Interspecific Crosses Research Articles

Intersectional Hybrids of the Relict Species, Box Huckleberry (Gaylussacia brachycera), with Dwarf Huckleberry (Gaylussacia dumosa)

Gaylussacia brachycera (box huckleberry) is a unique relict species and is the monospecific member of Gaylussacia sect. Vitis-idaea. As part of investigations to understand interspecific crossability in Gaylussacia, pollinations were made between evergreen 2x G. brachycera and deciduous 2x G. dumosa (dwarf huckleberry). The primary pollinations succeeded at a low level and produced four viable hybrids. Three of these hybrids had box huckleberry as the female, and one of them, dwarf huckleberry, as the female. Morphologically, these hybrids were distinct from the parents and were generally intermediate. The fertility of the hybrids was low, but one hybrid flowered sufficiently to allow collection of pollen and to backcross it as a male to box huckleberry. Four BC1 hybrids were produced from this cross. The F1 and BC1 hybrids were all verified using simple sequence repeat markers developed for the closely related genus Vaccinium. These hybrids are notable for being the first recorded hybrids of this rare species, G. brachycera, with any other Gaylussacia species, and these hybrids are expected to lead to a better understanding of species relationships both within Gaylussacia and between Gaylussacia and Vaccinium.

Genetic Variability and Association Studies for Morpho-floral Traits in Backcross Introgression Lines of Rice (Oryza sativa L.)

Background: Wild introgressions are pivotal in enriching the genetic diversity of cultivated varieties by introducing novel alleles beneficial for crop improvement. Understanding insights into genetic variability and association studies of morphological and floral traits are crucial for enhancing hybrid seed production in rice. Methods: 290 backcross introgression lines (BC4F2) from inter-specific cross of CRMS 32B (maintainer of male sterile line as low stigma exsertion recipient parent) cv. Oryza sativa with Oryza longistaminata (wild rice as high stigma exsertion donor parent) were assessed for 12 morpho-floral traits. The experiment was laid out in randomized complete block design (RCBD) at Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, during Kharif, 2019. Result: ANOVA results showed significant differences among lines for all examined traits. The phenotypic coefficient of variation (PCV) was slightly greater than genotypic coefficient of variation (GCV) for each trait. High PCV, GCV, heritability and genetic advance as percentage of mean were observed for dual stigma exsertion percentage (DSE%) and total stigma exsertion percentage (TSE%), whereas moderate to high values of these parameters were noted for single stigma exsertion percentage (SSE%), grain yield per plant (GYPP), effective tillers per plant (ETPP) and grains per panicle (GPP) traits. Most traits showed positive skewness, except traits SFP (spikelet fertility percentage), SSE% and TSE%. Most traits recorded leptokurtic kurtosis, whereas plant height (PH), GYPP and TSE% exhibited platykurtic kurtosis. TSE% displayed a highly significant positive association with SSE% and DSE%, while GYPP showed a significant positive correlation with ETPP and GPP, presenting a promising opportunity for simultaneous selection of these traits.

Hybridization and growth characteristics of interspecific crosses between Crassostrea hongkongensis and Crassostrea iredalei

