Improve Selection Efficiency Research Articles

Genetic mapping reveals complex architecture and candidate genes involved in common bean response to Meloidogyne incognita infection.

Root-knot nematodes (RKNs), particularly Meloidogyne incognita, are among the most damaging and prevalent agricultural pathogens due to their ability to infect roots of almost all crops. The best strategy for their control is through the use of resistant cultivars. However, laborious phenotyping procedures make it difficult to assess nematode resistance in breeding programs. For common bean, this task is especially challenging because little has been done to discover resistance genes or markers to assist selection. We performed genome-wide association studies and quantitative trait loci mapping to explore the genetic architecture and genomic regions underlying the resistance to M. incognita and to identify candidate resistance genes. Phenotypic data were collected by a high-throughput assay, and the number of egg masses and the root-galling index were evaluated. Complex genetic architecture and independent genomic regions were associated with each trait. Single nucleotide polymorphisms on chromosomes Pv06, Pv07, Pv08, and Pv11 were associated with the number of egg masses, and SNPs on Pv01, Pv02, Pv05, and Pv10 were associated with root-galling. A total of 216 candidate genes were identified, including 14 resistance gene analogs and five differentially expressed in a previous RNA sequencing analysis. Histochemical analysis indicated that reactive oxygen species might play a role in the resistance response. Our findings open new perspectives to improve selection efficiency for RKN resistance, and the candidate genes are valuable targets for functional investigation and gene editing approaches.

Deep Graph Convolutional Networks for Accurate Automatic Road Network Selection

The selection of road networks is very important for cartographic generalization. Traditional artificial intelligence methods have improved selection efficiency but cannot fully extract the spatial features of road networks. However, current selection methods, which are based on the theory of graphs or strokes, have low automaticity and are highly subjective. Graph convolutional networks (GCNs) combine graph theory with neural networks; thus, they can not only extract spatial information but also realize automatic selection. Therefore, in this study, we adopted GCNs for automatic road network selection and transformed the process into one of node classification. In addition, to solve the problem of gradient vanishing in GCNs, we compared and analyzed the results of various GCNs (GraphSAGE and graph attention networks [GAT]) by selecting small-scale road networks under different deep architectures (JK-Nets, ResNet, and DenseNet). Our results indicate that GAT provides better selection of road networks than other models. Additionally, the three abovementioned deep architectures can effectively improve the selection effect of models; JK-Nets demonstrated more improvement with higher accuracy (88.12%) than other methods. Thus, our study shows that GCN is an appropriate tool for road network selection; its application in cartography must be further explored.

History of development and results of selection of Solanaceae crops in FSBSI FSVC

The article presents a brief history of the establishment of the Laboratory of Plant Breeding and Seed Production of Solanaceae Crops of FSBSI FSVC. The process of development of tomato, pepper, eggplant and physalis breeding is shown from the beginning of the establishment until the present time. Practical selection of Solanaceae crops in FSBSI FSVC is directly connected with the name of Academician VASKhNIL A.V. Alpatyev, who is the founder of scientific research on thermophilic crops. On the basis of conducted scientific researches the technique of creation of cold-resistant, early-ripening cultivars of tomato was developed, including influence of certain conditions on parental forms and hybrid material from its first generations to increase adaptability to new, not characteristic conditions of selected material. Subsequently, this technique was applied to the breeding of sweet pepper, eggplant and physalis. Interspecific hybridisation was used to enrich the gene pool of Solanaceous crops. As a result of distant hybridization, the following cultivars were created: the original tomato cultivar Severyanin with large parthenocarpic fruits on 1 and 2 racemes; an anadrous mutant for use in breeding; ultra-rapid, short-stage forms for obtaining heterosis effect; the cultivar Vkusny with increased content of dry matter in fruits. On the basis of interspecific hybrid of Ph. ixocarpa x Ph. angulata, the cultivars Dessert and Lakomka, characterized by high yield and resistance to diseases, high content of sugars, pectin and absence of bitterness, are created. Types of pepper Capsicum chinense, C. frutescens and C. annuum were used to create resistant forms to viral diseases. Involvement of wild eggplant species (Solanum aethiopicum, S. macrocarpon) to the breeding process allowed to obtain hybrid combinations with flavonoids content 1,3 times higher and phenolcarboxylic acids 1,6–1,7 times higher than in S. melongena.The development of theoretical bases ofSolanaceae crops breeding for resistance to biotic and abiotic stressors, as well as for high quality production, allowed to create a series of cosmopolitan cultivars, which at present are in demand, both in production and as a source material. The current scientific priorities are to use innovative biotechnology and molecular marking methods to accelerate the breeding process and improve selection efficiency.

