F1 Hybrids Research Articles

Pachytene Analysis in the Genus <I>Oryza</I>

Pachytene analysis in the genus Oryza is the most fruitful line of approach to the elucidation of evolutionary problems. Cultivated species of this genus have more asymmetric karyotypes. The cell to cell variation in absolute lengths of the chromosomes in O. perennis var. barthii was shown to be due to general condensation differences and hence the data on relative lengths can be employed in the identification of the karyotype. Sterility In Japonica-indica rice hybrids is largely due to chromosome structural hybridity. Occurrence of 241 at metaphase I of the F1 hybrid O. sativa × O. officinalis is due to desynapsis rather than lack of homology between the constituent genomes. The F1 hybrid O. sativa × O. australiensis exhibits distinct timing imbalance in meiosis, the chromosomes of O. australiensis being earlier in condensation as well as migration. Pairing at pachytene is normal in the F1 hybrid O. perennis var. balunga × O. perennis var. cubensis. The F1 hybrid O. sativa × O. perennis exhibited several abnormalities in pairing at pachytene. The F1 hybird O. sativa (4x) × O. perennis var. longistalinata exhibited a high frequency of frying-pan-shaped tnvalents, indicatmg segmental homology between the genomes of the parents.

Image analysis and polyphenol profiling unveil red-flesh apple phenotype complexity.

The genetic basis of colour development in red-flesh apples (Malus domestica Borkh) has been widely characterised; however, current models do not explain the observed variations in red pigmentation intensity and distribution. Available methods to evaluate the red-flesh trait rely on the estimation of an average overall colour using a discrete class notation index. However, colour variations among red-flesh cultivars are continuous while development of red colour is non-homogeneous and genotype-dependent. A robust estimation of red-flesh colour intensity and distribution is essential to fully capture the diversity among genotypes and provide a basis to enable identification of loci influencing the red-flesh trait. In this study, we developed a multivariable approach to evaluate the red-flesh trait in apple. This method was implemented to study the phenotypic diversity in a segregating hybrid F1 family (91 genotypes). We developed a Python pipeline based on image and colour analysis to quantitatively dissect the red-flesh pigmentation from RGB (Red Green Blue) images and compared the efficiency of RGB and CIEL*a*b* colour spaces in discriminating genotypes previously classified with a visual notation. Chemical destructive methods, including targeted-metabolite analysis using ultra-high performance liquid chromatography with ultraviolet detection (UPLC-UV), were performed to quantify major phenolic compounds in fruits' flesh, as well as pH and water contents. Multivariate analyses were performed to study covariations of biochemical factors in relation to colour expression in CIEL*a*b* colour space. Our results indicate that anthocyanin, flavonol and flavanol concentrations, as well as pH, are closely related to flesh pigmentation in apple. Extraction of colour descriptors combined to chemical analyses helped in discriminating genotypes in relation to their flesh colour. These results suggest that the red-flesh trait in apple is a complex trait associated with several biochemical factors.

A New Mouse Model for Usher Syndrome Crossing Kunming Mice with CBA/J Mice

BackgroundPreviously, we discovered a strain of Kunming mice, referred to as the KMush/ush strain, that exhibited notably abnormal electroretinogram (ERG) readings and elevated thresholds for auditory brainstem responses (ABRs), which resembled the characteristics of Usher Syndrome (USH). We successfully identified the pathogenic genes, Pde6b and Adgrv1, after KMush/ush crossbred with CBA/CaJ mice, referred to as CBA-1ush/ush, CBA-2ush/ush or CBA-2ush/ush. In this investigation, we crossbred KMush/ush and CBA/J mice to establish novel recombinant inbred lines and analysed their phenotypic and genotypic characteristics. MethodsERG readings, ABR testing, fundus morphology, histological examination of the retina and inner ear, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, western blotting, DNA sequence analysis and behavioural experiments were performed to assess the phenotypes and genotypes of the progeny lines. ResultsNo obvious waveforms in the ERG were detected in F1 hybrid mice while normal ABR results were recorded. The F2 hybrids, which were called J1ush/ush or J2ush/ush, exhibited segregated hearing-loss phenotypes. J1ush/ush mice had a retinitis pigmentosa (RP) phenotype with elevated ABR thresholds, whereas J2ush/ush mice exhibited only the RP phenotype. Interestingly, J1ush/ush mice showed significantly higher ABR thresholds than wild-type mice at 28 days post born (P28), and RT-qPCR and DNA-sequencing analysis showed that Adgrv1 gene expression was significantly altered in J1ush/ush mice, but histological analysis showed no significant structural changes in the organ of Corti or spiral ganglia. Further elevation of ABR-related hearing thresholds by P56 manifested only as a reduced density of spiral ganglion cells, which differed significantly from the previous pattern of cochlear alterations in CBA-2ush/ush mice. ConclusionsWe successfully introduced the hearing-loss phenotype of inbred mice with USH into CBA/J mice, which provides a good animal model for future studies on the important physiological roles of the Adgrv1 gene in inner-ear structure and for therapeutic studies targeting Adgrv1-mutated USH.

