F1 Hybrids Research Articles

Exploitation of heterosis in chilli using genetic male sterile lines for red fruit yield with special reference to high rainfall conditions

High-quality red/dry chilli for spice, pharmaceutical and medicinal purposes is a major goal in chilli breeding. The male sterile lines have greater potential for the exploitation of heterosis in chilli to achieve this objective. Genetic male sterile lines with special traits like destalking and ability to withstand high rainfall were involved in heterosis breeding to identify hybrids for commercial and industrial purposes. Forty F1 hybrids were developed by crossing 4 diverse GMS lines with 10 testers using Line × Tester mating design to estimate heterosis, combing ability and gene action. The experiment involving 14 parents and 40 F1s, along with standard variety ‘CH-27’ was laid out in α-lattice square design in three replications during summer 2020 and 2021. The GMS lines MS 9-2 and MS 26-1 along with testers DPCh 10, VVG, DPCh 40 and Him Palam Mirch-2 showed significant GCA for marketable red/dry fruit yield and majority of their component traits. Ten F1 hybrids were identified with superiority for fruit yield based on mean performance, significant heterosis and SCA effects, providing an opportunity to utilize them in value-added products and dried spice purposes viz., MS 9-2 × HPM-2, MS 11-2 × DPCh 40, MS 9-2 × DPCh 40 and MS 9-2 × DPCh 101 with erect fruiting habit and that of MS 9-2 × DPCh 10, MS 26-1 × DPCh 10, MS 9-2 × PBC 535, MS 26-1 × VVG, MS 29-2 × DPCh 10 and MS 26-1 × DPCh 22- C with pendent fruits. The non-additive gene action was predominant in the expression of fruit yield, total red fruits/plant, oleoresin and capsanthin. A significant positive correlation among SCA, economic heterosis and per se performance is an indicative to identify superior hybrids. Multi-location testing of these hybrids shall pave way to exploit them commercially by making them available to the farmers.

Non-additive expression genes play a critical role in leaf vein ratio heterosis in Nicotiana tabacum L.

Heterosis, recognized for improving crop performance, especially in the first filial (F1) generation, remains an area of significant study in the tobacco industry. The low utilization of leaf veins in tobacco contributes to economic inefficiency and resource waste. Despite the positive impacts of heterosis on crop genetics, investigations into leaf-vein ratio heterosis in tobacco have been lacking. Understanding the mechanisms underlying negative heterosis in leaf vein ratio at the molecular level is crucial for advancing low vein ratio leaf breeding research. This study involved 12 hybrid combinations and their parental lines to explore heterosis associated with leaf vein ratios. The hybrids displayed diverse patterns of positive or negative leaf vein ratio heterosis across different developmental stages. Notably, the F1 hybrid (G70 × Qinggeng) consistently exhibited substantial negative heterosis, reaching a maximum of -19.79% 80 days after transplanting. A comparative transcriptome analysis revealed that a significant proportion of differentially expressed genes (DEGs), approximately 39.04% and 23.73%, exhibited dominant and over-dominant expression patterns, respectively. These findings highlight the critical role of non-additive gene expression, particularly the dominance pattern, in governing leaf vein ratio heterosis. The non-additive genes, largely associated with various GO terms such as response to abiotic stimuli, galactose metabolic process, plant-type cell wall organization, auxin-activated signaling pathway, hydrolase activity, and UDP-glycosyltransferase activity, were identified. Furthermore, KEGG enrichment analysis unveiled their involvement in phenylpropanoid biosynthesis, galactose metabolism, plant hormone signal transduction, glutathione metabolism, MAPK signaling pathway, starch, and sucrose metabolism. Among the non-additive genes, we identified some genes related to leaf development, leaf size, leaf senescence, and cell wall extensibility that showed significantly lower expression in F1 than in its parents. These results indicate that the non-additive expression of genes plays a key role in the heterosis of the leaf vein ratio in tobacco. This study marks the first exploration into the molecular mechanisms governing leaf vein ratio heterosis at the transcriptome level. These findings significantly contribute to understanding leaf vein ratios in tobacco breeding strategies.

