Search Results (924)

This study established an efficient in vitro regeneration system for Tibouchina granulosato (Desr.) Cogn. petiolated leaves to address the low propagation efficiency and propagatable germplasm shortages. The results revealed that the Murashige and Skoog (MS) medium supplemented with 1.1 mg/L of Zeatin (ZT) and 0.2 mg/L of 1-naphthyl acetic acid (NAA) was the optimal formulation for callus induction, yielding callus induction of 89.59%. For adventitious bud induction, the combination of 2.0 mg/L of 6-benzyladenine (BA) and 0.4 mg/L of NAA proved most effective, achieving an induction rate of 83.33%. Additionally, the adventitious shoots exhibited remarkable elongation when cultured in a medium containing 0.2 mg/L of BA and 0.04 mg/L of NAA. All explants rooted when treated with 0.5 mg/l NAA, inducing a mean number of 6.90 roots per plant and a survival percentage of 91.00%. This study provided technical support for the promotion of superior varieties and genetic improvement of Tibouchina granulosa. Full article

Drought stress is one of the key abiotic stress factors limiting the growth and development, yield formation, and improvement in the quality of jackfruit (Artocarpus heterophyllus). However, systematic evaluations of drought tolerance in jackfruit germplasm resources remain limited. In this study, six jackfruit cultivars were used as materials. By systematically comparing 26 indicators, including leaf structural characteristics, chlorophyll concentration, and photosynthetic parameters, the primary evaluation indicators for jackfruit drought tolerance were identified, and clear microscopic structural images of leaves from different jackfruit cultivars were obtained. In this study, significant differences were observed among different jackfruit germplasm resources in terms of leaf structure, chlorophyll concentration, and photosynthetic characteristics. Comprehensive analysis identified A. ‘Changyou’ as the jackfruit cultivar with the highest drought tolerance score and A. ‘Siji’ as the variety with the lowest drought tolerance score. By establishing a systematic evaluation system for jackfruit drought tolerance, it was found that jackfruit cultivars with high drought tolerance had significantly thicker palisade parenchyma than other cultivars, a rougher leaf epidermis, and more densely distributed stomata on the leaves, while their chlorophyll concentration was significantly lower than that of cultivars with lower drought tolerance scores. Jackfruit cultivars with the lowest drought resistance scores had significantly lower net photosynthetic rates, transpiration rates, stomatal conductance, and light saturation points than other cultivars. This study’s results established a drought resistance evaluation system for jackfruit germplasm resources, providing theoretical support for the selection and breeding of high-drought-resistant superior jackfruit cultivars. Full article

Germplasm resources embody the genetic diversity of plants and form the foundation for breeding and the ongoing improvement of elite cultivars. The establishment of germplasm banks, along with their systematic evaluation, constitutes a critical step toward the conservation, sustainable use, and innovative utilization of these resources. Liriodendron, a rare and endangered tree genus with species distributed in both East Asia and North America, holds considerable ecological, ornamental, and economic significance. However, a standardized evaluation system for Liriodendron germplasm remains unavailable. In this study, 297 Liriodendron germplasm accessions were comprehensively evaluated using 34 phenotypic traits and whole-genome resequencing data. Substantial variation was observed in most phenotypic traits, with significant correlations identified among several characteristics. Cluster analysis based on phenotypic data grouped the accessions into three distinct clusters, each exhibiting unique distribution patterns. This classification was further supported by principal component analysis (PCA), which effectively captured the underlying variation among accessions. These phenotypic groupings demonstrated high consistency with subsequent population structure analysis based on SNP markers (K = 3). Notably, several key traits exhibited significant divergence (p < 0.05) among distinct genetic clusters, thereby validating the coordinated association between phenotypic variation and molecular markers. Genetic diversity and population structure were assessed using 4204 high-quality single-nucleotide polymorphism (SNP) markers obtained through stringent filtering. The results indicated that the Liriodendron sino-americanum displayed the highest genetic diversity, with an expected heterozygosity (He) of 0.18 and a polymorphic information content (PIC) of 0.14. In addition, both hierarchical clustering and PCA revealed clear population differentiation among the accessions. Association analysis between three phenotypic traits (DBH, annual height increment, and branch number) and SNPs identified 25 highly significant SNP loci (p < 0.01). Of particular interest, the branch number-associated locus SNP_17_69375264 (p = 1.03 × 10⁻⁵) demonstrated the strongest association, highlighting distinct genetic regulation patterns among different growth traits. A minimal set of 13 core SNP markers was subsequently used to construct unique DNA fingerprints for all 297 accessions. In conclusion, this study systematically characterized phenotypic traits in Liriodendron, identified high-quality and core SNPs, and established correlations between key phenotypic and molecular markers. These achievements enabled differential analysis and genetic diversity assessment of Liriodendron germplasm, along with the construction of DNA fingerprint profiles. The results provide crucial theoretical basis and technical support for germplasm conservation, accurate identification, and utilization of Liriodendron resources, while offering significant practical value for variety selection, reproduction and commercial applications of this species. Full article

