F1 Hybrid Population Research Articles

Floral volatile chemical diversity in Hedychium F1 hybrid population

Floral scent profiles play crucial role in the ornamental values of cut flowers, and efficient floral scent profiling acquisition is a critical premise for quality assessment and genetic improvement of fragrant cut flowers. Despite the fact that cross breeding is an effective method for improving the fragrance of cut flowers, less focus has been paid on floral scent evaluation in cross populations due to the complexity of fragrance phenotype detection. In the current study, floral scent profile of Hedychium coronarium 'ZS', H. 'Jin' and their 110F1 hybrid cultivars were evaluated. Headspace solid phase microextraction- gas chromatography-mass spectrometry (HS–SPME–GC–MS) identified 33 volatile organic compounds (VOCs), including 15 monoterpenoids, 7 sesquiterpenoids, 9 phenylpropanoids, 1 fatty acid derivative, and 1 other, while proton transfer reaction-time of flight-mass spectrometry (PTR–ToF–MS) detected 68 masses. Correlation analysis indicated that β-myrcene, α-terpinene, eucalyptol, (E)-β-ocimene, cyclopentene, 3-isopropenyl-5, 5-, allo-ocimene, indole, isoamyl benzoate, (E)-β-famesene, m/z 74.069 and m/z 118.069 played an important role in sensory concentration of Hedychium flowers fragrance. Furthermore, partial least squares (PLS) analysis of VOCs and masses revealed that 44 masses were highly sensitive to 21 VOCs (8 monoterpenoids, 6 sesquiterpenoids, 5 benzenoids/phenylpropanoids, 1 fatty acid derivative, and indole). Overall, the data showed that two mass spectrometric methodologies were highly complementary, revealing a novel and dynamic perspective on volatile complex diversity of Hedychium F1 hybrid population cut flowers.

Insights Into the Genetics of the Zhonghua 11 Resistance to Meloidogyne graminicola and Its Molecular Determinism in Rice

Meloidogyne graminicola is a widely spread nematode pest of rice that reduces crop yield up to 20% on average in Asia, with devastating consequences for local and global rice production. Due to the ban on many chemical nematicides and the recent changes in water management practices in rice agriculture, an even greater impact of M. graminicola can be expected in the future, stressing the demand for the development of new sustainable nematode management solutions. Recently, a source of resistance to M. graminicola was identified in the Oryza sativa japonica rice variety Zhonghua 11 (Zh11). In the present study, we examine the genetics of the Zh11 resistance to M. graminicola and provide new insights into its cellular and molecular mechanisms. The segregation of the resistance in F2 hybrid populations indicated that two dominant genes may be contributing to the resistance. The incompatible interaction of M. graminicola in Zh11 was distinguished by a lack of swelling of the root tips normally observed in compatible interactions. At the cellular level, the incompatible interaction was characterised by a rapid accumulation of reactive oxygen species in the vicinity of the nematodes, accompanied by extensive necrosis of neighbouring cells. The expression profiles of several genes involved in plant immunity were analysed at the early stages of infection during compatible (susceptible plant) and incompatible (resistant plant) interactions. Notably, the expression of OsAtg4 and OsAtg7, significantly increased in roots of resistant plants in parallel with the cell death response, suggesting that autophagy is activated and may contribute to the resistance-mediated hypersensitive response. Similarly, transcriptional regulation of genes involved in hormonal pathways in Zh11 indicated that salicylate signalling may be important in the resistance response towards M. graminicola. Finally, the nature of the resistance to M. graminicola and the potential exploitation of the Zh11 resistance for breeding are discussed.

Mapping QTLs for spring green-up, plant vigor, and plant biomass in two lowland switchgrass populations.

The online version contains supplementary material available at 10.1007/s11032-022-01296-7.

A Novel Strategy to Reveal the Landscape of Crossovers in an F1 Hybrid Population of Populus deltoides and Populus simonii.

Although the crossover (CO) patterns of different species have been extensively investigated, little is known about the landscape of CO patterns in Populus because of its high heterozygosity and long-time generation. A novel strategy was proposed to reveal the difference of CO rate and interference between Populus deltoides and Populus simonii using their F1 hybrid population. We chose restriction site-associated DNA (RAD) tags that contained two SNPs, one only receiving the CO information from the female P. deltoides and the other from the male P. simonii. These RAD tags allowed us to investigate the CO patterns between the two outbred species, instead of using the traditional backcross populations in inbred lines. We found that the CO rate in P. deltoides was generally greater than that in P. simonii, and that the CO interference was a common phenomenon across the two genomes. The COs landscape of the different Populus species facilitates not only to understand the evolutionary mechanism for adaptability but also to rebuild the statistical model for precisely constructing genetic linkage maps that are critical in genome assembly in Populus. Additionally, the novel strategy could be applied in other outbred species for investigating the CO patterns.

