Cross Compatibility Research Articles

Evaluation of genetic diversity using simple sequence repeat markers and analysis of cross compatibility in hydrangeas

AbstractHydrangeas with large inflorescences are widely used as cut flowers and in floral arrangements. However, the genetic diversity of commercially grown hydrangeas has been limited owing to the breeding focus on popular species. Therefore, this study was conducted to suggest interspecific breeding strategies for expanding the genetic diversity in Hydrangea L. by evaluating genetic diversity in the seven main species collected in Korea and analyzing cross compatibility via intra- and interspecific hybridization. Interspecific diversity evaluation using simple sequence repeat markers resulted in the segregation of 35 varieties accounting for seven species into five groups as follows: (1) Hydrangea paniculate group, (2) Hydrangea arborescnes group, (3) Hydrangea anomala and Hydrangea aspera group, (4) Hydrangea quercifolia group, and (5) Hydrangea macrophylla and Hydrangea serrata group. Cross compatibility was confirmed via intra- and interspecific crossing, and hybrids were obtained in 18 crossing combinations. Intraspecific hybrids tend to be easy to obtain, but interspecific hybrids are difficult to obtain due to a variety of factors. While most of the interspecific hybrids were obtained using ovule culture, the crossing between H. macrophylla and H. serrata created hybrids from seed sowing, indicating that H. serrata is a subspecies of H. macrophylla. Bilateral and unilateral incompatibilities were observed across the obtained hybrids. Particularly, weak bilateral compatibility was observed between H. serrata and H.paniculata. Accordingly, it was proposed that hybrids between H. macrophylla and H. serrata can be successfully used as parental materials in crossing with H. paniculata to improve cold tolerance. In addition, cross compatibility was improved in interspecific crossing using H. macrophylla and H. arborescens as maternal plants. It is anticipated that these finding will help improve the genetic diversity in commercial hydrangeas.

Genetic analysis and identification of SSR marker linked topowdery mildew resistance in bitter gourd (<i>Momordica charantia </i>L.)

The inheritance of powdery mildew resistance in bitter gourd resistant line IIHR-144-1 was studied in cross with two susceptible lines Arka Harit and IIHR Sel-5-8. The segregation ratios in F2 and backcross progenies indicated that resistance is governed by dominant-recessive epistasis or dominant inhibitory epistasis, indicating the involvement of more than one pairs of genes, one dominant and one recessive for resistance along with other background minor genes in the resistant line IIHR-144-1. Bulk segregant analysis of F2 population of cross between IIHR-144-1 and Arka Harit using SSR markers identified McSSR 57 produced a polymorphic DNA fragment that co-segregated with disease reaction. Considering the cross compatibility between Momordica charantia L. and M. charantia var. muricata (IIHR-144-1) the resistance trait can be transferred to cultivated species through hybridization and selection.

Major chromosome rearrangements in intergeneric wheat × rye hybrids in compatible and incompatible crosses detected by GBS read coverage analysis

The presence of incompatibility alleles in primary amphidiploids constitutes a reproductive barrier in newly synthesized wheat-rye hybrids. To overcome this barrier, the genome stabilization process includes large-scale chromosome rearrangements. In incompatible crosses resulting in fertile amphidiploids, the elimination of one of the incompatible alleles Eml-A1 or Eml-R1b can occur already in the somatic tissue of the wheat × rye hybrid embryo. We observed that the interaction of incompatible loci Eml-A1 of wheat and Eml-R1b of rye after overcoming embryo lethality leads to hybrid sterility in primary triticale. During subsequent seed reproductions (R1, R2 or R3) most of the chromosomes of A, B, D and R subgenomes undergo rearrangement or eliminations to increase the fertility of the amphidiploid by natural selection. Genotyping-by-sequencing (GBS) coverage analysis showed that improved fertility is associated with the elimination of entire and partial chromosomes carrying factors that either cause the disruption of plant development in hybrid plants or lead to the restoration of the euploid number of chromosomes (2n = 56) in the absence of one of the incompatible alleles. Highly fertile offspring obtained in compatible and incompatible crosses can be successfully adapted for the production of triticale pre-breeding stocks.

