Dry Breeding and Dry Planting Techniques for Indica Hybrid Rice in Karst Mountain Areas of Gejiu City

Based on the arable land situation in Gejiu City,upland dry planting of indica hybrid rice is being expanded in Karst mountain areas with a rainfall of over 1400 mm and an altitude of 1100-1600 m to develop grain production.This paper gives a specific description of hybrid rice upland dry seedling technology,upland transplanting technology,fertilization technology,field management,weed prevention and control technology,and disease and pest control.

Key Techniques of an Ecological Pattern“Planting Rice in One Season and Breeding Red Swamp Crawfish in Three Seasons” for Green Production in Lixiahe Region of Jiangsu Province

Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus clarkii）, spatial and temporal coupling technology of ＂planting rice in one season and breeding red swamp crawfish in three seasons＂, green fertilization technology, green prevention and control technology, control technology of water level, and throwing technology of bait in Lixiahe region of Jiangsu Province were introduced successively, which can provide technical support for the development of ecological planting and breeding patterns and realization of green production in paddy fields.

Estimating Key Phenological Dates of Multiple Rice Accessions Using Unmanned Aerial Vehicle-Based Plant Height Dynamics for Breeding

Efficient and high-quality estimation of key phenological dates in rice is of great significance in breeding work. Plant height(PH) dynamics are valuable for estimating phenological dates. However, research on estimating the key phenological dates of multiple rice accessions based on PH dynamics has been limited. In 2022, field traits were collected using unmanned aerial vehicle(UAV)-based images across 435 plots, including 364 rice varieties. PH, dates of initial heading(IH) and full heading(FH), and panicle initiation(PI), and growth period after transplanting(GPAT) were collected during the rice growth stage. PHs were extracted using a digital surface model(DSM) and fitted using Fourier and logistic models. Machine learning algorithms, including multiple linear regression, random forest(RF), support vector regression, least absolute shrinkage and selection operator, and elastic net regression, were employed to estimate phenological dates. Results indicated that the optimal percentile of the DSM for extracting rice PH was the 95th(R^(2) = 0.934, RMSE = 0.056 m). The Fourier model provided a better fit for PH dynamics compared with the logistic models. Additionally, curve features(CF) and GPAT were significantly associated with PI, IH, and FH. The combination of CF and GPAT outperformed the use of CF alone, with RF demonstrating the best performance among the algorithms. Specifically, the combination of CF extracted from the logistic models, GPAT, and RF yielded the best performance for estimating PI(R^(2) = 0.834, RMSE = 4.344 d), IH(R^(2) = 0.877, RMSE = 2.721 d), and FH(R^(2) = 0.883, RMSE = 2.694 d). Overall, UAV-based rice PH dynamics combined with machine learning effectively estimated the key phenological dates of multiple rice accessions, providing a novel approach for investigating key phenological dates in breeding work.

3-28 Progress on Mutation Breeding Induced by Heavy Ion Beams and Planting Sweet Sorghum

During the past year, biophysics group at Institute of Modern Physics (IMP) obtained lots of achievements in theresearch of heavy-ion mutation breeding and production chain of sweet sorghum. In fundamental research field, amutant population of Arabidopsis thaliana induced by carbon ion beam radiation was established in M2 generation.The total mutation rate was 4.77%. A mutant marked 197#, which had frostbite-like, pale green, wrinkled anduneven leaves and displayed loose bracts and late maturation, was obtained and reported for the first time. Generough mapping results demonstrated that there were two mutation sites in the 1st and 4th chromosome of 197#mutant, indicating heavy ion radiation might induce more complicated mutations beyond our current recognition.The whole genome resequencing of this mutant is still in progress. In addition, high-yield strains of microbeswhich have potential value for commercial application, such as Corynebacterium glutamicum and Lacbobacillusthermophiles, were screened using heavy-ion mutation technique.

Corrigendum to“Migration pattern of a population of Barn Swallows(Hirundo rustica)breeding in East Asian tropical region”[Avian Res.15(2024)100192]

The authors regret that the caption of Fig.4 should be replaced as below.

