Fertile F1 Research Articles

Development of a set of monosomic alien addition lines from Gossypium raimondii in Gossypium hirsutum toward breeding applications in cotton

BackgroundGossypium raimondii Ulbr is a diploid wild cotton (2n = 26, D5D5) that originated in west-central Peru of South America and possesses desirable characteristics that are absent in the Upland cotton G. hirsutum. Many beneficial genes were lost from G. hirsutum in the process of domestication, leading to a narrowed genetic base and greater vulnerability to biotic and abiotic stresses. This genetic base can be expanded through distant hybridization using the superior genes of G. raimondii.ResultsIn this study, putative hexaploid F1 plants of G. hirsutum - G. raimondii were generated by interspecific hybridization. Analysis of its mitotic metaphase plates revealed the presence of 78 chromosomes, with each of the six chromosome-specific fluorescence in situ hybridization (FISH) probes (3D5, 5D5, 6D5, 7D5, 9D5, and 10D5) of G. raimondii exhibiting bright and distinct signals on its respective pair of chromosomes. Then, the fertile hexaploid F1 plants were continuously backcrossed with G. hirsutum and a set of G. hirsutum - G. raimondii monosomic alien addition lines (MAALs) were developed using SSR markers in successive backcrosses and self-crossing from BC2F1 to BC4F2. These MAALs were confirmed by chromosome-specific anchored SSRs and FISH. This set of MAALs exhibited abundant variation in morphological traits, agronomic characteristics, yield, and fiber quality traits, as well as in drought and salt resistance at seedling stage. Notably, MAAL_9D5 and MAAL_10D5 demonstrated excellent fiber length (FL), fiber uniformity (FU), fiber strength (FS), micronaire value, and fiber elongation (FE); At seeding stage, MAAL_8D5, MAAL9D5, MAAL_10D5, MAAL_12D5, and MAAL_13D5 showed salt resistance potential; while MAAL_1D5, MAAL_3D5, MAAL_4D5, MAAL_7D5, MAAL_8D5, MAAL_12D5, and MAAL_13D5 exhibited drought resistance potential. These MAALs will provide important genetic bridge materials for gene transfer from G. raimondii as well as for the study of Gossypium species genomes and their evolution.ConclusionsA set of Gossypium hirsutum - Gossypium raimondii MAALs were developed and they showed abundant variation in morphological, agronomic, yield, and fiber quality traits, as well as in drought and salt resistance at seedling stage.

Tetraploid interspecific hybrids between Asian and African rice species restore fertility depending on killer-protector loci for hybrid sterility.

Interspecific F1 hybrids between Asian (Oryza sativa) and African rice (Oryza glaberrima) exhibit severe sterility caused by the accumulation of hybrid sterility genes/loci at 15 or more loci. The mechanisms underlying the hybrid sterility genes are largely unknown; however, a few genes associated with the killer-protector system, which is the system most frequently associated with hybrid sterility genes, have been identified. We previously produced fertile plants as tetraploids derived from diploid interspecific F1 hybrids through anther culture; therefore, it was suggested that hybrid sterility could be overcome following tetraploidization. We investigated whether tetraploid interspecific plants produced by crossing are fertile and tested the involvement of hybrid sterility genes in the process. Fertile tetraploid interspecific F1 hybrid plants were obtained by crossing 2 tetraploids of O. sativa and O. glaberrima. To elucidate the relationships between pollen fertility and the hybrid sterility loci in the tetraploid F1 microspores, we performed genetic analyses of the tetraploid F2 hybrids and diploid plants obtained from the microspores of tetraploid interspecific hybrids by anther culture. The result suggested that the tetraploid interspecific hybrids overcame pollen and seed infertility based on the proportion of loci with the killer-protector system present in the tetraploids. The heterozygous hybrid sterility loci with the killer-protector system in the tetraploid segregate the homozygous killed allele (16.7-21.4%), with more than three-quarters of the gametes surviving. We theoretically and experimentally demonstrated that fertile rice progenies can be grown from tetraploid interspecific hybrids.

