Introgression Of Genes Research Articles

Genetic Diversity of Korean Wild Soybean Core Collections and Genome-Wide Association Study for Days to Flowering.

The utilization of wild soybean germplasms in breeding programs increases genetic diversity, and they contain the rare alleles of traits of interest. Understanding the genetic diversity of wild germplasms is essential for determining effective strategies that can improve the economic traits of soybeans. Undesirable traits make it challenging to cultivate wild soybeans. This study aimed to construct a core subset of 1467 wild soybean accessions of the total population and analyze their genetic diversity to understand their genetic variations. Genome-wild association studies were conducted to detect the genetic loci underlying the time to flowering for a core subset collection, and they revealed the allelic variation in E genes for predicting maturity using the available resequencing data of wild soybean. Based on principal component and cluster analyses, 408 wild soybean accessions in the core collection covered the total population and were explained by 3 clusters representing the collection regions, namely, Korea, China, and Japan. Most of the wild soybean collections in this study had the E1e2E3 genotype according to association mapping and a resequencing analysis. Korean wild soybean core collections can provide helpful genetic resources to identify new flowering and maturity genes near the E gene loci and genetic materials for developing new cultivars, facilitating the introgression of genes of interest from wild soybean.

Genetic Diversity of Global Faba Bean Germplasm Resources Based on the 130K TNGS Genotyping Platform

Novel germplasm resources are the key to crop breeding, with their genetic diversity and population structure analysis being highly significant for future faba bean breeding. We genotyped 410 global faba bean accessions using the 130K targeted next-generation sequencing (TNGS) genotyping platform, resulting in a total of 38,111 high-quality SNP loci by high-standard filtering. We found the polymorphism information content (PIC) and Nei’s gene diversity were 0.0905–0.3750 and 0.0950–0.5000, with averages of 0.2471 and 0.3035, respectively. After evaluating the genetic diversity of 410 accessions using Nei’s gene diversity and PIC, on the basis of their geographical origin (continent) and structure-analysis-inferred subpopulations, we found that the faba bean accessions from Asia (except China) and Europe had rich genetic diversity, while those from the winter sowing area of China were low. The 410 faba bean accessions were divided into four subpopulations according to population structure analysis and clustering analysis based on Nei’s (1972) genetic distance using the neighbor-joining (NJ) method. However, the same subpopulation contained materials from different geographical origins, thereby indicating that the gene flow or introgression occurred among the accessions. Results from NJ clustering based on shared allele genetic distance indicated that the 410 accessions were divided into three groups according to their dissemination routes. The genetic diversity analysis results demonstrated that the genetic relationships among the faba bean groups with similar ecological environments and geographic origins in neighboring regions or countries were closer and frequently found within the same group, while genetic variation among individuals was the main source of their total genetic variation.

The Prospects of gene introgression from crop wild relatives into cultivated lentil for climate change mitigation.

Crop wild relatives (CWRs), landraces and exotic germplasm are important sources of genetic variability, alien alleles, and useful crop traits that can help mitigate a plethora of abiotic and biotic stresses and crop yield reduction arising due to global climatic changes. In the pulse crop genus Lens, the cultivated varieties have a narrow genetic base due to recurrent selections, genetic bottleneck and linkage drag. The collection and characterization of wild Lens germplasm resources have offered new avenues for the genetic improvement and development of stress-tolerant, climate-resilient lentil varieties with sustainable yield gains to meet future food and nutritional requirements. Most of the lentil breeding traits such as high-yield, adaptation to abiotic stresses and resistance to diseases are quantitative and require the identification of quantitative trait loci (QTLs) for marker assisted selection and breeding. Advances in genetic diversity studies, genome mapping and advanced high-throughput sequencing technologies have helped identify many stress-responsive adaptive genes, quantitative trait loci (QTLs) and other useful crop traits in the CWRs. The recent integration of genomics technologies with plant breeding has resulted in the generation of dense genomic linkage maps, massive global genotyping, large transcriptomic datasets, single nucleotide polymorphisms (SNPs), expressed sequence tags (ESTs) that have advanced lentil genomic research substantially and allowed for the identification of QTLs for marker-assisted selection (MAS) and breeding. Assembly of lentil and its wild species genomes (~4Gbp) opens up newer possibilities for understanding genomic architecture and evolution of this important legume crop. This review highlights the recent strides in the characterization of wild genetic resources for useful alleles, development of high-density genetic maps, high-resolution QTL mapping, genome-wide studies, MAS, genomic selections, new databases and genome assemblies in traditionally bred genus Lens for future crop improvement amidst the impending global climate change.

