraded cropland soils remain unclear. To fill this knowledge gap, we conducted a field experiment with six treatments on typical degraded croplands in the subtropical region, including: no fertilizer (CK), conventional fertilization (CF), CF plus sugarcane bagasse at 20 t ha-1 or 40 t ha-1 , and CF plus sugarcane bagasse biochar at 20 t ha-1 or 40 t ha-1 . Soil physicochemical properties, aggregate composition, tomato yield, and N2O emission were monitored, and a 15N tracing technique was used to quantify soil N transformation rates. Organic amendments improved soil quality and structure and increased tomato yield relative to CK and CF, with biochar being more effective than sugarcane bagasse, particularly under high-rate application. In addition, organic amendments also accelerated the rates of gross N mineralization, autotrophic nitrification, microbial immobilization of ammonium (NH4+) and nitrate (NO3-), as well as NH4+ adsorption, but reduced the mean residence times of NH4+ and NO3-. These findings showed that organic amendments enhanced soil N turnover and inorganic N retention, with the most pronounced effects observed under the high-rate biochar treatment. Sugarcane bagasse did not significantly mitigate N2O emission relative to CF, whereas biochar treatments significantly reduced cumulative N2O emissions, yield-scaled N2O emissions, and the N2O emission factor. Notably, these N2O emission indicators were significantly negatively correlated with microbial NH4+ and NO3- immobilization rates and NH4+ adsorption rate, suggesting that biochar reduced N2O emissions by enhancing soil inorganic N retention. Overall, this study highlights that in subtropical degraded cropland soils, sugarcane bagasse biochar can play a key role in improving soil quality and regulating N transformation processes, which in turn controls inorganic N supply and retention and ultimately reduces N2O emissions.

Soil compaction from mechanical harvesting is a major constraint in sugarcane production. While its agronomic impacts are well-documented, the biological mechanisms underlying varietal tolerance remain unknown. In this study, we combined multi-year field trials, controlled-environment experiments, and molecular and metabolomic analyses to investigate the genetic variation for soil compaction tolerance and its biological basis in sugarcane. Field trials revealed significant compaction-induced yield reductions, up to 23 % in susceptible varieties. However, one genotype, GT44, consistently maintained yield and growth performance under compacted conditions, across successive crops. Greenhouse experiments further confirmed its superior tolerance. Anatomically, GT44 preserved root integrity under compaction, with no reduction or detachment of stele seen in compactionsensitive varieties. Hormonal profiling of roots revealed a unique response in GT44, notably a two-fold increase in jasmonic acid (JA) levels, suggesting a JA-mediated stress adaptation. To decrypt this mechanism, gene expression analysis in two root types, sett-roots (SR) and adventitious roots (R) of GT44 and a susceptible variety GL05-136 grown under compacted and normal soil was conducted. The gene expression and metabolome analysis revealed a jasmonate-mediated stress defense and plant growth mechanism likely involving flavonoids, and cell-wall remodelling and reinforcement and modulation of water transmembrane transporter activity. This inference is corroborated by the significant upregulation of genes involved jasmonate, isoflavonoids and cell wall biosynthesis, and their precursor pathways in GT44. Our findings thus point towards a synergistic JA-flavonoid-cell wall remodeling and reinforcement response as a key mechanism of compaction tolerance in GT44. To our knowledge, this is the first study reporting jasmonate signaling as a plausible dominant player in plant adaptation to soil compaction.