Assessment of Transgressive Segregants for Yield and its Component Traits in French Bean (Phaseolus vulgaris L.)

Background: Extreme phenotypes carried on by transgressive segregation are, moreover, heritably stable in contrast to heterosis. It has been hypothesized that the development of extreme or “transgressive” traits in segregating hybrid populations assists in the adaptive divergence of hybrid taxa. The investigation on French bean was experimented to evaluate transgressive segregants generated in the F2 generation for yield and related traits. Methods: The present study on French bean was conducted during rabi 2019 to 2022 to elicit data on transgressive segregants produced for yield and related traits in F2 generation. Fertile F1 hybrids were developed from three crosses: IC 632961 × Arka Sukomal, IC 632961 × Arka Arjun and Arka Arjun × IC 63296. Heterosis was estimated for yield and related traits in these hybrids. The F2 progeny were evaluated in open field condition. Mean, standard deviation and percentage of transgressive segregants were estimated for quantitative traits under investigation. Result: Transgressive segregants were observed in all three crosses, with the highest number of transgressive segregants for yield traits found in the progeny of the cross IC 632961 × Arka Sukomal. The identification and isolation of such transgressive segregants indicate that the parents possess favourable alleles and genes governing the traits of interest, which can be consolidated into a single or a few genotypes through stringent selection. Superior and desirable transgressive segregants were observed for all sixteen yield and its component traits, except for leaf length, in the two cross combinations Arka Arjun × IC 632961 and IC 632961 × Arka Arjun. The highest percentage of transgressive segregation was observed for the number of inflorescences per plant (79.49%), followed by the number of pods per plant (78.46%) and pod yield per plant (75.61%) in the F2 generation.

Fertile Intersectional F1 Hybrids of 4x Andean Blueberry (Vaccinium meridionale) and 4x American Cranberry (Vaccinium macrocarpon)

Vaccinium meridionale (section Pyxothamnus), a tetraploid species native to higher altitude locations in Jamaica, Colombia, and Venezuela, is of interest to Vaccinium breeders for its profuse, concentrated springtime flowering and monopodial plant structure, both of which may be useful in breeding for mechanical harvest. In this study, tetraploid V. meridionale was hybridized successfully as a male with 4x V. macrocarpon (section Oxycoccos, American cranberry). The first-generation hybrids with 4x cranberry were intermediate in morphology and notably vigorous. The 4x F1 hybrids displayed a vining plant structure, increased flower bud numbers, and white campanulate flowers. The F1 hybrids displayed modest fertility as females upon selfing and backcrossing to 4x V. macrocarpon. Evaluations of male fertility found good pollen production and a range of pollen quality ranging from very good to poor. Hybrids functioned well as males in crosses that used US 1930, a V. meridionale–V. vitis-idaea hybrid as the female. The fertility suggests that these hybrids, despite being derived from intersectional crosses, might be used conventionally in cranberry breeding without significant difficulty.

Genetic Assessment of Fertile F1 Hybrids between Two Hercules Beetles, Dynastes maya Hardy and D. grantii Horn (Scarabaeidae).

Although hybridization may complicate taxonomic practices, it can be common between animal species. Animal hybridization not only can help with generating phenotypic and species diversity in nature, but also with understanding the genetic and genomic basis of phenotypic evolution in the laboratory. We assessed the genetic composition of captive bred F1 hybrids between two Hercules beetle species using mitochondrial CO1 and nuclear loci from a double-digest restriction-site associated DNA sequencing (ddRADseq) library. We showed that the F1 hybrids were genetically clustered with samples from the maternal species, D. grantii, based on CO1 data. Nuclear genome data, on the other hand, clearly showed that the F1 individuals were genetically intermediate between D. maya, the paternal species, and D. grantii, based on a principal component analysis. Our results also revealed that sampling design may have a major impact on the inferred genetic structure and hybrid individuals using ddRADseq data sets. We discuss the importance and potential from studying the genomics of this hybrid progeny in terms of understanding the origin and maintenance of both intraspecific and interspecific phenotypic divergence and convergence.