Unearthing hybridization opportunities for augmenting biomass yield and harvest index in rajmash (Phaseolus vulgaris L.)

In present study, 21 F1 hybrids derived from crossing between seven female genotypes and three male testers following a line × tester mating design were evaluated for analyzing the component of genetic variation and heterosis of yield contributing traits. The components of variances due to gca and sca revealed the predominance of non-additive gene action for biomass and harvest index. The average better parent heterosis (BPH) and standard heterosis (SH) for Biomass yield (BY) was 43.71 and 114.67, respectively, and the average BPH and SH for the Harvest index (HI) was -13.04 and -20.45, respectively. The higher magnitude of the BPH and SH recorded for BY indicated that the scope for increasing the HI in Rajmash is limited and that further increases in productivity have to come mainly through enhanced BY. The parent RR21-01 and GR 1 were good general combiners for biomass, TRCR 3, TRCR 2, SKAU-R-19 and RKR 1033 for harvest index. Cross combinations IPR-277- 19 × HUR recorded positively significant sca effect for BY and IPR-277-19 × GR, TRCR 3 × GR 1, TRCR 2 × GR 1, IPR-205-19 × HUR, IPR-277-19 × GR 1, SKAU-R-19 ×RKR 1033, RR-21-01 × HUR and RR-21-12 × GR 1 for HI. These results demonstrate that the selection of parents should not only be based on per se performance but also on combining ability and heterosis for achieving genetic improvement in Rajmash,

Microplastic exposure is associated with epigenomic effects in the model organism Pimephales promelas (fathead minnow).

Microplastics have evolutionary and ecological impacts across species, affecting organisms' development, reproduction, and behavior along with contributing to genotoxicity and stress. As plastic pollution is increasing and ubiquitous, gaining a better understanding of organismal responses to microplastics is necessary. Epigenetic processes such as DNA methylation are heritable forms of molecular regulation influenced by environmental conditions. Therefore, determining such epigenetic responses to microplastics will reveal potential chronic consequences of this environmental pollutant. We performed an experiment across two generations of fathead minnows (Pimephales promelas) to elucidate transgenerational epigenetic effects of microplastic exposure. We exposed the first generation of fish to four different treatments of microplastics: two concentrations of each of pre-consumer polyethylene (PE) and PE collected from Lake Ontario. We then raised the first filial generation with no microplastic exposure. We used enzymatic methylation sequencing on adult liver tissue and homogenized larvae to evaluate DNA methylation differences among treatments, sexes, and generations. Our findings show the origin of the plastic had a larger effect in female minnows whereas the effect of concentration was stronger in the males. We also observed transgenerational effects, highlighting a mechanism in which parents can pass on the effects of microplastic exposure to their offspring. Many of the genes found within differentially methylated regions in our analyses are known to interact with estrogenic chemicals associated with plastic and are related to metabolism. This study highlights the persistent and potentially serious impacts of microplastic pollution on gene regulation in freshwater systems.