ABSTRACTCombined use of controlled‐release urea and conventional urea (CCU) is considered a practical strategy to simultaneously achieve the dual benefits of crop yield and nitrogen use efficiency (NUE). However, the overall impact of CCU on rice production is not well understood. A meta‐analysis was conducted to determine the effect of CCU on rice yield and NUE in China. The results revealed that CCU increased rice yield by 6.22% and NUE by 16.5% compared with conventional urea. Significant yield and NUE gains from CCU were evident only when the ratio of controlled‐release urea to total nitrogen input reached 0.6 or above. Rice yield and NUE were increased simultaneously at nitrogen rates ranging from 150 to 225 kg ha−1, with no significant improvement in grain yield and NUE with nitrogen supply beyond 290 and 327 kg ha−1, respectively. In addition, rice yield and NUE were significantly greater with split rather than single application of CCU. Also, rice yield and NUE were increased when mean annual temperature (MAT), mean annual precipitation (MAP) and soil available nitrogen (AN) were more than 10°C, 800 mm, and 50 mg kg−1, respectively. Soil pH and organic matter content were significant determinants of rice yield and NUE gains with CCU. Our findings clearly demonstrate that the combined use of controlled‐release urea and conventional urea will deliver significant gains in rice yield and NUE and that it should be proposed as an effective measure for sustainable rice production.

Flowering often perturbs carbon allocation in sugarcane, yet its transcriptomic–metabolomic basis remains unclear. We profiled two contrasting cultivars, Gui Tang 16-3285 (sugar increases during flowering) and Gui Tang 44 (sugar decreases), sampling apical tissues at five stages (Non-spikelet-bearing stage (NSB), Early booting stage (ESB), Late booting stage (LSB), Tasseling stage (TS), and Flowering stage (FS)). RNA-seq and untargeted LC–MS revealed a strong stage/genotype structure (PCA) with high reproducibility. Pairwise contrasts (FS vs. earlier stages) and time series clustering (Mfuzz) showed extensive, stage-resolved reprogramming with small cross-cultivar overlaps. GO/KEGG indicated that GT16 is enriched for central carbon processes and glucose response, whereas GT44 favors cell-wall remodeling (xylan/xyloglucan), amino/nucleotide sugar, and phenylpropanoid pathways. Integrated analysis identified opposing temporal features across omics layers: in GT16, late-rising metabolites—including sedoheptulose—were consistent with enhanced pentose phosphate/Calvin coupling that regenerates fructose-6-phosphate for sucrose biosynthesis; in GT44, early activation of wall and secondary sinks, together with trehalose/(trehalose-6-phosphate) T6P signatures, paralleled declining soluble sugars. Across cultivars we resolved 11 and 18 genes in reciprocal opposite-trend sets (most with clear temporal order) and eight vs. five metabolites with mirrored dynamics, nominating actionable biomarkers (e.g., sedoheptulose/S7P) and regulatory nodes. These results provide a mechanistic framework linking flowering stage to carbon partitioning and suggest practical levers—timing growth moderation/ripeners, prioritizing sucrose phosphate synthase/Sucrose Phosphate Phosphatase, tempering wall flux, to sustain sucrose during reproductive development and inform breeding for high-sugar, flowering-resilient ideotypes.

High sucrose content is a crucial breeding objective in sugarcane, with significant differences in sucrose accumulation patterns between early and late-maturing varieties during different growth stages. This study aimed to determine how differences in cane maturation affect proteins involved in sucrose metabolism. The isobaric tags for relative and absolute quantitation (iTRAQ) technique was employed to analyze intraspecific and interspecific proteomic differences between the early-maturing sugarcane variety 'GL05-136' and the late-maturing variety 'GR2' during the maturation period (January and February). A total of 3337 proteins were identified. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Clusters of Orthologous Genes analysis found that the differential proteins were mainly associated with metabolic processes, single biological processes, and cellular processes. A total of 47 differential proteins were identified in the four comparison groups (intra-variety temporal comparisons and inter-variety synchronous comparisons), 17 of which were enriched in a KEGG pathway, including glucose metabolism, stress resistance, and photosynthesis pathways. The differential proteins fructose-bisphosphate aldolase and disulfide isomerase were obtained after further screening of the contrast groups between varieties. These two proteins may be associated with differential cane maturation, sucrose synthesis and accumulation in sugarcane. These results provide more insights on sucrose accumulation and stalk maturation in sugarcane varieties.