Development of a High-Density Genetic Map for Muscadine Grape Using a Mapping Population from Selfing of the Perfect-Flowered Vine ‘Dixie’

Intraspecific diversity of the immune grape Muscadinia rotundifolia Michaux. can serve as a rich source of valuable resistance loci to the most widespread pathogens and pests of grapevine. While only one Run1/Rpg1 resistance locus has been introgressed from M. rotundifolia to the Vitis vinifera gene pool, a number of other genes conferring resistance to powdery mildew and downy mildew have been identified in various Muscadinia cultivars. A larger introduction of Muscadinia varieties to the European continent would greatly facilitate experiments of interspecific crosses as well as stimulate biotechnological efforts to overcome the main barrier to F1 fertility caused by the differences in chromosome number. For the successful introduction of Muscadinia into the new European environment, it is necessary to overcome the difficulties associated with the physiological characteristics of the species, such as insufficient cold tolerance and very late fruit ripening. To facilitate the further discovery of valuable loci in Muscadinia and their transfer to grapevine breeding programs, we constructed a high-density linkage map using an S1 mapping population obtained from the self-pollination of M. rotundifolia cv. Dixie maintained on the southern coast of Crimea. Using ddRADseq, 3730 SNPs were ordered across 20 linkage groups spanning 2753.6 cM of the total map length. No segregation in resistance to diseases and pests was observed among the 'Dixie' S1 population, suggesting the presence of homozygous non-segregating resistant loci in the genetic background of 'Dixie'. Markers with high segregation distortion showed a bias towards chromosomal intervals on linkage groups 10 and 20, where loci affecting the survival of 'Dixie' S1 progeny may be localized. QTLs with significant additive and dominance effects were discovered on LG14 and LG18, affecting the morphological traits associated with the vigor of growth and adaptability of young Muscadinia vines in the conditions of Crimea.

Maternal exposure to 4-vinylcyclohexene diepoxide during pregnancy induces subfertility and birth defects of offspring in mice

4-vinylcyclohexene diepoxide (VCD), widely used in industry, is a hazardous compound that can cause premature ovarian failure, but whether maternal VCD exposure affects the health and reproduction of offspring is unknown. Here we focused on the effects of VCD on fertility and physical health of F1 and F2 offspring in mice. The pregnant mice were injected intraperitoneally with different dosages of VCD once every day from 6.5 to 18.5 days post-coitus (dpc). We showed that maternal exposure to VCD during pregnancy significantly reduced the litter size and ovarian reserve, while increasing microtia occurrences of F1 mice. The cytospread staining showed a significant inhibition of meiotic prophase I progression from the zygotene stage to the pachytene stage. Mechanistically, the expression level of DNA damage marker (γ-H2AX) and BAX/BCL2 ratios were significantly increased, and RAD51 and DMC1 were extensively recruited to DNA double strand breaks sites in the oocytes of offspring from VCD-exposed mothers. Overall, our results provide solid evidence showing that maternal exposure to VCD during pregnancy has intergenerational deleterious effects on the offspring.

L-Arginine reverses maternal and pre-pubertal codeine exposure-induced sexual dysfunction via upregulation of androgen receptor gene and NO/cGMP signaling.