MdNAC5: a key regulator of fructose accumulation in apple fruit.

The sweetness of apple fruit is a key factor in the improvement of apple varieties, with fructose being the sweetest of the soluble sugars, playing a crucial role in determining the overall sweetness of the apple. Therefore, uncovering the key genes controlling fructose accumulation and deciphering the regulatory mechanisms of fructose are vitally important for the improvement of apple varieties. In this study, through BSA-seq and transcriptome analysis of the 'Changfu 2' × 'Golden Delicious' F1 hybrid population, MdNAC5 was identified as a key regulatory gene for fructose content. MdNAC5 was shown to significantly influence fructose accumulation in both apples and tomatoes. Furthermore, we conducted a detailed identification of sugar transporters and metabolic enzymes in apples, discovering that MdNAC5 can enhance fructose accumulation in vacuoles and the conversion of sucrose to fructose by binding to and activating the promoters of the vacuolar sugar transporter MdTST2 and the neutral invertase MdNINV6. Additionally, MdNAC5 regulated the MdEIN3.4-MdSWEET15a module, strengthening the unloading of sucrose in the phloem of the fruit. Our results reveal a new mechanism by which MdNAC5 regulates fructose accumulation in apples and provide theoretical foundations for improving apple sweetness through genetic modification.

Abnormal expression of LiASY1 and LiDMC1 is the main cause of sterility in F1 hybrids developed from Lagerstroemia speciosa and Lagerstroemia indica ‘Ebony Embers’

Lagerstroemia × ‘Xiaoxiang Huaxiu’ (an F1 hybrid of Lagerstroemia speciosa and Lagerstroemia indica ‘Ebony Embers’) exhibits significant sterility. Cytological studies have revealed numerous abnormal chromosomal behaviors during the meiotic division of pollen mother cells in L. × ‘Xiaoxiang Huaxiu’. Transcriptome sequencing identified that LiDMC1 and LiASY1 were expressed at very low levels in ‘Xiaoxiang Huaxiu’. To further verify whether the abnormal expression of LiDMC1 and LiASY1 was the fundamental cause of sterility in ‘Xiaoxiang Huaxiu’, we cloned the full-length gene sequences of LiDMC1 and LiASY1 from ‘Ebony Embers’. Using VIGS (virus-induced gene silencing) technology, pTRV1 and pTRV2 gene silencing vectors were employed to silence LiDMC1 and LiASY1 in the paternal parent ‘Ebony Embers’. The results indicated that in the double-silenced lines of ‘Ebony Embers’, the cytoplasm sizes of different tetrads during the tetrad stage varied significantly. There was a notable proportion of polyads, binucleate cells with micronuclei, and pentads. Additionally, pollen diameter varied significantly, closely resembling the sterility observed in ‘Xiaoxiang Huaxiu’. Pollen viability in the double-silenced ‘Ebony Embers’ decreased by 22.8%. This study demonstrates that the low expression of LiDMC1 and LiASY1 leads to abnormal microspore development in ‘Ebony Embers’, and their low expression is the cause of sterility in ‘Xiaoxiang Huaxiu’.

Unraveling the Genetic Mechanisms of Maize Ear Diameter Heterosis

Hybridization has long been a crucial strategy for breeders aiming to develop high-yield crops vital for global food security. However, the exact molecular mechanisms driving heterosis (hybrid vigor) remain a topic of debate. Maize (Zea mays), which demonstrates pronounced heterosis, serves as an ideal model for studying this phenomenon. In our study, we carefully measured phenotypic changes in ear diameter, tracing its development from the inflorescence meristem (IM) to the floral meristem (FM) stages. Our findings revealed a complex progression: the hybrid's ear diameter followed an additive pattern during the IM and spikelet pair meristem (SPM) stages, shifted to incomplete dominance at the spikelet meristem (SM) stage, and ultimately displayed over-dominance at the FM stage. Notably, significant phenotypic changes occurred during the SM stage with gene expression primarily showing non-additive patterns. Gene Ontology (GO) enrichment analysis highlighted the role of cell redox homeostasis genes, which exhibited over-dominant expression in hybrids, as key contributors to heterosis. Furthermore, we identified a distinct gene expression category - dominant maternal or paternal gene expression in F1 hybrids (DMP) - characterized by exclusive expression in the hybrid and one parent, while remaining inactive in the other. This category of DMP genes plays a pivotal role in shaping the diverse gene expression patterns observed in hybrids, distinguishing them from their parental lines. In conclusion, the widespread occurrence of non-additive expression seems to enhance the efficiency of biological processes and energy distribution in hybrids, ultimately driving the manifestation of heterosis.