Cross compatibility and endogenous phytohormone profiles in interspecific hybridization between Iris tectorum and Iris germanica

In order to introduce new valuable trait to other species, the interspecific hybridization is used in ornamental breeding. The success of interspecific hybridization is hindered by incompatibility occurring at various stages of hybridization. To character the barriers of interspecific hybridization between Iris tectorum and Iris germanica cultivars, this study investigated the compatibility of pre-fertilization and post-fertilization, and profiles of endogenous phytohormones in ovary of self-pollination and interspecific hybridization. After pollination, pollen tubes germinated, grew through style, and entered ovules in both self-pollination and interspecific hybridization. Thus, the interspecific incompatibility between I. tectorum and I. germanica cultivars were not caused by pre-fertilization barrier. The observations of embryo and endosperm development revealed that incompatibility of interspecific-hybridization occurred at post-fertilization stage during the development of the embryo. The degeneration of endosperms was observed at 15 days after pollination and no embryo was observed in the interspecific hybridization. The abnormal development of embryos and endosperms indicates that reproductive barriers between I. tectorum and I. germanica cultivars happened at post-fertilization stage. To character the profiles of endogenous phytohormones in the ovary of self-pollination and interspecific hybridization, concentration of auxins, cytokinins (CKs), gibberellins (GAs), abscisic acid (ABA), Jasmonate (JA), salicylic acid (SA), and their derivatives were analyzed by UPLC-ESI-MS/MS. The results showed concentrations of indole-3-acetic acid (IAA) and bioactive free based of CKs were highest in ovary of I. tectorum self-pollination (IT-Self), which has normally developed embryos and endosperms. Four bioactive forms of GAs were identified in this study, while the patterns of their concentration changes were not constant among different materials. Besides, the concentration of ABA was highest in unfertilized ovary of I. tectorum (IT-CK). According to the profiles of endogenous phytohormones, the abnormal development of embryos in interspecific hybridization might be caused by the low concentration of IAA and CKs, proper concentration of these phytohormone could be added into in vitro culture medium to rescue embryos of interspecific hybridization. The investigation of cross compatibility and endogenous phytohormone profiles in this study will provide insight for overcoming the barrier of interspecific hybridization and embryo rescue in Iris genus.

The reproductive isolation mechanism of allopatric sister species Iris dichotoma and I. domestica (Iridaceae) under the sympatric condition

In allopatric species, the geographical isolation is generally disregarded as a legitimate cause of isolation. Beside geographical isolation, the other prezygotic isolating mechanisms in allopatric species have not been well proved to cause isolation. In order to explore if two allopatric sister species Iris dichotoma and I. domestica (Iridaceae) have other prezygotic isolating mechanisms, the natural hybrids, the positions of pollen deposited on the honeybee's body, the insect visiting period and frequency, and the daily dynamic changes of pollen quantity were detected; the daily flowering times were compared; the interspecific crossing and the pollen transfer were tested; the flower-visiting insects were categorized and identified. No natural hybrids of the two species were detected under the sympatric condition. Their daily flowering times were significantly different but had 2.6 h overlap, during which they had good cross compatibility. They had common legitimate pollinators, but the visiting time did not overlap and I. domestica’s pollen quantity was down to 0 before I. dichotoma open. The same honeybee could visit both of them as I. domestica had pollen in the net house, but their pollens were deposited on different parts of the honeybee’s body. The temporal isolation caused complete reproductive isolation, and the difference in flower structure also played an important role in reproductive isolation.

Morphological relationships and cross compatibility of seven Dendrobium species in Indonesia

