Arbuscular mycorrhizal fungi （AMF） are key symbiotic microorganisms that support nutrient acquisition by grassland plants and contribute to soil structure maintenance. This review synthesizes current progress on how different forms of carbon input， nitrogen addition， and their interactions influence AMF in grassland ecosystems， focusing on colonization， hyphal growth， community composition， and symbiotic network structure. Elevated atmospheric CO₂ mainly promotes AMF hyphal growth and biomass accumulation by increasing belowground carbon allocation in plants. Biochar application and organic fertilizer addition improve soil physical properties and nutrient retention， thereby facilitating AMF colonization and community recovery. In contrast， the effects of soluble organic carbon inputs are moderated by plant functional group identity and nitrogen-phosphorus availability. Long‑term or high‑intensity nitrogen addition generally suppresses AMF， a response closely associated with soil acidification， reduced carbon allocation to mycorrhizae， and reorganization of AMF communities. The interactive effects of carbon inputs and nitrogen addition are constrained by carbon source characteristics， nitrogen legacy effects， and the availability of soil nutrients. Future research should increase the comparability of carbon input studies， clarify the combined regulatory roles of carbon source， nitrogen addition intensity and duration on AMF responses， and provide theoretical support for soil nutrient management and degraded grassland restoration.

Grasses in Pennisetum genus are important high-quality forages in tropical and subtropical regions， characterized by high biomass， strong stress tolerance， and excellent feeding value. They serve as a key resource to alleviate the shortage of forage supply in China. To date， 17 Pennisetum cultivars have been registered in China， most of which are adapted to the southern ecological zones， while there is a lack of stress-tolerant and high-yielding cultivars in northern China， highlighting an urgent need for breeding elite new varieties. This paper reviewed the research progress in conventional breeding techniques， including introduction and domestication， cross breeding， and mutation breeding， as well as molecular breeding approaches such as molecular marker-assisted breeding and genetic engineering. It also analyzed the existing problems， including the shortage of self-incompatible lines， low efficiency of distant hybridization， and an underdeveloped molecular breeding system. Finally， the paper discussed prospects for germplasm resource exploration， optimization of breeding objectives， and application of new technologies， aiming to provide a reference for genetic improvement and industrial development of Pennisetum forages.

Hybrid Pennisetum （Pennisetum glaucum × P. purpureum） is an important high-yield and high-quality forage grass； however， its poor cold tolerance restricts its cultivation and utilization in northern and high-latitude regions. Heavy-ion irradiation is a relatively new mutagenic approach and has been rarely applied in forage breeding. In this study， seeds of the hybrid Pennisetum cultivar ‘Bangde No.1’ were treated with heavy-ion irradiation at doses of 50， 100， 150， 200， and 300 Gy. Seedling growth traits and physiological responses under low-temperature stress were systematically evaluated to investigate the mutagenic effects of heavy-ion irradiation， establish a heavy-ion mutagenesis system for hybrid Pennisetum seeds， and develop novel cold-tolerant germplasm. The results showed that heavy-ion irradiation exerted a clear dose-dependent effect on hybrid Pennisetum. Among the treatments， 100 Gy not only maintained a high seedling establishment rate but also significantly increased soluble sugar content and the activities of superoxide dismutase （SOD） and peroxidase （POD）， reduced membrane damage， and resulted in the lowest semi-lethal temperature （LT₅₀） of plant mutants， indicating the strongest cold tolerance and relatively high mutagenic efficiency. Based on a comprehensive evaluation integrating laboratory and field assessments， principal component analysis， membership function analysis， field survival rate， and field overwintering rate， three potential cold-tolerant mutants were identified from the M₁ generation.

The GRAS family is a class of specific transcriptional regulatory factors widely present in plants， which play vital roles in regulating plant growth and development， as well as responses to biotic and abiotic stress. It is of great significance to explore the characteristics and functions of GRAS gene family in elephant grass （Pennisetum purpureum） and clarify their regulatory roles under low-temperature stress. Based on the genomic data of elephant grass， in this study we identified members of the GRAS gene family， and analyzed their chromosomal localization， physicochemical properties， gene structural characteristics， phylogenetic relationships， as well as the expression patterns of elephant grass materials with different cold resistance under low-temperature stress. The results showed that a total of 18 GRAS genes were identified in the elephant grass genome， which were distributed on 10 chromosomes and classified into five subfamilies via phylogenetic analysis. Cis-acting element analysis revealed that the promoter regions of 10 PpGRAS members contained regulatory elements related to low-temperature response. Collinearity analysis indicated that elephant grass shared more homologous genes with Sorghum bicolor than that with Oryza sativa. Expression pattern analysis demonstrated that the expression levels of multiple GRAS family members， especially genes such as PpGRAS7 and PpGRAS10 belonging to the LISCL subfamily， were significantly positively correlated with cold resistance capacity of materials. This study provides valuable references for further exploring the functions of elephant grass GRAS family and their response mechanisms to Low-temperature stress.