Investigation of genome-wide InDel distribution and segregation in Populus with restriction-site associated DNA sequencing data

Insertion or deletion polymorphism (InDel) is one of the main genetic variations in plant genomes. However, there are few studies on InDels across the whole genome in Populus. In this study, we investigated genome-wide InDels in Populus deltoides and Populus simonii and InDel segregation in their F1 hybrid population with restriction-site associated DNA sequencing (RAD-seq) data. A total of 119,066 InDels were identified in P. deltoides and P. simonii according to the reference genome of Populus trichocarpa, including 58,532 unique InDels in P. deltoides, 54,469 unique InDels in P. simonii, and 6,065 common InDels in both. Meanwhile, the distribution of these InDels was analyzed along chromosomes, indicating that the distribution patterns for both species were largely similar, but the average InDel density was slightly higher in P. deltoides than in P. simonii. GO annotation and enrichment analysis of those genes harboring InDels showed the same patterns between the two poplar species. It is interesting to find that the ratio (~ 46%) of the common InDels within genes to all common InDels was higher than that of the InDels within genes to all InDels in P. deltoides (~ 35%) or in P. simonii (~ 34%), possibly indicating that those InDels are more conservative between poplar species. Moreover, investigation of the InDel segregation patterns demonstrated that a large number of Mendelian InDels could be selected for genetic mapping in the F1 hybrid population. RAD-seq provides genome-wide insights into the InDel distributions in P. deltoides and P. simonii and the segregation patterns in their progeny, providing valuable genomic variation information for genetic and evolutionary studies in Populus.

Illustration of the variation in the content of flavanone rutinosides in various citrus germplasms from genetic and enzymatic perspectives.

In citrus, 1,6-rhamnosytransferase (1,6RhaT) and 1,2-rhamnosytransferase (1,2RhaT) catalyze flavanone-7-O-glucosides to form nonbitter flavanone rutinosides (FRs) and bitter flavanone neohesperidosides (FNs), respectively. As revealed in this study of fruit peels from 36 citrus accessions, FRs varied from undetectable levels in pummelo and kumquat to being the dominant flavonoids in sweet orange and loose-skin mandarins. Furthermore, a previously annotated full-length 1,6RhaT-like gene was identified as another 1,6RhaT-encoding gene by in vitro experiments. In total, 28 alleles of full-length 1,6RhaTs were isolated and classified into A, B and C types with only type A alleles encoding a functional protein. Coincidently, only the accessions that contained FRs harbored type A alleles, as was further verified in two F1 hybrid populations. Moreover, the inferior substrate conversion efficiency of 1,6RhaTs in comparison with that of 1,2RhaT in vitro might partly explain the lower proportions of FRs to total flavanone disaccharides in citrus hybrids harboring both functional rhamnosyltransferases. Our findings provide a better understanding of FR content variations among citrus and are meaningful for a mechanistic illustration of citrus flavonoid metabolism and fruit quality improvement practices.

Fitness consequences of hybridization between wild Newfoundland and farmed European and North American Atlantic salmon

Selection due to multi-generational domestication and genetically distinct origins raises concerns about potential fitness consequences of hybridization between farmed and wild Atlantic salmon. In Newfoundland (NF), Canada, the aquaculture industry uses the North American (NA) Saint John River strain, though site-specific permission has been granted to farm a European origin (EO) strain. We used complementary experiments to investigate differences in (1) dominance status and (2) growth and survival in allopatry (NF wild fish) versus sympatry (NF wild fish with NA/EO farmed individuals and related F1 hybrids) in contrasting tank and semi-natural stream environments. NA farmed salmon were more dominant than NF wild individuals, with hybrids being intermediate in expression and not differing from wild fish. EO farmed salmon also tended to dominate NF wild individuals, but not significantly. Competition with farmed fish and hybrids did not affect the growth of wild fish in sympatry versus allopatry in the tank environment. However, that was not the case in one instance in the stream environment where wild fish in sympatry with NA farmed fish and hybrids outgrew those in allopatry. Within sympatric treatments, both EO and NA farmed salmon outgrew wild individuals in the tank environment, but not always in the stream environment (exception: NA farmed). Hybrids tended to display intermediate growth performance relative to farmed and wild fish in both environments. Survival did not differ among cross types in either environment. These findings suggest that irrespective of distinct origins, both EO and NA farmed salmon displayed greater dominance and growth than NF wild salmon in the tank environment. However, in the stream environment, competition imposed by NA farmed fish and related hybrids on wild fish appeared less than that imposed by the EO strain and related hybrids, as evident in growth performance. Findings thus provide valuable insight into the effects of hybridization and, consequently, fitness-related trait differences among divergent EO and NA farmed, NF wild, and F1 hybrid populations of importance for the conservation and management of Atlantic salmon.