Although codeine has been reported to enhance sexual activity by improving penile reflexes, it has been shown to impair fertility indices. Also, codeine impairs ovarian steroidogenesis and folliculogenesis. Nonetheless, whether or not codeine exerts an epigenetic effect remains unclear. On the other hand, arginine has been speculated to enhance penile reflexes by upregulating NO/cGMP Signaling. The study evaluated the effect of maternal codeine exposure and prepubertal codeine and arginine treatments on F1 male sexual function and fertility indices, as well as the outcome of F2 progenies. In addition, the epigenetic programming mechanism was also explored. Forty three-week-old female rats were randomized into two groups (n = 20 rats/group); the control that received 0.5 ml of distilled water and the codeine-treated that received 5 mg/kg of codeine via gavage for eight weeks. Afterward, the female rats were paired for mating with sexually mature male rats. Rats were maintained on their pre-pregnancy treatments throughout pregnancy and lactation. FI progenies from each cohort (control and codeine-treated cohorts) were weaned at three weeks and randomized into four groups; the control, codeine-treated, L-arginine-treated (300mg/kg), and codeine + L-arginine-treated (n = 10 rats/group). Administration commenced a week post-weaning and lasted for eight weeks via gavage. Maternal codeine exposure did not alter body weight, but significantly reduced anogenital distance and anogenital index of F1 male offspring. Also, maternal codeine delayed preputial membrane separation, impaired male sexual competence, and penile reflexes of F1 male offsprings. These were associated with reduced dopamine, gonadotropins, and testosterone levels as well as suppressed expression of androgen receptor mRNA. In addition, maternal codeine downregulated NO/cGMP signaling, impaired fertility indices, and reduced the litter size, weight, and survival of F2 progenies. These alterations were observed to be aggravated by prepubertal codeine exposure but improved by prepubertal arginine treatment. In conclusion, codeine programmed sexual dysfunction by suppressing the levels of dopamine and testosterone, as well as repressing the expression of androgen receptor mRNA. In addition, codeine-induced epigenetic reprogramming was expressed in the F2 offsprings as reduced litter size and weight, and survival rate. Notably, these observations were worsened by prepubertal codeine exposure, but dampened by prepubertal arginine treatment.

COMPARATIVE MORPHOLOGY, BIOSYSTEMATICS, AND REPRODUCTIVE ECOLOGY OF PHACELIA STEBBINSII, P. MARCESCENS, AND P. QUICKII

Phacelia stebbinsii Constance & Heckerd, P. marcescens Eastw. ex J.F.Macbr., and P. quickii J.T.Howell are morphologically similar annual taxa endemic to the west side of the Sierra Nevada in California. Experimental crosses show P. quickii is reproductively isolated from the other two species, and that P. marcescens and P. stebbinsii readily produce fully fertile F1 and S2 hybrid progeny, but typically only when P. marcescens is the carpellate parent. The presence of geographic separation, habitat differences, unilateral crossability, pollen certation, and problems with cotyledon emergence in hybrid seedlings provide evidence P. stebbinsii is distinct from P. marcescens and they are maintained as separate species. Flower and fruit characters used to distinguish these three species from each other appear to be related to differences in seed dispersal and seedling establishment in different habitats.

Potential lines of black rice crossing with Jeliteng variety and their reciprocals

Climate change causes an increase in rice plant pests, one of them is brown planthopper. The effort through an assembly of black rice potential lines was made by mutation induction of Cempo Ireng black rice, but it’s only able to shorten the age of plant without being able to improve rice resistance to brown planthopper. Jeliteng as a new high yielding variety of black rice that is resistant to brown planthopper biotype 1 makes it worthy of being a potential parent source. Reciprocal crosses needed to be carried out to get offspring that have superior traits from both parents. This research aims to get F1 generation from the potential lines of black rice crossing with the Jeliteng variety and their reciprocals to improve local varieties of black rice. The research was conducted in the experimental field of the village of Gawanan, Sukoharjo Regency from August 2020 to April 2021. The planting materials were the Jeliteng variety as male parents while 6 potential lines of black rice 8, 13, 44, 46, 51, 52, and Cempo Ireng variety as female parents. Crosses were conducted by hand crossing technique on 14 sets. The data were analyzed descriptively and using the Chi-square test. The results showed that the crossing set could be crossed and produced fertile F1 generation. The length of grain, the width of grain, and the weight of a grain of the F1 varied in all sets. The skin colour of the F1 generation in all sets was mostly straw yellow with brown spots.

Identification and expression analysis of phospholipase C family genes between different male fertility accessions in pepper.

