The glyoxalase system, comprising glyoxalase I (GLYI) and glyoxalase II (GLYⅡ), serves as a key mechanism for detoxifying excess methylglyoxal (MG) in plants and plays an important role in responses to abiotic stress and pathogen infection. To date, genome-wide identification and expression analysis of GLY gene family have not been reported in sugarcane. In this study, we identified 50 SsGLYI genes and 52 SsGLYⅡ genes from the wild sugarcane Saccharum spontaneum, and systematically analyzed the physicochemical properties, gene structures, promoter cis-acting elements, and expression patterns. SsGLY genes were randomly distributed across 30 chromosomes. All 43 SsGLYI members contained a conserved Motif1 (PF00903), while all SsGLYII proteins possessed a conserved Motif1 (PF00753). A total of 39 SsGLYI proteins contained four metal-binding sites (H/Q, L, H, E), except SsGLYII8.1-8.4 from subfamily IV, which were Zn²⁺-dependent, the remaining SsGLYI proteins were Ni²⁺-dependent. Only 26 SsGLYI proteins contained both the THxHxDH metal-binding domain and the C/GHT active site. Collinearity analysis identified 41 pairs of collinear genes, among which 39 pairs had Ka/Ks values less than 1, indicating that the SsGLY gene family has undergone predominant purifying selection during evolution. The expression levels of SsGLYI subfamily V and SsGLYⅡ subfamily Ⅲ were higher than those of the other four subfamilies under infection by Sporisorium scitamineum. Notably, the expression of SsGLYI3.4 showed differences in its expression patterns between the resistant genotype YT93-159 and the susceptible genotype ROC22. Furthermore, we cloned the homologous gene ScGLYI-1 of SsGLYI3.4 from YT93-159, which was constitutively expressed and primarily localized to the chloroplast. Meanwhile, the expression of ScGLYI-1 could be up-regulated by exogenous salicylic acid (SA) and smut pathogen stress, indicating that this gene may play a crucial role in response to pathogen stress in sugarcane. This study would provide a theoretical foundation for further elucidating the function of glyoxalase genes in sugarcane.

Phytochrome-interacting factors (PIFs) are key transcription factors that regulate plant photomorphogenesis and play important roles in plant growth, development, and responses to environmental stresses. To date, PIF gene family have been identified in many plant species; however, systematic identification and analysis of the PIF gene family in Saccharum spontaneum L., a wild relative of sugarcane, have not yet been reported. In this study, the PIF gene family in S. spontaneum (SsPIF) was identified, and comprehensive analyses were conducted on the physicochemical properties of the encoded proteins,chromosomal localization, intra- and interspecific synteny relationships, and cis-acting elements in promoter regions. In addition, quantitative real-time PCR (qRT-PCR) was used to analyze the expression patterns of SsPIF genes in different tissues of sugarcane and under three plant hormone treatments. The results showed that 12 SsPIF gene were identified from the S. spontaneum genome. These genes encode proteins ranging from 435 to 765 amino acids in length, with molecular weights between 48.14‒83.91 kDa. The predicted isoelectric points (pI) ranged from 5.59 to 6.97; most SsPIF proteins had pI values close to neutral, while a few tended to be acidic or basic. Subcellular localization analysis indicated that all SsPIF proteins are localized in the nucleus. Chromosomal mapping revealed that the SsPIF genes are unevenly distributed across 10 chromosomes. Multiple sequence alignment demonstrated that all SsPIF family members contain conserved basic helix–loop–helix (bHLH) and APB domains, while members of the SsPIF3 subgroup possess a unique APA domain. Comparative synteny analysis showed that fourteen orthologous gene pairs exist between S. spontaneum and rice. Promoter analysis revealed that SsPIF genes are enriched in cis-acting elements related to light responsiveness, hormone signaling, and stress responses. The expression profiles of SsPIF genes exhibited clear tissue specificity, indicating their involvement in the growth and development of S. spontaneum. Furthermore, qRT-PCR analysis revealed distinct expression patterns of the twelve SsPIF genes in response to methyl jasmonate, gibberellin, and auxin treatments. Overall, these findings provide a solid foundation for further functional characterization of the SsPIF gene family and for elucidating their roles in regulating growth, development, and signal transduction pathways in S. spontaneum.