The seed yield and quality of the leguminous forage alfalfa （Medicago sativa L.） are significantly influenced by water and fertilizer management. This study aimed to investigate the effects of different water and phosphorus fertilizer treatments on seed yield and seed quality of alfalfa. The experiment was designed to combine treatments with different irrigation levels （600， 900， and 1200 m³·hm^-2） and phosphorus fertilizer rates （100， 200， and 300 kg·hm^-2）. Seed yield， yield components， soluble protein content， and starch content were measured. Additionally， multispectral information of 19 bands was acquired， and an nCDA-CNN model was constructed to evaluate the potential of multispectral image technology for seed detection under different water and fertilizer treatments. The results showed that the appropriate water and phosphorus fertilizer application significantly increased seed yield， protein content， and starch content （P<0.05）. Among all treatments， the combination of 600 m³·hm^-2 irrigation and 200 kg·hm^-2 phosphorus fertilizer achieved the highest seed yield （885.44 kg·hm^-2）， representing an increase of 287.96 kg·hm^-2 compared to the control. Higher soluble protein and starch contents of seeds were observed under the treatment with 600 m³·hm^-2 irrigation and 100 kg·hm^-2 phosphorus fertilizer. Path analysis indicated that the number of seeds per pod had a greater influence on seed yield. Multispectral image analysis revealed that the nCDA-CNN model accurately predicted alfalfa seeds subjected to different water and fertilizer treatments， with a recognition accuracy of 95%. This provides a high-throughput， non-destructive detection method for alfalfa seed production. Optimized water and fertilizer manag-ement can significantly enhance alfalfa seed production. Multispectral image technology combined with deep learning models holds important application prospects for quality detection and sustainable development in the grass seed industry.

To clarify the molecular characteristics of the WRKY gene family in highly cold-resistant Pennisetum alopecuroides and their functions in cold stress response， in this study we conducted systematic identification， phylogenetic analysis and cold stress-related expression pattern analysis of the WRKY gene family via combined genome-wide and transcriptome analyses. The results showed that a total of 104 PaWRKY genes with complete WRKY domains were identified， which were unevenly distributed on nine chromosomes. All the encoded proteins were hydrophilic， and most of them had poor in vitro stability and were susceptible to degradation. Based on phylogenetic analysis， the taxa were divided into seven subtribes， and Subtribe IIc comprises the most members， and ten core conserved motifs were predicted in total. Extensive homologous collinearity was found between this gene family and Oryza sativa subsp. japonica. The promoter regions of PaWRKY genes were enriched with numerous cis-acting elements responsive to abiotic stresses and phytohormones. Transcriptome data revealed that eight PaWRKY genes were differentially expressed under cold stress， including four upregulated and four downregulated genes， all of which harbored MeJA-responsive elements. This study clarified the molecular and evolutionary characteristics of the WRKY gene family in Pennisetum alopecuroides and screened out key cold stress-responsive genes， which laid a theoretical foundation for cold-tolerant molecular breeding of Pennisetum alopecuroides and evolutionary research of the WRKY gene family in Panicoideae.

Phytochrome A （phyA） is a key receptor that enables plants to perceive far-red light signals and regulates their growth， development， and stress responses. To investigate the function of the MsphyA gene and its molecular mechanism in response to abiotic stress in alfalfa （Medicago sativa L.）， this study conducted a bioinformatic analysis of the cloned MsphyA gene and detected its expression patterns under various abiotic stresses using qRT-PCR. Bioinformatic analysis revealed that the MsphyA gene has a CDS length of 3375 bp， encoding 1124 amino acids， and possesses typical PAS， GAF， and PHY motifs characteristic of the PHY family. Protein analysis indicated that MsphyA has a relative molecular mass of 124.3 kDa and a theoretical isoelectric point of 6.1. It is classified as an unstable， hydrophilic， non-secretory protein without a signal peptide and lacks transmembrane domains. Subcellular localization prediction suggested that MsphyA is localized to the nucleus. Phylogenetic analysis showed that MsphyA is most closely related to MtphyA from M. truncatula. qRT-PCR results demonstrated that salt， drought， acid， high-temperature， and low-temperature stresses all induced MsphyA expression. These findings indicate that MsphyA is widely involved in the abiotic stress responses in alfalfa. This study provides a foundation for further exploration of the MsphyA gene’s function.