Phospholipase C (PLC) is one of the major lipid-hydrolyzing enzymes, involved in lipid-mediating signal pathway. PLCs have been found to play a significant role in the growth and development of plants. In this study, the genome-wide identification and characteristic analysis of CaPLC family genes in pepper were conducted and the expression of two CaPLC genes were investigated. The results showed that a total of 11 CaPLC family genes were systematically identified, which were distributed on five chromosomes and divided into two groups based on their evolutionary relevance. Some cis-elements responding to different hormones and stresses were screened in the promoters of CaPLC genes. Quantitative real-time PCR indicated that the expression of CaPIPLC1 and CaPIPLC5 in flowers were dozens of times higher than in other tissues. In addition, with the development of flower buds, the relative expressions of CaPIPLC1 and CaPIPLC5 gradually increased in fertile materials R1 and F1. However, no expression of CaPIPLC1 and CaPIPLC5 were detected at all developmental stages of cytoplasmic male sterile lines (CMS) compared with fertile accessions. The study revealed the number and characteristics of the CaPLC family genes, which supplied a basic and systematic understanding of CaPLC family. In addition, these findings provided new insights into the role of CaPLC genes in pollen development and fertility restoration in pepper.

Unraveling patterns of disrupted gene expression across a complex tissue.

Whole tissue RNASeq is the standard approach for studying gene expression divergence in evolutionary biology and provides a snapshot of the comprehensive transcriptome for a given tissue. However, whole tissues consist of diverse cell types differing in expression profiles, and the cellular composition of these tissues can evolve across species. Here, we investigate the effects of different cellular composition on whole tissue expression profiles. We compared gene expression from whole testes and enriched spermatogenesis populations in two species of house mice, Mus musculus musculus and M. m. domesticus, and their sterile and fertile F1 hybrids, which differ in both cellular composition and regulatory dynamics. We found that cellular composition differences skewed expression profiles and differential gene expression in whole testes samples. Importantly, both approaches were able to detect large-scale patterns such as disrupted X chromosome expression, although whole testes sampling resulted in decreased power to detect differentially expressed genes. We encourage researchers to account for histology in RNASeq and consider methods that reduce sample complexity whenever feasible. Ultimately, we show that differences in cellular composition between tissues can modify expression profiles, potentially altering inferred gene ontological processes, insights into gene network evolution, and processes governing gene expression evolution.

Unraveling the Genetic Basis of Fertility Restoration for Cytoplasmic Male Sterile Line WNJ01A Originated From Brassica juncea in Brassica napus.

Crosses that lead to heterosis have been widely used in the rapeseed (Brassica napus L.) industry. Cytoplasmic male sterility (CMS)/restorer-of-fertility (Rf) systems represent one of the most useful tools for rapeseed production. Several CMS types and their restorer lines have been identified in rapeseed, but there are few studies on the mechanisms underlying fertility restoration. Here, we performed morphological observation, map-based cloning, and transcriptomic analysis of the F2 population developed by crossing the CMS line WNJ01A with its restorer line Hui01. Paraffin-embedded sections showed that the sporogenous cell stage was the critical pollen degeneration period, with major sporogenous cells displaying loose and irregular arrangement in sterile anthers. Most mitochondrial electron transport chain (mtETC) complex genes were upregulated in fertile compared to sterile buds. Using bulked segregant analysis (BSA)-seq to analyze mixed DNA pools from sterile and fertile F2 buds, respectively, we identified a 6.25 Mb candidate interval where Rfw is located. Using map-based cloning experiments combined with bacterial artificial chromosome (BAC) clone sequencing, the candidate interval was reduced to 99.75 kb and two pentatricopeptide repeat (PPR) genes were found among 28 predicted genes in this interval. Transcriptome sequencing showed that there were 1679 DEGs (1023 upregulated and 656 downregulated) in fertile compared to sterile F2 buds. The upregulated differentially expressed genes (DEGs) were enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) lysine degradation pathway and phenylalanine metabolism, and the downregulated DEGs were enriched in cutin, suberine, and wax biosynthesis. Furthermore, 44 DEGs were involved in pollen and anther development, such as tapetum, microspores, and pollen wall development. All of them were upregulated except a few such as POE1 genes (which encode Pollen Ole e I allergen and extensin family proteins). There were 261 specifically expressed DEGs (9 and 252 in sterile and fertile buds, respectively). Regarding the fertile bud-specific upregulated DEGs, the ubiquitin–proteasome pathway was enriched. The top four hub genes in the protein–protein interaction network (BnaA09g56400D, BnaA10g18210D, BnaA10g18220D, and BnaC09g41740D) encode RAD23d proteins, which deliver ubiquitinated substrates to the 26S proteasome. These findings provide evidence on the pathways regulated by Rfw and improve our understanding of fertility restoration.