Genetic changes in the genus Vitis and the domestication of vine.

The genus Vitis belongs to the Vitaceae family and is divided into two subgenera: Muscadinia and Vitis, the main difference between these subgenera being the number of chromosomes. There are many hypotheses about the origin of the genus, which have been formed with archaeological studies and lately with molecular analyses. Even though there is no consensus on the place of origin, these studies have shown that grapes have been used by man since ancient times, starting later on its domestication. Most studies point to the Near East and Greece as the beginning of domestication, current research suggests it took place in parallel in different sites, but in all cases Vitis vinifera (L.) subsp. sylvestris [Vitis vinifera (L.) subsp. sylvestris (Gmelin) Hagi] seems to be the species chosen by our ancestors to give rise to the now known Vitis vinifera (L.) subsp. vinifera [=sativa (Hegi)= caucasica (Vavilov)]. Its evolution and expansion into other territories followed the formation of new empires and their expansion, and this is where the historical importance of this crop lies. In this process, plants with hermaphrodite flowers were preferentially selected, with firmer, sweeter, larger fruits of different colors, thus favoring the selection of genes associated with these traits, also resulting in a change in seed morphology. Currently, genetic improvement programs have made use of wild species for the introgression of disease resistance genes and tolerance to diverse soil and climate environments. In addition, the mapping of genes of interest, both linked to agronomic and fruit quality traits, has allowed the use of molecular markers for assisted selection. Information on the domestication process and genetic resources help to understand the gene pool available for the development of cultivars that respond to producer and consumer requirements.

The broad use of the Pm8 resistance gene in wheat resulted in hypermutation of the AvrPm8 gene in the powdery mildew pathogen

BackgroundWorldwide wheat production is under constant threat by fast-evolving fungal pathogens. In the last decades, wheat breeding for disease resistance heavily relied on the introgression of chromosomal segments from related species as genetic sources of new resistance. The Pm8 resistance gene against the powdery mildew disease has been introgressed from rye into wheat as part of a large 1BL.1RS chromosomal translocation encompassing multiple disease resistance genes and yield components. Due to its high agronomic value, this translocation has seen continuous global use since the 1960s on large growth areas, even after Pm8 resistance was overcome by the powdery mildew pathogen. The long-term use of Pm8 at a global scale provided the unique opportunity to study the consequences of such extensive resistance gene application on pathogen evolution.ResultsUsing genome-wide association studies in a population of wheat mildew isolates, we identified the avirulence effector AvrPm8 specifically recognized by Pm8. Haplovariant mining in a global mildew population covering all major wheat growing areas of the world revealed 17 virulent haplotypes of the AvrPm8 gene that grouped into two functional categories. The first one comprised amino acid polymorphisms at a single position along the AvrPm8 protein, which we confirmed to be crucial for the recognition by Pm8. The second category consisted of numerous destructive mutations to the AvrPm8 open reading frame such as disruptions of the start codon, gene truncations, gene deletions, and interference with mRNA splicing. With the exception of a single, likely ancient, gain-of-virulence mutation found in mildew isolates around the world, all AvrPm8 virulence haplotypes were found in geographically restricted regions, indicating that they occurred recently as a consequence of the frequent Pm8 use.ConclusionsIn this study, we show that the broad and prolonged use of the Pm8 gene in wheat production worldwide resulted in a multitude of gain-of-virulence mechanisms affecting the AvrPm8 gene in the wheat powdery mildew pathogen. Based on our findings, we conclude that both standing genetic variation as well as locally occurring new mutations contributed to the global breakdown of the Pm8 resistance gene introgression.

Isolation, characterization, and functional verification of salt stress response genes of NAC transcription factors in Ipomoea pes-caprae.