Interspecific hybridization of oysters is a highly efficient breeding strategy that can produce commercially viable phenotypes. Crassostrea hongkongensis, the primary cultivar in southern China, faces increasing summer mortality risks and slow growth rates, which elevate commercial risks for farmers. C. iredalei, a commercially cultivated species in Southeast Asia, has been expanding its ecological niche northward in recent years, providing opportunities for interspecific hybridization with C. hongkongensis. This study conducted a 2 × 2 factorial cross between C. hongkongensis and C. iredalei (II: C. iredalei ♀ × C. iredalei ♂, HH: C. hongkongensis ♀ × C. hongkongensis ♂; IH: C. iredalei ♀ × C. hongkongensis ♂, HI: C. hongkongensis ♀ × C. iredalei ♂) and set up 6 salinity treatments (14, 17, 20, 23, 26 and 29 ppt) to explore the optimal salinity for embryo hatching. The results showed that the hybridization was successful, despite bidirectional fertilization and pronounced asymmetry in fertilization success. The optimal hatching salinity for C. iredalei and C. hongkongensis was 23 ppt and 17–20 ppt, respectively, while the optimal salinity for reciprocal hybrids was 20 ppt. Notably, the hatching rate of IH was lower than that of the control group at the optimal salinity. During the pelagic larval stage, hybrid larvae exhibited significant hybrid inferiority, with slower growth rates and higher mortality rates compared to intraspecific hybridization. It is worth noting that IH failed to overcome genetic incompatibility, resulting in complete mortality during the pelagic larval stage and failure to enter the growth stage. At the 360th day of the growth period, HI hybrids grown in Sanbaimen Sea exhibited significant hybrid vigor in shell height (15.65 %), and in Daya Bay Marine Biology Research Station, Chinese Academy of Sciences (MBRS), they showed significant single-parent hybrid advantages in shell height (28.44 %) and cumulative survival rate (58.11 %) compared to C. hongkongensis. In terms of gonadal development, HI hybrids were able to produce functional and viable gametes, although with some delay compared to their parents. The hybrid offspring inherited the phenotypic traits of their parents, with a grayish-yellow flesh color intermediate between the two oyster species. HI is a valuable genetic resource for oyster breeding, and its growth potential should be further explored to meet commercialization demands.

50 Awardee Talk: The role of non-traditional inheritance patterns among Bos indicus-Bos taurus crosses for global beef value chain considerations

Abstract Bos indicus-Bos taurus crosses have been effectively used in many production environments globally. Substantially higher amounts of hybrid vigor have been reported in these F1 crosses as compared with those involving only Bos taurus or only Bos indicus breeds. However, for many years, and in many environments, “unusual” aspects of calf growth have been documented among these crosses. Among F1 crosses, Bos indicus-sired calves (Bos indicus x Bos taurus) have birth weight 8 to 12 kg heavier than contemporary Bos taurus-sired calves (Bos taurus x Bos indicus); additionally, pronounced sexual dimorphism occurs where males may weigh 5 to 10 kg more than females from Bos indicus sires (Bos taurus dams) but 1 kg or less from Bos taurus sires (Bos indicus dams) in both natural service and embryo transfer calves. These reciprocal differences have been reported for fetal and placentome size mid gestation. Reciprocal differences in birth weight have also been reported among backcrosses and F2 calves, and also exist for longer gestation length from Bos indicus sires (Bos taurus dams). Increased birth weight and gestation length occur when more Bos indicus is present in the sire vs. the dam, and when Bos indicus influence is inherited through the sire vs. the dam. There is speculation that sex-specific genomic imprinting may be involved for reciprocal birth weight differences that are analogous to mouse interspecific crosses for litter weight. Reports of hybrid vigor retention among inter se matings after the F1 have been variable historically, and this variation may relate to how the foundational F1 parents were produced (Bos indicus- vs. Bos taurus-sired). Breed-of-origin haplotype on BTA5 has been shown to affect heifer pregnancy and rebreeding among F2 Nellore-Angus cows where Nellore-derived haplotypes had much lower performance compared with Angus-derived and hybrid haplotypes. Disproportionate calf sex has been reported among reciprocal F2 Nellore (Bos indicus)-Angus (Bos taurus) with 66.6% male calves from Nellore x Angus F1 sires. When retrospectively evaluating historical literature for reciprocal crosses, it appears that several instances occur with disproportionate calf sex percentage, and this phenomenon warrants further study. The extent that potential reciprocal differences may affect post-weaning growth and carcass traits has not been widely evaluated. Recent investigations have shown reciprocal F1 differences for some cell-mediated immune responses regarding T-lymphocyte proliferation, but no differences for humoral response. There needs to be additional research that completely characterizes the X chromosome of Bos indicus and Bos taurus origins and their roles for multiple production traits. There also needs to be more investigation of non-additive and parent-of-origin effects in genetic evaluations of Bos indicus-Bos taurus composites, particularly with desired first-generation breed percentage. Improved utilization of Bos indicus cattle and crosses will be instrumental in meeting global dietary protein demands.