High nitrogen (N) fertiliser input in Chinese sugarcane production has substantially increased the risk of reactive N (Nr) loss and crop productivity improvement for a long time. However, there is no comprehensive study of sustainable N management on different N loss pathways in a high N input cropping system of China. Here, a field experiment with 5 treatments (control (CK); conventional urea (OPT; 300 kg N ha(-1)); partial substitution of urea with coated urea (OPT-CU; 300 kg N ha(-1)); nitrification inhibitor (3,4-dimethylpyrazole phosphate, DMPP)blended urea (OPT-NI; 300 kg N ha(-1)); and partial substitution of urea with organic N fertilizer (OPT-ON; 300 kg ha(-1))) was conducted in a commercial sugarcane farm for two cropping years to understand how different N management strategies attenuate Nr losses (emission of ammonia and nitrous oxide (N2O), and N leaching) of sugarcane crops. The results showed that OPT-CU has increased sugarcane yield by 2.5 %-9.5 % and decreased ammonia and N2O emission by about 33.9 % and 44.4 %, respectively, compared with OPT treatment. Coated urea application however increased N leaching loss by 29.5 % (174 kg ha(-1)) relative to OPT (136 kg ha(-1)). OPTNI treatment decreased N2O emission by 53.0 % but increased ammonia volatilization as much as 52 %, compared with OPT treatment. Though the N leaching loss was similar to other treatments, cane yield of OPT-NI crops was 3.03-5.18 % lower than that OPT treatment. More significantly, in this study OPT-ON was found to reduce both ammonia and N2O emission by about 42.7 % and 32.5 %, respectively, but again N leaching loss (139 kg ha(-1)) and cane yield were comparable to OPT treatment. Taken together, our study concludes that partial substitution of synthetic N with organic N fertiliser could yield both economic and environmental benefits maximally, making sugarcane a more sustainable food and energy crop.

Sugarcane is a globally significant economic crop, and sugar content is a key determinant of its financial and industrial value. This study utilized sugar content information from spring-planted and ratoon sugarcane in six research regions across Guangxi, China from 2008 to 2023 along with concurrent meteorological data. By conducting statistical tests, the critical meteorological factors influencing the sugar content of sugarcane (effective cumulative temperature and rainfall) were identified. These factors were then used as independent variables to construct a vector autoregression (VAR) model, which was employed to analyze the spatiotemporal dynamic relationships between sugar content and meteorological variables across different planting periods. The empirical results demonstrated that the influence of effective cumulative temperature on sugar content across various regions and planting periods shifted from positive to negative in the short-term, eventually reverting to a positive effect after a period of alternating influences. The impact of rainfall mirrored effective cumulative temperature, though it was relatively less pronounced. The sugarcane in Nanning and Baise was less influenced by effective cumulative temperature and rainfall, with the short-term impact changing from positive to negative and diminishing over time. Our findings provide scientific insights for guiding the ecosystem management of sugarcane in China.

Plants are considered as sessile organisms that cannot avoid adverse environmental conditions and developed complex signaling networks composed of different pathways. WRKY transcription factors (TFs) are key regulators of various plant processes, including the responses to abiotic stresses. WRKY TFs are one of the largest family of transcriptional regulators found in plants. WRKY TFs act as molecular switches that modulate the expression of stress-responsive genes. Stress-induced WRKY TFs expression modulated by a complex transcriptional regulatory network that maintain the proper balance between growth, development, and stress responses. WRKY TFs typically interact with the W-box [TGACC(A/T)] of the target gene promoter to activate the expression of downstream genes. These TFs are associated in the regulation of different physiological processes. Overexpression of various WRKY genes faces the paradox of having various significant effects. These overexpression-associated undesirable phenotypes must be identified and removed for proper plant development. The present review summarized the recent development of various WRKY TFs during adverse environmental conditions as well as their role in plant growth, development and productivity for sustainable agriculture in near future.

