Interspecific Hybrids Research Articles

Arabidopsis leucine-rich repeat malectin receptor-like kinases regulate pollen-stigma interactions.

Flowering plants contain tightly controlled pollen-pistil interactions required for promoting intraspecific fertilization and preventing interspecific hybridizations. In Arabidopsis (Arabidopsis thaliana), several receptor kinases (RKs) are known to regulate the later stages of intraspecific pollen tube growth and ovular reception in the pistil, but less is known about RK regulation of the earlier stages. The Arabidopsis RECEPTOR-LIKE KINASE IN FLOWERS1 (RKF1)/RKF1-LIKE (RKFL) 1-3 cluster of 4 leucine-rich repeat malectin (LRR-MAL) RKs was previously found to function in the stigma to promote intraspecific pollen hydration. In this study, we tested additional combinations of up to 7 Arabidopsis LRR-MAL RK knockout mutants, including RKF1, RKFL1-3, LysM RLK1-INTERACTING KINASE1, REMORIN-INTERACTING RECEPTOR1, and NEMATODE-INDUCED LRR-RLK2. These LRR-MAL RKs were discovered to function in the female stigma to support intraspecific Arabidopsis pollen tube growth and to establish a prezygotic interspecific barrier against Capsella rubella pollen. Thus, this study uncovered additional biological functions for this poorly understood group of RKs in regulating the early stages of Arabidopsis sexual reproduction.

Phylogenomics reveal Populusgonggaensis as a hybrid between P.lasiocarpa and P.cathayana (Salicaceae).

High levels of intra-specific polymorphism and frequent hybridisation make it difficult to define species and correctly apply their scientific names. Populus L. is a challenging genus with plentiful natural and artificial hybrids. This study is a part of the project 'Flora of Pan-Himalaya' and aims to determine the taxonomic identity of P.gonggaensis N. Chao & J.R. He and to find out whether it is of hybrid origin. Whole-genome sequencing data were obtained from 57 samples. The SNP matrix was developed for phylogenetic reconstruction, ABBA-BABA statistics, PCA and ADMIXTURE analysis. The results indicate that P.gonggaensis is a spontaneous hybrid between P.lasiocarpa and P.cathayana. This study points out the importance of SNP data and comprehensive analyses for discovering the potential interspecific hybridisation and clarifies the usage of the name. In addition, the lectotype of P.gonggaensis was designated.

Two new Dryopteris taxa originated from distantly related congeners in China

AbstractSince the inception of genetic investigations into the origin of Dryopteris species belonging to D. subg. Erythrovariae in East Asia, around 20 taxa with hybrid ancestry have been identified. Among these species, some have arisen from distant interspecific hybridization events. In this study, we describe and illustrate two newly discovered hybrids from China: Dryopteris parabissetiana sp. nov., a triploid species, and D. ×tiantangzhaiensis nothosp. nov., a diploid hybrid within Dryopteridaceae. Morphologically, D. parabissetiana exhibits similarities to D. bissetiana but can be distinguished by its ovate scales, while D. ×tiantangzhaiensis clearly displays intermediate characteristics between D. gymnophylla and D. tsoongii. Phylogenetic analyses indicate that D. tsoongii serves as their maternal parent, while D. bissetiana and D. gymnophylla are their paternal parents, respectively. Furthermore, we propose a section‐level classification for such hybrids of mixed parental sections.

An integrative delimitation of the species boundaries within one hornbeam species complex (Betulaceae: Carpinus)