Improving Selection Efficiency of Crop Breeding With Genomic Prediction Aided Sparse Phenotyping.

Increasing the number of environments for phenotyping of crop lines in earlier stages of breeding programs can improve selection accuracy. However, this is often not feasible due to cost. In our study, we investigated a sparse phenotyping method that does not test all entries in all environments, but instead capitalizes on genomic prediction to predict missing phenotypes in additional environments without extra phenotyping expenditure. The breeders’ main interest – response to selection – was directly simulated to evaluate the effectiveness of the sparse genomic phenotyping method in a wheat and a rice data set. Whether sparse phenotyping resulted in more selection response depended on the correlations of phenotypes between environments. The sparse phenotyping method consistently showed statistically significant higher responses to selection, compared to complete phenotyping, when the majority of completely phenotyped environments were negatively (wheat) or lowly positively (rice) correlated and any extension environment was highly positively correlated with any of the completely phenotyped environments. When all environments were positively correlated (wheat) or any highly positively correlated environments existed (wheat and rice), sparse phenotyping did not improved response. Our results indicate that genomics-based sparse phenotyping can improve selection response in the middle stages of crop breeding programs.

Meta-QTL analysis and identification of candidate genes for quality, abiotic and biotic stress in durum wheat

The genetic improvement of durum wheat and enhancement of plant performance often depend on the identification of stable quantitative trait loci (QTL) and closely linked molecular markers. This is essential for better understanding the genetic basis of important agronomic traits and identifying an effective method for improving selection efficiency in breeding programmes. Meta-QTL analysis is a useful approach for dissecting the genetic basis of complex traits, providing broader allelic coverage and higher mapping resolution for the identification of putative molecular markers to be used in marker-assisted selection. In the present study, extensive QTL meta-analysis was conducted on 45 traits of durum wheat, including quality and biotic and abiotic stress-related traits. A total of 368 QTL distributed on all 14 chromosomes of genomes A and B were projected: 171 corresponded to quality-related traits, 127 to abiotic stress and 71 to biotic stress, of which 318 were grouped in 85 meta-QTL (MQTL), 24 remained as single QTL and 26 were not assigned to any MQTL. The number of MQTL per chromosome ranged from 4 in chromosomes 1A and 6A to 9 in chromosome 7B; chromosomes 3A and 7A showed the highest number of individual QTL (4), and chromosome 7B the highest number of undefined QTL (4). The recently published genome sequence of durum wheat was used to search for candidate genes within the MQTL peaks. This work will facilitate cloning and pyramiding of QTL to develop new cultivars with specific quantitative traits and speed up breeding programs.

Genetic Diversity and Heritability of Fruit Traits and Oil Content in Selected Almond Progenies and their Parents

Diversity is an essential issue for fruit crop breeding programs and improving selection efficiency. This study was targeted to investigate the genetic diversity and heritability of fruit parameters and oil content in almond progenies and their parents. The results exhibited notable genetic variation among the studied progenies and their parents. The highest phenotypic and genotypic variance coefficients were 13.05 and 11.18 for fruit length in in different genotypes, respectively. Also the highest broad sense heritability belonged to nut weight of genotype (0 and 89%). The lowest phenotypic and genotypic variance coefficients was 0.19 and 0.15, respectively, which was observed in kernel weight and the lowest broad sense heritability belonged to fruit thickness (68%). For oil content, which is important for qualitative improvement in breeding programs, there was a significant difference between examined progenies and their parents. Finally, in this study, it was found that some of the progenies were high in oil, for example, the hybrid A11-18 had 63.97% of oil that could be used in almond development programs.