当前甘蔗机械收获不能大面积推广的难点和痛点是机械碾压对甘蔗生长造成的负面影响.为了探明机械收获对桂糖47号(GT47)和桂糖31号(GT31)苗期主要农艺性状和重要生理指标的影响,为甘蔗机械收获的生理适应性评价和适宜机械收获品种选育提供理论参考.试验采用随机区组设计,设机械收获和人工收获2种处理,对比分析不同处理的发株率、分蘖率、叶片主要成分、根系活力及相关酶类的差异.结果表明,机械收获对GT31的发株率和分蘖率影响较大,对GT47发株率的影响不明显;2个甘蔗品种人工收获时的含氮量差异极显著,2种收获方式对GT47的含氮量影响不明显;人工收获时,GT47和GT31的全磷含量差异极显著,而机械收获时,2个品种的全磷含量无显著差异.钾含量受不同收获方式和不同甘蔗品种的影响都较大,无论是机械收获还是人工收获,GT47和GT31的全钾含量之间均存在极显著差异;不同收获方式下,不同甘蔗品种的根系活力差异较大,机械收获时,GT47和GT31的根系活力分别为0.53 mg/(g·h)和0.82 mg/(g·h),差异达到极显著水平,而人工收获时,2个品种的根系活力无明显差异;机械收获后,GT31根系的MDA含量在机械收获后极显著高于人工收获,而GT47根系的MDA含量在2种收获方式下无明显差异;机械收获时,GT47根系的CAT活性达到688.07 nmol/(min·g),极显著高于GT31;不同品种间,相同品种的不同收获方式间,根系的Pro含量和POD活性均差异不显著.不同甘蔗品种对不同收获方式的适应性存在差异,GT47在机械碾压后,在发株、分蘖等农艺性状和叶片营养、根系活力、根系抗逆相关酶类等生理指标变化上均表现出对机械碾压更快速和敏锐的反应能力,GT47较GT31更适宜机械收获.

[目的]探讨促生长化学调控剂对甘蔗节间伸长和糖分积累的影响,分析甘蔗产量与重要农艺性状间的相互关系,为定向化学调控甘蔗农艺性状及完善甘蔗高产高糖栽培技术提供参考依据.[方法]以甘蔗优良栽培品种桂糖58号(GT58)为试验材料,以不同促生长化学调控剂[硝酸钙(A)、硼酸(B)、磷酸二氢钾(C)、复硝酚钠(D)、赤霉素(E)、赤霉素+复硝酚钠(F)和赤霉素+硝酸钙+硼酸+磷酸二氢钾+复硝酚钠(G)]为化学调控剂处理组,以叶面喷施清水为对照组(CK),开展两年新植蔗田间小区试验,于节间伸长期喷施化学调控剂后在甘蔗不同生长发育时期测定其株高、节间伸长速率、糖分和产量.[结果]不同促生长化学调控剂处理甘蔗后,节间伸长速率表现为1.22～1.67 cm/d;平均节间数为21.30～23.90节;平均节间长为11.41～12.41 cm,且以含赤霉素调控剂的E和G处理极显著高于CK(P＜0.01,下同).含赤霉素调控剂的E和G处理甘蔗的株高均显著高于CK(P＜0.05,下同),茎径显著低于CK,有效茎数低于CK但差异不显著(P＞0.05),而最终产量均高于CK.在甘蔗节间糖分积累过程中,含赤霉素调控剂处理组(E、F和G处理)均可促进糖分在蔗茎中部和上部节间积累,促使不同部位节间的糖分含量快速达到工艺成熟期水平,还原糖含量快速降低至CK以下水平.相关分析结果表明,促生长化学调控剂处理组甘蔗的茎径与产量呈弱负相关,Pearson系数仅为-0.082,有效茎数与产量呈极显著正相关,株高与产量呈正相关.[结论]促生长化学调控剂可通过调控甘蔗节间伸长促进甘蔗株高形成,改善株高、茎径、有效茎数和产量性状及这些性状间的相互关系.其中,含赤霉素调控剂可有效促进节间伸长及糖分从中部节间至上部节间快速积累,增产增糖潜力巨大,可在甘蔗农艺性状的定向化学调控及完善甘蔗高产高糖栽培技术中应用.