AbstractBoth hybridization and intraspecific morphological variation across environmental gradients complicate species delineation. We aimed to discern both possibilities that may blur species boundaries in the Carpinus viminea–Carpinus laxiflora–Carpinus londoniana species complex. We conducted statistical analyses on 535 specimens encompassing the entire distribution of this species complex to identify phenotypic clusters. Additionally, we analyzed genetic divergence and probable hybridization between clusters using 76 individuals from 37 populations. Based on phenotypic and genetic clusters, we tentatively recognized four species: C. viminea, C. fargesii, C. laxiflora, and C. londoniana. Except for rare overlapping distributions between C. fargesii and C. londoniana, the redefined four species are mostly allopatric to each another based on their distributions. The morphological delimitation, species boundary and distribution of each species differ distinctly from past taxonomic treatments. For example, specimens previously identified under C. viminea, in fact, belong to three different species. Hybrids between C. fargesii and C. londoniana exhibit morphological traits similar to C. viminea, thereby contributing to difficulties in determining species boundaries and outlining species distributions. These findings suggest that local selection and geographical isolation may together have promoted both phenotypic and genetic divergences within this species complex. However, interspecific hybridization blurs species boundaries by producing hybrids with phenotypic similarity in addition to intraspecific variation. This study emphasizes the importance of statistical analyses of population‐level morphological and genetic variations across major distributional ranges for an integrative delimitation of species boundaries and the identification of hybridization and hybrids.

Detection and Characterization of Xylella fastidiosa subsp. fastidiosa in Rabbiteye Blueberry in South Carolina.

Xylella fastidiosa causes bacterial leaf scorch in southern highbush (Vaccinium corymbosum interspecific hybrids) and is also associated with a distinct disease phenotype in rabbiteye blueberry (V. virgatum) cultivars in the southeastern United States. Both X. fastidiosa subsp. fastidiosa and X. fastidiosa subsp. multiplex have been reported to cause problems in southern highbush blueberry, but so far only X. fastidiosa subsp. multiplex has been reported in rabbiteye cultivars in Louisiana. In this study, we report detection of X. fastidiosa in rabbiteye blueberry plants in association with symptoms of foliar reddening and shoot dieback. High throughput sequencing of an X. fastidiosa-positive plant sample and comparative analyses identified the strain in one of these plants as being X. fastidiosa subsp. fastidiosa. We briefly discuss the implications of these findings, which may spur research into blueberry as a potential inoculum source that could enable spread to other susceptible fruit crops in South Carolina.

Plasticity of parental CENH3 incorporation into the centromeres in wheat × barley F1 hybrids.

Incorporating the centromere-specific histone H3 protein CENH3 into the centromeric nucleosomes is indispensable for accurate centromere function and balanced chromosome segregation in most eukaryotes, including higher plants. In the cell nuclei of interspecific hybrids, divergent centromeric DNAs cohabit and lead the corresponding parental chromosomes through the mitotic and meiotic cell divisions. Depending on the transmission of the parental chromosomes carrying the CENH3-encoding genes, CENH3 proteins from one or both parents may be present in these hybrids. The incorporation of parental CENH3 proteins into the divergent centromeres and their role in the chromosome elimination process in interspecific hybrids is still poorly understood. Here, we produced wheat × barley F1 hybrids that carried different combinations of barley chromosomes with genes encoding for either one (αCENH3) or both barley CENH3 protein variants (α- and βCENH3). We generated specific antibodies distinguishing between the wheat CENH3 proteins and barley αCENH3 and applied them together with FISH probes to detect the precise pattern of parental CENH3 deposition into the wheat and barley centromeric nucleosomes. Analysis of somatic and meiotic nuclei of the wheat × barley hybrids revealed the plasticity of the maternal (wheat) CENH3 proteins to become incorporated into the paternal (barley) centromeric nucleosomes. However, no evidence for paternal CENH3 plasticity was detected in this study. The significance of the unilateral centromere plasticity and possible patterns of CENH3 incorporation into centromeres in interspecific hybrids are discussed.

Unidirectional hybridization between American paddlefish Polyodon spathula (Walbaum, 1792) and sterlet Acipenser ruthenus (Linnaeus, 1758).