Identification of Compounds That Contribute to Consumer Aroma Liking of Roasted American-European Hybrid Hazelnuts.

New interspecific hybrid hazelnut crosses between American (Corylus americana) and European (Corylus avellana) hazelnuts are being developed to support a commercial industry in the Midwest region of the United States. In this study, volatile compounds that impact consumer aroma liking of roasted hybrid hazelnuts (C. americana × C. avellana) were investigated by targeted and nontargeted GC/MS flavoromics. Chemical profiles from 10 roasted hybrid hazelnut samples were modeled with consumer aroma liking scores by orthogonal partial least-squares with good fit and predictive performance (R2 ≥ 0.92, Q2 ≥ 0.82, RMSECV = 0.2). Top ranked predictors positively correlated with liking included 12 aroma compounds and 4 profiled volatiles for the targeted and nontargeted methods, respectively. Sensory recombination testing of hazelnut samples with addition of the 12 predictive odorants was preferred by consumers (p < 0.001, Δ aroma liking = 2.2 on 9-point scale) and perceived as more roasty, nutty, and sweet compared to the control (p < 0.05). Addition of the 4 predictive volatiles at subthreshold levels also was preferred (p = 0.02) and perceived as less earthy and mushroom like than the control (p < 0.05).

Mixed models in the selection of interspecific crosses of Psidium spp. resistant to myrtle rust

Mixed models in the selection of interspecific crosses of Psidium spp. resistant to myrtle rust

Insight into the Morphological Diversification and Viral Disease Resistance in the Interspecific Crosses of Abelmoschus esculentus × Abelomsochus moschatus

Insight into the Morphological Diversification and Viral Disease Resistance in the Interspecific Crosses of Abelmoschus esculentus × Abelomsochus moschatus

Simultaneous extraction of tocochromanols and flavan-3-ols from the grape seeds: Analytical and industrial aspects

Grape processing generates large amounts of by-products, including seeds rich in hydrophilic and lipophilic antioxidants. This study demonstrates, for the first time, that subjecting grape seeds to a single ultrasound-assisted extraction (UAE) with aqueous ethanolic solutions yields both flavan-3-ols and tocochromanols in the final extract. Notably, the water content in ethanol significantly influences the extractability of tocochromanols more than flavan-3-ols. Solid-to-solvent ratios of 1:50 to 1:2 were tested for both analytical and industrial applications. A sustainable analytical approach for recovering flavan-3-ols and tocochromanols using 60% and 96.4% ethanol extractions was validated and employed to profile nineteen genotypes of lesser-studied interspecific grape crosses (Vitis spp.). Different genotypes showed a wide range of concentrations of tocopherols (1.6–6.3 mg/100 g), tocotrienols (1.0–17.4 mg/100 g), and flavan-3-ols (861–9994 mg/100 g). This indicated that the genetic background and maturity of the plant material are crucial factors from an industrial perspective due to the initial concentration of bioactive compounds. Finally, the study also discussed the fundamental aspects of hydrophobic antioxidant extractability from the lipid matrix with aqueous ethanol solutions and the limitations of the workflow, such as the non-extractable tocochromanols and their esters and the losses of these lipophilic antioxidants during extraction.

