Breeding in bread-making wheat varieties for Mediterranean climate: the need to get resilient varieties.

Introduction: Being one of the "big three" most cultivated cereals in the world, wheat plays a crucial role in ensuring global food/nutrition security, supplying close to 20% of the global needs for calories and proteins. However, the increasingly large fluctuations between years in temperatures and precipitation due to climate change cause important variations in wheat production worldwide. This fact makes wheat breeding programs a tool that, far from going out of fashion, is becoming the most important solution to develop varieties that can provide humanity with the sufficient amount of food it demands without forgetting the objective of quality. Material and methods: The National Institute of Agricultural and Veterinary Research in Portugal has carried out a long-term experiment (9 years) in different locations to test four different bread-making wheat cultivars, each representing important variations in germplasm. Wheat yield and quality traits obtained by official methods were recorded in 18 different environments regarding temperature and precipitation. Results and discussion: According to the ANOVA and PCA, protein content, wet gluten, dough tenacity, and extensibility were found to be highly affected by the environment. Paiva cultivar presented a higher yield in almost all the tested environments, but its quality traits varied enormously. Contrary behavior was recorded for Valbona cultivar. Antequera cultivar, with a production ranging between 4.7 and 9.3 tons/ha and a protein content between 11 and 16.8%, seems to be the most resilient cultivar regarding both productivity and quality of the flour with reference to changes in the main climate traits. The most ancient cultivar, Roxo, released in 1996, showed the worst results in this experiment, supporting the need to continue working in wheat breeding to meet the unavoidable changes in the environment.

Evaluation of industrial and consumer 3-D resin printer fabrication of microdevices for quality management of genetic resources in aquatic species.

Aquatic germplasm repositories can play a pivotal role in securing the genetic diversity of natural populations and agriculturally important aquatic species. However, existing technologies for repository development and operation face challenges in terms of accuracy, precision, efficiency, and cost-effectiveness, especially for microdevices used in gamete quality evaluation. Quality management is critical throughout genetic resource protection processes from sample collection to final usage. In this study, we examined the potential of using three-dimensional (3-D) stereolithography resin printing to address these challenges and evaluated the overall capabilities and limitations of a representative industrial 3-D resin printer with a price of US$18,000, a consumer-level printer with a price

Analysis and evaluation of Camellia oleifera Abel. Germplasm fruit traits from the high-altitude areas of East Guizhou Province, China.

Camellia oleifera, a significant woody edible oil species, was examined using 48 germplasm resources from high-altitude regions in East Guizhou Province, China, to analyze fruit quality. The analysis aimed to identify high-performance germplasm, providing theoretical and research foundations for selecting and cross-breeding superior C. oleifera varieties in these regions. Fifteen primary traits of mature fruits were measured and analyzed, including four phenotypic traits (single fruit weight, transverse diameter, longitudinal diameter, peel thickness) and eleven quality traits (fresh seed yield rate, dry seed yield rate, dry kernel yield rate, seed kernel oil content, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, α-linolenic acid, cis-11-eicosenoic acid). A comprehensive evaluation employing cluster and principal component analyses (PCA) was conducted. The cluster analysis categorized the germplasms into five groups at a squared Euclidean distance of 14, with the first category comprising 17 germplasms, the second 28, and the third, fourth, and fifth each containing one. PCA reduced the 15 traits to five principal components (PCs), with PC1 having the highest eigenvalue of 3.57 and a contribution rate of 23.8%, mainly representing phenotypic traits. PC2, contributing 20.44%, represented linoleic acid, while PC3, PC4, and PC5, with contribution rates of 12.99%, 9.13%, and 7.45% respectively, predominantly represented seed kernel oil content, fresh seed yield, and palmitoleic acid. Employing a weighted sum method, a comprehensive evaluation function was developed to calculate total scores for each superior individual, forming the basis for rankings and selections. Notable variability was detected in single fruit weight, peel thickness, and fresh and dry seed yields, while oleic acid exhibited the lowest coefficient of variation. Dry seed yield showed a robust positive correlation with seed kernel oil content and the concentrations of palmitic and linoleic acids, whereas seed kernel oil content was inversely correlated with cis-11-eicosenoic acid levels. Five PCs with eigenvalues > 1 were identified, highlighting the top ten superior individuals: QD (Qian Dong: the code of eastern Guizhou Province)-33 > QD-34 > QD-48 > QD-38 > QD-27 > QD-15 > QD-35 > QD-5 > QD-14 > QD-36. Thus, the 48 C. oleifera germplasms from East Guizhou's high-altitude areas demonstrate significant potential for enhancing traits such as single fruit weight, peel thickness, and fresh and dry seed yields. Specifically, QD-33, QD-34, and QD-48 exhibited superior comprehensive performance, designating them as prime candidates for variety selection and breeding.