Capsicum is one of the most economically significant vegetable crops worldwide, owing to its high content of bioactive compounds with nutritional, pharmacological, and industrial relevance. However, research has focused on C. annuum, often disregarding local diversity and secondary gene pools, which may contain hidden variation for quality traits. Therefore, this study evaluated the genetic and phenotypic diversity of 283 accessions from the Colombian germplasm collection in the agrobiodiversity hotspot of northwest South America, representing all five domesticated species of the genus. A total of 18 morphological, physicochemical, and biochemical fruit traits were assessed, including texture, color, capsaicinoid, and carotenoid content. The phenotypic data were integrated with genomic information obtained through genotyping-by-sequencing (GBS) using the C. annuum reference genome and a multispecies pangenome. Fixed-and-Random-Model-Circulating-Probability-Unification (FarmCPU) and Bayesian-information-and-Linkage-disequilibrium-Iteratively-Nested-Keyway (BLINK) genome-wide association studies (GWAS) were performed on both alignments, respectively, leading to the identification of complex polygenic architectures with 144 and 150 single nucleotide polymorphisms (SNPs) significantly associated with key fruit quality traits. Candidate genes involved in capsaicinoid biosynthesis were identified within associated genomic regions, terpenoid and sterol pathways, and cell wall modifiers. These findings highlight the potential of integrating pangenomic resources with multi-omics approaches to accelerate Capsicum improvement programs and facilitate the development of cultivars with enhanced quality traits and increased agro-industrial value. Full article

Agrobacterium-mediated transformation systems are extensively applied in japonica rice varieties. However, the adaptability of local rice varieties to existing transformation systems remains limited, owing to their complex genotypes, posing a substantial challenge to transformation. In this study, four local rice varieties were selected to optimize the effects of different culture media on callus induction, browning resistance, contamination resistance, callus tolerance, differentiation, regeneration, and root development, and then two varieties were selected to improve plant architecture and tiller development by CRISPR/Cas9-mediated gene editing, based on constructive transformation systems. The goal was to enhance the transformation efficiency of local varieties and innovate germplasms. The results demonstrated that japonica rice varieties XG293 and WD68 exhibited higher induction rates under the treatment of 2 mg/L 2,4-D (2,4-Dichlorophenoxyacetic acid) + 1 mg/L NAA (Naphthaleneacetic acid), whereas indica rice varieties H128 and E33 performed the best under 3 mg/L 2,4-D + 1 mg/L NAA. Severe browning in H128 was effectively mitigated by a carbon source of 20 g/L maltose supplemented with 40 mg/L ascorbic acid. Contamination after Agrobacterium infection was controlled by 300 mg/L Tmt (Timentin). Under a treatment of 200 µM/L acetosyringone +10 min infection duration, XG293 and WD68 exhibited higher callus tolerance, differentiation rates, and GUS staining rates, achieving transformation efficiencies of 43.24% and 52.38%, respectively. In contrast, H128 and E33 performed better under the treatment of 200 µM/L Acetosyringone + 5 min, with transformation efficiencies of 40.00% and 40.74%, respectively. The mutants after OsCCD7 gene editing in WD68 and H128 displayed a dwarfness of plant height, a significant increase in tiller numbers, and compact architecture. These findings demonstrate that an optimized combination of plant growth regulators and infection durations effectively improves transformation efficiency for local varieties, and the OsCCD7 gene regulates plant architecture and tiller development with variable effects, depending on the rice complex genotypes. This study provides a theoretical basis for the efficient transformation of local rice varieties and germplasm innovation. Full article