Unveiling the genetic landscape: Exploring the SSR-based genetic architecture and amino acid dissection of Gossypium barbadense and G. darwinii genomes

Genetic maps highlight the genome organization and structure but also provide the chance of tagging superior traits for crop improvement through marker-assisted selection. Amino acids are building blocks of proteins and perform crucial function in regulating the signaling of molecules involved in the development and growth of plants. Plant architecture also have an impact on crop productivity. In order to select elite cultivars for breeding and identification of favorable alleles and their functional properties, a deep understanding of genetic architecture and development of genetic map is essential. In present investigation, an interspecific cross of Gossypium barbadense XH-18 × G. darwinii 5-7 was made to develop a genetic map utilizing single sequence repeat markers for the dissection of amino acids involved in genetic architecture of G. barbadense and G. darwinii. We measured chromosomal distribution of 20 amino acids across the whole genome of both species. The map consists of 613 markers spread across all 26 chromosomes, covering 2371.4 cM of cotton genome with an average inter-marker distance of 9.35 cM. The marker number anchored on the chromosomes varied from 5 to 76 with an average of 23.57 on each chromosome. The Dt sub-genome had more markers (83.03%) than the At sub-genome (15.66%). Moreover, the longest chromosome was 143.387 cM, the shortest was 58.430 cM, and the average length was 91.207 cM. The Dt subgenome spans a greater genomic distance than the At subgenome. A sum of 21,035 genes were discovered, covering the complete genome of G. barbadense; G. darwinii and have been found to be involved in tRNA 3'-trailer cleavage, macromolecule modification, peptide deformylase activity, response to biotic stimulus and defense response. The minimum Glutamic acid (Glu), Histidine (His), and Lysine (Lys) were found on Chr.13 (0.00-17.74), Chr.02 (0.00-8.01), and Chr.06 (0.00-17.97), respectively found through chromosomal amino acid dissection. The genome-wide SSR interspecific genetic map of G. barbadense and G. darwinii is first of its kind, and studying chromosomal distribution of amino acids will set a landmark step to dissect the genome structure of G. darwinii.

The name for a well-known crop: Rumex kioviensis, a hybridogenous taxon derived from R. patientia × R. tianschanicus (Polygonaceae)

The new crops developed at the M.M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine in Kyiv from the initial artificial interspecific crosses Rumex patientia × R. tianschanicus are variously known in botanical and agricultural literature under the hybrid formula or informal names “Shchavnat”, “Hybrid Dock”, “Rumex K-1”, “Rumex OK-2”, or names of cultivars cv. ‘Kyivskyi Ultra’, cv. ‘Shpinat Uteusha’, cv. ‘Nastavnyk’, etc. A brief overview of the history of development of these cultivars is provided. These robust perennial plants are cultivated at present as spinach greens, fodder, and high-yield biomass producers for bioenergy applications in several European and other countries (Ukraine, the Czech Republic, Slovakia, Germany, Romania, etc.). Numerous agricultural, horticultural, and biotechnological publications about these new crops are now available, including various aspects of and data on their biochemistry, physiology, genetics, morphology, propagation, agrotechniques, biomass and biofuel production potential, nutritional value, etc. Also, these hybrid cultivars were reported in several regions of Central Europe as potentially invasive weeds escaped from cultivation. Considering the growing popularity of the Hybrid Dock as a green leaf vegetable, a biomass and biofuel producing crop (among other uses), and a potentially invasive alien, we think that a proper botanical name should be assigned to that taxon. Here it is described as a new hybridogenous species Rumex kioviensis Rakhmetov, A. Mosyakin &amp; Mosyakin. Diagnostic characters distinguishing this new taxon from its parent taxa and other related species are indicated. Some remaining taxonomic and nomenclatural problems regarding Asian taxa related to R. patientia are briefly discussed.

Vitis rotundifolia Genes Introgressed with RUN1 and RPV1: Poor Recombination and Impact on V. vinifera Berry Transcriptome.