Chromosome stability of synthetic Triticum turgidum–Aegilops umbellulata hybrids

BackgroundUnreduced gamete formation during meiosis plays a critical role in natural polyploidization. However, the unreduced gamete formation mechanisms in Triticum turgidum–Aegilops umbellulata triploid F1 hybrid crosses and the chromsome numbers and compostions in T. turgidum–Ae. umbellulata F2 still not known.ResultsIn this study, 11 T.turgidum–Ae. umbellulata triploid F1 hybrid crosses were produced by distant hybridization. All of the triploid F1 hybrids had 21 chromosomes and two basic pathways of meiotic restitution, namely first-division restitution (FDR) and single-division meiosis (SDM). Only FDR was found in six of the 11 crosses, while both FDR and SDM occurred in the remaining five crosses. The chromosome numbers in the 127 selfed F2 seeds from the triploid F1 hybrid plants of 10 crosses (no F2 seeds for STU 16) varied from 35 to 43, and the proportions of euploid and aneuploid F2 plants were 49.61% and 50.39%, respectively. In the aneuploid F2 plants, the frequency of chromosome loss/gain varied among genomes. The chromosome loss of the U genome was the highest (26.77%) among the three genomes, followed by that of the B (22.83%) and A (11.81%) genomes, and the chromosome gain for the A, B, and U genomes was 3.94%, 3.94%, and 1.57%, respectively. Of the 21 chromosomes, 7U (16.54%), 5 A (3.94%), and 1B (9.45%) had the highest loss frequency among the U, A, and B genomes. In addition to chromosome loss, seven chromosomes, namely 1 A, 3 A, 5 A, 6 A, 1B, 1U, and 6U, were gained in the aneuploids.ConclusionIn the aneuploid F2 plants, the frequency of chromosome loss/gain varied among genomes, chromsomes, and crosses. In addition to variations in chromosome numbers, three types of chromosome translocations including 3UL·2AS, 6UL·1AL, and 4US·6AL were identified in the F2 plants. Furthermore, polymorphic fluorescence in situ hybridization karyotypes for all the U chromosomes were also identified in the F2 plants when compared with the Ae. umbellulata parents. These results provide useful information for our understanding the naturally occurred T. turgidum–Ae. umbellulata amphidiploids.

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.

Insertion of short L1 sequences generates inter-strain histone acetylation differences in the mouse

BackgroundGene expression divergence between populations and between individuals can emerge from genetic variations within the genes and/or in the cis regulatory elements. Since epigenetic modifications regulate gene expression, it is conceivable that epigenetic variations in cis regulatory elements can also be a source of gene expression divergence.ResultsIn this study, we compared histone acetylation (namely, H3K9ac) profiles in two mouse strains of different subspecies origin, C57BL/6 J (B6) and MSM/Ms (MSM), as well as their F1 hybrids. This identified 319 regions of strain-specific acetylation, about half of which were observed between the alleles of F1 hybrids. While the allele-specific presence of the interferon regulatory factor 3 (IRF3) binding sequence was associated with allele-specific histone acetylation, we also revealed that B6-specific insertions of a short 3′ fragment of LINE-1 (L1) retrotransposon occur within or proximal to MSM-specific acetylated regions. Furthermore, even in hyperacetylated domains, flanking regions of non-polymorphic 3′ L1 fragments were hypoacetylated, suggesting a general activity of the 3′ L1 fragment to induce hypoacetylation. Indeed, we confirmed the binding of the 3′ region of L1 by three Krüppel-associated box domain-containing zinc finger proteins (KZFPs), which interact with histone deacetylases. These results suggest that even a short insertion of L1 would be excluded from gene- and acetylation-rich regions by natural selection. Finally, mRNA-seq analysis for F1 hybrids was carried out, which disclosed a link between allele-specific promoter/enhancer acetylation and gene expression.ConclusionsThis study disclosed a number of genetic changes that have changed the histone acetylation levels during the evolution of mouse subspecies, a part of which is associated with gene expression changes. Insertions of even a very short L1 fragment can decrease the acetylation level in their neighboring regions and thereby have been counter-selected in gene-rich regions, which may explain a long-standing mystery of discrete genomic distribution of LINEs and SINEs.

Phytochemical studies in some varieties of soybean [Glycine max (L.) Merr.] and their hybrids

In the present investigation, an attempt has been made to congregate the phytochemical studies done on intervarietal F1 hybrids of soybean (Glycine max L.) along with their parents. The eleven F1 hybrids were obtained by intervarietal crossing done using five varieties of soybean viz Bragg(BG), NRC7(NR), Punjab1(PN), PUSA98-14(PU) and JS9560(JS).Estimation of phenols was done by FCR Method using Gallic acid as standard. The total phenolic content was found highest in the cross JSXNR and lowest in BGXNR. Total tannin content was determined using FCR method. Total tannin content was highest in NRXJS and least in BGXPN. In addition, total flavonoids were determined using Alcl3 reagent and antioxidant activity by DPPH method. Total flavonoids was found maximum in PNXNR and least in PUXPN respectively. Highest Antioxidant Activity was 50.31% in JSXPN and lowest was 39.08% in NRXJS. The results suggested that besides protein and oil contents, the phenolic contents should also be considered as an important characteristic feature of soybean seeds, and as a potential selection criterion for antioxidant activity in soybean.