Multivariate Data Analysis Assisted Mining of Nutri-rich Genotypes from North Eastern Himalayan Germplasm Collection of Perilla (Perilla frutescens L.).

Understanding the nutritional diversity in Perilla (Perilla frutescens L.) is essential for selecting and developing superior varieties with enhanced nutritional profiles in the North Eastern Himalayan (NEH) region of India. In this study, we assessed the nutritional composition of 45 diverse perilla germplasm collected from five NEH states using standard protocols and advanced analytical techniques. Significant variability was observed in moisture (0.39-11.67%), ash (2.59-7.13%), oil (28.65-74.20%), protein (11.05-23.15%), total soluble sugars (0.34-3.67%), starch (0.01-0.55%), phenols (0.03-0.87%), ferric reducing antioxidant power (0.45-1.36%), palmitic acid (7.06-10.75%), stearic acid (1.96-2.29%), oleic acid (8.11-13.31%), linoleic acid (15.18-22.74%), and linolenic acid (55.47-67.07%). Similarly, significant variability in mineral content (ppm) was also observed for aluminium, calcium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, sodium, nickel, phosphorus, and zinc. Multivariate analyses, including hierarchical clustering analysis (HCA) and principal component analysis (PCA), revealed the enriched nutritional diversity within the germplasm. Correlation analysis indicated significant positive and negative relationships between nutritional parameters, indicating potential biochemical and metabolic interactions present in the perilla seeds. TOPSIS-based ranking identified promising genotypes for functional foods, pharmaceuticals, and nutritional applications. This study provides a first in-depth report of the nutritional composition and diversity of perilla germplasm in the NEH region, thus aiding in the identification of superior varieties for food and nutritional diversification and security.

First reports of several viruses and a viroid including a novel vitivirus in Japan, found through virome analysis of bulk grape genetic resources.

Virome analysis was performed on 174 grape genetic resources from the National Agriculture and Food Research Organization, Japan. A total of 20 bulk samples was prepared by grouping the vines into batches of 6-10 plants. Each of the bulk samples was analyzed using high-throughput sequencing, which detected 27 viruses and 5 viroids, including six viruses and one viroid reported in Japan for the first time (grapevine viruses F, L, and T, grapevine Kizil Sapak virus, grapevine Syrah virus 1, grapevine satellite virus, and grapevine yellow speckle viroid 2). In addition, a novel vitivirus was detected with a maximum nucleotide sequence identity of only 58% to its closest relative, grapevine virus A (GVA). The genome of this novel virus was 7,461 nucleotides in length and encoded five open reading frames showing the typical genomic structure of vitiviruses. Phylogenetic trees of vitiviruses placed it in a distinct position nearest to GVA or grapevine virus F (GVF) in genomes and amino acids of deduced replication-associated protein (RAP) and coat protein (CP). The amino acid sequence identities of RAP and CP with GVA, GVF, and other vitiviruses were a maximum of 53% and 73%, respectively, which were significantly below the species demarcation threshold of 80% in the genus. The low identity and phylogenetic analyses indicate the discovery of a novel vitivirus species provisionally named grapevine virus P.

Wild rice: unlocking the future of rice breeding.