Adverse environmental stress is a major environmental factor threatening food security, which is why improving plant stress resistance is essential for agricultural productivity and environmental sustainability. The NAC (NAM, ATAF, and CUC) transcription factors (TFs) play a dominant role in plant responses to abiotic and biotic stresses, but they have been poorly studied in Ipomoea pes-caprae. In this research, 12 NAC TFs, named IpNAC1-IpNAC12, were selected from transcriptome data. The homologous evolution tree divided IpNACs into four major categories, and six IpNACs were linearly associated with Arabidopsis ANAC genes. From the gene structures, protein domains, and promoter upstream regulatory elements, IpNACs were shown to contain complete NAC-specific subdomains (A-E) and cis-acting elements corresponding to different stress stimuli. We measured the expression levels of the 12 IpNACs under abiotic stress (salt, heat, and drought) and hormone treatment (abscisic acid, methyl jasmonate, and salicylic acid), and their transcription levels differed. IpNAC5/8/10/12 were located in the nucleus through subcellular localization, and the overexpressing transgenic Arabidopsis plants showed high tolerance to salt stress. The cellular Na+ homeostasis content in the mature and elongation zones of the four IpNAC transgenic sweetpotato roots showed an obvious efflux phenomenon. These conclusions demonstrate that IpNAC5/8/10/12 actively respond to abiotic stress, have significant roles in improving plant salt tolerance, and are important salt tolerance candidate genes in I. pes-caprae and sweetpotato. This study laid the foundation for further studies on the function of IpNACs in response to abiotic stress. It provides options for improving the stress resistance of sweetpotato using gene introgression from I. pes-caprae.

Response Surface Methodology for Optimization of Multiplex-PCR Protocols for Detection of TYLCV, TSWV and Fol Molecular Markers: Analytical Performance Evaluation.

Molecular markers linked to disease resistance genes which affect economically important crops are of great interest. In the case of tomato, a major focus on resistance breeding to multiple fungal and viral pathogens such as Tomato yellow leaf curl virus (TYLCV), Tomato spotted wilt virus (TSWV) and Fusarium oxysporum f. sp. lycopersici (Fol), have led to the introgression of several resistance genes; therefore, molecular markers have become important in molecular-assisted selection (MAS) of tomato varieties resistant to those pathogens. However, assays that allow simultaneous evaluation of resistant genotypes, such as multiplex PCR, need to be optimized and evaluated to demonstrate their analytical performance, as many factors can affect them. This work aimed to generate multiplex PCR protocols for the joint detection of the molecular markers associated with pathogen resistance genes in tomato plants that are sensitive, specific and repeatable. For the optimization a central composite design of a response surface methodology (RSM-CCD) was used. For analytical performance evaluation, specificity/selectivity and sensibility (limit of detection and dynamic range) were analyzed. Two protocols were optimized: the first one with a desirability of 1.00, contained two markers (At-2 and P7-43) linked to I- and I-3-resistant genes. The second one with a desirability of 0.99, contained markers (SSR-67, SW5 and P6-25) linked to I-, Sw-5-, and Ty-3-resistant genes. For protocol 1, all the commercial hybrids (7/7) were resistant to Fol, and for protocol 2, two hybrids were resistant to Fol, one to TSWV and one to TYLCV with good analytical performance. In both protocols, the varieties considered susceptible to the pathogens, no-amplicon or susceptible amplicons, were observed. The optimized multiplex PCR protocols showed dynamic ranges from 5.97 up to 161.3 ng DNA. The limit of detection was 17.92 ng and 53.76 ng DNA for protocols 1 and 2, respectively, giving 100% positive results in the test replicates. This method allowed to develop optimized multiplex PCR protocols with few assays which translates into less time and resources, without sacrificing method performance.

Historic samples reveal loss of wild genotype through domestic chicken introgression during the Anthropocene.

Human activities have precipitated a rise in the levels of introgressive gene flow among animals. The investigation of conspecific populations at different time points may shed light on the magnitude of human-mediated introgression. We used the red junglefowl Gallus gallus, the wild ancestral form of the chicken, as our study system. As wild junglefowl and domestic chickens readily admix, conservationists fear that domestic introgression into junglefowl may compromise their wild genotype. By contrasting the whole genomes of 51 chickens with 63 junglefowl from across their natural range, we found evidence of a loss of the wild genotype across the Anthropocene. When comparing against the genomes of junglefowl from approximately a century ago using rigorous ancient-DNA protocols, we discovered that levels of domestic introgression are not equal among and within modern wild populations, with the percentage of domestic ancestry around 20-50%. We identified a number of domestication markers in which chickens are deeply differentiated from historic junglefowl regardless of breed and/or geographic provenance, with eight genes under selection. The latter are involved in pathways dealing with development, reproduction and vision. The wild genotype is an allelic reservoir that holds most of the genetic diversity of G. gallus, a species which is immensely important to human society. Our study provides fundamental genomic infrastructure to assist in efforts to prevent a further loss of the wild genotype through introgression of domestic alleles.