Sugarcane family evaluation is a key technical method for screening excellent sugarcane hybrid combinations and assessing the breeding value of parents. In this study, 86 sugarcane hybrid combinations were used as the materials for family evaluation. Over consecutive years, investigations were carried out on yield-related traits (plant height, tillering and clump mass), sugar-content traits (brix), and disease/pest resistance traits (smut, top rot, and dead heart seedlings). Subsequently, key evaluation indicators for each trait, including heritability, combining ability, breeding value, and coefficient of variation, were calculated. By employing correlation analysis, principal component analysis, cluster analysis, and economic breeding value estimation, the field performance of each hybrid combination and the genetic contributions of the parents were comprehensively evaluated from multiple dimensions. For yield-related traits, cluster weight had an extremely significant positive correlation with both plant height and tiller number (P<0.01). Through principal component analysis, 5 high-yield hybrid combinations (Guitang 04-1545×Zhongtang 12-02) were screened out. Meanwhile, parents including female parent Q208 and male parent XTT22 exhibited outstanding GCA and possessed excellent genetic transmission capacity for yield. For disease and pest resistance traits, the incidence rates of smut and pokkah boeng disease showed an increasing trend year by year with the observation period, while the incidence rate of dead heart seedlings decreased annually. Among them, 5 hybrid combinations (Yuetang 03-373× CP84-1198) exhibited strong comprehensive disease resistance. For sugar-related traits, 5 hybrid combinations (Yunzhe 05-51×Guitang 00-122) performed excellently in brix value and specific combining ability (SCA). Additionally, parents including female parent Yunrui 15-90 and male parent Guitang 04-1001 showed significant high-sugar genetic characteristics, making them excellent parent materials for breeding high-sugar varieties. In the comprehensive trait evaluation, the results of principal component analysis and cluster analysis mutually verified each other. Finally, hybrid combinations with excellent comprehensive performance (LCP85-384×Yuetang 94-128) and core parents with outstanding comprehensive traits (including female parent Guitang 04-1545 and male parent XTT22) were screened out. The results of the study could provide important references for the directional breeding of specialized sugarcane varieties with high yield, high sugar content and disease resistance, as well as the scientific selection and matching of parents in hybrid breeding.

A systematic multi-trait assessment was conducted using principal component analysis, membership function method, and cluster analysis to comprehensively evaluate the agronomic performances of 15 Yunzhe-type innovative sugarcane germplasm lines in Kaiyuan, Yunnan and identify superior parents for high-yield and high-sugar breeding. The main cultivated variety Yunzhe 05-51 was used as the control. Nine key agronomic traits, plant height (PH), stalk diameter (SD), single stalk weight (SSW), millable stalk number per hectare (MSPH), cane yield (CY), fiber content (FC), juice extraction rate (JE), apparent purity (AP), and sucrose content in cane (SC) were measured under both plant cane and first ratoon conditions. The results showed that the coefficients of variation for the traits ranged from 4.81% to 21.02%, with single stalk weight and cane yield exhibiting the greatest variation. Correlation analysis indicated that plant height, stalk diameter, and single stalk weight were significantly positively correlated with cane yield. Principal component analysis extracted three principal components, which together accounted for 82.436% of the total variance, representing yield structure, sugar quality, and stalk population characteristics, respectively. Based on the comprehensive evaluation D-values derived from the membership function method, there were 11 materials higher than the control. They were ranked as follows from high to low, Yunzhe 2018-124>Yunzhe 2018-95>Yunzhe 2018-120>Yunzhe 2017-121>Yunzhe 2018-92>Yunzhe 2016-166>Yunzhe 2017-131>Yunzhe 2016-145>Yunzhe 2014-170>Yunzhe 2014- 224>Yunzhe 2014-222>Yunzhe 05-51. Cluster analysis classified the germplasm into three groups. Group Ⅰ was identified as the high-yield type, and Group Ⅲ as the high-sugar type. Further screening identified the germplasm with outstanding single traits. High-yield types included Yunzhe 2017-121, Yunzhe 2018-124, and Yunzhe 2018-95. High-sugar types included Yunzhe 2014-222, Yunzhe 2016-145, and Yunzhe 2017-152. High-fiber types included Yunzhe 2017-152 and Yunzhe 2018-120, which are suitable as the parents for breeding mechanization-adapted varieties. Both Yunzhe 2018-124 and Yunzhe 2018-95 demonstrated excellent performances in yield and quality related traits, indicating a high potential as core parents for high-yield and high-sugar sugarcane breeding. The materials could provide valuable germplasm support for sugarcane variety selection in Yunnan and other ecologically similar regions.