Creating large EMS populations for functional genomics and breeding in wheat

Wheat germplasm is a fundamental resource for basic research,applied studies,and wheat breeding,which can be enriched normally by several paths,such as collecting natural lines,accumulating breeding lines,and introducing mutagenesis materials.Ethyl methane sulfonate(EMS)is an alkylating agent that can effectively introduce genetic variations in a wide variety of plant species.In this study,we created a million-scale EMS population(MEP)that started with the Chinese wheat cultivars‘Luyan 128’,‘Jimai 38’,‘Jimai 44’,and‘Shannong 30’.In the M1 generation,the MEP had numerous phenotypical variations,such as>3,000 chlorophyll-deficient mutants,2,519 compact spikes,and 1,692 male sterile spikes.There were also rare mutations,including 30 independent tillers each with double heads.Some M1 variations of chlorophyll-deficiency and compact spikes were inheritable,appearing in the M2 or M3 generations.To advance the entire MEP to higher generations,we adopted a single-seed descendent(SSD)approach.All other seed composites of M2 were used to screen other agronomically important traits,such as the tolerance to herbicide quizalofop-P-methyl.The MEP is available for collaborative projects,and provides a valuable toolbox for wheat genetics and breeding for sustainable agriculture.

Rice Heat Tolerance Breeding: A Comprehensive Review and Forward Gaze

The yield potential of rice is seriously affected by heat stress due to climate change. Since rice is a staple food globally, it is imperative to develop heat-resistant rice varieties. Thus, a thorough understanding of the complex molecular mechanisms underlying heat tolerance and the impact of high temperatures on various critical stages of the crop is needed. Adoption of both conventional and innovative breeding strategies offers a long-term advantage over other methods, such as agronomic practices, to counter heat stress. In this review, we summarize the effects of heat stress, regulatory pathways for heat tolerance, phenotyping strategies, and various breeding methods available for developing heat-tolerant rice. We offer perspectives and knowledge to guide future research endeavors aimed at enhancing the ability of rice to withstand heat stress and ultimately benefit humanity.

Simulation Modeling in Plant Breeding: Principles and Applications

Conventional plant breeding largely depends on phenotypic selection and breeder＇s experience, therefore the breeding efficiency is low and the predictions are inaccurate. Along with the fast development in molecular biology and biotechnology, a large amount of biological data is available for genetic studies of important breeding traits in plants, which in turn allows the conduction of genotypic selection in the breeding process. However, gene information has not been effectively used in crop improvement because of the lack of appropriate tools. The simulation approach can utilize the vast and diverse genetic information, predict the cross performance, and compare different selection methods. Thus, the best performing crosses and effective breeding strategies can be identified. QuLine is a computer tool capable of defining a range, from simple to complex genetic models, and simulating breeding processes for developing final advanced lines. On the basis of the results from simulation experiments, breeders can optimize their breeding methodology and greatly improve the breeding efficiency. In this article, the underlying principles of simulation modeling in crop enhancement is initially introduced, following which several applications of QuLine are summarized, by comparing the different selection strategies, the precision parental selection, using known gene information, and the design approach in breeding. Breeding simulation allows the definition of complicated genetic models consisting of multiple alleles, pleiotropy, epistasis, and genes, by environment interaction, and provides a useful tool for breeders, to efficiently use the wide spectrum of genetic data and information available.

A Preliminary Study on Breeding of Ideal Plant in Millet

To further increase millet yield, the ideal plant in millet has become the goal of high yield breeding for millet. Taking crossbreeding or dynamic breeding technique as dominant and technologies such as modern selection or system selection as subsidiary, progenies with ideal plant are selected by using new germplasms such as Lilvgu and Lizigu with the significant difference in plant type to other cultivars as parents. The ge- netic characteristics of new germplasms in breeding are also emphatically analyzed to summarize the breeding experience of ideal plant, which has been proved that the combination of ideal plant and heterosis utilization is one of the important ways to raise millet yield breakthrough.

Genomic dissection of widely planted soybean cultivars leads to a new breeding strategy of crops in the post-genomic era

Soybeans specially the widely planted cultivars have been dramatically improved in agronomic performance and is well adapted to local planting environments after long-time domestication and breeding.Uncovering the unique genomic features of popular cultivars will help to understand how soybean genomes have been modified through breeding.We re-sequenced 134 soybean cultivars that were released and most widely planted over the last century in China.Phylogenetic analyses established that these cultivars comprise two geographically distinct sub-populations:Northeast China (NE) versus the HuangHuai-Hai River Valley and South China (HS).A total of 309 selective regions were identified as being impacted by geographical origins.The HS sub-population exhibited higher genetic diversity and linkage disequilibrium decayed more rapidly compared to the NE sub-population.To study the association between phenotypic differences and geographical origins,we recorded the vegetative period under different growing conditions for two years,and found that clustering based on the phenotypic data was closely correlated with cultivar geographical origin.By iteratively calculating accumulated genetic diversity,we established a platform panel of cultivars and have proposed a novel breeding strategy named "Potalaization"for selecting and utilizing the platform cultivars that represent the most genetically diversity and the highest available agronomic performance as the "plateau"for accumulating elite loci and traits,breeding novel widely adapted cultivars,and upgrading breeding technology.In addition to providing new genomic information for the soybean research community,the "Potalaization"strategy that we devised will also be practical for integrating the conventional and molecular breeding programs of crops in the post-genomic era.