The Bph45 Gene Confers Resistance against Brown Planthopper in Rice by Reducing the Production of Limonene.

Brown planthopper (BPH), a monophagous phloem feeder, consumes a large amount of photoassimilates in rice and causes wilting. A near-isogenic line 'TNG71-Bph45' was developed from the Oryza sativa japonica variety 'Tainung 71 (TNG71) carrying a dominant BPH-resistance locus derived from Oryza nivara (IRGC 102165) near the centromere of chromosome 4. We compared the NIL (TNG71-Bph45) and the recurrent parent to explore how the Bph45 gene confers BPH resistance. We found that TNG71-Bph45 is less attractive to BPH at least partially because it produces less limonene. Chiral analysis revealed that the major form of limonene in both rice lines was the L-form. However, both L- and D-limonene attracted BPH when applied exogenously to TNG71-Bph45 rice. The transcript amounts of limonene synthase were significantly higher in TNG71 than in TNG71-Bph45 and were induced by BPH infestation only in the former. Introgression of the Bph45 gene into another japonica variety, Tainan 11, also resulted in a low limonene content. Moreover, several dominantly acting BPH resistance genes introduced into the BPH-sensitive IR24 line compromised its limonene-producing ability and concurrently decreased its attractiveness to BPH. These observations suggest that reducing limonene production may be a common resistance strategy against BPH in rice.

Study of the Genetic Diversity of Some Wild Sunflower Species Using ISSR Markers

Wild sunflower species are adapted to diverse habitats and possess considerable variability for biotic and abiotic traits, therefore wild germplasm can be a real source for improving the narrow genetic base of the cultivated sunflower crop by introgression of new genes which were previously identified in wild genotypes. In order to effectively exploit these genes in cultivated genotypes, researchers need more information regarding the quantity and distribution of the genetic variability available within the wild sunflower species, which can offer a multitudine of valuable traits for traditional or molecular breeding. This study was conducted to reveal the genetic diversity of wild and cultivated sunflower genotypes using ISSR markers. From a total of 19 ISSR markers, which were used to evaluate the genetic diversity, eight markers (UBC808, UBC823, UBC834, UBC836, UBC840, UBC845, UBC853, 17899A) clearly differentiated the wild sunflower genotypes from the wild sunflower and/or the cultivated sunflower. The primers amplified a total of 120 alleles ranging from 10 to 22 alleles per marker. A wide range of fragment length was detected among the accessions, from 140 to over 1500 bp. The neighbor-joining dendrogram, based on Rogers genetic distance, of the genotypes studied consisted of two main clusters of different sizes: five entries were grouped into cluster A and the remaining six entries were grouped into cluster B. It is interesting that genotypes of Helianthus anuus L., Helianthus maximiliani and Helianthus argophyllus were clustered together. Another aspect observed, refers to interspecific variability for Helianthus debilis genotypes. Regarding the PCA, the first two principal axes accounted for 26.8% (CP1) and 16.1% (CP2) of the total variation, respectively, together explaining 42.9% of the total variability. In the future, this molecular genetic information can be combined with morphological and biochemical data to improve the sunflower breeding program.

Inheritance for tolcv and eb resistance in tomato using S. Habrochaites and S. Pimpinellifolium

) have been utilized for introgression of ToLCV and EB resistant gene into 12 susceptible cultivars bearing good yield traits. Most of the crosses of EC-520060 exhibited 13 (resistant): 3 (susceptible) genetic ratio but ‘Flora Dade × EC-520060’ expressed 3:1 genetic ratio. The crosses of EC-521080 have diverse genetic ratio of 1:2:1, 3:1 and 1:3. In result of inheritance of EB, the crosses of EC-520060 revealed 3:1 genetic ratio, and the crosses of EC-521080 represented 1:3, 1:2:1 and 3:1 genetic ratio. The crosses of EC-520060 and EC-521080 showed additive, dominance × dominance and additive × additive genetic models for both ToLCV and EB diseases. The inheritance among crosses and genetics of variables can be utilized for improvement of resistant tomato.