Combining Ability Analysis of Yield and Quality Traits in Pumpkin [Cucurbita moschataduch. Ex Poir

The present analysis was carried out with aims to estimate the general and specific combining ability of pumpkin involving six parents namely, Arka Chandan (P1), Ambili (P2), Arka Suryamukhi(P3), Pusa Vishwas (P4), CO 2 (P5) and CO 1 (P6) and 30 F1 hybrids obtained through full diallel analysis in randomized block design with three replication. The observation were recorded for eighteen traits viz., vine length, node number at which first male flower anthesis, node number at which first female flower anthesis, number of primary branches vine-1, days to first male flower anthesis, days to first female flower anthesis, number of male flowers vine-1, number of female flowers vine-1, sex ratio, number of fruits vine-1, fruit weight, polar diameter of fruit, equatorial diameter of fruit, flesh thickness, 100 seed weight, carotene content, total soluble solids and yield vine-1.. The analysis of variance for combining ability among various traits in pumpkin revealed that there were significant differences for all the traits. Among the parents, Ambili was the best general combiner for number of fruits vine-1, yield vine-1 and yield contributing traits. The highest desirable SCA were obtained from a cross of Ambili x Arka Suryamukhi for yield and attributing traits, which was the best and promising hybrid.

Maternal 129S1/SvImJ background attenuates the placental phenotypes induced by chronic paternal alcohol exposure

Paternal alcohol use is emerging as a plausible driver of alcohol-related growth and patterning defects. Studies from our lab using an inbred C57Bl/6 J mouse model suggest that these paternally-inherited phenotypes result from paternally programmed deficits in the formation and function of the placenta. The 129S1/SvImJ genetic background is typically more susceptible to fetoplacental growth defects due to strain-specific differences in placental morphology. We hypothesized that these placental differences would sensitize 129S1/SvImJ-C57Bl/6 J hybrid offspring to paternally-inherited fetoplacental growth phenotypes induced by paternal alcohol exposure. Using a limited access model, we exposed C57Bl/6 J males to alcohol and bred them to naïve 129S1/SvImJ dams. We then assayed F1 hybrid offspring for alterations in fetoplacental growth and used micro-CT imaging to contrast placental histological patterning between the preconception treatments. F1 hybrid placentae exhibit larger placental weights than pure C57Bl/6 J offspring but display a proportionally smaller junctional zone with increased glycogen content. The male F1 hybrid offspring of alcohol-exposed sires exhibit modest placental hyperplasia but, unlike pure C57Bl/6 J offspring, do not display observable changes in placental histology, glycogen content, or measurable impacts on fetal growth. Although F1 hybrid female offspring do not exhibit any measurable alterations in fetoplacental growth, RT-qPCR analysis of placental gene expression reveals increased expression of genes participating in the antioxidant response. The reduced placental junctional zone but increased glycogen stores of 129S1/SvImJ-C57Bl/6 J F1 hybrid placentae ostensibly attenuate the previously observed placental patterning defects and fetal growth restriction induced by paternal alcohol use in the C57Bl/6 J strain.

Morphological variation of tail bone among two chicken breeds and their F1 progeny.