Hybrid Sterility, Genetic Conflict and Complex Speciation: Lessons From the Drosophila simulans Clade Species.

The three fruitfly species of the Drosophila simulans clade— D. simulans, D. mauritiana, and D. sechellia— have served as important models in speciation genetics for over 40 years. These species are reproductively isolated by geography, ecology, sexual signals, postmating-prezygotic interactions, and postzygotic genetic incompatibilities. All pairwise crosses between these species conform to Haldane’s rule, producing fertile F1 hybrid females and sterile F1 hybrid males. The close phylogenetic proximity of the D. simulans clade species to the model organism, D. melanogaster, has empowered genetic analyses of their species differences, including reproductive incompatibilities. But perhaps no phenotype has been subject to more continuous and intensive genetic scrutiny than hybrid male sterility. Here we review the history, progress, and current state of our understanding of hybrid male sterility among the D. simulans clade species. Our aim is to integrate the available information from experimental and population genetics analyses bearing on the causes and consequences of hybrid male sterility. We highlight numerous conclusions that have emerged as well as issues that remain unresolved. We focus on the special role of sex chromosomes, the fine-scale genetic architecture of hybrid male sterility, and the history of gene flow between species. The biggest surprises to emerge from this work are that (i) genetic conflicts may be an important general force in the evolution of hybrid incompatibility, (ii) hybrid male sterility is polygenic with contributions of complex epistasis, and (iii) speciation, even among these geographically allopatric taxa, has involved the interplay of gene flow, negative selection, and positive selection. These three conclusions are marked departures from the classical views of speciation that emerged from the modern evolutionary synthesis.

Interspecific Hybridization Between Vigna radiata and Vigna mungo Towards the Broadening of Genetic Base for MYMV Disease Resistance and Generating Variability

Background: The main cause for low yield in greengram is its susceptibility to Mungbean Yellow Mosaic Virus (MYMV) which is the most prevalent and destructive viral pathogen cause 85% yield lose. Inter specific hybridization between Vigna radiata and Vigna mungo could be an alternate approach to develop MYMV resistant genotypes in greengram which leads to additional source of creating variability for desirable attributes including yield, nutritional quality, biotic and abiotic stresses. Methods: The present investigation was carried out at National Pulses Research Centre (NPRC), Tamil Nadu Agricultural University, Vamban during 2016-2017. Interspecific hybridization has been effected between Vigna radiata var. VBN (Gg)2, VBN (Gg) 3 (as females) and Vigna mungo Var. Mash 114 (as male) during Summer 2016. The interspecific F1 hybrids, F2 and F3 populations were evaluated during Kharif 2016, Rabi 2016-17 and summer 2017 respectively. The F2 and F3 populations were evaluated for days to 1st flowering, days to maturity, plant height (cm), number of branches / plant, number of clusters / plant, number of pods / clusters, pod length (cm), number of seeds / pod, number of pods / plant, single plant yield (g.). The MYMV resistance has been confirmed under infector row method using CO 5 as susceptible check variety. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV), Heritability (h2) in broad sense, genetic advance as per cent of mean, Skewness and Kurtosis were estimated for yield and yield components. Result: Four true F1 plants were recovered in Vigna radiata var. VBN (Gg)2 x Vigna mungo Var. Mash 114 cross combination. The fertile F1 had the shallow lobbed leaf of Vigna radiata var. VBN (Gg)2 and black colour seed of Vigna mungo var. Mash 114 with pollen fertility of 42.0 per cent and crossability of 12.50%. Most interestingly all the four interspecific F1 plants were free from MYMV disease. In F2 generation, only one healthy plant was survived which had a pod, stem and branching behaviour of blackgram and greengram characters of lobbed leaf and green seed colour. In F3 generation, number of branches per plant, number of clusters per plant, number of pods per plant, pod length and seed yield per plant had high GCV, high PCV, high heritability coupled with high genetic advance as per cent of mean. Present study suggests that MYMV resistant cultivars of greengram can be explored through interspecific hybridization with Vigna mungo var. Mash 114 as a source of resistance and the hidden transgressive segregants can be recovered in F3 generation.