Caracterização molecular de acessos de feijão comum por meio de marcadores microssatélites

ABSTRACT The common bean, a legume of significant economic importance, is renowned for its extensive genetic variability. It is crucial to comprehend genetic diversity, analyze population structure, and understand relationships among commercial classes of accessions to facilitate genetic improvement. This study aimed to molecularly characterize 143 common bean accessions by employing 25 SSR molecular markers. The objectives were to estimate genetic diversity, analyze genetic structure, and cluster populations using the UPGMA and PCoA methods. A total of 105 alleles were amplified using microsatellite loci, and the observed heterozygosity was lower than expected across all loci, indicating inbreeding within the populations. Among the loci, 22 were highly informative, demonstrating their effectiveness and polymorphism in detecting genetic diversity. The genetic variability within the population was found to be the highest, while variation between populations was the lowest. The analysis of population structure revealed the presence of three populations with a notable rate of gene introgression. The UPGMA analysis categorized the accessions into 15 groups, but they did not form distinct clusters based on their geographic regions or gene pool. The first two principal coordinates accounted for 13.95% of the total variation among the accessions. The SSR markers employed effectively detected genetic variability among the common bean accessions, revealing that their genetic diversity was not correlated with their geographic distribution in this study.

Resistance to Pythium root rot and anthracnose among Kenyan common bean genotypes and marker-assisted introgression of resistance genes

ABSTRACT Common bean (Phaseolus vulgaris L.) is an important food legume crop and major protein source in Kenya and many parts of the world. However, the yields are low due to the diseases like anthracnose caused by Colletotrichum lindemunthianum and Pythium root rots. The study, therefore, sought to screen Kenyan common bean genotypes for anthracnose and Pythium resistance and to improve the resistance of local landraces to the two diseases. Local landraces and commercial cultivars were screened for resistance under greenhouse conditions for Pythium and in vitro for anthracnose. The results showed that majority of the landraces were moderately resistant to anthracnose and Pythium root rot. The study further utilized molecular markers linked to anthracnose and Pythium resistance, respectively, to determine their potential to detect specific resistance genes among the test genotypes. None of the markers amplified the test genotypes except the control genotypes pointing toward different resistance genes. Further, cultivars G2333 and KK8 were used as donor parents for anthracnose and Pythium resistance, respectively, in a marker-assisted backcross breeding program involving three high-yielding farmer-preferred landraces. A number of lines were developed that carry both resistance genes. These lines can be advanced for release as new cultivars to enhance common bean production in Kenya.

Screening microsatellite markers for establishing parental polymorphism in Indian rice (Oryza sativa L.)

The experiment was conducted to investigate the parental diversity along the rice genome and to understand and screen out the SSR markers-indicated polymorphism between two indica rice (Oryza sativa L.) cultivars. Namely K343, the most well-liked rice variety in the hill zone of the Jammu Region, and RML22, a rice line created at IRRI, Philippines. The study is to select polymorphic markers (Simple Sequence Repeat- SSR) associated with hill ecologies rice cultivars and additional research projects like gene pyramiding and background selection to recover the recurrent parent genome (RPG) in blast gene introgression in elite lines. 450 SSR markers, evenly distributed throughout the rice genome, were used to assess the parental polymorphism between these genotypes. Of these two cultivars, 51 markers (11.33%) showed polymorphism with bands in different spectrums throughout the genome. The study has been used to Marker Assisted Backcross (MAB) breeding to integrate rice blast resistance genes in the parental genotype. The pool of polymorphic markers has the potential to use in similar studies and work, with a high probability of polymorphism for the cultivars of hill ecologies, and thus increase the chance of selection of probability in marker selection.

Biomimetic Strategies for Developing Abiotic Stress-Tolerant Tomato Cultivars: An Overview

The tomato is one of the most important vegetables in the world. The demand for tomatoes is high in virtually any country, owing to their gastronomic versatility and nutritional and aromatic value. Drought, salinity, and inadequate temperature can be major factors in diminishing yield, affecting physiological and biochemical processes and altering various metabolic pathways, from the aggregation of low molecular-weight substances to the transcription of specific genes. Various biotechnological tools can be used to alter the tomato genes so that this species can more rapidly or better adapt to abiotic stress. These approaches range from the introgression of genes coding for specific enzymes for mitigating a prevailing stress to genetic modifications that alter specific metabolic pathways to help tomato perceive environmental cues and/or withstand adverse conditions. In recent years, environmental and social concerns and the high complexity of the plant response may increase the attention of applied plant biotechnology toward biomimetic strategies, generally defined as all the approaches that seek to develop more sustainable and acceptable strategies by imitating nature's time-tested solutions. In this review, we provide an overview of some of the genetic sequences and molecules that were the objects of biotechnological intervention in tomato as examples of approaches to achieve tolerance to abiotic factors, improving existing nature-based mechanisms and solutions (biomimetic biotechnological approaches (BBA)). Finally, we discuss implications and perspectives within the GMO debate, proposing that crops modified with BBA should receive less stringent regulation.