Sugar beet (Beta vulgaris L.) is a biennial herbaceous plant belonging to the genus Beta within the family Amaranthaceae. Its root tuber can be used as an effective source for sucrose production. In the pursuit of sustainable development and maximizing the economic value of crops, the full utilization of crop germplasm resources and efficient production is necessary. To better facilitate the collection and utilization of sugar beet germplasm resources, this study used 106 accessions of multigerm sugar beet germplasm provided by the Key Laboratory of Molecular Genetic Breeding for sugar beet as materials. We evaluated the core collections constructed under various strategies using relevant genetic parameters and ultimately established two core collection construction strategies based on morphological and molecular markers. The optimal strategy based on morphological data was “Euclidean distance + Multiple clustering deviation sampling + UPGMA + 25% sampling proportion”, while the optimal strategy based on molecular marker data was “Jaccard distance + Multiple clustering random sampling + UPGMA + 20% sampling proportion”. In addition, representativeness evaluation of the core collection was conducted based on parameters related to both morphology and molecular markers. Principal component analysis (PCA) was utilized for the final determination of the core collection. The results showed that for both the morphological parameters and molecular marker-related parameters, there were no significant differences between the constructed core collection and the original germplasm; the phenotypic distribution frequencies were basically similar. Principal component analysis indicated that the core collection possessed a population structure similar to that of the original germplasm. The constructed core collection had good representativeness. This study, for the first time, proposed a core collection construction approach suitable for sugar beet by integrating morphological and molecular marker methodologies. It aimed to provide a scientific basis for the utilization and development of sugar beet germplasm resources, genetic improvement, and the breeding of new cultivars. Full article

Water scarcity poses a substantial challenge for turfgrass irrigation in the drought- and heat-stressed Desert Southwest region of the United States. Bermudagrass (Cynodon spp.), renowned for its exceptional drought resistance, is the predominant warm-season turfgrass in the region. Selecting and using drought-resistant bermudagrass cultivars remains a primary strategy for sustaining the turfgrass industry in the region. This study evaluated 48 hybrid bermudagrasses (Cynodon dactylon × C. transvaalensis Burtt-Davy), including two commercial cultivars (‘TifTuf’ and ‘Tifway’, as controls), under 80% × ETo (0.8ET), 60% × ETo (0.6ET) and 40% × ETo (0.4ET) reference evapotranspiration (ETo) replacement irrigation systems at Maricopa, AZ. The experiment was laid out in a split-plot design with two replications, where the 3 irrigation treatments were assigned to main plots and 48 genotypes were in sub-plots. Analysis of data from two years (2022 and 2023) revealed significant differences among bermudagrass hybrids, irrigation treatments, and their interaction effects. The hybrids exhibited substantial variation for spring green-up, density, turf color, and quality. With the largest deficit irrigation treatment 40% × ETo (0.4ET), OSU2104, OSU2106, and OSU2105 showed greater mean greenness and aesthetic quality scores than recorded for ‘TifTuf’ (6.5), a popular drought-tolerant cultivar. The results highlight the prevalence of genetic variation in germplasm with potential for development of improved varieties for drought tolerance. Full article