Germplasm resources serve as the foundations of advancements in breeding and are crucial for maintaining food security. Wild rice species of the genus Oryza include rich sources of genetic diversity and high adaptability, making them a substantial resource for rice breeding. The discovery of wild-type cytoplasmic male sterility resources enabled the achievement of the 'three lines' goal in hybrid rice, significantly increasing rice yields. The application of resistance alleles from wild rice enables rice production to withstand losses caused by stress. Reduced genetic diversity due to rice breeding poses a significant limitation to further advances and can be alleviated through a systematic use of wild genetic resources that integrate geographic, climatic and environmental data of the original habitat, along with extensive germplasm collection and identification using advanced methods. Leveraging technological advancements in plant genomics, the understanding of genetic mechanisms and the application of artificial intelligence and gene editing can further enhance the efficiency and accuracy of this process. These advancements facilitate rapid isolation and functional studies of genes, and precise genome manipulation. This review systematically summarizes the utilization of superior genes and germplasm resources derived from wild rice sources, while also exploring the collection, conservation, identification and utilization of further wild rice germplasm resources. A focus on genome sequencing and biotechnology developments is leading to new breeding and biotechnology opportunities. These new opportunities will not only promote the development of rice varieties that exhibit high yields, superior stress resistance and high quality but also expand the genetic diversity among rice cultivars.

Assessment and phenotypic identification of millet germplasm (Setaria italica L.) in Liaoning, China.

Aims: This study evaluated millet germplasms in Liaoning Province to support the collection, preservation and innovation of millet germplasm resources. Methods: The study was conducted from 2018 to 2020, involved the selection of 105 millet germplasm resources from the Germplasm Bank of the Liaoning Academy of Agricultural Sciences (LAAS), the observation and recording of 31 traits, and the application of multivariate analysis methods to assess phenotypic diversity. Results: From the diversity analysis and correlation analysis, it was found that the tested traits had abundant diversity and complex correlations among them. Principal component analysis (PCA) comprehensively analyzed all quantitative traits and extracted seven principal components. Grey relational analysis (GRA) highlighted the varied contributions of different traits to yield. Through systematic cluster analysis (SCA), the resources were categorized into six groups at Euclidean distance of 17.09. K-mean cluster analysis determined the distribution interval and central value of each trait, then identified resources with desirable traits. Conclusion: The results revealed resources that possess characteristics such as upthrow seedling leaves, more tillers and branches, larger and well-formed ears, and lodging resistance prefer to higher grain yield. It was also discovered that the subear internode length (SIL) could be an indicator for maturity selection. Four specific resources, namely, Dungu No. 1, Xiao-li-xiang, Basen Shengu, and Yuhuanggu No. 1, were identified for further breeding and practical applications.

The CIMMYT Australia ICARDA Germplasm Evaluation concept: a model for international cooperation and impact.

Bread wheat germplasm is accessed from the International Maize and Wheat Improvement Centre (CIMMYT) and the International Centre for Agricultural Research in the Dry Areas (ICARDA) by Australian wheat breeders and researchers through the CIMMYT Australia ICARDA Germplasm Evaluation (CAIGE) program. The CAIGE program coordinates the selection, importation, quarantine, dissemination, and evaluation of the imported bread wheat germplasm and the management of associated data and information. This paper describes the CAIGE model and assesses both the genetic and economic impacts of these materials on the Australian wheat industry after commercialisation of wheat breeding in the early 21st century and the establishment of CAIGE. The CAIGE concept was validated using data collected and analysed from multi-environment trials between 2017 and 2020. The impact of cultivars with and without CAIGE contribution to pedigree on yield was estimated using production-by-variety statistics. Net gain in yield, estimated as the yield difference between CAIGE and Non-CAIGE varieties, was multiplied by the percentage contribution to pedigree to estimate the additional yield. The CAIGE bread wheat program identified diverse, high-yielding, and disease-resistant germplasm and significantly improved the capture and dissemination of information. The benefit-cost ratio, calculated as the sum of benefits divided by investments, indicated that, for every dollar invested in CAIGE, a further $20 was generated in benefits. The internal rate of return was estimated at 163% and the modified rate at 18%. The benefits of these international materials to Australian wheat breeding remained significant.

PidTools: Algorithm and web tools for crop pedigree identification analysis.