Artificial selection of the Green Revolution gene Semidwarf 1 is implicated in upland rice breeding

Semidwarf breeding has boosted crop production and is a well-known outcome from the first Green Revolution. The Green Revolution gene Semidwarf 1(SD1), which modulates gibberellic acid(GA) biosynthesis, plays a principal role in determining rice plant height. Mutations in SD1 reduce rice plant height and promote lodging resistance and fertilizer tolerance to increase grain production. The plant height mediated by SD1 also favors grain yield under certain conditions. However, it is not yet known whether the function of SD1 in upland rice promotes adaptation and grain production. In this study, the plant height and grain yield of irrigated and upland rice were comparatively analyzed under paddy and dryland conditions. In response to dryland environments, rice requires a reduction in plant height to cope with water deficits. Upland rice accessions had greater plant heights than their irrigated counterparts under both paddy and dryland conditions, and appropriately reducing plant height could improve adaptability to dryland environments and maintain high grain yield formation. Moreover, upland rice cultivars with thicker stem diameters had stronger lodging resistance, which addresses the lodging problem. Knockout of SD1 in the upland rice cultivar IRAT104 reduced the plant height and grain yield, demonstrating that the adjustment of plant height mediated by SD1 could increase grain production in dryland fields. In addition, an SD1 genetic diversity analysis verified that haplotype variation causes phenotypic variation in plant height. During the breeding history of rice, SD1 allelic mutations were selected from landraces to improve the grain yield of irrigated rice cultivars, and this selection was accompanied by a reduction in plant height. Thus, five known mutant alleles were analyzed to verify that functional SD1 is required for upland rice production. All these results suggest that SD1 might have undergone artificial positive selection in upland rice, which provides further insights concerning greater plant height in upland rice breeding.

META-R:A software to analyze data from multi-environment plant breeding trials

META-R(multi-environment trial analysis in R)is a suite of R scripts linked by a graphical user interface(GUI)designed in Java language.The objective of META-R is to accurately analyze multi-environment plant breeding trials(METs)by fitting mixed and fixed linear models from experimental designs such as the randomized complete block design(RCBD)and the alpha-lattice/lattice designs.META-R simultaneously estimates the best linear and unbiased estimators(BLUEs)and the best linear and unbiased predictors(BLUPs).Additionally,it computes the variance-covariance parameters,as well as some statistical and genetic parameters such as the least significant difference(LSD)at 5%significance,the coefficient of variation in percentage(CV),the genetic variance,and the broad-sense heritability.These parameters are very important in the selection of top performing genotypes in plant breeding.META-R also computes the phenotypic and genetic correlations among environments and between traits,as well as their statistical significance.The genetic correlations between environments or traits can be visualized in a biplot graph or a tree diagram(dendrogram).Genetic correlations are very important for identifying environments with similar behavior or making indirect selection and identifying the most highly associated traits.META-R performs multi-environment analyses by using the residual maximum likelihood(REML)method;these analyses can be done by environment,across environments by grouping factors(stress conditions,nitrogen content,etc.)and across environments;the analyses across environments can be done with a pre-defined degree of heritability.

Modeling and simulation of recurrent phenotypic and genomic selections in plant breeding under the presence of epistasis

Recurrent selection is an important breeding method for population improvement and selecting elite inbreds or fixed lines from the improved germplasm.Recently,a computer simulation tool called QuMARS has been developed,which allows the simulation and optimization of various recurrent selection strategies.Our major objective in this study was to use the QuMARS tool to compare phenotypic recurrent,marker-assisted recurrent,and genomic selections(abbreviated respectively as PS,MARS and GS)for both short-and long-termbreeding procedures.ForMARS,twomarker selection models were considered,i.e.,stepwise(Rstep)and forward regressions(Forward).For GS,three prediction models were considered,i.e.,genomic best linear unbiased predictors(GBLUP),ridge regression(Ridge),and regression by Moore-Penrose general inverse(InverseMP).To generate genotypes and phenotypes for a given individual during simulation,one additive and two epistasis genetic models were considered with three levels of heritability.Results demonstrated that selection responses from GBLUP-based GS and MARS(Forward)were consistently greater than those from PS under the additive model,particularly in early selection cycles.In contrast,selection response from PS was consistently superior over MARS and GS under epistatic models.For the two epistasis models,total genetic variance and the additive variance component were increased in some cases after selection.Through simulation,we concluded that GS and PS were effective recurrent selection methods for improved breeding of targeted traits controlled by additive and epistatic quantitative trait loci(QTL).QuMARS provides an opportunity for breeders to compare,optimize and integrate new technology into their conventional breeding programs.