First evidence of WW superfemale for hybrid sturgeon, the bester (Huso huso × Acipenser ruthenus)

Sex control offers a promising strategy for cost-effective aquaculture in certain fish species. Sturgeons, which utilize the ZZ/ZW sex determination system, are particularly valuable for producing high-priced black caviar derived from female roes, making all-female production highly desirable. However, this goal has yet to be fully realized. In this study, we identified a short genomic region specific to the Z and W genomic scaffolds of Acipenser ruthenus and developed a polymerase chain reaction (PCR) method to distinguish between the Z and W alleles. Using PCR, 1280 A. ruthenus, 66 A. baerii baerii, and 31 F2 hybrids of besters (Huso huso × A. ruthenus) were genotyped, revealing either a single Z amplicon or dual Z plus W amplicons in an approximately 1:1 ratio. This indicates successful discrimination of the ZZ/ZW genotypes. Additionally, gonadal sex was identified in 145 of the genotyped individuals, all of which corresponded to their genetic sex. Gynogenetic individuals of the F3 bester hybrid were also genotyped, with 25 of 112 (22.3 %) exhibiting only W amplicons, identifying them as WW superfemales. These findings contribute to the advancement of all-female sturgeon production for aquaculture, facilitating the efficient farming of these highly prized species.

Fertility restorer gene CaRf and PepperSNP50K provide a promising breeding system for hybrid pepper.

Cytoplasmic male sterility (CMS) is pivotal in plant breeding and widely employed in various crop hybrids, including pepper. However, the functional validation of the restorer of fertility (Rf) gene in pepper has been lacking until now. This study identifies and characterizes CaRf, a single dominant locus crucial for restoring CMS in the pepper strong recovery inbred line Zhangshugang. The CaRf gene encodes a mitochondria-targeted pentatricopeptide repeat protein, validated through the induction of male sterility upon its silencing in hybrid F1 plants. To enhance pepper breeding efficiency, 176 important pepper breeding parent materials were resequenced, and a PepperSNP50K liquid-phase breeding chip was developed, comprising 51 172 markers. Integration of CaRf functional characterization and PepperSNP50K facilitated the development of a high-quality red pepper hybrid. These findings provide significant insights and practical strategies for advancing molecular-designed breeding in peppers.

Identification of stable restorers and high-yielding hybrids using diverse sorghum male sterile cytoplasmic sources and established pollen parents under different water regimes

Sorghum hybrids demonstrated increased productivity and helped offset the decreasing cultivated areas, particularly in Asia. The diversity in cytoplasmic male sterility systems, stability of restorers and high yield of sorghum is an important factor for achieving food security and sustainability. In sorghum, hybrid production has been limited to A1 cytoplasmic source to date, primarily due to limited number of restorers on other cytoplasmic sources. This work aimed at filling this gap through diversifying and assessing the producibility and stability of cytoplasmic backgrounds across environments, evaluating the stability of restorers across cytoplasms and environments, and evaluating the performance of the hybrid F1 products under different water regimes across cropping seasons. The effects of genotypes and interactions between the genotypes and the tested environments were shown visually using GGE biplot, which also categorized the genotypes based on performance per se and stability. Analysis of variance revealed significant (P< 0.001) differences between genotypes, environments and their interaction components for all the plant characteristics studied. The various GGE biplot patterns revealed that the restorers G4 (IS 33844-5), G5 (M 35-1-19), G8 (ICSV 15014), and G10 (ICSR 13009) were stable across environments and cytoplasms. We observed the following order of superiority in cytoplasmic restoration and seed producibility, A2 >A1>A3 >A4. The A2 cytoplasm can therefore reliably offer seed producibility advantage to commercial seed producers. Furthermore, the which-won–where model for hybrid grain yield revealed specific adaptations of hybrid genotypes G143, G195 and G215 to first mega environment (E1 and E3), whereas G167, G110, and G112 were adapted to the second mega-environment (E2 and E4). With a GGE biplot goodness of fit of 70% the best possible yield- and stability-based ranking of hybrid genotypes was G143, G215, G189, G200, G69, G162, G119, G54, and G81. The newly uncovered hybrid products should therefore be considered for downstream testing stages and candidates for release and commercial cultivation. Clearly, this work resulted in novel findings particularly in terms of seed producibility, universal restorers across the 4 cytoplasms and environments, and superior and stable hybrid products, all of which are expected to add value to conventional and heterosis breeding in the process of sorghum cultivar development.