Interspecific hybridizations among sturgeon species are feasible and often bidirectional. The American paddlefish (Polyodon spathula) from Family Polyodontidae and sturgeon species from Family Acipenseridae were reported capable of hybridization, but viable hybrids have been described only in crosses with the American paddlefish as paternal parents. In the reciprocal cross, the hybrids were not viable however embryos start to develop and reach late gastrula and early neurula stages. The goal of this study was to examine the hybridization between the sterlet sturgeon (Acipenser ruthenus) and the American paddlefish. Hybrid and purebred crosses were produced by artificial fertilization. Viable hybrid offspring were harvested (three month old) and verified in the families produced by female sterlet crossing with male American paddlefish. In the reciprocal hybrid crosses with female American paddlefish and male sterlet, the embryos development did not pass over 120 h post fertilization, indicating the unidirectional hybridization between American paddlefish and sterlet. Chromosome counting showed for the same ploidy level of viable hybrid and parent species. Analysis of three microsatellite markers confirmed the unidirectional hybridization between the American paddlefish and the sterlet species. Overall, the inferred genetic cause suggests that unidirectional hybridization between American paddlefish and sterlet may be the case not only for these two species but likely also between American paddlefish and other sturgeon species.

Landscape and Fruit Evaluation of Three Privet (Ligustrum sp.) Cultivars in Florida

Chinese privet (Ligustrum sinense) has escaped cultivation in 20 states in the USA and is classified as a noxious weed in Florida, where its use is prohibited. There is confusion among producers and consumers surrounding the invasive status of its cultivars. In Florida, cultivars of an invasive wildtype species are also invasive unless proven otherwise and exempted from an invasive ruling. This study evaluated the fruiting and landscape performance of two cultivars of Chinese privet, ‘Variegatum’ (variegated privet) and ‘Sunshine’ (sunshine privet), and an interspecific hybrid of another form of privet, ‘NCLX1’ (L. × vicaryi, Golden Ticket®), planted in southwest, northcentral, and north Florida. ‘Sunshine’ and ‘Variegatum’ privet both performed well throughout the study with average quality ratings ranging from 3.2 to 4.9 (scale of 1–5) and a 100% survival rate during the nearly two-year study. ‘NCLX1’ privet also had a 100% survival rate at the southwest and northcentral sites, but 80% survival at the north Florida site. ‘Variegatum’ privet grew the largest in both height and width compared to ‘Sunshine’ and ‘NCLX1’ privet, that had similar heights. ‘Variegatum’ and ‘NCLX1’ privet flowered during the study, but ‘Sunshine’ privet did not. ‘Variegatum’ privet was the only cultivar evaluated to produce mature fruit and show clear signs of reversion back to its green wildtype form. The DNA content of all three cultivars suggests they are diploids, as is the wildtype form of Chinese privet. These results provide potential alternatives to Chinese privet for use in landscapes but recommend avoiding ‘Variegatum’ privet, due to its frequent reversion to the wildtype and its abundant fruit production.

Karyotypic stasis and swarming influenced the evolution of viral tolerance in a species-rich bat radiation

The emergence of COVID-19 and severe acute respiratory syndrome (SARS) has prioritized understanding bats' viral tolerance. Myotis bats are exceptionally species rich and have evolved viral tolerance. They also exhibit swarming, a cryptic behavior where large, multi-species assemblages gather for mating, which has been hypothesized to promote interspecific hybridization. To resolve the coevolution of genome architecture and their unusual antiviral tolerance, we undertook a phylogenomic analysis of 60 Old World Myotis genomes. We demonstrate an extensive history of introgressive hybridization that has replaced the species phylogeny across 17%-93% of the genome except for pericentromeric regions of macrochromosomes. Introgression tracts were enriched on microchromosome regions containing key antiviral pathway genes overexpressed during viral challenge experiments. Together, these results suggest that the unusual Myotis karyotype may have evolved to selectively position immune-related genes in high recombining genomic regions prone to introgression of divergent alleles, including a diversity of interleukin loci responsible for the release of pro-inflammatory cytokines.

Chaotic spindles causes abnormal chromosome behavior in an interspecific sexual hybrid of Urochloa

Chaotic spindles causes abnormal chromosome behavior in an interspecific sexual hybrid of Urochloa

The use of the 5S rDNA IGS region for DNA barcoding and molecular taxonomy of two Ukrainian species of the genus Tulipa L.