Fancy breeds of Japanese indigenous chicken display extensive morphological diversity, particularly in tail feathers. Although marked differences in tail and bone traits have been reported between Tosa-jidori (wild type) and Minohikichabo (rich type) breeds, little is known about the pattern of genetic inheritance in cross experiments. Therefore, this study aimed to investigate the strain and sex effects, and inheritance patterns, in the morphometric variation of pygostyle bones among Tosa-jidori, Minohikichabo, and their F1 hybrids. Five morphological traits, angle of the apex of the pygostyle, pygostyle length, margo cranialis length, tail feather number, and body weight, were evaluated at the adult stage. A significant strain difference was detected in all traits, whereas significant sex differences were observed in only three traits, but not in the angle of the apex of the pygostyle and tail feather number. In F1 hybrids, the angle of the apex of the pygostyle was significantly different to that of Tosa-jidori but not that of Minohikichabo, whereas the pygostyle length and tail number of F1 hybrids were significantly different from those of Minohikichabo but not those of Tosa-jidori. A significant heterosis effect was found in the margo cranialis length and body weight. All five traits showed nonadditive inheritance patterns but varied in each trait between partial dominance (angle of the apex of pygostyle), full dominance (pygostyle length and tail feather number), and over-dominance (margo cranialis length and body weight). Interestingly, different patterns of genetic inheritance in the F1 hybrid were observed at different locations, even within the same pygostyle bone. Using the Japanese indigenous chicken model, these results provide a substantial step toward understanding the genetic architecture of morphology in chickens.

Whole genome resequencing identifies candidate genes and allelic variation in the MdNADP-ME promoter that regulate fruit malate and fructose contents in apple

Soluble sugar and organic acids are key determinants of fruit organoleptic quality and directly affect the commodity value and economic returns of fruit crops. We conducted whole genome sequencing (WGS) of the apple varieties ‘Gala’ and ‘Xiahongrou’, along with their F1 hybrid, to construct a high-density bin map. Our quantitative genetic analysis pinpointed 53 quantitative trait loci (QTL)s related to 11 sugar and acid traits. We identified a candidate gene, MdNADP-ME, responsible for malate degradation, on a stable QTL of linkage group (LG) 15. Sequence analysis revealed an A/C SNP in the promoter region (MEp-799) that influences the binding of the transcription factor MdMYB2, impacting MdNADP-ME expression. In our study of various apple genotypes, this SNP was linked to malate and fructose levels. We also developed a dCAPS marker associated with fruit fructose content. These results substantiate the role of MdNADP-ME in maintaining the equilibrium of sugar and acid content in apple fruits.

Investigation of heat stress responses and adaptation mechanisms by integrative metabolome and transcriptome analysis in tea plants (Camellia sinensis).

Extreme high temperature has deleterious impact on the yield and quality of tea production, which has aroused the attention of growers and breeders. However, the mechanisms by which tea plant varieties respond to extreme environmental heat is not clear. In this study, we analyzed physiological indices, metabolites and transcriptome differences in three different heat-tolerant tea plant F1 hybrid progenies. Results showed that the antioxidant enzyme activity, proline, and malondialdehyde were significantly decreased in heat-sensitive 'FWS' variety, and the accumulation of reactive oxygen molecules such as H2O2 and O2- was remarkably increased during heat stress. Metabolomic analysis was used to investigate the metabolite accumulation pattern of different varieties in response to heat stress. The result showed that a total of 810 metabolites were identified and more than 300 metabolites were differentially accumulated. Transcriptional profiling of three tea varieties found that such genes encoding proteins with chaperon domains were preferentially expressed in heat-tolerant varieties under heat stress, including universal stress protein (USP32, USP-like), chaperonin-like protein 2 (CLP2), small heat shock protein (HSP18.1), and late embryogenesis abundant protein (LEA5). Combining metabolomic with transcriptomic analyses discovered that the flavonoids biosynthesis pathway was affected by heat stress and most flavonols were up-regulated in heat-tolerant varieties, which owe to the preferential expression of key FLS genes controlling flavonol biosynthesis. Take together, molecular chaperons, or chaperon-like proteins, flavonols accumulation collaboratively contributed to the heat stress adaptation in tea plant. The present study elucidated the differences in metabolite accumulation and gene expression patterns among three different heat-tolerant tea varieties under extreme ambient high temperatures, which helps to reveal the regulatory mechanisms of tea plant adaptation to heat stress, and provides a reference for the breeding of heat-tolerant tea plant varieties.