Traffic form and season of wear affect responses of fine fescues

AbstractThe performance of fine fescue (Festuca spp.) species and cultivars may differ by traffic form or the season of wear simulation. Two trials were initiated in 2012 to evaluate the effect of traffic form (abrasive wear vs. cleated traffic) and season of wear (spring, summer, or autumn) on 10 fine fescues seeded in North Brunswick, NJ. Plots were visually assessed for the fullness of turfgrass canopy (FTC) and leaf bruising. Verdure and soil physical properties were assessed after the last assessment period in the traffic form trial. Abrasive wear constantly reduced the FTC (14–30%) of fine fescues compare to the non‐trafficked control, while the FTC of plots with cleated traffic was similar to the non‐trafficked control towards the end of the study. Although both traffic forms caused soil compaction, cleated traffic resulted in a more compacted soil. Abrasive wear improved selection efficiency for fine fescues compared to cleated traffic. The FTC response of fine fescues cultivars interacted with the season of wear; thus, screening for fine fescues with improved ability to withstand abrasive wear might be more effective and accurate during spring to avoid high disease pressure and other confounding stresses during summer. ‘Blueray’ and ‘Beacon’ hard fescue, ‘Quatro’ sheep fescue, and ‘Radar’ Chewings were more traffic tolerant than other fine fescue cultivars under low disease pressure. The propensity of fine fescues to bruising under wear needs to be assessed in both summer and autumn.

Identification and characterization of QTLs for fruit quality traits in peach through a multi-family approach

BackgroundFruit quality traits have a significant effect on consumer acceptance and subsequently on peach (Prunus persica (L.) Batsch) consumption. Determining the genetic bases of key fruit quality traits is essential for the industry to improve fruit quality and increase consumption. Pedigree-based analysis across multiple peach pedigrees can identify the genomic basis of complex traits for direct implementation in marker-assisted selection. This strategy provides breeders with better-informed decisions and improves selection efficiency and, subsequently, saves resources and time.ResultsPhenotypic data of seven F1 low to medium chill full-sib families were collected over 2 years at two locations and genotyped using the 9 K SNP Illumina array. One major QTL for fruit blush was found on linkage group 4 (LG4) at 40–46 cM that explained from 20 to 32% of the total phenotypic variance and showed three QTL alleles of different effects. For soluble solids concentration (SSC), one QTL was mapped on LG5 at 60-72 cM and explained from 17 to 39% of the phenotypic variance. A major QTL for titratable acidity (TA) co-localized with the major locus for low-acid fruit (D-locus). It was mapped at the proximal end of LG5 and explained 35 to 80% of the phenotypic variance. The new QTL for TA on the distal end of LG5 explained 14 to 22% of the phenotypic variance. This QTL co-localized with the QTL for SSC and affected TA only when the first QTL is homozygous for high acidity (epistasis). Haplotype analyses revealed SNP haplotypes and predictive SNP marker(s) associated with desired QTL alleles.ConclusionsA multi-family-based QTL discovery approach enhanced the ability to discover a new TA QTL at the distal end of LG5 and validated other QTLs which were reported in previous studies. Haplotype characterization of the mapped QTLs distinguishes this work from the previous QTL studies. Identified predictive SNPs and their original sources will facilitate the selection of parents and/or seedlings that have desired QTL alleles. Our findings will help peach breeders develop new predictive, DNA-based molecular marker tests for routine use in marker-assisted breeding.

Epitope-Imprinted Magnetic Nanoparticles as a General Platform for Efficient In Vitro Evolution of Protein-Binding Aptamers.

Aptamers are usually created by in vitro selection using a strategy termed systematic evolution of ligands by exponential enrichment (SELEX). Although numerous SELEX alternatives with improved selection efficiency have been developed, the overall success rate of SELEX at present is still not very ideal, which remains a great obstacle to aptamer-based research and application. In this study, an efficient and facile SELEX method was developed for in vitro screening of protein-binding aptamers, applying epitope-imprinted magnetic nanoparticles (MNPs) that exhibit highly favorable binding properties as a general affinity platform. As a proof of the principle, myoglobin (Mb) and β2-microglobulin were employed as two target proteins. Two satisfied aptamers toward each target protein, with the dissociation constant at the 10-8 M level and cross-reactivity less than 16.5%, were selected within three rounds, taking only 1 day. A dual aptamer-based fluorescence sandwich assay was constructed using a pair of the selected aptamers. The resulting assay allowed for quantitatively detecting Mb in human serum and distinguishing acute myocardial infarction patients from healthy individuals. The epitope-imprinted MNP-based SELEX is straightforward and generally applicable for a wide range of target proteins, providing a promising aptamer selection tool for aptamer-based research and real-world applications.