Gonadal Development and Differentiation of Hybrid F1 Line of Ctenopharyngodon idella (♀) × Squaliobarbus curriculus (♂)

The hybrid F1 offspring of Ctenopharyngodon idella (♂) and Squaliobarbus curriculus (♀) exhibit heterosis in disease resistance and also show abnormal sex differentiation. To understand the mechanism behind gonadal differentiation in the hybrid F1, we analyzed the transcriptomes of C. idella, S. curriculus, and the hybrid F1; screened for genes related to gonad development in these samples; and measured their expression levels. Our results revealed that compared to either C. idella or S. curriculus, the gene expressions in most sub-pathways of the SNARE interactions in the vesicular transport pathway in the hypothalamus, pituitary, and gonadal tissues of their hybrid F1 offspring were significantly up-regulated. Furthermore, insufficient transcription of genes involved in oocyte meiosis may be the main reason for the insufficient reproductive ability of the hybrid F1 offspring. Through transcriptome screening, we identified key molecules involved in gonad development, including HSD3B7, HSD17B1, HSD17B3, HSD20B2, CYP17A2, CYP1B1, CYP2AA12, UGT2A1, UGT1A1, and FSHR, which showed significant differences in expression levels in the hypothalamus, pituitary, and gonads of these fish. Notably, the expression levels of UGT1A1 in the gonads of the hybrid F1 were significantly higher than those in C. idella and S. curriculus. These results provide a scientific basis for further research on the gonadal differentiation mechanism of hybrid F1 offspring.

Combining ability for grain yield and low-N tolerance of intermediate/late maturing maize (Zea mays) inbred lines

ABSTRACT Low soil nitrogen (N) is a significant challenge to maize (Zea mays L.) production in Sub-Saharan Africa, particularly for small-scale farmers. Developing maize hybrids tolerant to low N is crucial for improving yields under such conditions. This study examined the genetic basis of agronomic traits in intermediate/late maturing maize inbred lines under contrasting N conditions, focusing on general combining ability (GCA) and specific combining ability (SCA) effects. Two hundred and thirty-seven F1 hybrids from 79 inbred lines crossed with three testers in a line x tester mating design, were evaluated across eight environments in Nigeria. Line x tester analysis revealed that GCA effects, primarily from lines, predominantly influenced grain yield and other traits across both N conditions, except for ear height and plant aspect under low N, where SCA effects also had significant impact. A significant (p ≤ 0.01) positive correlation was observed between GCA and SCA effects, suggesting a positive relationship between additive and non-additive genetic components. Lines SMLW146 and SMLW147 were identified as valuable resources for breeding low-N tolerant hybrids. Additionally, considering non-additive effects, hybrids SMLW22 × SAM50M and SMLW106 × SAM50M (under low-N) and SMLW3 × IITA1876, SMLW84 × IITA1876, and SMLW165 × IITA1876 (under optimum-N) were promising combinations for high grain yield. Morphological traits like plant height and ear height, phenological traits like days to anthesis and silking, and qualitative traits like ear aspect and plant aspect were identified as important for selecting genotypes with improved grain yield under low-N conditions.

Mitonuclear effects on sex ratio persist across generations in interpopulation hybrids.