Abstract. Lestari NKD, Deswiniyanti NW, Sari NKY, Murna IM, Rizqy AN. 2023. Morphological relationships and cross compatibility of seven Dendrobium species in Indonesia. Biodiversitas 24: 3550-3558. The development of Dendrobium hybrid orchids in Indonesia has received less attention. This study aimed to obtain the morphological characteristics and taxonomical relationships of Dendrobium species, their interspecific and intersectional compatibility for hybridization, as well as the fertility of hybridized Dendrobium orchids. Seven Dendrobium species from several sections were used, namely D. phalaenopsis, D. lineale, D. stratiotes, D. macrophyllum, D. nobile, D. heterocarpum and D. bracteosum. We characterized the seven species based on morphological traits and investigated the taxonomical relationships using hierarchical cluster analysis by dendrogram charts. We then crossed the seven species to produce hybrids and the hybrids were then cultured in vitro. The hybridization and in vitro culture data were analyzed using an ANOVA test with Duncan's post hoc test when the results significantly differed. The results showed that the taxonomical relationship was clustered based on the sections of each Dendrobium species. The highest percentage of hybridization compatibility was found in D. phalaenopsis and D. lineale with 61.9% while the lowest was in D. nobile, and D. bracteosum (0%). Germination percentages in in vitro culture ranged from 40% to 100% for both interspecific and intersectional crosses, except for intersectional crosses of D. nobile, which failed to germinate. The findings of this study suggest that the results of interspecies and intersectional crossing showed that the highest compatibility was indicated by D. phalaenopsis and D. lineale. Therefore, they are highly recommended as the parents of hybrid orchids.

Factors of difference in intra- and inter-ploid cross compatibility in asparagus

Factors of difference in intra- and inter-ploid cross compatibility in asparagus

Genome of tetraploid sour cherry (Prunus cerasus L.) 'Montmorency' identifies three distinct ancestral Prunus genomes.

Sour cherry (Prunus cerasus L.) is a valuable fruit crop in the Rosaceae family and a hybrid between progenitors closely related to extant Prunus fruticosa (ground cherry) and Prunus avium (sweet cherry). Here we report a chromosome-scale genome assembly for sour cherry cultivar Montmorency, the predominant cultivar grown in the USA. We also generated a draft assembly of P. fruticosa to use alongside a published P. avium sequence for syntelog-based subgenome assignments for 'Montmorency' and provide compelling evidence P. fruticosa is also an allotetraploid. Using hierarchal k-mer clustering and phylogenomics, we show 'Montmorency' is trigenomic, containing two distinct subgenomes inherited from a P. fruticosa-like ancestor (A and A') and two copies of the same subgenome inherited from a P. avium-like ancestor (BB). The genome composition of 'Montmorency' is AA'BB and little-to-no recombination has occurred between progenitor subgenomes (A/A' and B). In Prunus, two known classes of genes are important to breeding strategies: the self-incompatibility loci (S-alleles), which determine compatible crosses, successful fertilization, and fruit set, and the Dormancy Associated MADS-box genes (DAMs), which strongly affect dormancy transitions and flowering time. The S-alleles and DAMs in 'Montmorency' and P. fruticosa were manually annotated and support subgenome assignments. Lastly, the hybridization event 'Montmorency' is descended from was estimated to have occurred less than 1.61 million years ago, making sour cherry a relatively recent allotetraploid. The 'Montmorency' genome highlights the evolutionary complexity of the genus Prunus and will inform future breeding strategies for sour cherry, comparative genomics in the Rosaceae, and questions regarding neopolyploidy.

Unstructured grid dynamical modeling of planetary atmospheres using planetMPAS: The influence of the rigid lid, computational efficiency, and examples of Martian and Jovian application

We present a new planetary global circulation model, planetMPAS, based on the state-of-the-art NCAR MPAS General Circulation Model. Taking advantage of the cross compatibility between WRF and MPAS, planetMPAS includes most of the planetWRF physics parameterization schemes for terrestrial planets such as Mars and Titan. PlanetMPAS also includes a set of physics that represents radiative transfer, dry convection, moist convection and its associated microphysics for the Jovian atmosphere. We demonstrate that, despite the rigid-lid approximation, planetMPAS is suitable to simulate the climate systems in Martian and Jovian atmospheres with potential application to slow-rotating planets such as Titan. Simulations using planetMPAS show that the new model can reproduce many aspects of the observed features on Mars and Jupiter, such as the seasonal CO2 cycle, polar argon enrichment, zonal mean temperature, and qualitative dust opacity on Mars, as well as the equatorial superrotation and banded zonal wind patterns on Jupiter.

