Search Results (20)

The increasing demand for novel cut chrysanthemum cultivars has underscored the significance of precision breeding techniques, with particular emphasis on hybridization and molecular tools. This study aimed to assess the cross-compatibility of selected chrysanthemum cultivars and to evaluate the genetic, quantitative, and qualitative diversity among the resulting F₁ progenies. A total of six hybrid combinations were generated using five commercial parental cultivars. Ploidy levels were determined via flow cytometry and chromosome counting, confirming that all parents were allohexaploid (2n = 6x = 54). Pollen viability and germination rates varied significantly among male parents, influencing hybridization success. A total of 30,391 seeds were obtained, with germination rates ranging from 2.69% to 10.73%, depending on the cross combination. F₁ progenies showed considerable phenotypic variability in flowering time, flower stalk length, flower diameter, and branch weight. Molecular characterization using eight iPBS primers revealed a high polymorphism rate (93%) with a mean Polymorphism Information Content (PIC) value of 0.614, confirming substantial genetic diversity among genotypes. Cluster and principal coordinate analyses demonstrated that most F₁ genotypes grouped closely with their maternal parents, although unique genomic variations were also detected. The integration of morphological and molecular data provides valuable insights for selecting superior genotypes and optimizing breeding strategies. This study highlights the importance of evaluating hybridization potential and genetic diversity in the development of commercially viable cut chrysanthemum cultivars. Full article

Paeonia ludlowii is a threatened and valuable germplasm in the cultivated tree peony gene pool, with distinctive traits such as tall stature, pure yellow flowers, and scarlet foliage in autumn. However, the crossability barrier limits gene transfer from P. ludlowii to cultivated tree peony. Therefore, our study investigated the reasons for the lack of crossability between P. ludlowii and Paeonia ostii ‘Fengdan’. Distant cross pollination (DH) resulted in the formation of many calloses at the ends of the pollen tubes, which grew non-polar, twisted, entangled, and often stopped in the style. Pollen tubes elongated the fastest in self-pollination (CK), and pollen tubes elongated faster and fewer pollen tube abnormalities were observed in stigmas treated with KCl solution before pollination (KH) than in DH. During pollen–pistil interactions, the absence of stigma exudates, high levels of H₂O₂, O₂⁻, MDA, ^•OH, ABA, and MeJA, and lower levels of BR and GA₃ may negatively affect pollen germination and pollen tube elongation in the pistil of P. ostii ‘Fengdan’. Pollen tubes in CK and KH penetrated the ovule into the embryo sac at 24 h after pollination, whereas only a few pollen tubes in DH penetrated the ovule at 36 h after pollination. Pre-embryo abnormalities and the inhibition of free nuclear endosperm division resulted in embryo abortion in most of the fruits of DH and many fruits of KH, which occurred between 10 and 20 days after pollination, whereas embryos in CK developed well. Early embryo abortion and endosperm abortion in most of the fruits of DH and KH led to seed abortion. Seed abortion in KH and DH was mainly due to an insufficient supply of auxins and gibberellins and lower content of soluble protein and soluble sugars. The cross failure between P. ludlowii and P. ostii ‘Fengdan’ is mostly caused by a pre-fertilization barrier. KH treatment can effectively promote pollen tube growth and facilitate normal development of hybrid embryos. These findings provide new insights into overcoming the interspecific hybridization barrier between cultivated tree peony varieties and wild species. Full article

Endovascular revascularization is a critical strategy in managing total occlusions of the femoropopliteal artery, a significant challenge in patients with peripheral artery disease (PAD). This review provides a comprehensive analysis of procedural strategies, highlighting the role of drug-coated balloons, atherectomy devices, and advanced crossing techniques like subintimal recanalization and re-entry methods. It discusses the importance of lesion-specific considerations, such as the use of atherectomy devices for un-crossable or un-dilatable lesions and the effectiveness of drug-coated balloons in reducing restenosis. Emerging techniques, including the PIERCE needle-cracking method and intravascular lithotripsy, offer novel approaches for treating heavily calcified plaques. Moreover, the review compares endovascular interventions with surgical bypass, noting that while minimally invasive techniques are preferred for high-risk patients, a hybrid approach may be optimal for selected cases. Despite advances, challenges remain regarding long-term outcomes and the management of complex calcified lesions, emphasizing the need for ongoing research and innovation in this field. Full article