GRAS transcription factors play a crucial role in plant response to abiotic stresses. In this study, 61 members of the rice GRAS family, categorized into nine subfamilies, were identified by searching the latest genome sequence of rice. The OsGRAS genes that may respond to abiotic stresses were predicted by analyzing the cis-acting elements of the promoters of the genes and the structural features of the proteins. The results showed that the known OsGRAS drought-tolerant genes and OsGRAS salt-tolerant genes have a special structure in their protein structures, and nine genes that may be related to drought tolerance and six genes that may be related to salt tolerance were predicted in this study based on these special structures. The results of tissue expression profiling showed that OsGRAS family genes were expressed in different degrees during plant growth and development, and the expression of DELLA, PAT1, and HAM subfamily members was generally high. Finally, the analysis of the expression levels of 16 randomly selected OsGRAS genes under drought and salt stress conditions showed significant up-regulation of OsGRAS14 and OsGRAS21 under both stress treatments, and OsGRAS52 was significantly down-regulated under drought stress and up-regulated under salt stress. The present study provides important clues for exploring the molecular basis of the mechanism of rice response to abiotic stress, and also provides new ideas for the improvement of rice germplasm resources. Full article

Studying comprehensive performance is fundamental for the effective utilisation of broomcorn millet (Panicum miliaceum L.) germplasm resources and breeding of new varieties. However, compared with other major crops, research on broomcorn millet germplasm resources is limited, and the trait variations of broomcorn millet are unclear. In this study, three qualitative and seven quantitative traits of 933 broomcorn millet core collections were analysed to provide the basis for improving utilisation of broomcorn millet germplasm resources. The seed colour was a strong phenotypic trait and had eight variants. The 933 resources exhibited three panicle types: lateral (74.5%), scattered (18.4%), and compact (7.1%). They exhibited two inflorescence colours: green (54.7%) and purple (45.3%). Pearson’s correlation analysis revealed that 1000-seed weight significantly correlated with plant height, length of panicle, and number of main stem segments. The period of duration positively correlated with 1000-seed weight but negatively correlated with the number of uniserial panicles. Cluster analysis based on the quantitative traits indicated that all resources were divided into three groups, and each group had its respective characteristics. The analysis of core germplasm resources of broomcorn millet in this study provided a basis to explore excellent genes and for breeding of excellent varieties. Full article

Seed vigor critically determines sowing performance, while grain quality fundamentally influences commercial value. Elucidating the genetic mechanisms governing these traits is critical for enhancing both seed vigor and grain quality in rice cultivation. Here, we demonstrate that the endosperm-specific gene OsEnS-42 is highly expressed in germinating seeds and developing seeds at the early filling stage. OsEnS-42 is localized in the nucleus and cytoplasm. The seed vigor of OsEnS-42 knockout plants decreased, manifested as decreases in germination rate, seedling length, and root length. In addition, OsEnS-42 knockout plants showed increased chalkiness and amylose content. The transcriptome and physiological indicators showed that OsEnS-42 regulates seed vigor through soluble sugars and redox metabolism, and regulates grain quality via soluble sugars and seed development-related enzymes. Haplotype analysis of OsEnS-42 across global rice germplasm revealed four distinct haplotypes (Hap 1–4) with subspecies-specific distributions. Crucially, accessions with Hap 4 exhibit a lower percentage of grain with chalkiness than accessions with Hap 1 (predominantly indica), enabling marker-assisted introgression to reduce chalkiness without subspecies barriers. Meanwhile, accessions with Hap 2 show lower amylose content, providing targets for specialty rice breeding. Our findings elucidate the pathways through which OsEnS-42 regulates seed vigor and grain quality, and provide new molecular breeding targets for improving seed vigor and grain quality in rice. Full article