Self-pollination, intra- and interspecific crosses in tomatoes

Tomato genotypes ( Solanum spp.) have genetic variability of most desirable features, such as resistance to biotic and abiotic stresses. However, incompatibility of crosses of wild genotypes with domesticated tomatoes, or even between wild genotypes, hinders the breeding process. Thus, knowledge of the reproductive biology of genotypes and conditions is necessary to maximize the success of artificial crossings. This study evaluated the compatibility of self-pollination, intra- and interspecific controlled crosses, stigma receptivity, and pollen viability in tomato genotypes. We used two commercial genotypes S. lycopersicum (‘RVTM08’ and ‘Redenção’) and seven accessions of wild tomato genotypes (‘AF 26970’, ‘LA-1401’, ‘AF 19684’, ‘LA-1967’, ‘PI-127826’, ‘PI-134417’, and ‘LA-716’). We evaluated all crosses and their reciprocals, besides the self-pollinations. The variables evaluated were fruit index (FI), number of seeds per fruit (SN), and seed germination percentage (GP). Stigma receptivity and grains’ pollen viability index (PVI) were also assessed. The results showed that ‘LA-1967’ was self-incompatible, had a low PVI, and generated fruit without seeds in most crosses. As female parents, ‘RVTM08’, ‘Redenção’, ‘AF 26970’, ‘LA-1401’, and ‘AF 19684’ showed higher FI and SN. There was a wide diversity of reproductive characteristics between the genotypes and crosses that did not influence GP. Compatibility of crosses in tomatoes is determined by the female parent choice and can be affected by stigma receptivity and the PVI.

Impact of pollination strategies on fruit set and fruit growth attributes in jasmine

Jasmine occupies predominant position among the flower crops in India in terms of area, production and productivity. The demand for jasmine flowers is growing day by day owing to its wide range of uses and there is a pressing need for improving the crop by exploring strategies to evolve diverse genotypes. The present study focuses on the hybridization of Jasminum spp with the objective of introgression of desirable traits that would aid in creation of wider genetic variability. Pollination is the basis in any hybridization programme. The main aim of this research study was to determine the suitable pollination methods among self, open and cross pollination and to assess the effect of the pollination methods on the fruit set and fruit characteristics. The results of the study revealed that the overall response of J. auriculatum was found effective with maximum fruit set percentage. J. auriculatum cv Parimullai yielded the highest fruit set of 76.43% under open pollination and the least fruit set rate of 2.14% under self-pollination. Among the possible cross combination involving J. auriculatum and J. grandiflorum cultivars as seed parents with various pollen parents, J. flexile showed considerable results. Cross combination of J. auriculatum x J. flexile recorded maximum fruit set revealing best cross compatibility while crosses involving J. sambac resulted in no fruit set indicating the prevalence of fertilization barriers that hinder hybridization.

Evaluation of compatible crosses of Agaricus bisporus and their genetic characterization

Evaluation of compatible crosses of Agaricus bisporus and their genetic characterization

400.6: OPTN Kidney Allocation Policy Change Impact on OPO Resource Allocation

Objective: This study evaluates the impact of the UNOS kidney allocation policy change requiring offers be made first to candidates at transplant hospitals within a 250-mile nautical radius of the donor hospital based on median allocation time expended by one large OPO with 78 transplant centers (including 14 local centers) that span 5 UNOS regions and 15 DSAs within its primary sharing radius. Methods: This was a single OPO, multi-center observational study. Renal distribution time (RDT) defined as the time from donor cross-clamp to when a kidney is available to a center for a specific recipient including complete donor information and a compatible final cross match was evaluated for kidneys allocated 12 months pre and post policy change. Median RDT and utilization rates were evaluated for kidneys with KDPI < 60% and kidneys with KDPI >= 60%. The OPO continued hardwired best practices pre-recovery post policy change that included transplant center review of the offer, confirming patient(s) readiness and a final cross match for at least 5 candidates prior to recovery. The OPO also required an understanding with the accepting center at final kidney acceptance including confirmation of patient status, intent for pulsatile preservation, identified center back up patients and timing of transplant surgery. Results: Between 3/15/2020 and 3/14/2021 pre policy change, the OPO recovered 1171 kidneys with a 73% utilization rate resulting in the transplantation of 859 kidneys. Between 3/15/2021 and 3/14/2022 post policy change, the OPO recovered 1336 kidneys with a 75% utilization rate resulting in the transplantation of 1005 kidneys. The proportion of kidneys placed locally decreased from 60% to 23% X2 (1, N = 1864) = 253.0262, p < 0.01. Median RDT for kidneys with KDPI >= 60% increased significantly from 6.4 hours to 9.5 hours. Conclusions: OPOs face increased challenges executing efficient kidney allocation, interacting with more centers per donor. Increased RDTs can be attributed to the number of transplant centers and patients within 250 nautical miles, increased interactions between OPOs and transplant centers, and transplant center use of third-party services that insulate the surgeon or nephrologist.