Thanks to several Vitis vinifera backcrosses with an initial V. vinifera L. × V. rotundifolia (previously Muscadinia rotundifolia) interspecific cross, the MrRUN1/MrRPV1 locus (resistance to downy and powdery mildews) was introgressed in genotypes phenotypically close to V. vinifera varieties. To check the consequences of introgressing parts of the V. rotundifolia genome on gene expression during fruit development, we conducted a comparative RNA-seq study on single berries from different V. vinifera cultivars and V. vinifera × V. rotundifolia hybrids, including 'G5' and two derivative microvine lines, 'MV102' (resistant) and 'MV32' (susceptible) segregating for the MrRUN1/RPV1 locus. RNA-Seq profiles were analyzed on a comprehensive set of single berries from the end of the herbaceous plateau to the ripe stage. Pair-end reads were aligned both on V. vinifera PN40024.V4 reference genome, V. rotundifolia cv 'Trayshed' and cv 'Carlos', and to the few resistance genes from the original V. rotundifolia cv '52' parent available at NCBI. Weighted Gene Co-expression Network Analysis (WGCNA) led to classifying the differentially expressed genes into 15 modules either preferentially correlated with resistance or berry phenology and composition. Resistance positively correlated transcripts predominantly mapped on the 4-5 Mb distal region of V. rotundifolia chromosome 12 beginning with the MrRUN1/MrRPV1 locus, while the negatively correlated ones mapped on the orthologous V. vinifera region, showing this large extremity of LG12 remained recalcitrant to internal recombination during the successive backcrosses. Some constitutively expressed V. rotundifolia genes were also observed at lower densities outside this region. Genes overexpressed in developing berries from resistant accessions, either introgressed from V. rotundifolia or triggered by these in the vinifera genome, spanned various functional groups, encompassing calcium signal transduction, hormone signaling, transcription factors, plant-pathogen-associated interactions, disease resistance proteins, ROS and phenylpropanoid biosynthesis. This transcriptomic insight provides a foundation for understanding the disease resistance inherent in these hybrid cultivars and suggests a constitutive expression of NIR NBS LRR triggering calcium signaling. Moreover, these results illustrate the magnitude of transcriptomic changes caused by the introgressed V. rotundifolia background in backcrossed hybrids, on a large number of functions largely exceeding the ones constitutively expressed in single resistant gene transformants.

Development and characterisation of novel durum wheat-H. chilense 4Hch chromosome lines as a source for resistance to Septoria tritici blotch.

The use of wild species as a source of genetic variability is a valued tool in the framework of crop breeding. Hordeum chilense Roem. et Schult is a wild barley species that can be a useful genetic donor for sustainable wheat breeding which carries genes conferring resistance to some diseases or increasing grain quality, among others. Septoria tritici blotch (STB), caused by the Zymoseptoria tritici fungus, is one of the most important wheat diseases worldwide, affecting both bread and durum wheat and having a high economic impact. Resistance to STB has been previously described in H. chilense chromosome 4Hch. In this study, we have developed introgression lines for H. chilense chromosome 4Hch in durum wheat using interspecific crosses, advanced backcrosses, and consecutive selfing strategies. Alien H. chilense chromosome segments have been reduced in size by genetic crosses between H. chilense disomic substitution lines in durum wheat and durum wheat lines carrying the Ph1 deletion. Hordeum chilense genetic introgressions were identified in the wheat background through several plant generations by fluorescence in situ hybridisation (FISH) and simple sequence repeat (SSR) markers. An STB infection analysis has also been developed to assess STB resistance to a specific H. chilense chromosome region. The development of these H. chilense introgression lines with moderate to high resistance to STB represents an important advance in the framework of durum breeding and can be a valuable tool for plant breeders.