Excessive use of nitrogen (N) fertilizer for sugarcane cultivation is a significant cause of greenhouse gas emission. N use-efficiency (NUE) of sugarcane is relatively low, and considerable effort is now directed to exploit biological nitrogen fixation (BNF) in sugarcane. We hypothesize that genetic base-broadening of sugarcane using high-BNF Saccharum spontaneum, a wild progenitor of sugarcane, will help develop N-efficient varieties. We found remarkable genetic variation for BNF and growth in S. spontaneum accessions, and BNF in some accessions remained highly resilient to inorganic N application. Physiological and molecular analyses of two S. spontaneum accessions with high-BNF capacity and growth, namely G152 and G3, grown under N replete and low N conditions showed considerable similarity for total N, NH4-N, soluble sugar, indoleacetic acid, gibberellic acid, zeatin and abscisic acid content; yet, they were strikingly different at molecular level. Global gene expression analysis of G152 and G3 grown under contrasting N supply showed genotype effect explaining much of the gene expression variation observed. Differential gene expression analysis found an over-representation of carbohydrate and amino acid metabolism and transmembrane transport genes in G152 and an enrichment of lipid metabolism and single-organism processes genes in G3, suggesting that distinctly divergent metabolic strategies are driving N-related processes in these accessions. This was attested by the remarkable variation in carbon, N, amino acid and hormone metabolism-related gene expression in G152 and G3 under high- and low-N supply. We conclude that both accessions may be achieving similar BNF and growth phenotypes through overlapping but distinctly different biochemical and molecular mechanisms.

Sugarcane is a major food and bioenergy crop globally.It pro-duces～80％of sugar consumed worldwide,with Brazil and India together accounting for 61％of world sugarcane produc-tion in 2021[1].Globally,sugarcane is the 5th largest crop by production value and acreage,and it is also the second largest bioenergy crop[1,2].Modern sugarcane is an interspecific hybrid(Saccharum species hybrid)of wild progenitor species Saccharum officinarum(2n=80;x=10)andSaccharumspon-taneum(2n=40 to 130;x=8)[3].This genetically complex polyploid crop with varied chromosome numbers(100 to 130)has one of the largest genomes(～10 kb)among plants,making sugarcane breeding considerably slow and challenging.

健康种苗是保持良种的优良种性、减少病虫害发生最有效的措施之一,但由于其生产成本高、栽培条件要求严格等问题而导致推广应用缓慢.本团队在国内首次提出扦插技术应用于甘蔗健康种苗良种繁育的设想,为进一步验证扦插技术的可行性及其优势,设置原苗、剪主茎、扦插 3 个处理,研究了扦插技术下甘蔗健康种苗 1 年新植 2 年宿根的表现,综合分析扦插栽培模式的整体效果和收益,为扦插技术在甘蔗健康种苗快速繁育上的推广应用和进一步研究发展提供参考依据.结果表明:甘蔗健康种苗原苗剪去主茎后分蘖率显著提高,有效茎数显著增加,产量无显著影响;扦插处理的有效茎数显著多于其他处理,由于生长时间短导致新植蔗产量显著低于其他处理;各处理宿根产量无显著差异;"剪主茎+扦插"栽培模式的新植产量(66.07 t/hm2)略低于原苗处理(69.89 t/hm2),第 1 年、第 2 年宿根产量与原苗处理互有高低,但差异不大,3 年的总产量(274.05 t/hm2)与原苗处理(277.09 t/hm2)相当.新植时,"剪主茎+扦插"栽培模式可比原苗种植节约生产成本 10505 元/hm2,但产值减少 1987 元/hm2,合计增加收益 8518 元/hm2;综合新植和宿根共 3 年计算,共增加收益 8924 元/hm2.因此,综合判断认为扦插可应用于甘蔗健康种苗快繁.该技术可节省健康种苗的购买生产费用,从而节约甘蔗健康种苗繁育生产成本,增加收益;在采用合理的扦插和栽培技术情况下,甘蔗产量和收益将进一步提高;该技术的可操作性和实用性强,进一步研究和应用该技术,对促进甘蔗优良新品种的推广应用、良种更新换代具有积极意义.