Improving selection efficiency in ornamental breeding

Improving selection efficiency in ornamental breeding

Estimation of the F2 generation segregation variance and relationships among growth, frost damage, and bud break in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) wide-crosses

Creation of second generation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) hybrids based on parents from geographically distant locations did not appreciably increase variance in height, frost damage and bud break. New and favorable trait combinations between height and the two adaptive traits were found in the F2 populations. Increased genetic variance and new trait combinations can improve selection efficiency in terms of selection response and increased adaptability. This project tested a novel method for generating higher genetic variance and new trait combinations in Douglas-fir populations. Parents from Southern British Columbia (BC), Washington (WA), Oregon (OR), and Northern BC (NBC) were crossed within each provenance; then selections from BC were crossed with the other sources to create three F1 interpopulation generations. Unrelated random selections from the same F1 population were subsequently crossed to produce three F2 populations. The parental, F1 and F2 generations were concurrently grown in three field tests and were evaluated for height, frost damage, and bud break date. Significant segregation variances were found only in the BCxNBC cross for height in two sites and frost damage in one site and in the BCxOR cross for bud break in one site. In the BCxNBC cross, correlations between breeding values for height and frost damage changed from 0.71 in F1 to − 0.04 in F2 and between height and bud break from − 0.71 to − 0.26. In the BC-OR cross, correlations between height and bud break changed from − 0.71 in F1 to − 0.49 in F2. Our results suggest that creation of wide-cross hybrids may not be very effective in increasing segregation variance in traditional tree improvement programs but in some cases may be considered to increase diversity of trait combinations.

Genetic Dissection of Grain Yield and Agronomic Traits in Maize under Optimum and Low-Nitrogen Stressed Environments.

Understanding the genetic basis of maize grain yield and other traits under low-nitrogen (N) stressed environments could improve selection efficiency. In this study, five doubled haploid (DH) populations were evaluated under optimum and N-stressed conditions, during the main rainy season and off-season in Kenya and Rwanda, from 2014 to 2015. Identifying the genomic regions associated with grain yield (GY), anthesis date (AD), anthesis-silking interval (ASI), plant height (PH), ear height (EH), ear position (EPO), and leaf senescence (SEN) under optimum and N-stressed environments could facilitate the use of marker-assisted selection to develop N-use-efficient maize varieties. DH lines were genotyped with genotyping by sequencing. A total of 13, 43, 13, 25, 30, 21, and 10 QTL were identified for GY, AD ASI, PH, EH, EPO, and SEN, respectively. For GY, PH, EH, and SEN, the highest number of QTL was found under low-N environments. No common QTL between optimum and low-N stressed conditions were identified for GY and ASI. For secondary traits, there were some common QTL for optimum and low-N conditions. Most QTL conferring tolerance to N stress was on a different chromosome position under optimum conditions.

English

Coffee supports livelihoods of approximately 125 million families worldwide and over 700,000 households in Kenya. The epidemics of Coffee berry disease (CBD), caused by Colletotrichum kahawae, destroy up to 80% of the developing berries on susceptible varieties. The control of the disease using chemicals accounts for 30 to 40% of the production cost and contributes to environment pollution, hence the use of resistant varieties. Resistance to CBD is conferred by three genes; R, T that are dominant and k which is recessive, from coffee varieties Rume Sudan (RS), Hibrido de Timor (HDT) and K7 respectively. Although the T gene has been mapped, there is need for genetic mapping of the other genes to improve selection efficiency. The objective of this study was to evaluate F2 populations of RS x SL28 for their suitability to genetic mapping of the R gene in RS. Resistance to CBD was evaluated by hypocotyl inoculation on their F3 progenies. The data was subjected to Analysis of Variance (ANOVA) and Chi Square (χ²) test. The ANOVA result showed significant differences (P≤0.05) between the genotypes to CBD resistance. The phenotypic ratio of resistance to susceptible plants fitted the 3:1 monohybrid inheritance ratio for a dominant gene using the χ² test (χ² = 1.0565 and P=0.30207, P≤0.05), hence confirming the suitability of the F2 populations for the identification of the DNA marker for R gene in RS. Key words: Rume Sudan, SL 28, Coffee Berry Disease, mapping population, hypocotyl, inoculation. &nbsp