Ethylene response factors （ERFs） are key regulatory proteins involved in plant responses to abiotic stresses. In this study， based on the genome data of Pennisetum purpureum， 53 members of the PpERF gene family were identified. The encoded proteins ranged from 191 to 1145 amino acids in length， with predicted isoelectric points ranging from 4.75 to 11.79 and molecular weights ranging from 20 536.11 to 124 866.3 Da. Among these genes， three were not mapped to the chromosomes， whereas the remaining genes were unevenly distributed across eight chromosomes. Phylogenetic analysis classified the PpERF genes into three evolutionary clades. Most PpERF proteins contained highly conserved Motifs 1， 2， and 4， and multiple stress-responsive cis-acting elements were identified in their promoter regions. Expression analysis showed that 11 PpERF genes exhibited spatiotemporal expression specificity under low-temperature stress， among which PpERF17， PpERF21， and PpERF32 were significantly upregulated after 24 h of cold treatment. Transient overexpression assays in tobacco further demonstrated that these three genes significantly enhanced plant tolerance to low-temperature stress. This study provides a theoretical basis for elucidating the molecular mechanisms underlying low-temperature responses in Pennisetum purpureum and offers potential candidate genes for the breeding of cold-tolerant forage grasses.

To clarify the key indicators for evaluating the cold tolerance of perennial forage Pennisetum spp.， a total of 42 Pennisetum germplasms were used as experimental materials in this study. Combining indoor low-temperature simulation with field trials， we analyzed the growth and physiological characteristics at the seedling stage and full growth period， overwintering rate， and their correlations of Pennisetum. The results showed that： Low-temperature stress significantly reduced seedling dry matter accumulation by 41.55% and plant height by 11.53%. The malondialdehyde （MDA） content in leaves and tiller nodes increased significantly by 90.43% and 108.48%， respectively. Osmotic regulation substances and antioxidant enzyme activities exhibited distinct responses to low temperature. A total of 9 indicators including soluble sugar and MDA contents in tiller nodes and leaves were screened out by principal component analysis to characterize cold tolerance at the seedling stage. Four accessions including ‘Sumu No.2’ ‘Guimu No.1’， Hybrid Pennisetum No.7 and Sweet Elephant Grass exhibited strong cold tolerance with an above 75% overwintering rate， while WQ Hybrid Pennisetum and Chinese Forage Grass showed weak cold tolerance with a below 50% overwintering rate.The overwintering rate was significantly negatively correlated with MDA content in tiller nodes， and significantly positively correlated with bud soluble sugar content. Soluble sugar and MDA contents were crucial indicators for characterizing the cold tolerance of Pennisetum. This study provides a theoretical foundation for the breeding and innovation of new Pennisetum germplasms with high cold tolerance.

The features of ecological restoration， ornamental garden， and forage values are possessed by pennisetum plants. Research on the genetic diversity of pennisetum germplasm resources can be conducted to offer theoretical basis for new variety breeding， development， and utilization. In this study， 48 Pennisetum germplasm resources were used as materials. Through phenotypic trait determination and SSR molecular marker technology， phenotypic characteristics， genetic diversity， and population structure were systematically evaluated. The results showed that the coefficient of variation for four phenotypic traits was observed to range from 28.10% to 96.92%， with a genetic diversity index of 2.49 to 2.83， indicating rich diversity. Plant height was found to be significantly positively correlated with leaf width， while tillering was observed to be significantly negatively correlated with plant height and significantly negatively correlated with leaf width. Phenotypic clustering was determined to be divisible into three categories. A total of 122 alleles were detected from 20 primer pairs by SSR markers， with an average of 6.10 per pair. Shannon’s diversity index was measured to range from 0.35 to 0.64， polymorphism information content was measured to range from 0.25 to 0.79， and the average genetic distance was calculated to be 0.43. UPGMA clustering was divided into three to five categories as the similarity coefficient was increased， and the population genetic structure was determined to be divisible into three groups with significant differences in genetic background among groups. In this study， the genetic diversity and population structure of 48 Pennisetum germplasm resources were elucidated， and a theoretical foundation was laid for subsequent germplasm identification and new variety breeding.