Eukaryotic energy production requires tight coordination between nuclear and mitochondrial gene products. Because males and females often have different energetic strategies, optimal mitonuclear coordination may be sex-specific. Previous work found evidence for sex-specific mitonuclear effects in the copepod Tigriopus californicus by comparing two parental lines and their reciprocal F1 crosses. However, an alternative hypothesis is that the patterns were driven by the parental source of nuclear alleles. Here we test this alternative hypothesis by extending the same cross to F2 hybrids, who receive both maternal and paternal nuclear alleles from F1 hybrids. Results confirm mitonuclear effects on sex ratio, with distorted ratios persisting from the F1 to F2 generations, despite reduced fitness in F2 hybrids. No sex by cross interactions were found for other phenotypic traits measured. Mitochondrial DNA content was higher in females. Both routine metabolic rate and oxidative DNA damage were lower in F2 hybrids than in parentals. The persistence of sex-specific mitonuclear effects, even in the face of F2 hybrid breakdown, attests to the magnitude of these effects, which contribute to the maintenance of within-population mitochondrial DNA polymorphisms.

Effects of progesterone administered to maternal rats during the teratogenesis-sensitive period through different routes on neurobehavior and gut microbiota in offspring

Objective: Progesterone (P4) is the optimal agent for luteal support in assisted reproductive technologies. Despite the availability of various formulations, the impacts of P4 treatment administered through different routes on offspring growth remain unevaluated. This study aimed to investigate and compare the effects of P4 administration through three different routes in pregnant rats during the teratogenesis-sensitive period on fertility outcomes and the behavior, plasma P4 and pregnenolone levels, and alterations in gut microbiota in the filial generation (F1) of offspring. Methods: Female rats that mated successfully were randomly classified into four groups: Group 1, the normal control group; Group 2, the IG group, in which utrogestan was administered via intragastric gavage; Group 3, the IM group, in which P4 was administered via intramuscular injection; and Group 4, the VAGIN group, in which P4 sustained-release vaginal gel was administered through the vagina. Except for the control group, P4 was administered in other groups through their respective routes for 13 consecutive days daily during the teratogenic-sensitive gestation period (days 6–18). The fertility outcomes of the maternal rats were observed, and open-field and three-chamber social preference tests were conducted to assess anxiety and social behavior, along with an exhaustive swimming experiment to evaluate the motor endurance of the offspring. Plasma P4 and pregnenolone levels in the offspring were measured, and fecal samples were assessed using gut microbiota sequencing and subsequent bioinformatics analysis. Results: No significant alterations in fertility outcomes were observed through three P4 administration routes—intragastric gavage, intramuscular injection, and vaginal administration—in rats. However, in behavioral experiments in offspring, a significant increase was observed in swimming time in the IG group than in the control group (P = 0.013). Furthermore, the offspring in the IG group exhibited a marked decrease in non-social behaviors compared with the control group (P = 0.030). No significant behavioral changes were observed in the F1 offspring in the open-field test. Additionally, the offspring in the IG group exhibited a significant elevation in plasma pregnenolone levels compared with the control group (P = 0.019) 30 days after birth. No notable differences in the α-diversity of gut microbiota were observed among the groups. However, significant differences in β-diversity were observed in both the IG and IM groups compared with the control group, indicating that P4 treatment via the two routes exhibited a significant impact on the gut microbiota composition of F1 offspring. Distinct differences were observed in the gut microbiota of the offspring among the three P4 treatment groups, with 22, 28, and 33 differential bacterial taxa identified in the IG, IM, and VAGIN groups, respectively, using linear discriminant effect size analysis, whereas Olivella appeared exclusively in the control group rather than in the P4 treatment groups. Conclusion: Oral administration of P4 to maternal rats during the teratogenesis-sensitive period enhanced motor endurance and plasma pregnenolone levels and altered the composition of the gut microbiota in the offspring. Our findings demonstrated different effects on offspring growth when P4 is administered orally, intramuscularly, or vaginally.

PDE9A Inhibition Improves Coronary Microvascular Rarefaction and Left Ventricular Diastolic Dysfunction in the ZSF1 Rat Model of HFpEF.