Crop pedigrees incorporate information on the kinship and genetic evolutionary history of breeding materials. Complete and accurate pedigree information is vital for effective genetic improvement of crops and maximal exploitation of heterosis in crop production. It is difficult for breeders to accurately extrapolate the selection of germplasm resources with missing genealogical information based on breeding experience. In this study, an algorithm called PidTools was developed, consisting of five sets of algorithms from three core modules, for accurate pedigree identification analysis. The algorithms and associated tools are suitable for all crops, for the reconstruction and visualization of a complete pedigree for breeding materials. The algorithm and tools were validated with the model crop maize. A genotype database was constructed using Maize6H-60K array data from 5791 maize inbred lines. The pedigree of the maize inbred line Jing72464 was identified without prior provision of any parental information. The pedigree information for Zheng58 was fully identified at the genome-wide scale. With regard to group identification, the parents of a doubled-haploid group were identified based on the genotyping data. The pedigree of 21 Dan340 derived lines were visualized using PidTools. The algorithms are incorporated into a user-friendly online analytical platform, PidTools-WS, with an associated customizable toolkit program, PidTools-CLI. These analytical tools and the present results provide useful information for future maize breeding. The PidTools online analysis platform is available at https://PidTools.plantdna.site/.

Diversity of ecotypes of five species of ryegrass from Northwestern Spain by phenotypic traits and microsatellites.

BACKGROUND: The Agricultural Research Centre of Mabegondo (Xunta de Galicia, A Coruña, Spain) conserves one of the most important collections of phytogenetic resources of ecotypes and natural populations of grassland species from northwestern Spain, among them populations of ryegrass (Lolium spp.), one of the most cultivated forage grasses in the world. The objective of the present study was to evaluate the diversity among commercial cultivars and natural ryegrass populations with phenotypic traits and molecular markers. RESULTS: Eleven polymorphic microsatellites loci were used to analyze 58 ecotypes and 10 cultivars (680 DNA samples in total) differentiating 673 genotypes. Two main groups were detected by the Structure analysis, one related to Lolium perenne and a second to Lolium multiflorum. The first group showed two subgroups and the second three. The cluster of L. multiflorum showed two subgroups not related with the third cluster including commercial varieties, one from the Canary Islands (with Lolium rigidum included) and a second one from northwestern Spain, which presented specific agromorphological characteristics, such as lower FES (number of days from 1 January, when three heads per plant were flowering per plot), CRE (growth in flowering, in g of dry matter), and AIN (number of inflorescences per plant). CONCLUSIONS: This is the first time that a large amount of data on ryegrass from the Iberian Peninsula has been analyzed, obtaining a clear genetic differentiation of the autochthonous varieties from the commercial varieties analyzed. In addition, the genetic structure found in the ecotypes was related to the phenotypic variation analyzed. Being of interest in the conservation of biodiversity and in obtaining better adapted varieties of ryegrasses, due to their specific phenotypic traits, such as a lower FES, CRE and AIN.

Advances in genome sequencing and artificially induced mutation provides new avenues for cotton breeding.

Cotton production faces challenges in fluctuating environmental conditions due to limited genetic variation in cultivated cotton species. To enhance the genetic diversity crucial for this primary fiber crop, it is essential to augment current germplasm resources. High-throughput sequencing has significantly impacted cotton functional genomics, enabling the creation of diverse mutant libraries and the identification of mutant functional genes and new germplasm resources. Artificial mutation, established through physical or chemical methods, stands as a highly efficient strategy to enrich cotton germplasm resources, yielding stable and high-quality raw materials. In this paper, we discuss the good foundation laid by high-throughput sequencing of cotton genome for mutant identification and functional genome, and focus on the construction methods of mutant libraries and diverse sequencing strategies based on mutants. In addition, the important functional genes identified by the cotton mutant library have greatly enriched the germplasm resources and promoted the development of functional genomes. Finally, an innovative strategy for constructing a cotton CRISPR mutant library was proposed, and the possibility of high-throughput screening of cotton mutants based on a UAV phenotyping platform was discussed. The aim of this review was to expand cotton germplasm resources, mine functional genes, and develop adaptable materials in a variety of complex environments.

Utilizing digitized occurrence records of Midwestern feral Cannabis sativa to develop ecological niche models.