Sugarcane (Saccharum spp.) is the most significant global sugar crop, contributing approximately 80% of total sugar production worldwide. Developing high-yielding and high-sugar-content varieties is critical for enhancing sugar industry sustainability. To support this goal and optimize hybrid breeding strategies, this study evaluated 71 sugarcane hybrid combinations derived from 75 parental lines, using six key agronomic traits: plant height, stalk diameter, brix (juice sugar content), number of effective stalks, cane yield and sugar yield. The main objective was to assess general combining ability (GCA) and specific combining ability (SCA), to identify superior parental lines and hybrid combinations for sugarcane breeding programs. The GCA/SCA analyses were performed using the R software. Clustering analyses were conducted based on combining ability values to classify parental materials and hybrid combinations into distinct genetic performance groups. Results showed substantial genetic variation across hybrids, particularly in yield-related traits, with coefficients of variation exceeding 39.00% for effective stalks, cane yield and sugar yield, highlighting significant breeding potential. Conversely, brix exhibited the lowest variation (8.05%), indicating high genetic stability for sugar content traits. Notably, HoCP05-902, GT96-211, YT93-124, YT93-159, GT00-122 and YR05-704 were identified as elite male parents, while GT94-119, CP72-1210 and Eros were outstanding female lines. Two combinations, CP72-1210×GT96-211 and GT94-119×YT93-159, exhibited superior GCA and SCA values, achieving excellent performance in both yield and sugar content. Additionally, GCA/SCA ratio analysis revealed that cane yield exhibited significant additive effects primarily inherited from the male parent. In conclusion, this research provides valuable theoretical guidance and genetic resources for sugarcane breeding, highlighting key parental lines and hybrid combinations that can serve as core materials in developing next-generation high-yield, high-sugar sugarcane cultivars.

The study aimed to investigate the physiological responses of intergeneric hybrid Erianthus arundinaceus× Saccharum spontaneum L offspring at the seedling stage under drought stress, to identify novel sugarcane germplasm resources with better drought stress tolerance. The results would provide a theoretical basis for breeding and utilizing drought-tolerant new sugarcane varieties. Thirteen hybrid progenies and the sugarcane variety ROC22 were used as the experimental materials in a barrel experiment. The contents of malondialdehyde (MDA), soluble sugars (SS), soluble protein (SP), proline (PRO), and the activities of peroxidase (POD) and superoxide dismutase (SOD), were measured in sugarcane seedling leaves under mild and severe drought stress, and control (normal watering). A comprehensive evaluation of drought tolerance in thirteen progenies and ROC22 was conducted based on drought resistance coefficients, membership function values, and the comprehensive drought tolerance evaluation index (D value), to screen and identify drought-tolerant sugarcane germplasm resources. Under different drought treatments, the content of SS, SP, PRO, MDA, and the activities of SOD and POD were elevated in the seedling leaves of hybrid progenies. Notably, under severe drought stress, the physiological indicators of AS08-2-28 were significantly higher than those of ROC22. Based on the D value, seven progenies exhibiting greater drought tolerance than ROC22 at the seedling stage were identified, ranked as follows: AS08-2-28>AS11-1-101>AS11-4-44>AS11-75-1>AS12-A6-21>AS12-A6-5>AS12-176-5. This study evaluated the drought tolerance of the hybrid progenies at the seedling stage and successfully screened seven sugarcane germplasm resources with strong drought resistance. The findings would provide a foundational basis for the future mining of drought-related genes and offer scientific guidance and experimental support for the effective utilization of intergeneric hybrid complex offspring in breeding new sugarcane varieties with enhanced drought tolerance.