Fertile Intersectional F1 Hybrids of 4x Vaccinium meridionale (Section Pyxothamnus) and Highbush Blueberry, V. corymbosum (Section Cyanococcus)

Vaccinium meridionale (section Pyxothamnus), a tetraploid species native to higher altitude locations in Jamaica, Colombia, and Venezuela, is of considerable interest to blueberry breeders for its profuse, concentrated flowering and monopodial plant structure, both of which may be useful in breeding for mechanical harvest. In this study, tetraploid V. meridionale was successfully hybridized as a male with 4x V. corymbosum (section Cyanococcus, highbush blueberry). The first-generation hybrids with highbush blueberry selections were intermediate in morphology and notably vigorous. The 4x F1 hybrids displayed variable branching structure, dormancy, prolificacy, fruit wax, etc.; however, most appear to be deciduous to semi-evergreen, with small, dark-colored fruit. The F1 hybrids displayed good fertility as females in backcrosses to 4x highbush and these crosses have produced numerous offspring morphologically indistinguishable from 4x highbush at the seedling stage. Evaluations of male fertility found variation for pollen production and quality but, significantly, found some clones with very good shed, high stainability, and almost complete tetrad production. The fertility suggests that these hybrids, despite being derived from intersectional crosses, might be conventionally used without significant difficulty. These hybrids also have potential value for the nascent V. meridionale breeding efforts occurring in Colombia, South America.

Divergence in flowering time is a major component contributing to reproductive isolation between two wild rice species (Oryza rufipogon and O. nivara).

It is of critical importance for our understanding of speciation process to determine the forms of reproductive isolation and their relative importance in species divergence. Oryza nivara and O. rufipogon are direct ancestors of Asian cultivated rice and a progenitor-daughter species pair. Investigating the reproductive isolation between them provides insights into plant speciation and helps understanding of the rice domestication. Here, we quantitatively measured the major components of reproductive isolation between the two species based on common garden and crossing experiments for three pairs of sympatric populations in Nepal, Cambodia and Laos. We revealed significant differences in the flowering times between species pairs, with O. nivara flowering much earlier than O. rufipogon. A very weak reduction in seed set but no reduction in F1 viability and fertility were detected for the crosses between species relative to those within species. Moreover, we detected asymmetrical compatibility between species and found that emasculation significantly decreased pollination success in O. nivara but not in O. rufipogon. Our study demonstrates that the divergence between O. nivara and O. rufipogon is maintained almost entirely by the difference in flowering times and suggests that differential flowering times contribute to both habitat preferences and reproductive isolation between species.

Hybridization between Camelina sativa (L.) Crantz and common Brassica weeds

The movement of genes between crops and closely-related weeds has the potential to create economic and environmental problems. Camelina sativa (L.) Crantz is a promising oilseed crop and minor weed in North America, but ecological risk assessment is needed to predict crop-weed gene flow. In this study, reciprocal crosses between C. sativa cultivars and 17 Brassicaceae species in the genera Arabidopsis, Arabis, Barbarea, Camelina, Cardamine, Erysimum, and Lepidium were performed. F1 hybrids were formed between C. sativa cultivars and three species: Camelina alyssum (Mill.) Thell., Camelina microcarpa Andrz. Ex DC., and Capsella bursa-pastoris (L.) Medik. None of the other Brassica species formed hybrid offspring. F1 hybrids from C. sativa × C. alyssum showed the same pollen viability and fecundity as the parents, while hybrids from C. sativa × C. microcarpa had reduced pollen viability, silicle (pod) number and seed production. Intergeneric F1 hybrids from Camelina sativa × Capsella bursa-pastoris were sterile and this correlated with large decreases in pollen viability and number of ovules/flower. In addition, the SSR markers could be applied to identify progenies in C. sativa breeding programs as well as auxiliarily assess possibility of gene flow between C. sativa and weedy relatives. Principle coordinate analysis (PCoA) made from SSR markers clearly divided into 12 species into five groups of species. Especially, C. sativa was classified into one group with those two interfertile C. microcarpa, and C. alyssum but distinctly separated from Camelina hispida var. grandiflora (Boiss.) Hedge, Camelina laxa C. A. Mey and Camelina rumelica Velen. This division among the Camelina species was consistent with their capacity to produce fertile F1 hybrids with C. sativa. The hybridization results suggest that gene flow is likely between cultivated C. sativa and the North American weeds C. alyssum and C. microcarpa.