Fermiophobic light Higgs boson in the type-I two-Higgs-doublet model

The null results in the new physics searches at the LHC do not exclude a light new particle if the particle is fermiophobic. A good example is the fermiophobic Higgs boson hf in the type-I two-Higgs-doublet model, which occurs if we adopt α=π/2 and the inverted scenario where the heavier CP-even Higgs boson is the observed one at a mass of 125 GeV. We first obtain the still-valid parameter space satisfying the theoretical requirements, flavor-changing neutral currents in B physics, the cutoff scale above 1 TeV, Higgs precision data, and the direct search bounds at high energy colliders. We also study the high energy scale behavior of the allowed parameter points via the renormalization group equation analysis. An important result is that the fermiophobic type-I can maintain the stability of the scalar potential all the way up to the Planck scale if mhf is larger than half the observed Higgs boson mass. Since the decay modes of hf→γγ, H±→hfW±, and A→hfZ are dominant, the productions of pp→Ahf/H±hf/H±A/H+H− yield the four-photon final states at the LHC. We suggest the processes of 4γ+VV′ (V(′)=Z,W±) as the discovery channels that supplement 4γ+V, since they have compatible cross sections and enjoy the background-free environment.

Interacting host modifier systems control Wolbachia-induced cytoplasmic incompatibility in a haplodiploid mite.

Reproductive parasites such as Wolbachia spread within host populations by inducing cytoplasmic incompatibility (CI). CI occurs when parasite‐modified sperm fertilizes uninfected eggs and is typified by great variation in strength across biological systems. In haplodiploid hosts, CI has different phenotypic outcomes depending on whether the fertilized eggs die or develop into males. Genetic conflict theories predict the evolution of host modulation of CI, which in turn influences the stability of reproductive parasitism. However, despite the ubiquity of CI‐inducing parasites in nature, there is scarce evidence for intraspecific host modulation of CI strength and phenotype. Here, we tested for intraspecific host modulation of Wolbachia‐induced CI in haplodiploid Tetranychus urticae mites. Using a single CI‐inducing Wolbachia variant and mitochondrion, a nuclear panel was created that consisted of infected and cured near‐isogenic lines. We performed a highly replicated age‐synchronized full diallel cross composed of incompatible and compatible control crosses. We uncovered host modifier systems that cause striking variation in CI strength when carried by infected T. urticae males. We observed a continuum of CI phenotypes in our crosses and identified strong intraspecific female modulation of the CI phenotype. Crosses established a recessive genetic basis for the maternal effect and were consistent with polygenic Mendelian inheritance. Both male and female modulation interacted with the genotype of the mating partner. Our findings identify spermatogenesis as an important target of selection for host modulation of CI strength and underscore the importance of maternal genetic effects for the CI phenotype. Our findings reveal that intraspecific host modulation of CI is underpinned by complex genetic architectures and confirm that the evolution of reproductive parasitism is contingent on host genetics.

Percentage Expression of Lewis B, Rh-e, N and ABO Antigens in descents of Bonny Kingdom, River, State, Nigeria.