Hemp (Cannabis sativa L.) has historically played a vital role in agriculture across the globe. Feral and wild populations have served as genetic resources for breeding, conservation, and adaptation to changing environmental conditions. However, feral populations of Cannabis, specifically in the Midwestern United States, remain poorly understood. This study aims to characterize the abiotic tolerances of these populations, estimate suitable areas, identify regions at risk of abiotic suitability change, and highlight the utility of ecological niche models (ENMs) in germplasm conservation. The Maxent algorithm was used to construct a series of ENMs. Validation metrics and MOP (Mobility-oriented Parity) analysis were used to assess extrapolation risk and model performance. We also projected the final projected under current and future climate scenarios (2021-2040 and 2061-2080) to assess how abiotic suitability changes with time. Climate change scenarios indicated an expansion of suitable habitat, with priority areas for germplasm collection in Indiana, Illinois, Kansas, Missouri, and Nebraska. This study demonstrates the application of ENMs for characterizing feral Cannabis populations and highlights their value in germplasm conservation and breeding efforts. Populations of feral C. sativa in the Midwest are of high interest, and future research should focus on utilizing tools to aid the collection of materials for the characterization of genetic diversity and adaptation to a changing climate.

Unraveling popping quality through insights on kernel physical, agro-morphological, and quality traits of diverse popcorn (Zea mays var. everta) inbreds from indigenous and exotic germplasm.

Popcorn is a specialty corn with worldwide popularity as a snack. Despite having great market demand, genetic improvement in popping quality is limited, which is caused by the limited germplasm utilization and narrow genetic base. An assortment of diverse germplasm, their effective characterization, and integration into popcorn breeding pipeline is the foundation for an efficient breeding program. Here, kernel characteristics, popping quality traits, and agro-morphological traits were evaluated across three locations on a diverse panel of 48 popcorn inbreds derived from diverse landraces and populations of exotic and indigenous origin. The variations due to genotypes, locations, and genotype × location interaction were highly significant. The popping quality traits recorded wide variation with a high coefficient of genotypic determination. The kernel dimensions, kernel density, test weight, and grain yield were negatively correlated with popping quality traits. Genotypes with rice-type kernels exhibited better popping quality than pearl-type kernels. Analysis of genotype × location (G×L) interaction identified two target locations for the key popping quality trait, popping expansion volume. PMI-PC-175, PMI-PC-187, PMI-PC-188, and PMI-PC-189 were identified as superior genotypes over checks for desirable popping quality, agronomic performance, and high grain yield. The contrasting inbreds for popping quality and flake shape (mushroom vs. butterfly) can be utilized for developing mapping populations to enhance our understanding of molecular aspects of popping quality traits. Further, the promising inbreds can be utilized in the genetic improvement of popcorn and crossed to develop superior popcorn hybrids. The results suggest a potential opportunity to establish an efficient popcorn breeding program.

Analysis of the Correlation between Persimmon Fruit-Sugar Components and Taste Traits from Germplasm Evaluation.

Persimmon fruits are brightly colored and nutritious and are fruits that contain large amounts of sugar, vitamins, mineral elements, and phenolic substances. The aim of this study was to explore the differences in fruit-sugar components of different persimmon germplasms and their relationships with phenotypic and flavor indices through the determination of phenotypes and sugar components and through electronic-tongue indices, which provided the basis and inspiration for the selection of different sugar-accumulating types of persimmon fruits and the selection of high-sugar persimmon varieties. Our results showed that persimmon germplasm fruit-sugar components were dominated by sucrose, glucose and fructose and that the remaining sugar components were more diverse but less distributed among the various germplasm types. Based on the proportion of each sugar component in the fruit, persimmon germplasms can be categorized into sucrose-accumulating and reduced-sugar-accumulation types. Sucrose-accumulating types are dominated by sucrose, galactose, fucose and inositol, while reduced-sugar-accumulation types are dominated by glucose, fructose, mannose-6-phosphate, and xylose. The content of sugar components in the germplasm persimmon of fruits of different types and maturity periods of also differed, with significant differences in sugar components between PCNA (pollination-constant non-astringent) and PCA (pollination-constant astringent) fruits. Cluster analysis classified 81 persimmon germplasms into three clusters, including cluster I-A, with low glucose and fructose content, and cluster I-B, with medium glucose, fructose, and sucrose contents. Cluster II was high in sucrose and fructose. Cluster III had high contents of glucose and fructose and low contents of sucrose and inositol.

[Research progress in molecular pharmacognosy of Andrographis paniculata].