CO-ADMINISTRATION OF RESVERATROL RESCUED LEAD-INDUCED TOXICITY IN DROSOPHILA MELANOGASTER

Lead toxicity poses a significant environmental concern linked to diverse health issues. This study explores the potential mitigating effects of resveratrol on lead-induced toxicity in Drosophila melanogaster. Adult fruit flies, aged three days, were orally exposed to lead (60mg/L), Succimer (10mg), and varying concentrations of resveratrol (50, 100, and 150mg). The investigation encompassed the assessment of selected biological parameters, biochemical markers, oxidative stress indicators, and antioxidant enzymes. Resveratrol exhibited a dose-dependent enhancement of egg-laying, eclosion rate, filial generation output, locomotor activity, and life span in D. melanogaster, significantly to 150mg of diet. Most of the investigated biochemical parameters were significantly rescued in lead-exposed fruit flies when co-treated with resveratrol (p < 0.05). However, oxidative stress remained unaffected by resveratrol. The findings suggest that resveratrol effectively protects against lead toxicity in Drosophila melanogaster and may hold therapeutic potential as an agent for managing lead poisoning in humans.

The Stimulation of Chemical Male Sterility for F1 Hybrid Lettuce (Lactuca Sativa Var. Longifolia) Production

Male sterility is a unique application in the production of F1 hybrid seeds of some important species. Today, while F1 hybrid lettuce varieties of abroad origin take their place in the Türkiye seed market, unfortunately, we do not have a native F1 hybrid variety. Besides, F1 hybrid seed production has become a prestige for multi-national companies regardless of the type of vegetable. Within this perspective, the effects of some chemical hybridizing agents (CHAs) such as E4FO, Ethrel and GA3 on male sterilizing activity in lettuce cultivars (Maylight352 F1, Presidential and Yedikule) were evaluated. Therefore, pollen presence in the early bud stage, seed formation and seed viability (germination) were examined. The applications had different effects on pollen presence, seed formation and seed germination, and thus male sterility. Ethrel was not effective at low doses, but at high doses, it caused flower bud deformation and growth retardation. E4FO is partially effective, but the application doses are low. Therefore, E4FO should be used at higher than 1500 ppm and 2000 ppm. GA3 applications produced the best results in stimulating male sterility, and full sterility (% 100) was achieved from 200, 250 and 300 ppm in all cultivars. As a result, 200 ppm GA3 was determined as the recommendable dose in the production of Fı hybrid lettuce.

Genome-wide analysis with additive and epistasis effects reveals growth-related loci and candidate genes in hybrid Argopecten scallops

The first filial (F1) generation from the successful hybridization of bay scallops (Argopecten irradians) and Peruvian scallops (A. purpuratus) exhibits significant heterosis, playing a crucial role in enhancing the germplasm and increasing yields of the scallops. However, there is significant variation in the growth traits of the F1 hybrid population, and there is little information concerning its hereditary basis. To unravel the heterosis mechanism and identify key loci and genes contributing to superhybrids, genome-wide association study (GWAS) with additive and epistasis models were conducted for six growth-related traits in the F1 hybrid scallop population in this study. In total, 18,789,547 single nucleotide polymorphisms (SNPs) were identified after filtering from 198 hybrid individuals, comprising 63.5% of maternal loci and 36.5% of paternal loci. The additive model revealed 2768 associated SNPs and 14 candidate genes, with most of the loci associated with the body mass traits. The additive-additive epistatic model identified 133,094 SNP interaction pairs and 20 candidate gene pairs with exon region SNPs, which were predominantly associated with shell morphology traits. Almost all the SNP pairs associated with body mass traits were maternal-maternal interactions, but the shell morphology traits had the most maternal-paternal and maternal-maternal interactions, suggesting that body mass traits might be affected mainly by maternal effects and that parental interaction effects mainly contributed to the shell size of the hybrid scallops. Both in the shell morphology and the body mass traits, multiple loci participate in epistasis, interacting with more than one locus and forming high-order epistatic interactions, which could be critical factors contributing to the heterosis observed in hybrid scallops. The identified associated loci and candidate genes not only constitute valuable resources for the molecular breeding of hybrid scallops, contributing to the improvement of growth-related traits, but also revealed mechanisms underlying heterosis in aquatic species, providing insights into the advantages of heterosis and paving the way for future research on hybridization in aquatic organisms.