Taxonomic identification of closely related representatives of the genus Tulipa L. is complicated by the convergent similarity of morphological characters, interspecific hybridization, polyploidy and asexual reproduction. Among the tulips in the flora of Ukraine, the most problematic is the status of taxa of the complex species T. sylvestris L. Aim. To examine the organization and evolution of the nuclear 5S rDNA IGS region for four closely related Tulipa taxa and to evaluate the possibility of its use in the molecular taxonomy of this plant group. Methods. PCR amplification, cloning and sequencing of 5S rDNA repeat units, bioinformatic and phylogenetic analysis. Results. In this work, 5S rDNA repeats were sequenced for the species T. graniticola and T. ophiophylla, which are considered to be synonyms of T. sylvestris L. by many authors. We also assembled the main ribotypes from full-genome libraries of short Illumina reads for T. patens, and T. saxatilis, the species related to T. sylvestris. A comparative analysis of the structure of 5S rDNA sequences and a phylogenetic analysis based on the IGS region were carried out. Conclusions. A high level of 5S rDNA IGS variability has been demonstrated for representatives of the subgenus Eriostemones of the genus Tulipa. The use of 5S rDNA IGS for phylogenetic analysis enabled the clear delimitation of the closely related species T. saxatilis, T. patens, and the complex species T. sylvestris, as well as the delineation of the taxa with the controversial status, T. graniticola and T. ophiophylla. Therefore, the use of this region of the nuclear genome is a promising approach to the molecular taxonomy of the genus Tulipa.

Quantitative 2D fruit shape analysis of a wide range of pear genetic resources toward shape design breeding

The shape of a fruit is one of the main characteristics of fruit morphology, and its quantitative description is crucial to improve fruit quality. However, the shape of a pear fruit is relatively complex, and difficult to describe comprehensively. This study aimed to quantitatively analyze the morphological diversity of 2D fruit shapes of 276 cultivars, covering 6 groups including Pyrus pyrifolia, Pyrus bretschneideri, Pyrus ussuriensis, Pyrus sinkiangensis, Pyrus communis and interspecific hybridization, and discover shape traits with high heritability. Through an automated image processing method, the fruit contour was first accurately extracted, and then geometrical parameters and Fourier descriptors of the pear fruit shape were obtained. Furthermore, principal components (PCs) of the Fourier descriptors were analyzed, and the broad-sense heritability (H2) of the PCs and standardized width (WSD) were estimated. After that, the pear shape stability was calculated, and cultivars were clustered by their shape characteristics. This paper mainly discusses the longitudinal section, as the cross-section variation among cultivars is small. For the longitudinal section, the results showed more than 95 % of the two-dimensional shape variation can be explained by only six principal components; WSD20, WSD30 and PC1 have high H2; the shape stability of western pear was the lowest; a new class of shape was found by clustering the shape traits. The results indicated that the proposed pipeline can provide an objective and comprehensive quantitative description of pear fruit shape for a wide range of cultivars, which is necessary to discover the key genes determining pear shape. This approach is also beneficial for research on pear breeding and germplasm resource management.

Fruit Quality Assessment of Novel Hybrid Pummelo × Sweet Orange and Its Molecular Characterization Using Acidity Specific Markers.