Protection of viticultural biodiversity: genetic and phenotypic characterisation of grapevine varieties from the northwest coastal area of Tuscany (Italy)

To explore the grapevine biodiversity of some minor viticultural districts located in the northwest coastal area of Tuscany, a total of 99 grapevine samples were collected from field borders or no longer cultivated areas and analysed at the molecular level using 12 microsatellite markers (SSR). The results revealed the presence of 58 unique genotypes among which 42 already known varieties (36 belonging to the Vitis vinifera species and 6 Vitis interspecific crosses) and 16 hitherto unreported genetic profiles. About 50 % of the accessions (52 out of 99) were vegetatively propagated and planted in a vineyard collection to protect them from extinction and to record their phenotypic characteristics. This research has highlighted the potential for using several grapevine cultivars that were probably once widespread and can henceforth be cultivated again to help revive the eco-wine tourism of the Tuscan heroic vineyards and add prestige to the local wine panorama.

Phenotypic characterization and gene mapping of hybrid necrosis in Triticum durum–Haynaldia villosa amphiploids

Key messagePhenotypical, physiological and genetic characterization was carried out on the hybrid necrosis gene from Haynaldia villosa, and the related gene Ne-V was mapped to chromosome arm 2VL.Introducing genetic variation from wild relatives into common wheat through wide crosses is a vital strategy for enriching genetic diversity and promoting wheat breeding. However, hybrid necrosis, a genetic autoimmunity syndrome, often occurs in the offspring of interspecific or intraspecific crosses, restricting both the selection of hybrid parents and the pyramiding of beneficial genes. To utilize the germplasms of Haynaldia villosa (2n = 2x = 14, VV), we conducted wide hybridization between durum wheat (2n = 4x = 28, AABB) and multiple H. villosa accessions to synthesize the amphiploids (2n = 6x = 42, AABBVV). This study revealed that 61.5% of amphiploids derived from the above crosses exhibited hybrid necrosis, with some amphiploids even dying before reaching maturity. However, the initiation time and severity of necrosis varied dramatically among the progenies, suggesting that there were multiple genetic loci or multiple alleles in the same genetic locus conferring to hybrid necrosis in H. villosa accessions. Genetic analysis was performed on the F2 and derived F2:3 populations, which were constructed between amphiploid STH59-1 with normal leaves and amphiploid STH59-2 with necrotic leaves. A semidominant hybrid necrosis-related gene, Ne-V, was mapped to an 11.8-cM genetic interval on the long arm of chromosome 2V, representing a novel genetic locus identified in Triticum-related species. In addition, the hybrid necrosis was correlated with enhanced H2O2 accumulation and cell death, and it was influenced by the temperature and light. Our findings provide a foundation for cloning the Ne-V gene and exploring its molecular mechanism.

Association study of allelic variation identified at yield contributing loci in rice (Oryza sativa L.)

The knowledge of functionally characterized genes and linked markers that govern grain yield and its related traits were used to unravel the markers/genes that associate with diversity of yield traits in a panel 30 novel rice genotypes comprising of indica, japonica, aromatic, landraces, interspecific crosses (O.glaberrima/O.sativa) etc. The ANOVA showed significant differences (P=&lt;0.001) for all traits among the genotypes. Molecular analysis was done by employing 37 gene-specific markers targeting 24 yield governing genes in rice. Two markers viz., RM223(YLD) on chromosome 8 and GW004(GW2, LOC_Os02g14720) on chromosome 2 were identified as polymorphic. Average PIC (polymorphic information content) value for these primers was 0.37, suggesting the availability of accountable variability at these loci. Cluster analysis grouped the genotypes into three clusters. Marker-trait-association analysis revealed significant association of the marker GW004 with panicle length, plant height and filled grains in rice. Pearson correlation study also supported the molecular associations through significant phenotypic associations for trait pairs plant height and filled grains, panicle length and plant height. The phenotypic variance explained (R2%) by the marker across panicle length, plant height and filled grains was ≥15%, suggesting major role of the locus/gene in controlling respective traits. Thus, GW004 marker could be employed in breeding programs for simultaneous selection of three traits panicle length, plant height and filled grains. From the current study it can be concluded that allelic variation studies using novel genotypes can result in the identification of suitable donors along with trait associated markers for rice yield improvement.