Introduction: The presence of rare blood group antibodies in the blood of donors/recipients stimulate red cell alloimmunization and constitute a major cause of transfusion related reaction after a compatible ABO cross match, yet remain one of the less routinely assessed prior to blood donation and transfusion in Nigeria. This cross-sectional study was carried out among indigenes of Bonny kingdom in Rivers State Nigeria to access the percentage expression of Lewis B, Rh-e, N and ABO antigens in descent of Bonny Kingdom Rivers State Nigeria. Materials and Methods:- One hundred and twenty (120) apparently healthy subjects consisting of sixty (60) females and sixty (60) males aged between 18-50 years all indigenes of Bonny Kingdom were recruited by structured questionnaire for the study. 4mls of venipuncture blood was aseptically collected from each participant into vacutainer bottle containing 0.5 mL of 1.2 mg/mL dipottasium ethylenediaminetetraacetic acid anticoagulant and a 5% cell suspension was prepared and used to determine the various blood groups antigens using the standard tube Agglutination technique. Results: Results obtained shows a total of 94.1% (113) of the participants expressed Rh-e antigen, 45.8% (55) male and 48.3% (58) females. 7.5% (9) of the participants expressed the N antigen, 3.3% (4) male and 4.2% (5) females. 4.2% (5) of the study population expressed Lewis B antigen, 2.5% (3) males and 1.7% (2) female. The ABO system showed 68.5% (79) O blood group, 29.1% (35) male and 36.7% (44) female. 22(18.3%) typed for A blood group, 11.6% (14) male and 6.7% (8) female. For B blood group 14.2% (17) persons were typed, 7.5% (9) male and 6.7% (8) female while 1.6% (2) persons were typed as AB and they are all females. Conclusion: Rh-e phenotype occurred highest among the study participants. The proportion of the population without the expression of these antigens of the blood group tested has the potential to be alloimmunized during blood transfusion and develop antibodies, some of which can be responsible for transfusion reactions and haemolytic disease of the new born. This study has provided baseline data on the distribution of some blood group antigens in the Bonny Kingdom of Rivers State in Nigeria. Based on the finding in this study, it is recommended that Rh-e grouping be carried out on pregnant mothers, blood donors and recipients before transfusion; while Lewis B and N blood groups may be subjected to expansive population testing.

Half diallel of F1 tomato hybrid and its double cross-compatibility

Abstract. Farid M, Anhsori MF, Ridwan I, Dungga NE, Ermiyanti I. 2022. Half diallel of F1 tomato hybrid and its double cross-compatibility. Biodiversitas 23: 1813-1821. Breeding program for improvement of tomato fruit can be done through diallelic crosses genetic combinations. Therefore, genetic evaluation is needed to meet the breeding objective. This process can be combined with crosses between F1 to produce high diversity. However, evaluating the crosses' compatibility is required to increase the effectiveness of the assembly process. This study aimedto assess the half-diallel crosses of F1 tomatoes in the field and determine the most compatible pair cross combinationsin forming double and three-way F1 populations. This study was carried out in the Experimental Farm of the Faculty of Agriculture, Hasanuddin University. The field evaluation was arranged ina randomized complete block design with ten genotypes, while the compatibility evaluationwas carried out using 6 F1 half diallel as the parents. The results showed that the Mawar and Chung varieties were better parents in the crossings. Furthermore, the results showed that F1 K/M (the best yield component), M/C (the best TDS and Lycopene traits), and BC/K (the genotype has good traits of yield component, TDS and Lycopene) were the best single F1 crosses that could be inherited to the F2 generation. In contrast, F1 K/M and F1 K/C crosses were the best male and female parents, respectively. The recommended double-crosses include K/C//BC/M, and BC/C//K/M, while for the F1 unbalanced three-way cross was K/C//K/M.