There is considerable diversity in newly developed pummelo × sweet orange citrus hybrids. Most hybrids showed lower peel thickness and high juice yield but there is a lack of information on fruit quality parameters and molecular characterization. Therefore, the aim of the current study is to determine the content of antioxidants and properties of the fresh juice of 24 new pummelo × sweet orange citrus hybrids (Citrus maxima [Burm. f.] Osbeck × Citrus sinensis [L.] Osbeck) and the parental genotypes along with molecular characteristics determined using acidity specific markers. The correlation and estimate of inheritance of the fruit juice properties: ascorbic acid, total phenol, total flavonoid, total antioxidant, total soluble solid and sugar contents, pH, titratable acidity, along with sensory evaluation was performed. Molecular characterization of these hybrids was carried out using de novo generated acidity specific simple sequence repeat (SSR) markers. The main constituents of the fruit juice of pummelo × sweet orange hybrids were observed in the range of w(ascorbic acid)=40.00-58.13 mg/100 g, total phenols expressed as gallic acid equivalents w(GAE)=40.67-107.33 mg/100 g, total antioxidants expressed as Trolox equivalents b(Trolox)=2.03-5.49 µmol/g, total flavonoids expressed as quercetin equivalents w(QE)=23.67-59.33 mg/100 g, along with other properties: total soluble solids=7.33-11.33 %, w(total sugar)=2.10-5.76 %, w(reducing sugar)=1.69-2.78 %, w(non-reducing sugar)=0.39-3.17 % and titratable acidity 1.00-2.11 %. The above parameters differed significantly in the fruit juice of the evaluated pummelo × sweet orange hybrids. Considering these parameters, the hybrids SCSH 17-9, SCSH 13-13, SCSH 11-15 and SCSH 3-15 had superior antioxidant properties in terms of these parameters. A higher heritability (≥80 %) was also observed for all juice properties. Molecular characterization of pummelo × sweet orange hybrids showed that >50 % of the hybrids were grouped with medium acidity parents. Both molecular and biochemical parameter-based clustering showed that interspecific hybrids exhibit transgressive segregation with increased antioxidants that help alleviate the health problems. These newly developed pummelo × sweet orange citrus hybrids are a valuable source of high-quality antioxidants for a healthy diet. The identification of trait markers that enable selection at the seedling stage is of great benefit to citrus breeders, as the characteristic features of a mature tree are not yet visible at the juvenile stage.

Comparative efficacy of different cotton hybrids containing Bt genes against Pectinophora gossypiella (Saunders)

Field experiment was conducted at Agricultural Research Station, Dharwad farm, during 2018 and 2019 toevaluate performance of eighteen different cotton genotypes representing four different Bt events. Damage due to pink bollworm (PBW) was least in intraspecific (H×H) hybrids compared to interspecific hybrids (H×B) hybrids. Cotton hybridEverest recorded least flower damage of 9.40 per cent, followed by Jadoo (9.71%) and were on par. The highest per centflower damage of 22.57 was registered in (H × H) non Bt hybrid DCH-32. Least boll damage of 13.93 per cent was recordedin Everest BG-II and was on par with Jadoo (14.94%) and highest per cent boll damage of 41.26 was recorded in DCH-32The seed cotton yield was highest in Everest BG-II (15.20 q/ha). Among BG-I genotypes, VCH-5 (Event-1) recordedhighest yield (9.84 q/ha) and the least yield was recorded in DCH-32(5.97 q/ha).

Interspecific hybridization and inoculation with Pantoea eucalypti improve forage performance of Lotus crop species under alkaline stress.

This study was designed to elucidate the physiological responses of three Lotus forage accessions to alkaline stress, and the influence of inoculating with Pantoea eucalypti endophyte strain on alkaline stress mitigation. A diploid L. corniculatus (Lc) accession, L. tenuis (Lt), and the interspecific hybrid Lt × Lc obtained from these two parental lines were exposed to alkaline stress (pH 8.2). Both Lt and the Lt × Lc hybrid are alkaline-tolerant compared to Lc, based on observations that dry mass was not reduced under stress, and there were no chlorosis symptoms on leaf blades. In all three Lotus accessions, Fe2+ concentration under stress decreased in aerial parts and simultaneously increased in roots. Inoculation with P.eucalypti considerably increased Fe2+ content in shoots of all three Lotus forage species under alkaline treatment. Photochemical efficiency of PSII was affected in Lc accession only when exposed to alkaline treatment. However, when cultivated under alkalinity with inoculation, plants recovered and had photosynthetic parameters equivalent to those in the control treatment. Together, the results highlight the importance of inoculation with P. eucalypti, which contributes significantly to mitigating alkaline stress. All results provide useful information for improving alkaline tolerance traits of Lotus forage species and their interspecific hybrids.