Heart failure with preserved ejection fraction (HFpEF) commonly arises from comorbid diseases, such as hypertension, obesity, and diabetes mellitus. Selective inhibition of phosphodiesterase 9A (PDE9A) has emerged as a potential therapeutic approach for treating cardiometabolic diseases. Coronary microvascular disease (CMD) is one of the key mechanisms contributing to the development of left ventricular (LV) diastolic dysfunction in HFpEF. Our study aimed to investigate the mechanisms by which PDE9A inhibition could ameliorate CMD and improve LV diastolic function in HFpEF. The obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid (ZSF1) rat model of HFpEF was employed in which it was found that a progressively developing coronary microvascular rarefaction is associated with LV diastolic dysfunction when compared to lean, nondiabetic hypertensive controls. Obese ZSF1 rats had an increased cardiac expression of PDE9A. Treatment of obese ZSF1 rats with the selective PDE9A inhibitor, PF04447943 (3 mg/kg/day, oral gavage for 2 weeks), improved coronary microvascular rarefaction and LV diastolic dysfunction, which was accompanied by reduced levels of oxidative and nitrosative stress markers, hydrogen peroxide, and 3-nitrotyrosine. Liquid chromatography-mass spectrometry (LC-MS) proteomic analysis identified peroxiredoxins (PRDX) as downregulated antioxidants in the heart of obese ZSF1 rats, whereas Western immunoblots showed that the protein level of PRDX5 was significantly increased by the PF04447943 treatment. Thus, in the ZSF1 rat model of human HFpEF, PDE9A inhibition improves coronary vascular rarefaction and LV diastolic dysfunction, demonstrating the usefulness of PDE9A inhibitors in ameliorating CMD and LV diastolic dysfunction through augmenting PRDX-dependent antioxidant mechanisms.

Transcriptomic Study of Different Stages of Development in the Testis of Sheep.

Numerous genes govern male reproduction, modulating testicular development and spermatogenesis. Our study leveraged RNA-Seq to explore candidate genes and pivotal pathways influencing fecundity in an F1 hybrid of Southdown × Hu sheep testes across four developmental milestones: M0 (0 months old, newborn), M3 (3 months old, sexually immature), M6 (6 months old, sexually mature), and Y1 (1 years old, adult). Histological examination using hematoxylins and eosin staining revealed that the cross-sectional area of the spermatid tubules and the number of supportive cells increased in the other groups, as compared to the M0 group. The cross-sectional area of the vasculature and the number of supporting cells were found to be significantly increased in all other groups in comparison to the M0 group. We conducted GO and KEGG analyses of the differentially expressed genes (DEGs) in the three comparison groups and identified key pathways, including cAMP, MAPK, ECM-receptor interactions, PI3K-Akt, and FOXO signaling, which are closely related to testicular development and spermatogenesis. Notably, alternative splicing (AS) events were markedly elevated in M6 and Y1 stages. Key genes like GATA4, GATA6, SMAD4, SOX9, YAP1, ITGB1 and MAPK1 emerged as significantly enriched in these pathways, potentially orchestrating the transition from immature to mature testes in sheep. These findings offer valuable insights into male reproductive potential and can inform strategies for optimizing animal breeding.

Identification of molecular markers linked to leaf rust resistance gene Lr13 in wheat

Aim. Identification of codominant molecular markers closely linked to the Lr13 leaf rust resistance gene. Methods. PCR with detection in a polyacrylamide gel. Hybridological analysis. Phytopathology evaluation. Statistical analysis. Results. PCR analysis of varieties carrying the Lr13 gene and near-isogenic lines of the Thatcher variety with genes for resistance to leaf rust Lr13 (TcLr13), Lr16 (TcLr16), Lr23 (TcLr23) and the F2 population TcLr13 x TcLr34 by the microsatellite loci Xbarc13, Xbarc55, Xgwm148, Xwmc261, Xgwm271, Xwmc272, Xwmc344, Xbarc361, Xgwm410, Xwmc474, Xwmc477 and Xgwm630 was performed. To test the two microsatellite loci Xgwm148 and Xwmc344 as candidate markers for the Lr13 gene, we used the F2 population, which was obtained from crossing two near-isogenic lines of the Thatcher variety with leaf rust resistance genes Lr13 (TcLr13) and Lr34 (TcLr34). Conclusions. When comparing the genotyping data of F2 hybrids and the phenotypic manifestation of resistance to leaf rust, it was determined that the microsatellite locus Xwmc344 is closely linked to the Lr13 gene.