Sugarcane is a globally important cash crop and bioenergy crop, playing a critical role in promoting economic development in sugarcane-producing countries. Phosphorus is an essential nutrient for plants, and low phosphorus availability in soil often constrains the quality and yield of sugarcane in China. S. officinarum serves as an important genetic foundation for modern sugarcane varieties. Elucidating the low-phosphorus tolerance mechanisms in phosphorus-efficient genotypes of S. officinarum is of significant theoretical and practical importance for screening and breeding phosphorus-efficient sugarcane varieties, improving phosphorus fertilizer utilization efficiency, and promoting the development of the sugarcane industry. The study was aimed to explore the response characteristics of different S. officinarum genotypes under low-phosphorus stress from the perspectives of root morphology and physiological adaptations, identify key factors affecting phosphorus absorption, and provide a theoretical basis for improving nutrient utilization efficiency in sugarcane through root plasticity modification. Phosphorus-efficient S. officinarum genotypes (48 Mouna and Loether) and phosphorus-inefficient genotypes (NC20 and Badila) were used in the study. Under two phosphorus supply conditions, low phosphorus (0.2 μmol/L KH₂PO₄) and normal phosphorus (1000 μmol/L KH₂PO₄), comparative analyses were conducted on root morphological indices, low-phosphorus tolerance indices, root activity, acid phosphatase activity, and other physiological characteristics of each variety. The results indicated that low-phosphorus stress could inhibit the growth and development of various sugarcane tropical varieties to different degrees. Among them, the phosphorus-efficient variety Loether was the least affected by low-phosphorus stress in terms of plant height, stem dry weight, and whole-plant biomass, while its root dry weight and root-to-shoot ratio significantly increased. Low-phosphorus stress promoted increases in total root length, total root surface area, and total root volume in both Loether and 48 Mouna, with Loether exhibiting the most pronounced increase. The specific root length, specific root surface area, and specific root volume of most varieties decreased, with NC20 showing the greatest reduction. Additionally, all varieties exhibited root thinning. Furthermore, under low-phosphorus stress, 48 Mouna and Loether demonstrated higher root low-phosphorus tolerance indices, root activity, and phosphorus acquisition capacity. In conclusion, this study reveals that the phosphorus-efficient tropical varieties 48 Mouna and Loether can better optimize root architecture, enhance phosphorus absorption interfaces, maintain strong root activity and enzymatic adaptability, effectively improve phosphorus absorption and utilization efficiency, and exhibit strong adaptability to low-phosphorus stress.

Lodging resistance is an important trait in sugarcane breeding. Accurate evaluation of the lodging resistance of germplasm resources is of great significance for breeding lodging-resistant varieties. This study investigated the effects of agronomic traits and stalk fiber components on lodging resistance using 16 sugarcane germplasm materials. The key traits affecting lodging resistance were identified by grey correlation analysis, and the comprehensive evaluation was carried out by using membership function method and cluster analysis method to screen excellent lodging resistance germplasm and its key traits, so as to provide germplasm resources and theoretical reference for sugarcane lodging resistance breeding. The results showed that the sugarcane germplasm materials with the strongest lodging resistance were Yunzhe 17501, Guiliu 05136 and Yuetang 93159. Among them, stem diameter, effective stem number, plant height and cellulose content were the key factors affecting the lodging resistance of sugarcane.

The study systematically investigated the long-term regulatory effects of returning sugarcane organic materials to the field on soil physicochemical properties, microbial communities, and sugarcane growth to solve the problems of soil acidification, organic matter attenuation and structural degradation in sugarcane fields on dry slopes in China. Through a three-year barrel planting experiment (including one new planting season and two-year ratoon season), four types of sugarcane organic materials were returned to the field, including filter mud (T₁), sugarcane bagasse ash (T₂), sugarcane leaves (T₃), sugarcane bagasse (T₄), along with control (without organic amendment). Soil nutrients, physical structure, microbial diversity, root morphology, yield and sugar content were measured. The four sugarcane organic materials returned to the field reduced soil bulk density and improved soil mechanical properties and pore structure, but significant difference were observed in the effects of different materials. T₁ and T₂ significantly increased soil pH, total organic carbon (TOC), alkali-hydrolyzable nitrogen (AN) and available phosphorus (AP). T₁ consistently optimized deep soil structure, and T₂ had a significant effect on improving available potassium (AK) and water retention. T₃ and T₄ mainly increased soil TOC content, but T₄ aggravated soil acidification during the new planting season. T₃ and T₄ promoted the formation of highly stable large aggregates, with significant short-term effect. Although T₁ and T₂ promoted the formation of mechanically stable large aggregates, the water stability was poor. T₁ and T₂ had significant and long-lasting effects on improving the diversity and richness of soil bacteria and fungi, T₃ promoted microbial activity in the early stage but inhibited it in the later stages, and T₄ significantly restored microbial diversity in the later stages. T₁ had the most significant effect on increasing yield and sugar content, T₂ had an outstanding effect on promoting root development and had significantly effects on increasing yield and sugar content. T₃ had a certain yield-increasing effect in the later stages. T₄ led to a yield reduction and was not conducive to sugar accumulation. Overall, the effects of returning different sugarcane organic materials to the field varied significantly. Filter mud (T₁) proved to be the optimal material, combining long-term soil improvement, enhanced microbial diversity, and increased yield and sugar content. Sugarcane bagasse ash (T₂) was suitable for short-term water retention and root growth, but the risk of deep soil compaction must be controlled. Sugarcane leaves (T₃) should be accompanied by nitrogen fertilizer. Sugarcane bagasse (T₄) returning to field requires decomposition pretreatment. This study could provides theoretical support for the precise return of sugarcane organic materials to the field and the sustainable management of cultivated land in red soil areas.