Nonconventional yeasts and hybrids for low temperature handcrafted sparkling ciders elaboration in Patagonia

Yeasts play a crucial role in transforming apple must into cider. While Saccharomyces cerevisiae (Sc) has been traditionally associated to cider fermentations worldwide, cryotolerant species such as Saccharomyces uvarum (Su) as well as natural S. cerevisiae × S. uvarum (Sc×Su) hybrids have also been detected in ciders fermented at low temperatures.This study aimed to evaluate the ability of two Patagonian cryotolerant yeast strains (Su and Se) and their interspecific hybrids with a Sc to conduct handcrafted apple must fermentations and a second fermentation process (champenoise method). The main chemical parameters and sensory quality of the resulting sparkling beverages was also analysed.Firstly, Sc×Se and Sc×Su hybrids were evaluated in their fermentative features at laboratory scale. Hybrids were compared with their respective parental species evidencing significant differences in the physicochemical and aromatic composition of the obtained base ciders.Both Su parental strain and the hybrid Sc×Se were selected for performing pilot scale fermentations (250 L) using natural (non-sterilized) apple juice at two different temperatures: 20 °C and 13 °C. Sc parental strain was also evaluated for comparative purposes. All base ciders obtained were then subjected to a second fermentation.A high implantation capacity of both Su and the hybrid was evidenced at the lowest evaluated temperature, while commercial Sc strain was not detected at the final fermentation stage, independently from the temperature. All sparkling ciders exhibited distinct physicochemical profiles. Ciders inoculated with commercial Sc (but effectively fermented with local Sc strains) allowed the development of malolactic fermentation (MLF) in processes carried out at both temperatures. Contrarily, no MLF was observed in ciders inoculated with either Su or the hybrid. Sparkling ciders fermented with Su displayed the highest concentrations of 2-phenylethanol and 2-phenylethyl acetate, regardless of the fermentation temperature. Conversely, ciders fermented with the hybrid at 20 °C exhibited the highest concentrations of ethyl octanoate and ethyl decanoate, contributing to floral and fruity notes in the beverage.Sensory analysis conducted with untrained individuals revealed a preference for sparkling ciders produced with the hybrid strain at both 20 °C and 13 °C. The cider fermented at 20 °C exhibited floral notes, sweetness, and a full body, while ciders fermented at 13 °C displayed moderate acidity and a well-balanced profile. Conversely, a trained panel described the cider fermented at 20 °C with Su as a fruity and acidic beverage, whereas the ciders fermented at 13 °C exhibited intense bitterness and acidity.This study highlights the potential of cryotolerant Saccharomyces species and hybrids in the development of new starter cultures for producing artisanal sparkling ciders with distinctive properties.

Separating phases of allopolyploid evolution with resynthesized and natural Capsella bursa-pastoris

Allopolyploidization is a frequent evolutionary transition in plants that combines whole-genome duplication (WGD) and interspecific hybridization. The genome of an allopolyploid species results from initial interactions between parental genomes and long-term evolution. Distinguishing the contributions of these two phases is essential to understanding the evolutionary trajectory of allopolyploid species. Here, we compared phenotypic and transcriptomic changes in natural and resynthesized Capsella allotetraploids with their diploid parental species. We focused on phenotypic traits associated with the selfing syndrome and on transcription-level phenomena such as expression-level dominance (ELD), transgressive expression (TRE), and homoeolog expression bias (HEB). We found that selfing syndrome, high pollen, and seed quality in natural allotetraploids likely resulted from long-term evolution. Similarly, TRE and most down-regulated ELD were only found in natural allopolyploids. Natural allotetraploids also had more ELD toward the self-fertilizing parental species than resynthesized allotetraploids, mirroring the establishment of the selfing syndrome. However, short-term changes mattered, and 40% of the cases of ELD in natural allotetraploids were already observed in resynthesized allotetraploids. Resynthesized allotetraploids showed striking variation of HEB among chromosomes and individuals. Homoeologous synapsis was its primary source and may still be a source of genetic variation in natural allotetraploids. In conclusion, both short- and long-term mechanisms contributed to transcriptomic and phenotypic changes in natural allotetraploids. However, the initial gene expression changes were largely reshaped during long-term evolution leading to further morphological changes.

Separating phases of allopolyploid evolution with resynthesized and natural Capsella bursa-pastoris.