Background: Maize is an important food crop in cold regions, especially in Northeast China. However, its short growth period and low-temperature stress pose challenges to the breeding of high-yield hybrids. With climate warming, the maize planting area continues to expand to high latitudes. Research on cold-region maize is of great significance to ensure food security and sustainable agricultural development. However, most of the current maize research is concentrated in temperate and tropical regions, and there are few studies on cold-region maize. Methods: Based on this, this study selected some representative cold-region maize materials and materials whose adaptability has not yet been verified, and used a semi-diallel hybrid design for hybridization to determine the general combining ability (GCA) and specific combining ability (SCA) to screen out excellent breeding materials suitable for cold regions. Field experiments were carried out under four different cold environments, and 55 hybrid progenies and their parents were evaluated. The double allele hybridization analysis based on the Griffing method 2 (model 1) showed that the specific combining ability (SCA) and general combining ability (GCA) effects of each trait were significant. Results: The GCA mean square of all traits except yield and number of grains per row was greater than the SCA mean square, indicating that additive gene effects were dominant and genetic improvement through selective breeding was feasible. Hayman plot analysis under four environments showed that yield, ear length, number of grains per row, water content, and plant height were mainly controlled by superdominant genes, while stem thickness, number of nodes, and ear position were controlled by some dominant genes. Conclusions: Parent P1 contained more recessive genes in yield traits, but more dominant genes in number of grains per row, number of nodes, and ear position; P3 contained more dominant genes in yield and water content, but more recessive genes in number of nodes and ear position; P7 contained more recessive genes in most traits; and P9 contained more dominant genes in most traits. P9 and P6 represent excellent parental germplasm, among which the hybrid combinations P1 × P9, P2 × P5, P3 × P10, P4 × P6, P5 × P8, P6 × P9, P7 × P10, and P8 × P10 all show hybrid vigor exceeding that of their parents and have high breeding value. Full article

Kiwifruit (Actinidia spp.) is a globally important economic fruit with high nutritional value. Fruit peelability, defined as the mechanical ease of separating the peel from the fruit flesh, is a critical quality trait influencing consumer experience and market competitiveness and has emerged as a critical breeding target in fruit crop improvement programs. The present review systematically synthesized existing studies on kiwifruit peelability, and focused on its evolutionary trajectory, genotypic divergence, quantitative evaluation, possible underlying mechanisms, and artificial manipulation strategies. Kiwifruit peelability research has advanced from early exploratory studies in New Zealand (2010s) to systematic investigations in China (2020s), with milestones including the development of evaluation metrics and the identification of genetic resources. Genotypic variation exists among kiwifruit genera. Several Actinidia eriantha accessions and the novel Actinidia longicarpa cultivar ‘Guifei’ exhibit superior peelability, whereas most commercial Actinidia chinensis and Actinidia deliciosa cultivars exhibit poor peelability. Quantitative evaluation highlights the need for standardized metrics, with “skin-flesh adhesion force” and “peel toughness” proposed as robust, instrument-quantifiable indicators to minimize operational variability. Mechanistically, peelability is speculated to be governed by cell wall polysaccharide metabolism and phytohormone signaling networks. Pectin degradation and differential distribution during fruit development form critical “peeling zones”, whereas ethylene, abscisic acid, and indoleacetic acid may regulate cell wall remodeling and softening, collectively influencing skin-flesh adhesion. Owing to the scarcity of easy-to-peel kiwifruit cultivars, artificial manipulation methods, including manual peeling benchmarking, lye treatment, and thermal peeling, can be employed to further optimize kiwifruit peelability. Currently, shortcomings include incomplete genotype-phenotype characterization, limited availability of easy-peeling germplasms, and a fragmented understanding of the underlying mechanisms. Future research should focus on methodological innovation, germplasm development, and the elucidation of relevant mechanisms. Full article