Successful pollination and fertilization are crucial for grain setting in cereals. Wheat is an allohexaploid autogamous species. Due to its evolutionary history, the genetic diversity of current bread wheat (Triticum aestivum) cultivars is limited. Introducing favorable alleles from related wild and cultivated wheat species is a promising breeding strategy for resolving this issue. However, wide hybridization between bread wheat and its relatives is hampered by the presence of suppressor genes and difficulties in crossing. Optimized methods for observing pollen tubes are essential for understanding the mechanism of crossability between wheat and its relatives. Here, we improved the crossing procedure between bread wheat and rye (Secale cereale) and established an optimized protocol for visualizing pollen tube behavior. Crossing via detached spike culture significantly enhanced crossing efficiency and phenotypic stability. A combination of canonical aniline blue staining and optimized clearing and sectioning allowed us to visualize pollen tube behavior. The proportion of rye pollen tubes reaching the micropyle was lower than that for pollen tubes germinated on the stigmatic hair, explaining why the hybrid seed-setting rate was approximately 75% instead of 100%. This method sheds light on wide hybridization through deeper visualization of the insides of pistils. Full article

Interspecific hybridization between two different Brassicaceae species, namely Brassica rapa ssp. pekinensis (♀) (AA, 2n = 2x = 20) and genetically modified Brassica napus (♂) (AACC, 2n = 4x = 38), was performed to study the transmission of a herbicide resistance gene from a tetraploid to a diploid Brassica species. Initially, four different GM B. napus lines were used for hybridization with B. rapa via hand pollination. Among the F1 hybrids, the cross involving the B. rapa (♀) × GM B. napus (♂) TG#39 line exhibited the highest recorded crossability index of 14.7 ± 5.7. However, subsequent backcross progenies (BC1, BC2, and BC3) displayed notably lower crossability indices. The F1 plants displayed morphological characteristics more aligned with the male parent B. napus, with significant segregation observed in the BC1 generation upon backcrossing with the recurrent parent B. rapa. By the BC2 and BC3 generations, the progeny stabilized, manifesting traits from both parents to varying degrees. Cytogenetic analysis revealed a substantial reduction in chromosome numbers, particularly in backcrossing progenies. BC1 plants typically exhibited 21–25 chromosomes, while BC2 progenies showed 21–22 chromosomes, and by the BC3 generation, stability was achieved with an average of 20 chromosomes. SSR marker analysis confirmed the progressive reduction of C-genome regions, retaining minimal C-genome-specific bands throughout successive backcrossing. Despite the extensive elimination of C-genome-specific genomic regions, the glyphosate resistance gene from the male parent B. napus was introgressed into BC3 progenies, suggesting that the glyphosate resistance gene located and introgressed in A-chromosome/genome regions of the Brassica plants. Full article

This paper proposes a golden sine grey wolf optimizer (GSGWO) that can be adapted to the obstacle-crossing function to solve the path planning problem of obstacle-crossable robot. GSGWO has been improved from the gray wolf optimizer (GWO), which provide slow convergence speed and easy to fall into local optimum, especially without obstacle-crossing function. Firstly, aiming at the defects of GWO, the chaotic map is introduced to enrich the initial population and improve the convergence factor curve. Then, the convergence strategy of the golden sine optimizer is introduced to improve the shortcomings of GWO, such as insufficient convergence speed in the later stage and the ease with which it falls into the local optimum. Finally, by adjusting the working environment model, path generation method and fitness function, the path-planning problem of the obstacle-crossing robot is adapted. In order to verify the feasibility of the algorithm, four standard test functions and three different scale environment models are selected for simulation experiments. The results show that in the performance test of the algorithm, the GSGWO has higher convergence speed and accuracy than the GWO under different test functions. In the path-planning experiment, the length, number and size of inflection points and stability of the path planned by the GSGWO are better than those of the GWO. The feasibility of the GSGWO is verified. Full article