Thermotolerance and Physiological Traits as Fast Tools to Heat Tolerance Selection in Experimental Sugarcane Genotypes

Heat stress limits the growth, development, and yield of crop plants when it occurs during short or long periods of time. An experiment was conducted with the objectives of (i) evaluating the cell membrane thermostability (CMT) as an indicator of heat tolerance in sugarcane and to determine its relationship with physiological parameters under heat-stressed conditions, and (ii) evaluating the utility of CMT for selecting heat-tolerant genotypes in a breeding program. A total of nine elite experimental, and four commercial sugarcane genotypes were evaluated for CMT, and the results are expressed as relative cell injury (RCI). Six genotypes were classified as highly tolerant and seven as highly sensitive. We concluded that the use of RCI, as an indicator of CMT in sugarcane genotypes, is a suitable useful parameter for selecting the genotypes tolerant to heat stress in a breeding program. This procedure, combined with other characters, helps to identify sugarcane plants with the ability to maintain a high yield photosynthetic rate under stressful field conditions. Furthermore, it offers an opportunity to improve selection efficiency over that of field testing, since high temperature stresses do not occur consistently under field conditions.

TeV Electrons and Positrons Measured by PAMELA Spectrometer

Abstract-The PAMELA magnetic spectrometer was launched onboard the Resurs-DK1 satellite to the Earth polar orbit with altitude of 350–600 km to study the fluxes of cosmic ray particles and antiparticles in a wide energy range. Starting science operation in July 2006, PAMELA spectrometer performed continuous observation without major interruption till January 2016 collected about 10 billion trigger events. New analysis included data for all period of observations in 2006–2016 with improved selection efficiency and it allows to extend measurements of total electron and positron flux in TeV region with better statistic accuracy. In this paper, the observed energy spectrum of electrons and positrons is presented and compared with the other modern measurements.

A Cost–Benefit Analysis of DNA Informed Apple Breeding

Incorporating DNA-informed breeding techniques can improve selection efficiency for desired traits as compared with conventional breeding methods that do not use DNA-informed techniques. Incorporation of DNA technologies requires additional costs associated with reagents, equipment, and labor. To elucidate the cost-effectiveness of DNA-informed breeding in perennial crops with multiple years per generation, we conducted a cost–benefit analysis examining incorporation of marker-assisted selection (MAS), a type of DNA-informed breeding, applied to an apple breeding program. Annual operational costs for a midwest apple breeding program were used to develop a simulation with inputs including itemized costs and per unit costs for procedures at each breeding program stage. Simulations compared costs of MAS breeding techniques to conventional breeding methods to identify the break-even point (BEP) where cost-savings associated with MAS equals the accrued additional costs. Additional sensitivity analyses were conducted to examine changes in laboratory costs, seedling maintenance costs, and seedling evaluation costs. We found the BEP for this program occurs when MAS results in a removal rate of 13.18%, and changes to other costs (i.e., maintenance costs) result in a smaller percent decrease to the overall program budget. Our findings are useful to perennial crop breeding programs in which managers are considering incorporating DNA-informed breeding techniques.

Aptamer Displacement Reaction from Live-Cell Surfaces and Its Applications.

The DNA strand displacement reaction has had sustained scientific interest in building complicated nucleic acid-based networks. However, extending the fundamental mechanism to more diverse biomolecules in a complex environment remains challenging. Aptamers bind with targeted biomolecules with high affinity and selectivity, thus offering a promising route to link the powers of nucleic acid with diverse cues. Here, we describe three methods that allow facile and efficient displacement reaction of aptamers from the living cell surface using complement DNA (cDNA), toehold-labeled cDNA (tcDNA), and single-stranded binding protein (SSB). The kinetics of the DNA strand displacement reaction is severely affected by complex physicochemical properties of the natural membrane. Toehold-mediated and SSB-mediated aptamer displacement exhibited significantly enhanced kinetics, and they completely removed the aptamer quickly to avoid a false signal caused by aptamer internalization. Because of its simplicity, aptamer displacement enabled detection of membrane protein post-translation and improved selection efficiency of cell-SELEX.

Electrochemical SELEX Technique for the Selection of DNA Aptamers against the Small Molecule 11-Deoxycortisol.