Drought-Tolerant Rice at Molecular Breeding Eras:An Emerging Reality

Rice(Oryza sativa L.)stands as the most significantly influential food crop in the developing world,with its total production and yield stability affected by environmental stress.Drought stress impacts about 45%of the world’s rice area,affecting plants at molecular,biochemical,physiological,and phenotypic levels.The conventional breeding method,predominantly employing single pedigree selection,has been widely utilized in breeding numerous drought-tolerant rice varieties since the Green Revolution.With rapid progress in plant molecular biology,hundreds of drought-tolerant QTLs/genes have been identified and tested in rice crops under both indoor and field conditions.Several genes have been introgressed into elite germplasm to develop commercially accepted drought-tolerant varieties,resulting in the development of several drought-tolerant rice varieties through marker-assisted selection and genetically engineered approaches.This review provides up-to-date information on proof-of-concept genes and breeding methods in the molecular breeding era,offering guidance for rice breeders to develop drought-tolerant rice varieties.

Effect of Preplant Fertilizer on Agronomic and Physiological Traits of Soybean Cultivars from Different Breeding Programs

Understanding the changes in agronomic and physiological traits associated with yield genetic gain is important for soybean production and future breeding strategy. The objective of this study was to compare the older and modern cultivars to learn whether the yield improvements depend on preplant fertilizer or the plant productivity improvement, A set of older cultivars, with their modern counterparts derived from breeding programs in Liaoning and Ohio were evaluated for their agronomic and physiological traits under different fertilizer levels from 2004 to 2006. There was no improvement of response to N and P preplant fertilizer for genotypes. After more than 70 yr breeding, soybean breeders made some improvements in agronomic and physiological traits that contribute to yield increase. When compared to older cultivar, modern Liaoning and Ohio cultivars were shorter and more resistance to lodging, had greater leaf density, higher harvest index, more leaf area per plant, and greater photosynthetic rate, transpiration rate and stomatal conductance at the beginning of seed development. Ohio cultivars were more resistant to lodging as if selected for easy harvest by combine, even under high N and P preplant fertilizer level, which resulted in Ohio cultivars with higher and stable yield productivity.

State of the science and challenges of breeding landscape plants with ecological function

Exotic plants dominate esthetically-managed landscapes,which cover 30–40 million hectares in the United States alone.Recent ecological studies have found that landscaping with exotic plant species can reduce biodiversity on multiple trophic levels.To support biodiversity in urbanized areas,the increased use of native landscaping plants has been advocated by conservation groups and US federal and state agencies.A major challenge to scaling up the use of native species in landscaping is providing ornamental plants that are both ecologically functional and economically viable.Depending on ecological and economic constraints,accelerated breeding approaches could be applied to ornamental trait development in native plants.This review examines the impact of landscaping choices on biodiversity,the current status of breeding and selection of native ornamental plants,and the interdisciplinary research needed to scale up landscaping plants that can support native biodiversity.

Tomato detection method using domain adaptive learning for dense planting environments

This study aimed to address the challenge of accurately and reliably detecting tomatoes in dense planting environments,a critical prerequisite for the automation implementation of robotic harvesting.However,the heavy reliance on extensive manually annotated datasets for training deep learning models still poses significant limitations to their application in real-world agricultural production environments.To overcome these limitations,we employed domain adaptive learning approach combined with the YOLOv5 model to develop a novel tomato detection model called as TDA-YOLO(tomato detection domain adaptation).We designated the normal illumination scenes in dense planting environments as the source domain and utilized various other illumination scenes as the target domain.To construct bridge mechanism between source and target domains,neural preset for color style transfer is introduced to generate a pseudo-dataset,which served to deal with domain discrepancy.Furthermore,this study combines the semi-supervised learning method to enable the model to extract domain-invariant features more fully,and uses knowledge distillation to improve the model's ability to adapt to the target domain.Additionally,for purpose of promoting inference speed and low computational demand,the lightweight FasterNet network was integrated into the YOLOv5's C3 module,creating a modified C3_Faster module.The experimental results demonstrated that the proposed TDA-YOLO model significantly outperformed original YOLOv5s model,achieving a mAP(mean average precision)of 96.80%for tomato detection across diverse scenarios in dense planting environments,increasing by 7.19 percentage points;Compared with the latest YOLOv8 and YOLOv9,it is also 2.17 and 1.19 percentage points higher,respectively.The model's average detection time per image was an impressive 15 milliseconds,with a FLOPs(floating point operations per second)count of 13.8 G.After acceleration processing,the detection accuracy of the TDA-YOLO model on the Jetson Xavier NX development board is 90.95%,the mAP value is 91.35%,and the detection time of each image is 21 ms,which can still meet the requirements of real-time detection of tomatoes in dense planting environment.The experimental results show that the proposed TDA-YOLO model can accurately and quickly detect tomatoes in dense planting environment,and at the same time avoid the use of a large number of annotated data,which provides technical support for the development of automatic harvesting systems for tomatoes and other fruits.