The study conducted a two-year field experiment to explore the effects of pesticide application via under-mulch drip irrigation on the control efficacy of major pests and comprehensive benefits in the field propagation of disease-free sugarcane original seedlings. With no pesticide application as the control (CK), four treatments were simultaneously set up, two drip irrigation pesticide application treatments (T₁ and T₂: applying 40% chlorantraniliprole·thiamethoxam WG via drip irrigation 3 times and 2 times, respectively), one unmanned aerial vehicle (UAV) spraying treatment (T₃: spraying 40% chlorantraniliprole·thiamethoxam WG 2 times), and one conventional root application treatment (T₄: applying 4% imidacloprid·bisultap GR 2 times). A comprehensive comparative analysis was performed on indicators such as the control efficacy against sugarcane borers, thrips, and aphids, as well as the propagation efficiency and economic benefits of disease-free sugarcane original seedlings, aiming to provide a theoretical basis for scientifically guiding sugarcane elite seed propagation bases to utilize existing under-mulch drip irrigation systems for efficient and economical control of major pests. In the early stage of seedling propagation, the two drip irrigation treatments (T₁ and T₂) exhibited the best control efficacy against the rate of borer-induced dead heart seedlings, reaching over 76.00%, with the dead heart seedling rate controlled below 1.20%, which was significantly lower than that of other pesticide treatments. In the middle and late stages of propagation, UAV spraying T₃ showed the highest control efficacy against the rate of borer-damaged plants, reaching 72.00%, followed by the two drip irrigation treatments T₁ and T₂ with control efficacy ranging from 61.00% to 66.00%. Specifically, except that the rate of borer-damaged plants of T₃ was significantly lower than that of T₂ in the 2023 experiment, there was no significant difference in the rate of borer-damaged plants between T₃ and T₁, T₂. Conventional root application T₄ had the lowest control efficacy, and the rate of borer-damaged plants was significantly lower than that of other pesticide treatments. In terms of the rates of borer-damaged internodes and borer-damaged buds, drip irrigation treatment T₁ (applied 3 times) showed the highest control efficacy, both reaching over 82.00%, with the rates of borer-damaged internodes and buds controlled below 0.73% and 0.28%, respectively, which were significantly lower than those of other pesticide treatments. For the two foliar pests (thrips and aphids), UAV spraying T₃ showed better control efficacy than other treatments, reaching over 70.00%, but there was no significant difference compared with the two drip irrigation treatments. In terms of seedling propagation efficiency, drip irrigation treatments T₁ and T₂ had the highest number of effective buds, reaching 138.71×10⁴, 136.53×10⁴ buds per hectare, respectively, which was more than 6.12% higher than that of conventional root application T₄, but there was no significant difference compared with UAV spraying T₃. In terms of comprehensive propagation benefits, compared with CK, drip irrigation treatments T₁ and T₂ had the highest increase in net income, reaching 31 300, 30 400 yuan/hm², respectively, with an input-output ratio of above 1∶30, which was much higher than the input-output ratio of approximately 1∶21 for UAV spraying T₃ and conventional root application T₄. Comprehensively, applying 40% chlorantraniliprole·thiamethoxam WG via drip irrigation 3 times can sustainably and efficiently control borers, thrips and aphids, balances propagation efficiency and benefits, and has the lowest rate of borer-damaged internodes in seed canes. Thus, it can be used as the optimal scheme for controlling above-ground pests in the field propagation of disease-free sugarcane original seedlings.