Allopolyploidization is a frequent evolutionary transition in plants that combines whole-genome duplication (WGD) and interspecific hybridization. The genome of an allopolyploid species results from initial interactions between parental genomes and long-term evolution. Distinguishing the contributions of these two phases is essential to understanding the evolutionary trajectory of allopolyploid species. Here, we compared phenotypic and transcriptomic changes in natural and resynthesized Capsella allotetraploids with their diploid parental species. We focused on phenotypic traits associated with the selfing syndrome and on transcription-level phenomena such as expression-level dominance (ELD), transgressive expression (TRE), and homoeolog expression bias (HEB). We found that selfing syndrome, high pollen, and seed quality in natural allotetraploids likely resulted from long-term evolution. Similarly, TRE and most down-regulated ELD were only found in natural allopolyploids. Natural allotetraploids also had more ELD toward the self-fertilizing parental species than resynthesized allotetraploids, mirroring the establishment of the selfing syndrome. However, short-term changes mattered, and 40% of the cases of ELD in natural allotetraploids were already observed in resynthesized allotetraploids. Resynthesized allotetraploids showed striking variation of HEB among chromosomes and individuals. Homoeologous synapsis was its primary source and may still be a source of genetic variation in natural allotetraploids. In conclusion, both short- and long-term mechanisms contributed to transcriptomic and phenotypic changes in natural allotetraploids. However, the initial gene expression changes were largely reshaped during long-term evolution leading to further morphological changes.

Taxonomy, Distribution and Habitat of the Giant Trechus Beetles Endemic to Mt. Choke, Ethiopia (Coleoptera: Carabidae)

The Holarctic ground beetle genus Trechus Clairville, 1806, is highly diverse in the Ethiopian highlands, both in terms of species numbers and morphology. Particularly noteworthy are the extraordinarily large species of the subgenus Abyssinotus Quéinnec and Ollivier, 2021, with a body length up to 8.5 mm, that occur on Mt. Choke in northern Ethiopia. Recent, intensive field work on Mt. Choke resulted in a significantly large number of specimens that are the basis for our taxonomic revision of the species related to the giant species, T. dimorphicus Pawłowski, 2001 and T. gigas Pawłowski, 2001. We describe three new species and one new subspecies and discuss a likely interspecific hybrid that combines morphological character states of representatives of the dimorphicus and gigas subgroups of Abyssinotus. An iconography of males and females as well as photographs of the aedeagi of all the considered species are presented. The distributions of the species are detailed and knowledge of the species-specific habitat preferences is summarized. Based on the distributions and habitat specificity, a threat assessment based on the current land use pattern at Mt. Choke is provided.

Differential responses of genotype × environment interaction on Agronomic interventions affect the yield and quality of essential oil of interspecific basil hybrid of Ocimum basilicum L. × Ocimum kilimandscharicum

The investigations on interspecific hybrid basil were carried out in two distinct agro-climatic regions of India: Lucknow (Uttar Pradesh) and Rangareddy (Telangana). The experiment used an RCBD replicated thrice in each trial in each of the three seasons/environments: Jaid, Karief, and Rabi. The morphological and chemical changes of an interspecific basil hybrid/variety were studied across environments/seasons, and locations. All morphological traits and essential oil production are affected by the environment/seasons and location. The essential oil production and linalool concentration were found to be consistent. A high-quality linalool essential oil was discovered throughout the environment and locales. The biplot contrasted the test seasons/environments, as well as the researched locations and their interactions, visually. The ‘r' correlation between measured (M) and predicted (P) values was 0.998, and the predicted (P), means, and instability values (I) were all calculated using ATC coordinates. The ‘r' between GGE distance (GD) and entry means was also −0.952. This means that a higher absolute number indicates less stability, whereas a lower absolute value indicates a high level of stability. In summary, significant amounts of linalool-rich essential oil were obtained in the Northern Region (Lucknow) during the Jaid season (69.76 %) and the Southern Region (Hyderabad) during the Rabi season (69.88 %). This hybrid/variety's linalool content and essential oil yield averaged 190.78 kg/ha across seasons/environments and locations, with a linalool content of 67.91 %. Due to its high yield of top-notch linalool essential oil, the basil hybrid/variety that is particularly stable in terms of essential oil yield with high linalool content across seasons and places should be suggested for large-scale cultivation.