Molecular pharmacognosy as an emerging interdisciplinary subject based on molecular biology and Chinese materia medica aims to study the synthesis and molecular regulation of secondary metabolites in medicinal plants. Andrographis Herba, the dried aboveground part of Andrographis paniculata, has liver-protecting, bile secretion-promoting, heat-clearing, toxin-removing, antimicrobial, and anti-inflammatory effects. The quality instability caused by plant varieties, environment, and technology in the production of A. paniculata is a limiting factor for the sustainable development of this industry. Based on the research methods of molecular pharmacognosy and omics, the regulation of secondary metabolites of A. paniculata has become the key solution to the quality problems of A. paniculata. This paper summarized the recent research achievements in the molecular pharmacognosy of A. paniculata, including molecular identification of the resources, genetic diversity, multi-omics, biosynthesis of active compounds, and germplasm resource innovation, and prospected the future development trend in this field. In-depth research of molecular pharmacognosy of A. paniculata will provide more scientific and effective technical support for the development of its medicinal value, give new insights into the cultivation of new A. paniculata varieties, and promote the high-quality sustainable development of this industry.

Genome-Wide Association Study Reveals the Genetic Basis of Crude Fiber Components in Brassica napus L. Shoots at Stem Elongation Stage.

Brassica napus is currently the principal field crop for producing materials for primary, secondary and tertiary industries. B. napus shoots at stem elongation stage are rich in anthocyanins, vitamin C and mineral elements such as selenium, calcium and zinc, and represent a new type of green vegetable. However, the high crude fiber (CF) content of B. napus shoots affects their taste, and few studies have focused on the quality traits of these vegetables. In this study, we investigated five traits related to the CF components, including neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), hemicellulose (Hem) and cellulose (Cel), of B. napus shoots. Whole-genome resequencing at a depth of ∼20× was utilized to genotype an association panel of 202 diverse accessions, which resulted in the identification of 6,093,649 single nucleotide polymorphisms (SNPs) and 996,252 indels, respectively. A genome-wide association study (GWAS) was performed for the five CF-related traits based on the phenotypic data observed in four environments. A total of 1,285 significant SNPs were detected at the threshold of -log10 (p) = 5.16, and 97 significant association regions were obtained. In addition, seven candidate genes located on chromosomes A2 (one gene), A8 (three genes), A9 (two genes) and C9 (one gene) related to CF traits were identified, and ten lines containing low CF contents were selected as excellent germplasm resources for breeding. Our results contributed new insights into the genetic basis of CF traits and suggested germplasm resources for the quality improvement of B. napus shoots.

Genetic analysis of popping quality traits and development of superior quality popcorn hybrids for a sustainable popcorn breeding program in India.

BACKGROUND: Popcorn is the most popular specialty maize and it makes a significant contribution to the Indian and global economies. Despite perfect exploration of heterosis in field corn, progress in popcorn breeding remains constrained due to its narrow genetic base, leading to a significant dependence on imports. In this study, 15 landrace- and population-derived inbreds from temperate and tropical germplasm were crossed with five testers, which are the parents of superior popcorn hybrids, in a line × tester mating design. RESULTS: Significant variation was observed in popping quality and agronomic traits among crosses evaluated across three locations representing diverse maize-based agro-climatic zones in India. Additive genetic variance governed the traits related to popping quality, whereas dominance variance was responsible for the agronomic traits. In addition to significant heterosis specific to certain traits, we identified promising crosses that exhibited superior performance in both popping quality and grain yield (GY). The genotype + genotype × environment (GGE) biplot methodology identified PMI-PC-104 and PMI-PC-101 as the best discriminating testers for popping quality traits and Dpcl-15-90 for GY. Lines PMI-PC-205, PMI-PC-207, and PMI-PC-209 were the best general combiners for popping quality traits and GY. The heterotic groups identified based on GGE-biplots and the magnitude, direction and stability of combining ability effects would serve in the development of competitive popcorn hybrids for a sustainable popcorn market. CONCLUSION: Using the additive nature of popping quality traits and the dominant nature of GY, recurrent intrapopulation selection can be employed to derive desirable popping quality inbreds with high GY for genetic enhancement. Desirable popping quality alleles from novel germplasm can thus be combined with high-yielding domestic elite inbreds to establish a sustainable popcorn breeding program. © 2024 Society of Chemical Industry.

Towards Pathogen-Free Coconut Germplasm Exchange.