Marker assisted backcrossing of alcobaca gene into two elite tomato breeding lines

Tomato is one of the most important vegetable crops cultivated and consumed worldwide. Demand is increasing daily because of increase in per capita fresh fruit consumption. Despite the economic importance of tomato, it has relatively short shelf-life after ripening and experiences remarkable post-harvest losses. This study was aimed at using marker-assisted backcrossing (MABC) to transfer shelf-life gene (alc) into the genetic background of two elite Ghanaian tomato breeding lines. The MABC derived lines at BC2F3 were evaluated to confirm selections using molecular markers. All the MABC-derived lines gave significant extended shelf life compared to the checks except for Alc-LA3134, the alc donor parent, which was, however, not significantly different from one of the backcrosses (BC2F2.3-E-80-19-26). This confirms that the genetic regulation of the shelf-life trait is dependent on the alc gene. The performance of the donor check (Alc-LA3134) against the 12 MABC-derived lines indicated no significant differences for the fruit firmness (except for BC2F2.3-E-80-19-4), number of locules per fruit and shelf life (for only BC2F2.3-E-80-19-26), thus suggesting similar backgrounds of the MABC as the recurrent parents. A considerable increase in the shelf-life value was observed among the MABC-derived lines. The introgression of the alc gene into cultivated tomatoes for extended shelf-life could reduce post-harvest losses of tomato in Ghana.

Assessment of seedling traits of rice landraces under different saline conditions

Salinity is one of the major abiotic stresses affecting rice growth and yield worldwide. In rice, the most critical stages which affect salinity at a greater level are germination, vegetative and reproductive stages.It is very important to know the genotypic variation among landraces under saline conditions at the seed germination stage to reduce the harmful effect of salinity. The present study conducted on Petri plate was mainly for assessing germination, relative water content and seedling parameters of eleven rice landraces with check landrace Pokali under three different salt concentrations (75mM, 125mM and 150mM). Two-way ANOVA gave the variations among the genotypes, treatments and their interactions. The present study showed that Mundan, Odiyan, Muttadan, Kallimadiyan and Vellimuthu had less percentage reduction in growth parameters at the germination stage. Odiyan and Mundan showed less percentage reduction in fresh weight (36.09%) and shoot length (25.61%) respectively, in relative water content (10.70% and 16.07%, respectively) at higher concentrations of salinity (150mM) compared to control. Pokali, Chembakam and Odiyan showed good germination parameters under three different saline treatments compared to other genotypes. Biplot analysis showed 65.4% variation between the treatments, whereas the variation between the genotypes was around 13.3%. Screening of landraces for salinity tolerance at the seed germination stage is the most reliable method to identify the salt tolerant line at the early seedling stage. The present study can be used for further screening programme at the vegetative stage for the identification of potential salt tolerant lines to improve breeding and gene introgression studies.

THE INFLUENCE OF ALIEN GENES OF RESISTANCE TO COMMON DISEASES ON AGRONOMIC CHARACTERISTICS OF BREAD WINTER WHEAT IN THE DRY CONDITIONS OF SOUTHERN UKRAINE