Hybridizations were made between a 2x V. vitis-idaea (sect. Vitis-idaea, lingonberry) and 2x V. fuscatum (sect. Cyanococcus, Black Highbush Blueberry) as part of a project aimed at understanding the crossability and compatibility of these but specifically aimed at assessing the possibilities for improvement and utilization of lingonberry. The crosses succeeded at a low level, and six hybrids were produced and genetically verified. When tested for ploidy level, five of the six hybrids were found to be triploids and one was found to be a tetraploid. Hybrids were intermediate in morphology and only fertile at very low levels, largely due to their triploid nature. Several of these hybrids produced progeny when used as females and pollinated with 6x V. virgatum-derived males, indicating viable unreduced 2n ovules. Similar crosses were made between lingonberry and 2x V. elliottii (sect. Cyanococcus, Elliott’s Blueberry). These crosses produced two genetically verified hybrids, which were also determined to be triploids. These hybrids were effectively sterile. The production of triploids from 2x × 2x crosses indicates that there is a natural selection for a reproductive genome balance of two V. vitis-idaea:one Cyanococcus. The success of secondary hybridizations with hexaploid materials suggests that the triploid hybrids may be used to advance the utilization and recombination of lingonberry germplasm. Full article

Oryza officinalis Wall is a potential genetic resource for rice breeding; however, its distant genome limits its crossing ability with cultivated rice. The interspecific hybridization of O. officinalis and cultivated rice, establishment of its tissue culture, and induction of polyploidy are ways to improve O. officinalis’s poor crossability. We developed an interspecific hybrid and studied its reproductive pollen development process in this work, and the results showed that abortive pollens (81.94%) and embryo sac abnormalities (91.04%) were the key causes of its high sterility. In order to induce callus formation in interspecific hybrid explants, two different culture media, namely Chu’s N-6 medium (N6) and 1/2 Murashig and Skoog medium (1/2 MS), were employed. Additionally, two plant growth regulators (PGRs), namely 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BA), along with L-proline (Pro) and acid hydrolyzed casein, were utilized in the experiment. The optimal N6 medium, supplemented with 2.0 mg·L⁻¹ 2,4-D, produced the highest induction rate (80.56 ± 5.44)%. For callus differentiation and proliferation, the MS medium supplemented with 2.0 mg·L⁻¹ BA + 0.2 mg·L⁻¹ NAA produced the highest differentiation rate (75.00 ± 4.97)% and seedling emergence ratio (28.97 ± 4.67)%. The optimal combination for seedling rooting was the 1/2 MS medium supplemented with 2.0 mg L⁻¹ NAA and 0.2 mg L⁻¹ BA, which produced an average of 13.95 roots per plant. For polyploidy induction in the interspecific hybrid, the concentration of colchicine treatment at 400 mg·L⁻¹ for three days is an ideal protocol. We devised tissue culture and interspecific hybrid polyploidy induction to overcome O. officinalis’ poor crossability and introduce its favorable features into cultivated rice. Full article

Stair climbing is one of the most challenging tasks for vehicles, especially when transporting people and heavy loads. Although many solutions have been proposed and demonstrated in practice, it is necessary to further improve their climbing ability and safety. This paper presents a systematic review of the scientific and engineering stair climbing literature, providing brief descriptions of the mechanism and method of operation and highlighting the advantages and disadvantages of different types of climbing platform. To quantitatively evaluate the system performance, various metrics are presented that consider allowable payload, maximum climbing speed, maximum crossable slope, transport ability and their combinations. Using these metrics, it is possible to compare vehicles with different locomotion modes and properties, allowing researchers and practitioners to gain in-depth knowledge of stair-climbing vehicles and choose the best category for transporting people and heavy loads up a flight of stairs. Full article