Coconut (Cocos nucifera L.) is an important palm species that serves as the mainstay of several industries and contributes to the livelihoods of millions of smallholder farmers. International exchange of coconut germplasm has been undertaken for several decades to facilitate the conservation of selected varieties within global genebanks and for the distribution to farmers and scientists. In vitro systems are a convenient and an efficient method for the exchange of coconut germplasm. However, it is possible that these tissue culture systems can transfer lethal pathogens causing a threat to the importing countries. In this review, the following topics are discussed: the major disease-causing agents of concern, the various tissues that could be used for coconut germplasm exchange, and the techniques available for the detection and elimination of disease-causing agents from various transmission systems. Additionally, the lack of clear, science-backed guidelines to facilitate the exchange of in vitro coconut materials is raised, along with recommendations for future studies to ensure the safe movement of coconut germplasm without biosecurity risks.

Identification of candidate gene associated with maize northern leaf blight resistance in a multi-parent population.

KEY MESSAGE: QTL mapping combined with genome-wide association studies, revealed a potential candidate gene for  resistance to northern leaf blight in the tropical CATETO-related maize line YML226, providing a basis for marker-assisted selection of maize varieties Northern leaf blight (NLB) is a foliar disease that can cause severe yield losses in maize. Identifying and utilizing NLB-resistant genes is the most effective way to prevent and control this disease. In this study, five important inbred lines of maize were used as parental lines to construct a multi-parent population for the identification of NLB-resistant loci. QTL mapping and GWAS analysis revealed that QTL qtl_YML226_1, which had the largest phenotypic variance explanation (PVE) of 9.28%, and SNP 5-49,193,921 were co-located in the CATETO-related line YML226. This locus was associated with the candidate gene Zm00001d014471, which encodes a pentatricopeptide repeat (PPR) protein. In the coding region of Zm00001d014471, YML226 had more specific SNPs than the other parental lines. qRT-PCR showed that the relative expressions of Zm00001d014471 in inoculated and uninoculated leaves of YML226 were significantly higher, indicating that the expression of the candidate gene was correlated with NLB resistance. The analysis showed that the higher expression level in YML226 might be caused by SNP mutations. This study identified NLB resistance candidate loci and genes in the tropical maize inbred line YML226 derived from the CATETO germplasm, thereby providing a theoretical basis for using modern marker-assisted breeding techniques to select genetic resources resistant to NLB.

Exploring genetic diversity and population structure in Cinnamomum cassia (L.) J.Presl germplasm in China through phenotypic, chemical component, and molecular marker analyses.

Cinnamomum cassia (L.) J.Presl, a tropical aromatic evergreen tree belonging to the Lauraceae family, is commonly used in traditional Chinese medicine. It is also a traditional spice used worldwide. However, little is currently known about the extent of the genetic variability and population structure of C. cassia. In this study, 71 individuals were collected from seven populations across two geographical provinces in China. Nine morphological features, three chemical components, and single nucleotide polymorphism (SNP) markers were used in an integrated study of C. cassia germplasm variations. Remarkable genetic variation exists in both phenotypic and chemical compositions, and certain traits, such as leaf length, leaf width, volatile oil content, and geographic distribution, are correlated with each other. One-year-old C. cassia seedling leaf length, leaf width, elevation, and volatile oil content were found to be the main contributors to diversity, according to principal component analysis (PCA). Three major groupings were identified by cluster analysis based on the phenotypic and volatile oil data. This was in line with the findings of related research using 1,387,213 SNP markers; crucially, they all demonstrated a substantial link with geographic origin. However, there was little similarity between the results of the two clusters. Analysis of molecular variance (AMOVA) revealed that the genetic diversity of C. Cassia populations was low, primarily among individuals within populations, accounting for 95.87% of the total. Shannon's information index (I) varied from 0.418 to 0.513, with a mean of 0.478 (Na=1.860, Ne =1.584, Ho =0.481, He =0.325, and PPB =86.04%). Genetic differentiation across populations was not significant because natural adaptation or extensive exchange of seeds among farmers between environments, thus maintaining the relationship. Following a population structure analysis using the ADMIXTURE software, 71 accessions were found to be clustered into three groups, with 38% of them being of the pure type, a finding that was further supported by PCA. Future breeding strategies and our understanding of the evolutionary relationships within the C. cassia population would benefit greatly from a thorough investigation of phenotypic, chemical, and molecular markers.