Abstract Introduction. A combination of fungal diseases and drought can cause significant yield losses of winter wheat (Triticum aestivum L.). It is known that alien traits introduced through wide hybridisation into wheat genome contribute to breeding of cultivars with a higher yield potential in arid environments. Aim. The impact of alien genes of resistance to widespread diseases and morphological characters on the main agronomic traits in the arid environments of the Southern Steppe of Ukraine was analysed. Methods. The lines were grown in a control nursery designed in 5 and 10 m2 plots on the black earth area in the 2019–2021 vegetative periods consecutively under the arid system without irrigation. The plant material included 153 experimental wheat lines of different origin with six check cultivars for the arid climate zone of Ukraine. The data on eight agronomic (quantitative scores) and six plant pathological (point scores) traits were collected and subjected to statistical analysis to comprehend the contribution of the diversity and connections between the characters. Results. Due to the successful introgression of alien genes from all sources involved in hybridisation, the majority of lines were resistant to one of the rust species. The lines derived from the sample containing the translocation 1BL.1RS in the karyotype and Triticum timopheevii Zhuk. in the pedigree were resistant to all rust species. The lines containing the alien genes Lr42 and Hs showed a higher yield than the recurrent cultivar and standard ones. There was a negative correlation between the protein content and grain yield in 2020 (r = −0.40***). A weak positive correlation was found between the yield and resistance to yellow rust (Rsp = 0.19* in 2019 and Rsp = 0.26*** in 2020) or tolerance to Septoria leaf blotch (Rsp = 0.14 in 2019 and Rsp = 0.27*** in 2020). Under drought conditions, the yield reduced by 32.5% in 2020 and by 70% in 2021. The drought resistance index directly correlated with the yield in the dry conditions of 2020 (r = 0.69***), and also was inversely proportional to the yield values (r = −0.26**) obtained in favorable conditions. Conclusions. The studied experimental lines have a potential for use in the wheat improvement programs for resistance to the diseases in Southern Ukraine. For further breeding, eighteen lines with a high weight of 1000 kernels, protein content, and yield, and resistance to drought or disease were identified, and four promising drought-tolerant lines have been selected.

Dwarf Tomato Plants Allow for Managing Agronomic Yield Gains with Fruit Quality and Pest Resistance through Backcrossing

Increased productivity, nutritional quality, and pest resistance have been primary breeding goals. However, managing such increases in a genotype is challenging. In this context, gene introgression using dwarf plants is an alternative; however, there are no dwarf Santa Cruz tomato varieties for direct use in breeding programs. Therefore, the objective of this study was to improve fruit quality and pest resistance through successive backcrossing of dwarf Santa Cruz tomato populations with agronomic potential. Six and 13 dwarf tomato populations obtained from the first and second backcrossing, respectively, the donor parent, and the commercial cultivar ‘Santa Clara’ as the check, totalling 21 treatments, were evaluated. Univariate analysis and computational intelligence were used to evaluate the best genotypes. All agronomic variables showed significant and progressive increases after the first and second backcrossing. The highlighted BC2 populations were Sci#16.1-2, Sci#25.1,1-2, Sci#25.1,2-2, Sci#3.1,1-2, Sci#3.1,2-2, Sci#8.3,1-2, and Sci#8.3,2-2, with significant increases in mean fruit weight, pulp thickness, fruit length and diameter, and acyl sugar content. The selected BC2 populations can be used as male parents to obtain normal hybrids to achieve increased productivity, nutritional quality, and a broader spectrum of pest resistance owing to the presence of acyl sugars in the leaflets.

High heterogeneity in genomic differentiation between phenotypically divergent songbirds: a test of mitonuclear co-introgression.

Comparisons of genomic variation among closely related species often show more differentiation in mitochondrial DNA (mtDNA) and sex chromosomes than in autosomes, a pattern expected due to the differing effective population sizes and evolutionary dynamics of these genomic components. Yet, introgression can cause species pairs to deviate dramatically from general differentiation trends. The yellowhammer (Emberiza citrinella) and pine bunting (E. leucocephalos) are hybridizing avian sister species that differ greatly in appearance and moderately in nuclear DNA, but that show no mtDNA differentiation. This discordance is best explained by adaptive mtDNA introgression-a process that can select for co-introgression at nuclear genes with mitochondrial functions (mitonuclear genes). To better understand these discordant differentiation patterns and characterize nuclear differentiation in this system, we investigated genome-wide differentiation between allopatric yellowhammers and pine buntings and compared it to what was seen previously in mtDNA. We found significant nuclear differentiation that was highly heterogeneous across the genome, with a particularly wide differentiation peak on the sex chromosome Z. We further investigated mitonuclear gene co-introgression between yellowhammers and pine buntings and found support for this process in the direction of pine buntings into yellowhammers. Genomic signals indicative of co-introgression were common in mitonuclear genes coding for subunits of the mitoribosome and electron transport chain complexes. Such introgression of mitochondrial DNA and mitonuclear genes provides a possible explanation for the patterns of high genomic heterogeneity in genomic differentiation seen among some species groups.