Identification of candidate genes controlling cold tolerance at the early seedling stage from Dongxiang wild rice by QTL mapping, BSA-Seq and RNA-Seq

BackgroundThe cold tolerance of rice is closely related to its production and geographic distribution. The identification of cold tolerance-related genes is of important significance for developing cold-tolerant rice. Dongxiang wild rice (Oryza rufipogon Griff.) (DXWR) is well-adapted to the cold climate of northernmost-latitude habitats ever found in the world, and is one of the most valuable rice germplasms for cold tolerance improvement.ResultsTranscriptome analysis revealed genes differentially expressed between Xieqingzao B (XB; a cold sensitive variety) and 19H19 (derived from an interspecific cross between DXWR and XB) in the room temperature (RT), low temperature (LT), and recovery treatments. The results demonstrated that chloroplast genes might be involved in the regulation of cold tolerance in rice. A high-resolution SNP genetic map was constructed using 120 BC5F2 lines derived from a cross between 19H19 and XB based on the genotyping-by-sequencing (GBS) technique. Two quantitative trait loci (QTLs) for cold tolerance at the early seedling stage (CTS), qCTS12 and qCTS8, were detected. Moreover, a total of 112 candidate genes associated with cold tolerance were identified based on bulked segregant analysis sequencing (BSA-seq). These candidate genes were divided into eight functional categories, and the expression trend of candidate genes related to ‘oxidation-reduction process’ and ‘response to stress’ differed between XB and 19H19 in the RT, LT and recovery treatments. Among these candidate genes, the expression level of LOC_Os12g18729 in 19H19 (related to ‘response to stress’) decreased in the LT treatment but restored and enhanced during the recovery treatment whereas the expression level of LOC_Os12g18729 in XB declined during recovery treatment. Additionally, XB contained a 42-bp deletion in the third exon of LOC_Os12g18729, and the genotype of BC5F2 individuals with a survival percentage (SP) lower than 15% was consistent with that of XB. Weighted gene coexpression network analysis (WGCNA) and modular regulatory network learning with per gene information (MERLIN) algorithm revealed a gene interaction/coexpression network regulating cold tolerance in rice. In the network, differentially expressed genes (DEGs) related to ‘oxidation-reduction process’, ‘response to stress’ and ‘protein phosphorylation’ interacted with LOC_Os12g18729. Moreover, the knockout mutant of LOC_Os12g18729 decreased cold tolerance in early rice seedling stage signifcantly compared with that of wild type.ConclusionsIn general, study of the genetic basis of cold tolerance of rice is important for the development of cold-tolerant rice varieties. In the present study, QTL mapping, BSA-seq and RNA-seq were integrated to identify two CTS QTLs qCTS8 and qCTS12. Furthermore, qRT-PCR, genotype sequencing and knockout analysis indicated that LOC_Os12g18729 could be the candidate gene of qCTS12. These results are expected to further exploration of the genetic mechanism of CTS in rice and improve cold tolerance of cultivated rice by introducing the cold tolerant genes from DXWR through marker-assisted selection.

Interspecific Hardy Geranium Progenies: Morphological Characterization and Genetic Evaluation

Hardy geranium is a popular ornamental plant with a high market demand. As a result, there is a strong need for continuous innovation to improve its ornamental qualities. Interspecific hybridization is a widely used technique for introducing desirable traits and creating new cultivars with added value. To explore the possibilities of creating novelty within the Geranium genus, we conducted 2438 interspecific crosses over three flowering seasons, resulting in the successful harvest of 445 seeds and the final production of 82 seedlings. Using embryo rescue increased the germination rate of a seedling from 0.17% to 1.01%. To validate the paternal genetic contribution in the new seedlings, we used amplified fragment length polymorphism (AFLP) to assess the proportion of uniquely inherited paternal markers in all seedlings. AFLP analysis confirmed that 54 of the 82 seedlings were indeed true hybrids (65.8% hybridization success rate). A morphological evaluation of the flowers and leaves, including flower diameter (mm), style length (mm), number of flowers, flowering period (weeks), and color of both flowers and leaves, provided further confirmation of the F1 hybrid status of the seedlings. The results of our interspecific breeding demonstrated the efficiency of interspecific hybridization in hardy geraniums and its potential to create distinctive and novel cultivars for the ornamental market.