The chickpea (Cicer arietinum L.) is a key legume crop in Mediterranean agriculture, valued for its nutritional profile and adaptability. However, its productivity is severely impacted by drought stress. To identify microbial solutions that enhance drought resilience, we isolated seven Mesorhizobium strains from chickpea nodules collected in southern Spain and evaluated their cultivar-specific symbiotic performance. Two commercial cultivars (Pedrosillano and Blanco Lechoso) and twenty chickpea germplasms were tested under growth chamber and greenhouse conditions, both with and without drought stress. Initial screening in a sterile substrate using nodulation assays, shoot/root dry weight measurements, and acetylene reduction assays identified three elite strains (ISC11, ISC15, and ISC25) with superior symbiotic performance and nitrogenase activity. Greenhouse trials under reduced irrigation demonstrated that several strain–cultivar combinations significantly mitigated drought effects on plant biomass, with specific interactions (e.g., ISC25 with RR-98 or BT6-19) preserving over 70% of shoot biomass relative to controls. Whole-genome sequencing of the elite strains revealed diverse taxonomic affiliations—ISC11 as Mesorhizobium ciceri, ISC15 as Mesorhizobium mediterraneum, and ISC25 likely representing a novel species. Genome mining identified plant growth-promoting traits including ACC deaminase genes (in ISC11 and ISC25) and genes coding for auxin biosynthesis-related enzymes. Our findings highlight the potential of targeted rhizobial inoculants tailored to chickpea cultivars to improve crop performance under water-limiting conditions. Full article

Browning significantly impacts the commercial value of luffa (luffa cylindrica) and is primarily driven by the metabolic processes of phenolic acids. Investigating changes in phenolic acids during browning aids in understanding the physiological mechanisms underlying this process and provides a basis for improving storage, processing, variety breeding, and utilization of germplasm resources. This study compared browning-resistant (‘30’) and browning-sensitive (‘256’) luffa varieties using high-throughput sequencing and metabolomics techniques. The results revealed 55 genes involved in the phenylpropanoid biosynthesis pathway, including 8 phenylalanine ammonia-lyase (PAL) genes, 20 peroxidase (POD) genes, 2 polyphenol oxidase (PPO) genes associated with tyrosine metabolism, and 37 peroxisome-related genes. Real-time quantitative (qPCR) was employed to validate 15 browning-related genes, revealing that the expression levels of LcPOD21 and LcPOD6 were 12.5-fold and 25-fold higher in ‘30’ compared to ‘256’, while LcPAL5 and LcPAL4 were upregulated in ‘30’. Enzyme analysis showed that catalase (CAT) and phenylalanine ammonia-lyase (PAL) activities were higher in ‘30’ than in ‘256’. Conversely, superoxide dismutase (SOD) and polyphenol oxidase (PPO) activities were reduced in ‘30’, whereas CAT activity was upregulated. The concentrations of cinnamic acid, p-coumaric acid, trans-5-O-(4-coumaroyl)mangiferic acid, and caffealdehyde were lower in browning-resistant luffa ‘30’ than in browning-sensitive luffa ‘256’, suggesting that their levels influence browning in luffa. These findings elucidate the mechanisms underlying browning and inform strategies for the storage, processing, and genetic improvement of luffa. Full article

Stevia rebaudiana Bertoni, a semi-perennial herb from the Asteraceae family, is native to the Paraguay–Brazil border region. The growing industrial interest in this species is due to its natural sweetening properties, such as steviol and its derivatives, which offer sweetness without adding calories. Morphological traits are crucial for assessing genetic variability and ensuring distinctness, homogeneity, and stability (DHS) for cultivar protection. This study characterized 19 elite Stevia genotypes from Embrapa Cerrados’ Active Germplasm Bank (BAG) using 21 morphological descriptors from Brazil’s Ministry of Agriculture, Livestock, and Supply (MAPA). Genetic distances were calculated using the simple coincidence index complement method, and clustering was performed via the Unweighted Pair-Group Method with Arithmetic Mean (UPGMA). The results showed that 17 of the 21 descriptors (>80%) effectively differentiated the genotypes, revealing significant genetic variability. Dendrogram analysis identified at least four major similarity groups, highlighting the potential of these genotypes for Stevia breeding programs. These findings underscore the suitability of these elite genotypes for developing superior varieties adapted to Cerrado conditions, supporting future cultivation and genetic improvement efforts. Full article