Topgrafting as a tool in operational Scots pine breeding

Effective breeding requires multiplying desired genotypes,keeping them at a convenient location to perform crosses more efficiently,and building orchards to generate material for reforestation.While some of these aims can be achieved by conventional grafting involving only rootstock and scion,topgrafting is known to deliver all in a shorter time span.In this study,Scots pine scions were grafted onto the upper and lower tree crowns in two clonal archives with the aim of inducing early female and male strobili produc-tion,respectively.Their survival rates and strobili production were analyzed with generalized linear mixed models.Sur-vival was low(14%)to moderate(41%),and mainly affected by the topgraft genotype,interstock genotype,crown posi-tion and weather conditions in connection with the grafting procedure.Survival was not affected by the cardinal position in the crown(south or north).Male flowering was ample three years after grafting and reached 56%in the first year among live scions,increasing to 62 and 59%in consecutive years.Female flowering was scarce and was 9%at first,later increasing to 26 and 20%of living scions but was strongly affected by the topgraft genotype.In one subset of scions,female flowering was observed 1 year after grafting.Overall,flowering success was mainly affected by the topgraft and interstock genotypes,and secondary growth of scions.This is one of few reports on topgrafting in functional Scots pine clonal archives.

Breeding and Seed Reproduction Techniques of a New Tetraploid Common Buckwheat Variety‘Pintianqiao 3’

[Objectives]This study was conducted to actively carry out the breeding of new tetraploid common buckwheat varieties and its supporting breeding techniques.[Methods]Pintianqiao 3 is a new tetraploid common buckwheat variety developed by College of Agriculture of Shanxi Agricultural University and Agricultural Genetic Resources Center of Shanxi Agricultural University,using‘Pintianqiao 1’as the parent,through mutation treatment with 0.2%colchicine aqueous solution,grain selection,plant selection,isolation and identification,variety comparison,regional test and field investigation.The variety has chromosomes 2n=4X=32,and shows a spring sowing period of 101 d and a summer sowing period of 80 d,large flowers and seeds(with a 1000-grain weight of 41.4 g),and good resistance to lodging.[Results]From 2021 to 2022,Pintianqiao 3 participated in the independent joint regional test of common buckwheat varieties in Shanxi Province,and the average yield in 10 test positions was 1.8 kg,equivalent to 1800 kg/hm^(2),which was 8.4%higher than the control.It passed the field investigation conducted by Shanxi provincial expert group for identification of non-major crop varieties in Dongyang and Kelan experimental sites on September 2-3,2022.On January 4,2024,it passed the preliminary examination of Shanxi Provincial Crop Variety Approval Committee.The seed reproduction technique of Pintianqiao 3 including land selection,preparation before sowing,sowing,field management and timely harvesting has been developed.[Conclusions]This study provides technical support for the demonstration and popularization of this new variety.

Seed Storability in Rice: Physiological Foundations, Molecular Mechanisms, and Applications in Breeding

Long-term storage of crop seeds is critical for the conservation of germplasm resources, ensuring food supply, and supporting sustainable production. Rice, as a major food staple, has a substantial stock for consumption and production worldwide. However, its food value and seed viability tend to decline during storage. Understanding the physiological responses and molecular mechanisms of aging tolerance forms the basis for enhancing seed storability in rice. This review outlines the latest progress in influential factors, evaluation methods, and identification indices of seed storability. It also discusses the physiological consequences, molecular mechanisms, and strategies for breeding aging-tolerant rice in detail. Finally, it highlights challenges in seed storability research that require future attention. This review offers a theoretical foundation and research direction for uncovering the mechanisms behind seed storability and breeding aging-tolerant rice.