Analysis of Component of Genetic Variance, Combining Ability, Gene Action and Heterotic Response in Rice (Oryza sativa. L)

Rice (Oryza sativa L.) is an important staple crop, particularly in Asia, where it feeds more than half the world's population. The analysis of variance (ANOVA) for nine traits in a rice breeding experiment with seven lines, three testers, 24 F1 hybrids, and two checks indicated significant variations between treatments, showing significant genetic diversity. General combining ability (GCA) effects revealed that line MTU 1010 and tester NDR 2026 had favorable GCA effects on grain yield per plant, but NDR 2064 and Barani Deep had negative effects. Three crosses, showed considerable favorable benefits on grain yield due to specific combining ability (SCA). Heterosis analysis identified promising crosses, including Gopal Bhag × Prakhar and NDR-2064 × NDR-2026, that demonstrated considerable positive heterosis above the parent and standard varieties Shushk Samrat and Ashwani. These findings emphasize the possibility of specific crosses to improve grain production in rice breeding efforts.

Application of feed enriched with humic additive from peat and dry garlic powder when growing juvenile Siberian sturgeon on an industrial line of cage aquaculture

Cage aquaculture, used in modern industrial sturgeon farming, differ from recirculating water supply systems (RAS) by more natural habitat conditions of fish growing, which are optimal for broodstocks development and maintaining and producing fish seeding material and is more economical. The dominant species for sturgeon aquaculture in Russia and throughout the world is Siberian sturgeon, Acipenser baerii Brandt, 1869, adapted to extreme temperature conditions. When this fish was grown at industrial cage aquaculture enterprises in the European North of Russia under natural conditions, the survival rate of the objects was 99%; growth rates exceeded those of sterlet, Russian sturgeon and F1 hybrids of Russian and Siberian sturgeon; the feed ratio was better compared to fish kept in cages in the Southern Federal District. Seven-year-old sturgeons reared in cages under such conditions had a maximum live weight of more than 8 kg, their physiological parameters were better than those of objects kept in a RAS; indices of reproductive system corresponded to the normal values. To increase the efficiency of keeping Siberian sturgeon in cage aquaculture in the extreme conditions of the Northern regions, feed enriched with multifunctional biologically active compounds of natural origin is used. In this production experiment, the basic forage included the feed additive Humiton of peat humic compounds origin at a dose of 25 ml/kg and/or dried garlic powder at a dose of 30 g/kg; both components previously have shown effectiveness in growing juvenile Siberian sturgeon under RAS conditions. In the experiment, all additives showed activity in all assessed indicators, but the greatest effect was observed when using garlic powder or its combination with Humiton additive. The effectiveness of additives is due to adaptogenic and immunomodulatory effects, the ability to favorably influence the function of the digestive system and improve the absorption of feed nutrients.

Resistance to the insect vector Bemisia tabaci enhances the robustness and durability of tomato yellow leaf curl virus resistance conferred by Ty-1