Aptamers have received considerable attention due to their numerous advantages as biorecognition receptors. However, the tediousness and high cost of the conventional selection process of aptamers remain major challenges that limit their widespread use. To overcome these limitations, here we designed a new electrochemical SELEX platform that enables a rapid, efficient, and cost-effective enrichment method for the identification of aptamers, particularly against small molecules. The selection platform is based on the immobilization of the target analyte on gold electrodes that leads to improved selection efficiency and enables in situ monitoring of the enriched DNA using square-wave voltammetry. Compared with the conventional SELEX method, this selection protocol avoids the use of beads as a solid matrix and fluorescently labeled DNA, which is usually required for small molecules, thus offering simplified aptamer/target incubation, washing, and elution steps. Moreover, the DNA recovery can be detected by simply measuring the current of the electrodes in a ferro/ferricyanide redox couple. This would eliminate the need for fluorescence labeling, which significantly reduces the cost of the procedure. The approach was successfully applied for the selection of high-affinity aptamers that bind specifically to the small molecule 11-deoxycortisol hormone using eight rounds. One of the selected aptamers that showed a dissociation constant at the subnanomolar level was used to construct a competitive voltammetric aptasensor exhibiting high sensitivity, selectivity against other steroid analogues, and possible applicability in serum samples. Thus this SELEX approach offers great promise for a faster, simpler, and more economic aptamer identification method for various targets including small molecules for a wide variety of applications.

Marker-assisted breeding of hexaploid spring wheat in the Canadian prairies

Bread wheat (Triticum aestivum L.) is an important crop and export commodity for Canada. Increased global population, demand for superior quality grains, and rapidly evolving pathogens have necessitated the breeding of high-yielding, disease-resistant wheat cultivars. Significant improvements in breeding efficiency can be made through advances in wheat genetics and genomics to develop tools that accelerate genetic gains in wheat. The identification of genes and quantitative trait loci for economically important traits and the development of associated molecular markers have the potential to improve selection efficiency. Marker-assisted selection enriches desirable allelic frequency, complements phenotypic data, and facilitates gene stacking. Molecular markers have been developed for various genes and quantitative trait loci conferring resistance to leaf rust, stripe rust, stem rust, Fusarium head blight, loose smut, common bunt, leaf spot, wheat blossom midge, and wheat stem sawfly. Markers are available for wheat grain and flour characteristics as well. Agronomic traits such as vernalization requirement, day-length sensitivity, and plant height can also be selected using molecular markers. Validated single nucleotide polymorphism based markers are a useful tool in breeding new wheat varieties for the Canadian prairies. In the current review, we present a compilation of validated molecular markers that are polymorphic and potentially useful for Canadian wheat breeding.

Genetic Mapping With Allele Dosage Information in Tetraploid Urochloa decumbens (Stapf) R. D. Webster Reveals Insights Into Spittlebug (Notozulia entreriana Berg) Resistance.

Urochloa decumbens (Stapf) R. D. Webster is one of the most important African forage grasses in Brazilian beef production. Currently available genetic-genomic resources for this species are restricted mainly due to polyploidy and apomixis. Therefore, crucial genomic-molecular studies such as the construction of genetic maps and the mapping of quantitative trait loci (QTLs) are very challenging and consequently affect the advancement of molecular breeding. The objectives of this work were to (i) construct an integrated U. decumbens genetic map for a full-sibling progeny using GBS-based markers with allele dosage information, (ii) detect QTLs for spittlebug (Notozulia entreriana) resistance, and (iii) seek putative candidate genes involved in defense against biotic stresses. We used the Setaria viridis genome a reference to align GBS reads and selected 4,240 high-quality SNP markers with allele dosage information. Of these markers, 1,000 were distributed throughout nine homologous groups with a cumulative map length of 1,335.09 cM and an average marker density of 1.33 cM. We detected QTLs for resistance to spittlebug, an important pasture insect pest, that explained between 4.66 and 6.24% of the phenotypic variation. These QTLs are in regions containing putative candidate genes related to defense against biotic stresses. Because this is the first genetic map with SNP autotetraploid dosage data and QTL detection in U. decumbens, it will be useful for future evolutionary studies, genome assembly, and other QTL analyses in Urochloa spp. Moreover, the results might facilitate the isolation of spittlebug-related candidate genes and help clarify the mechanism of spittlebug resistance. These approaches will improve selection efficiency and accuracy in U. decumbens molecular breeding and shorten the breeding cycle.