Asymmetrical reproductive interference between Aedes aegypti and Aedes albopictus: Implications for coexistence.

Aedes aegypti and Aedes albopictus are two sympatric mosquito species that compete with each other for resources when their breeding habitats overlap. This study examines what happens when sympatric Ae. aegypti and Ae. albopictus mosquitoes' mate with each other and other species by looking at insemination rates, fecundity, and hatchability rate. We performed controlled mating experiments in laboratory setting, assessing both conspecific and interspecific crosses. We measured insemination rates, egg numbers, and hatching success to examine the reproductive interference dynamics between these two distinct mosquito species. In the context of conspecific mating, it was observed that both female Ae. aegypti and Ae. albopictus exhibited high insemination rates, with percentages of 98% and 94% respectively. However, interspecific mating exhibited interesting asymmetries: Ae. albopictus males achieved a notable insemination success rate of 28% when mating with Ae. aegypti females, while Ae. aegypti males achieved only an 8% insemination success with Ae. albopictus females. Additionally, females that mated with interspecific males had reduced production of viable eggs compared to conspecific mating. Most notably, interspecific mating resulted in the production of infertile eggs, while conspecific mating led to successful hatching. The study reveals that Ae. aegypti and Ae. albopictus can asymmetrically interfere with each other's reproduction, causing a 'satyr' effect. This understanding of interspecific competition and reproductive interference in these mosquito species could impact their coexistence in shared breeding habitats.

A catalogue of recombination coldspots in interspecific tomato hybrids.

Increasing natural resistance and resilience in plants is key for ensuring food security within a changing climate. Breeders improve these traits by crossing cultivars with their wild relatives and introgressing specific alleles through meiotic recombination. However, some genomic regions are devoid of recombination especially in crosses between divergent genomes, limiting the combinations of desirable alleles. Here, we used pooled-pollen sequencing to build a map of recombinant and non-recombinant regions between tomato and five wild relatives commonly used for introgressive tomato breeding. We detected hybrid-specific recombination coldspots that underscore the role of structural variations in modifying recombination patterns and maintaining genetic linkage in interspecific crosses. Crossover regions and coldspots show strong association with specific TE superfamilies exhibiting differentially accessible chromatin between somatic and meiotic cells. About two-thirds of the genome are conserved coldspots, located mostly in the pericentromeres and enriched with retrotransposons. The coldspots also harbor genes associated with agronomic traits and stress resistance, revealing undesired consequences of linkage drag and possible barriers to breeding. We presented examples of linkage drag that can potentially be resolved by pairing tomato with other wild species. Overall, this catalogue will help breeders better understand crossover localization and make informed decisions on generating new tomato varieties.

Inheritance of Mitochondria in Pelargonium Section Ciconium (Sweet) Interspecific Crosses

We have studied the inheritance of mitochondria in Pelargonium section Ciconium using 36 interspecific crosses generated. We designed KASP markers targeting four mitochondrial loci, belonging to the mitomes of four main crossing parents, enabling tracking the transmission of each mitome in the crosses. These markers discriminate between an individual species versus the other section Ciconium species. We found that maternal inheritance of mitochondria is most frequent, with occasional occurrences of paternal inheritance, while biparental inheritance is rare. For a P. multibracteatum crossing series, we found ambiguous results. Our results confirm those of previous studies, namely, that paternal inheritance of mitochondria can occur in P. sect Ciconium but that the instance is rare and much less common than is the case for chloroplasts.