Comparing Outcomes of COVID-19 vs NonCOVID-19 Lung Transplant Recipients on ECMO as a Bridge to Transplant

PurposeDespite advances in treatments for COVID-19, a subset of patients develop end stage lung disease, necessitating lung transplantation. However, COVID-19 ARDS often requires prolonged intubation with sedation and paralytics, resulting in profound deconditioning. As such, extracorporeal membranous oxygenation (ECMO) is a useful bridge to transplant to allow for a wakeful state and facilitate rehab. This study compares outcomes among patients with COVID-19 and nonCOVID-19 lung disease placed on ECMO as a bridge to transplant.MethodsAll patients on veno-venous ECMO prior to lung transplantation at a single center from Jan 2020 - Oct 2021 were identified. Patient characteristics and post-transplant outcomes were abstracted for comparison.ResultsA total of 7 patients were identified in the COVID-19 (C) cohort and 11 in the nonCOVID-19 (NC) cohort. Age and LAS at transplant were similar (Table 1). As expected, total duration on ECMO was longer for C cohort patients (85.4 vs 14.5 days). Patients in the C cohort had longer ischemia times and more returns to the OR within 72 hours of transplant (71% vs 45%). Rates of hemodialysis within 30 days of transplant were lower in the C cohort (14% vs 18%). Further, C cohort patients had higher rates of detectable donor specific antibodies by IgG (71% vs 55%), though all were negative by C1q and compatible cross matches. While total and ICU lengths of stay were longer in the C cohort, this group had a shorter post-transplant hospital length of stay. Median time post-transplant was 212 days for the C cohort and 154 days for the NC cohort; survival was 100% for both groups at follow up.ConclusionFor patients with COVID-19 ARDS, ECMO is a useful bridge to transplant to mitigate complications associated with prolonged mechanical ventilation. These preliminary data suggest prolonged periods of ECMO pre-transplant do not result in significant adverse events post-transplant. Additional analyses of graft function and survival at 6 and 12 months are ongoing.

Cross compatibility in intraspecific and interspecific hybridization in yam (Dioscorea spp.)

Yam (Dioscorea spp.) is a staple crop for millions of people in the tropics and subtropics. Its genetic improvement through breeding is being challenged by pre-zygotic and post-zygotic cross-compatibility barriers within and among species. Studies dissecting hybridization barriers on yam for improving the crossability rates are limited. This study aimed to assess the cross-compatibility, which yielded fruit set, viable seeds and progeny plants in an extensive intraspecific and interspecific crossing combinations in a yam genetic improvement effort to understand the internal and exogenous factors influencing pollination success. Cross-compatability was analyzed at the individual genotype or family level using historical data from crossing blocks and seedling nurseries from 2010 to 2020 at the International Institute of Tropical Agriculture (IITA). The average crossability rate (ACR) was lower in interspecific crossing combinations (6.1%) than intraspecific ones (27.6%). The seed production efficiency (SPE) values were 1.1 and 9.3% for interspecific and intraspecific crosses, respectively. Weather conditions and pollinator's skills are the main contributors to the low success rate in the intraspecific cross combinations in yam breeding. At the same time, genetic distance and heterozygosity played little role. Interspecific cross barriers were both pre-zygotic and post-zygotic, resulting from the evolutionary divergence among the yam species. Dioscorea rotundata had higher interspecific cross-compatibility indices than D. alata. Distant parents produced intraspecific crossbred seeds with higher germination rates compared to closest parents (r = 0.21, p = 0.033). This work provided important insights into interspecific and intraspecific cross-compatibility in yam and suggested actions for improving hybridization practices in yam breeding programs.

Genetic control of compatibility in crosses between wheat and its wild or cultivated relatives.

SummaryIn the recent years, the agricultural world has been progressing towards integrated crop protection, in the context of sustainable and reasoned agriculture to improve food security and quality, and to preserve the environment through reduced uses of water, pesticides, fungicides or fertilisers. For this purpose, one possible issue is to cross‐elite varieties widely used in fields for crop productions with exotic or wild genetic resources in order to introduce new diversity for genes or alleles of agronomical interest to accelerate the development of new improved cultivars. However, crossing ability (or crossability) often depends on genetic background of the recipient varieties or of the donor, which hampers a larger use of wild resources in breeding programmes of many crops. In this review, we tried to provide a comprehensive summary of genetic factors controlling crossing ability between Triticeae species with a special focus on the crossability between wheat (Triticum aestivum L.) and rye (Secale cereale), which lead to the creation of Triticale (x Triticosecale Wittm.). We also discussed potential applications of newly identified genes or markers associated with crossability for accelerating wheat and Triticale improvement by application of modern genomics technologies in breeding programmes.