Fertility, hatchability and livability up to first laying age of Aseel and F1 of Hilly (Red Jungle × Hilly) chicken under intensive rearing system

A study was conducted between June 2008 and May 2009 on Aseel and F1 of Hilly chicken under intensive rearing system at Chattogram district of Bangladesh. Livability, fertility and hatchability are the key features to poultry breeders. Because poor fertility and low hatchability incur loss in breeding operations and less livability significantly impact net returns. Therefore, higher fertility and hatchability and lower mortality of birds should be of direct interest to the poultry breeders. Hence the aim of this study was to estimate fertility, hatchability and livability up to first laying age of Aseel and F1 of Hilly chicken. The Aseel and F1 of Hilly chickens were collected from the Sarail Upazila of Brahmanbaria district and hill tract regions of Bangladesh. After collection, the chickens were kept in breeding flock as male and female ratio 1:1. The egg was stored in room temperature and hatched by the electric incubator. Fertility of Aseel and F1 of Hilly chicks was found to be 95% and 75%, respectively. The hatchability of Aseel and F1 of Hilly chicken based on fertile eggs was detected 94.74% and 86.67% but in case of total eggs the hatchability of the two genotypes was 90% and 65%, respectively. Livability of Aseel and F1 of Hilly chicks up to first laying age was 88.89% and 46.15%, respectively. The first laying age of both Aseel and F1 of Hilly were 210 and 180 days, respectively. Based on fertility, hatchability and livability, Aseel chicken was better than F1 of Hilly chicken. So, the former breed is better for conservation issue than the later in the ex-situ conservation system.

A paternal hypercaloric diet affects the metabolism and fertility of F1 and F2 Wistar rat generations

Increased fat and carbohydrate intakes based on the Western diet are important lifestyle modifications that lead to hypercaloric inputs, obesity, and male fertility negative effects. Epigenetic transmission may also predispose descended generations to chronic diseases, such as obesity, type 2 diabetes, behavioral, and reproductive disorders. The present study sought to evaluate the influence of a high-fat-high-sugar (HFHS) diet supplied to Wistar rats from 25 to 90 days of life on reproductive and metabolic parameters in male generations F0, F1, and F2. The standard group received the normocaloric - Nuvilab Quimtia® -3.86 kcal/kg. The hypercaloric diet (HD) group received the HFHS diet - PragSoluções® -4.77 kcal/kg. Body weight, adiposity, F1 and F2 prepubertal age evaluations, oral glucose tolerance test, insulin tolerance test, organ weights, sperm count and morphology assessments, and histometric testicular analyses were performed. The HFHS diet promoted dyslipidemia, higher adiposity, lower relative organ weights, and higher mean kidney weight, decreased mean testicle and parenchyma weights and lower height of seminiferous epithelium (HE) for the F0 generation. F1 and F2 offspring of HD group displayed early preprepubertal development, although did not alter the metabolic parameters. Decreased HE and tubular testicular compartment volumetric density and increased intertubular testicular compartment volumetric density and volume in the F1 generation of HD group were observed. Alterations in histometry of intertubular testicular compartment were also noted. It is concluded that the HFHS experimental model altered only paternal metabolic parameters. However, reproductive parameters of the three generations were affected.