In patients undergoing percutaneous coronary intervention, the second-generation drug-eluting stents (DES) are considered the gold standard of care for revascularization. By reducing neointimal hyperplasia, drug-eluting coronary stents decrease the need for repeat revascularizations compared with conventional coronary stents without an antiproliferative drug coating. It is important to note that early-generation DESs were associated with an increased risk of very late stent thrombosis, most likely due to delayed endothelialization or a delayed hypersensitivity reaction to the polymer. Studies have shown a lower risk of very late stent thrombosis with developing second-generation DESs with biocompatible and biodegradable polymers or without polymers altogether. In addition, research has indicated that thinner struts are associated with a reduced risk of intrastent restenosis and angiographic and clinical results. A DES with ultrathin struts (strut thickness of 70 µm) is more flexible, facilitates better tracking, and is more crossable than a conventional second-generation DES. The question is whether ultrathin eluting drug stents suit all kinds of lesions. Several authors have reported that improved coverage with less thrombus protrusion reduced the risk of distal embolization in patients with ST-elevation myocardial infarction (STEMI). Others have described that an ultrathin stent might recoil due to low radial strength. This could lead to residual stenosis and repeated revascularization of the artery. In CTO patients, the ultrathin stent failed to prove non-inferiority regarding in-segment late lumen loss and showed statistically higher rates of restenosis. Ultrathin-strut DESs with biodegradable polymers have limitations when treating calcified (or ostial) lesions and CTOs. However, they also possess certain advantages regarding deliverability (tight stenosis, tortuous lesions, high angulation, etc.), ease of use in bifurcation lesions, better endothelialization and vascular healing, and reducing stent thrombosis risk. In light of this, ultrathin-strut stents present a promising alternative to existing DESs of the second and third generation. The aims of the study are to compare ultrathin eluting stents with second- and third-generation conventional stents regarding procedural performance and outcomes based on different lesion types and specific populations. Full article

Background: Balloon uncrossable lesions are defined as lesions that cannot be crossed with a balloon after successful guidewire crossing. Methods: We analyzed the association between balloon uncrossable lesions and procedural outcomes of 8671 chronic total occlusions (CTOs) percutaneous coronary interventions (PCIs) performed between 2012 and 2022 at 41 centers. Results: The prevalence of balloon uncrossable lesions was 9.2%. The mean patient age was 64.2 ± 10 years and 80% were men. Patients with balloon uncrossable lesions were older (67.3 ± 9 vs. 63.9 ± 10, p < 0.001) and more likely to have prior coronary artery bypass graft surgery (40% vs. 25%, p < 0.001) and diabetes mellitus (50% vs. 42%, p < 0.001) compared with patients who had balloon crossable lesions. In-stent restenosis (23% vs. 16%. p < 0.001), moderate/severe calcification (68% vs. 40%, p < 0.001), and moderate/severe proximal vessel tortuosity (36% vs. 25%, p < 0.001) were more common in balloon uncrossable lesions. Procedure time (132 (90, 197) vs. 109 (71, 160) min, p < 0.001) was longer and the air kerma radiation dose (2.55 (1.41, 4.23) vs. 1.97 (1.10, 3.40) min, p < 0.001) was higher in balloon uncrossable lesions, while these lesions displayed lower technical (91% vs. 99%, p < 0.001) and procedural (88% vs. 96%, p < 0.001) success rates and higher major adverse cardiac event (MACE) rates (3.14% vs. 1.49%, p < 0.001). Several techniques were required for balloon uncrossable lesions. Conclusion: In a contemporary, multicenter registry, 9.2% of the successfully crossed CTOs were initially balloon uncrossable. Balloon uncrossable lesions exhibited lower technical and procedural success rates and a higher risk of complications compared with balloon crossable lesions. Full article

Hybridization between Cucumis species, including cultivated melon (C. melo), is hampered by Interspecific Reproductive Barriers (IRBs). However, the nature of IRBs in Cucumis is largely unknown. This study explores locations, timing, and contribution to reproductive isolation (RI) of pre- and post-zygotic IRBs in Cucumis. To do this, we assessed crossability among Cucumis African wild species and C. melo at the pre-zygotic level by visualizing pollen tubes under fluorescence microscopy and, post-zygotically, by evaluating fruit/seed set and F₁ hybrid fertility. Genetic distances among Cucumis species were inferred from Genotyping-by-Sequencing, and its correlation with RI stages was analyzed. Observed pre- and post-zygotic IRBs included pollen tube arrest, fruit set failure, and hybrid male sterility. Unilateral cross-incongruity/incompatibility (UCI) was detected in some hybridizations, and dominant gene action is suggested for pistil-side UCI in interspecific F₁ hybrids. Notably, the allotetraploid C. ficifolius was very fertile as a seed parent but infertile in all reciprocal crosses. Contribution to RI was found significant for both pre- and post-zygotic IRBs. Additionally, a significant positive correlation was detected between genetic distance and pre- and post-zygotic RI stages. Interestingly, UCI offers an accessible system to dissect the genetics of IRBs in Cucumis, which may facilitate the use of wild relatives in breeding. Full article