Tomato yellow leaf curl virus (TYLCV) is a begomovirus (genus Begomovirus, family Geminiviridae) transmitted persistently by the whitefly Bemisia tabaci. It causes tomato yellow leaf curl disease (TYLCD), resulting in significant yield losses worldwide. TYLCD is controlled mainly by using F1 hybrid tomato cultivars harboring the TYLCV resistance gene Ty-1. However, infected Ty-1-bearing tomato plants accumulate viral DNA, which may eventually lead to the emergence of a resistance-breaking TYLCV variant. Recently, a B. tabaci-resistant tomato line derived from the introgression of type IV leaf glandular trichomes and acylsucrose secretion from wild tomato (Solanum pimpinellifolium) was shown to effectively control the spread of TYLCV. In this study, we combined B. tabaci resistance and Ty-1-based TYLCV resistance to increase the robustness and durability of the TYLCD resistance mediated by Ty-1 in tomato plants. Specifically, we characterized and used a Group 2-like isolate of the Israel strain of TYLCV (TYLCV-IL-G2) that contributes to TYLCD epidemics in southeastern Spain. A comparison with isolates of the previously identified TYLCV variant revealed TYLCV-IL-G2 has a similar host range, but it induces a slightly more severe TYLCD in Ty-1-bearing tomato plants. Moreover, we demonstrated that acylsucrose-producing B. tabaci-resistant tomato plants can limit the spread of TYLCV-IL-G2 better than a near-isogenic line lacking type IV trichomes and unable to secrete acylsucrose. Pyramiding Ty-1-based TYLCV resistance and B. tabaci resistance provided by type IV glandular trichomes helped to decrease the effects of TYLCV on Ty-1-bearing tomato plants as well as the likelihood of TYLCV evolution in infected plants.

Rootstock Effects on Tomato Fruit Composition and Pollinator Preferences in Tomato

Food security is threatened by climate change and associated abiotic stresses that affect the flowering stage and the biochemistry of flowers and fruits. In tomato, managed insect pollination and grafting elite tomato varieties onto robust rootstocks are widely practiced commercially to enhance tomato crop profitability, particularly under suboptimal conditions. However, little is known about rootstock–pollinator interactions and their impact on the chemical composition of fruit. In this study, a commercial tomato F1 hybrid (Solanum lycopersicum L.) was self-grafted and grafted onto a set of experimental rootstocks and cultivated under optimal and saline (75 mM NaCl) conditions in the presence of managed bumblebee pollinators (Bombus terrestris). The number of visits (VN) and total visiting time (TVT) by pollinators to different grafted plants were monitored through an RFID (radio-frequency identification) tracking system, while targeted metabolites (hormones, sugars, and organic and amino acids) and mineral composition were analyzed in the fruit juice by UHPLC-MS and ICP-OES, respectively. Pollinator foraging decisions were influenced by the rootstocks genotype and salinity treatment. Experimental rootstocks predominantly increased pollinator attraction compared to the self-grafted variety. Interestingly, the pollinator parameters were positively associated with the concentration of abscisic acid, salicylic acid, malate and fumarate, and tyrosine in salinized fruits. Moreover, a high accumulation of sodium was detected in the fruits of the plants most visited by pollinators, while rootstock genotype-specific responses were found for nitrogen and potassium concentrations. In addition to the known effect on yield, these findings underscore the synergic interactions between rootstocks, pollinators, and environmental stressors on tomato fruit composition.

QTL Mapping of Melampsora Leaf Rust Resistance and Yield Component Traits in the SalixF1 Hybrid Common Parent Population

ABSTRACTThe first step in trait introgression is to identify and assess novel sources of variation. For shrub willow (Salix) breeders, there is an abundance of understudied species within a genus that readily hybridizes. Breeding targets in shrub willow center on traits contributing to biomass yield for bioenergy. These include stem biomass, insect and pathogen resistance, and leaf architecture traits. More specifically, breeding for durable resistance to willow leaf rust (Melampsora spp.) is of particular importance as the pathogen can significantly reduce biomass yields in commercial production. The Salix F1 hybrid common parent population (Salix F1 HCP) was created to characterize the variation among eight species‐hybrid families and map QTL for targeted traits. A female and male S. purpurea were used as common parents in crosses made to male S. suchowensis, S. viminalis, S. koriyanagi, and S. udensis and female S. viminalis, S. integra, S. suchowensis to produce eight families that were planted in field trials at Cornell AgriTech in Geneva, NY and phenotyped. Using 16 previously described parental backcross linkage maps and two newly generated S. purpurea consensus maps, we identified 215 QTL across all eight families and in every parent. These included 15 leaf rust severity, 61 herbivory, 65 leaf architecture, and 74 yield component QTL, resulting in 50 unique overlapping regions within the population. These genetic loci serve as an important foundation for future shrub willow breeding, and each interspecific family was identified as a novel source of useful alleles for trait introgression into high yielding cultivars.