Fruit Agronomic and Quality Traits of Tomato F1 Hybrids Derived from Traditional Varieties

The high genetic diversity of the tomato and its high micronutrient content make this fruit very interesting from an economic and nutritional point of view. The genetic erosion suffered by this crop, due to breeding objectives based on yield and marketing, makes it necessary to return to the origins in search of the nutritional and organoleptic quality lost in traditional varieties. In this study, the agronomic, physical, organoleptic, and nutritional characteristics of eighteen F1 hybrids, obtained by crossing fourteen traditional varieties, previously selected for their quality, were studied in order to select genotypes of superior quality that could be candidates for new varieties. All the parameters studied were strongly influenced by genotype, with a wide range between varieties. Most of the experimental hybrids showed higher quality scores than the commercial hybrids used as controls, due to the extensive selection process carried out on the parents in previous work. Principal component analysis revealed the characteristics of each hybrid that distinguished it from the others. Some hybrids (H1, H2, and H4) stood out for their high concentration of active compounds, others (H14, H13, H8, H15, H7, and H9) for their agronomic performance and high β-carotene content, and H3 was the only one to contain chlorophyll in its ripe fruits. Finally, the evaluation index allowed the selection of five hybrids with interesting characteristics, combining good yield performance and high quality. The results of this work have allowed for the selection of a group of hybrids with high organoleptic and nutritional quality which will be used as parents in a breeding programme, in which their characteristics will be fixed and their resilience will be increased through the introduction of virus resistance.

Chlorophyll content and leaf area correlated with corn (Zea mays) yield components in F&lt;sub&gt;1&lt;/sub&gt; hybrids

Chlorophyll content and leaf area are important biochemical and biophysical regulators of water, energy and carbon exchange during photosynthesis. The present study was carried out during 2020 (autumn) and 2021 (spring) at the agronomy experimental station, College of Agricultural Engineering Science, Salahaddin University, Erbil, Iraq to identify the relationship of chlorophyll and leaf area with yield and yield-related characteristics among 8 introduced corn (Zea mays L.) F1 hybrids. Results demonstrated that the 8 hybrids were significantly different from each other for the number of kernels/row, number of leaves/ear, chlorophyll content and leaf area. Hybrid-by-year interaction was significant for ear yield, ear length, ear diameter, number of rows/ear, number of kernels/row and number of leaves/ear. No relationships phenotypically and genetically were found among chlorophyll with yield and yield-related traits in both the years. However, phenotypic and genotypic correlations were significant between leaf area and yield contributing traits in autumn 2020. Short vectors or obtuse angles by biplot analysis showed the same direction for correlation analysis. In conclusion, more information in future plant breeding programmes at phenotypic and DNA levels are required to represent the relationship between chlorophyll content with yield and yield-related traits. However, different correlations between leaf areas in the two growing years might be owing to the fluctuated local environmental factors during the plant growth period and/or no adaptation of new hybrids to the local environments.

Identification of candidate genes associated with growth and development of sheep from a crossbred population using genome-wide association studies

The article presents the results of a search for genome-wide associations with phenotypic traits characterizing the growth and development of sheep from a crossbred population obtained from crossing Romanov sheep and F1 hybrid rams (Romanov sheep x Katahdin). The phenotype database included ten body measurements (withers height, sacral height, back height, chest depth, chest width, ischial tuberosity width, body length, oblique body length, chest girth, pastern girth) recorded at the age of 6 days, 3, 6 and 9 months. Genotyping of sheep was carried out using high-density DNA chips containing about 600,000 SNP markers. Genome-wide association studies (GWAS) were performed using regression analysis in the STATISTICA 10 program. The search for candidate genes localized in the SNP region was performed using Ensembl genome browser 110. There was carried out an analysis of the matches of the identified SNPs with known quantitative trait loci (QTLs) described in the Sheep Quantitative Trait Locus Database. There were found SNPs that were significantly associated with the studied phenotypic traits overlapped with the QTLs, among which the most common categories were “Body weight (slaughter)”, “Muscle weight in carcass”, “Body weight (live)” and “Bone weight in carcass”. There has been established that SNPs significantly associated with exterior traits were localized within or in the immediate vicinity of 64 genes. There were found potential candidates regulating the growth of muscle (FOXO3, PRKAG3, MYOZ2, and ANKRD1) and cartilage tissues FGF12) and involved in metabolic processes, which were critical for the growth of lambs (CLDN, ALB, and MRC1). Along with the known in sheep functional candidates (CAST and SCD5) , there were identified genes that were not previously described in sheep, but regulated growth and development processes in other livestock species including genes RAB28, PRKAG3 and FOXO3. The identified SNPs can be recommended for inclusion in marker-guided selection programs in sheep breeding.