Interspecific hybridization between transgenic crops and their wild relatives is a major concern for transgene dispersal in the environment. Under controlled conditions, artificial hand pollination experiments were performed in order to assess the hybridization potential and the fitness of interspecific hybrids between Brassica rapa and genetically modified (GM) Brassica napus. Initially, six subspecies of B. rapa were hybridized with GM B. napus through hand pollination. In the resulting F₁ hybrids, the combination of B. rapa ssp. narinosa (♀) × GM B. napus (♂) had the highest crossability index (16.9 ± 2.6). However, the F₁ selfing progenies of B. rapa ssp. rapa (♀) × GM B. napus were found to be more effective in producing viable future generations with the highest crossability index (1.6 ± 0.69) compared to other subspecies. Consequently, they were used for the generation of F₂ and F₃ progenies. The 18 different morphological characteristics among the parental cross-combinations and F₁ hybrid progenies were measured and visualized through hierarchical clustering. Different generations were found to be grouped based on their different morphological characteristics. The chromosome numbers among the interspecific hybrids ranged from 2n = 29 to 2n = 40. Furthermore, the SSR markers revealed the presence of genomic portions in the hybrids in comparison with their parental lines. There is a high possibility of transgene flow between GM B. napus and B. rapa. The study concluded that the interspecific hybrids between B. napus and B. rapa can be viable and can actively hybridize up to F₃ generations and more. This suggests that the GM B. napus can disperse the transgene into B. rapa, and that it can pass through for several generations by hand pollination in a greenhouse environment. Full article

In nature, interspecific hybridization occurs frequently and can contribute to the production of new species or the introgression of beneficial adaptive features between species. It has great potential in agricultural systems to boost the process of targeted crop improvement. In the advent of genetically modified (GM) crops, it has a disadvantage that it involves the transgene escaping to unintended plants, which could result in non-specific weedy crops. Several crop species in the Brassica genus have close kinship: canola (Brassica napus) is an ancestral hybrid of B. rapa and B. oleracea and mustard species such as B. juncea, B. carinata, and B. nigra share common genomes. Hence, intraspecific hybridization among the Brassica species is most common, especially between B. napus and B. rapa. In general, interspecific hybrids cause numerous genetic and phenotypic changes in the parental lines. Consequently, their fitness and reproductive ability are also highly varied. In this review, we discuss the interspecific hybridization and reciprocal hybridization studies of B. napus and B. rapa and their potential in the controlled environment. Further, we address the fate of transgenes (herbicide resistance) and their ability to transfer to their progenies or generations. This could help us to understand the environmental influence of interspecific hybrids and how to effectively manage their transgene escape in the future. Full article

Wild relatives of okra represent a good source of variation for breeding programs, particularly for traits related to biotic and abiotic stresses and fruit quality. However, wild species remain largely unexploited for okra breeding. The cultivated okra accession Abelmoschus esculentus cv. ‘Arka Anamika’ was crossed with three wild accessions: Abelmoschus manihot, Abelmoschus ficulens and Abelmoschus moschatus. The crossability was estimated based on fruit set, seed set and germination rate. The results of cross compatibility studies revealed that the crosses are compatible only when cultivated A. esculentus is used as a female, and reciprocal crosses were not successful in any of the three wild species. Higher fruit set (87.2%) and seed germination (92%) were obtained from the crosses ‘Arka Anamika’ × Abelmoschus manihot. The interspecific F₁s exhibited normal growth, flowering and fruit formation, but the hybrids were completely sterile on selfing due to abnormal meiosis. Characterization of the parents and interspecific hybrids revealed that the interspecific hybrids were generally more vigorous than the parents and displayed greater alliance towards their wild parent. The sterile F₁s were further treated with 0.1% colchicine to restore fertility. The three interspecific crosses showed considerable differences in mean performance and heterosis over mid parent and better parent. The cross ‘A. Anamika’ × A. manihot displayed positive heterosis over mid parent and better parent for the yield traits, viz., fruit yield per plant, number of fruits per plant, number of primary branches per plant and plant height. The information obtained in the study on crossability relationship, phenotypic characterization and heterosis in interspecific hybrids will assist breeders in the development of prebreeding material. Full article