Variation in the promoter of the sorbitol dehydrogenase gene MdSDH2 affects binding of the transcription factor MdABI3 and alters fructose content in apple fruit.

Fructose (Fru) content is a key determinant of fruit sweetness and quality. An F1 hybrid population of the apple cultivars 'Honeycrisp' × 'Qinguan' was used to investigate the quantitative trait locus (QTL) regions and genes controlling Fru content in fruit. A stable QTL on linkage group (LG) 01 in 'Honeycrisp' was detected on the single nucleotide polymorphism (SNP) genetic linkage maps. In this region, a sorbitol dehydrogenase (SDH) gene, MdSDH2, was detected and showed promoter variations and differential expression patterns between 'Honeycrisp' and 'Qinguan' fruits as well as their hybrids. A SNP variant (A/G) in the MdSDH2 promoter region (SDH2p-491) affected the binding ability of the transcription factor MdABI3, which can affect the expression of MdSDH2. Promoter sequences with an A nucleotide at SDH2p-491 had stronger binding affinity for MdABI3 than those with a G. Among 27 domesticated apple cultivars and wild relatives, this SNP (A/G) was associated with Fru content. Our results indicate that MdSDH2 can alter Fru content as the major regulatory gene and that ABA signaling might be involved in Fru content accumulation in apple fruit.

Diversity and Distribution of Anatomical Characteristics Involved with Drought Resistance of Inter-Specific (Saccharum spp. Hybrid × S. spontaneum) Sugarcane F1 Hybrid Population

Diversity and Distribution of Anatomical Characteristics Involved with Drought Resistance of Inter-Specific (Saccharum spp. Hybrid × S. spontaneum) Sugarcane F1 Hybrid Population

Performance inheritance and combining ability of spring barley accessions

Purpose and objectives. To establish the gene interaction types in the performance inheritance, to evaluate the combining abilities and effects of genes for this trait in spring barley accessions.
 Materials and methods. We investigated 75 F1 spring barley hybrid combinations derived from crossing 25 female forms with three male ones (chaffy and naked). Crossing was conducted in accordance with topcross design. F1 seeds and parents were sown with a cassette breeding planter SKS-6A. Grain pea was the forecrop. The plot area was 0.20 m2. The interrow distance was 0.20 m; the inter-plot tracks were of 0.50 m. Crossings were performed in two replications. Plants were harvested manually, with roots.
 For structural analysis, 20 typical plants were chosen from each F1 hybrid population, and the performance inheritance was determined by dominance degree (hp). The obtained data were grouped and gene interaction types were determined as per G.M. Beil and R.E. Atkins’s classification. Using two-factor analysis of variance in STATISTICA 10, we found significant differences between the GCA and SCA variances for the performance and evaluated the combining ability effects.
 Results and discussion. In 2019–2020, the features of 22 spring barley cultivars and three lines were described in terms of the gene interaction types in the performance inheritance and combining ability. On this basis, the prospects of biotype selections were evaluated. In the arid conditions of 2019, F1 only showed positive over dominance, while in favorable 2020 the inheritance types varied from positive to negative overdominance. In the two years, the general combining ability was high in female cultivars Khors and Troian. The male components did not show consistently high GCA for the both years. Hybrids between accessions with a high GCA and accessions with a lower or intermediate GCA may be promising in breeding due appearance of positive transgressions in the offspring. In 2019, the SCA effects were significantly strong in female forms Troian, Datcha, Gladys, Grace, Gatunok, Modern, and Herkules and in male forms Ahrarii and Scrabble.
 Conclusions. The study found that the gene interaction types in the spring barley performance inheritance depended on cross combinations and growing conditions. In unfavorable 2019, F1 only showed positive overdominance (heterosis), while in favorable 2020, positive overdominance, positive dominance and intermediate inheritance were observed. In 2019–2020, the high GCA was seen in female cultivars Khors and Troian. The strong SCA effects were noticed in female components Troian, Datcha, Gladys, Grace, Gatunok, Modern, and Herkules and male forms Agrarii and Scrabble. The hybrid combinations with the maximum probability of producing transgressive segregants have been selected

A chromosome-scale genome sequence of pitaya (Hylocereus undatus) provides novel insights into the genome evolution and regulation of betalain biosynthesis

Pitaya (Hylocereus) is the most economically important fleshy-fruited tree of the Cactaceae family that is grown worldwide, and it has attracted significant attention because of its betalain-abundant fruits. Nonetheless, the lack of a pitaya reference genome significantly hinders studies focused on its evolution, as well as the potential for genetic improvement of this crop. Herein, we employed various sequencing approaches, namely, PacBio-SMRT, Illumina HiSeq paired-end, 10× Genomics, and Hi-C (high-throughput chromosome conformation capture) to provide a chromosome-level genomic assembly of ‘GHB’ pitaya (H. undatus, 2n = 2x = 22 chromosomes). The size of the assembled pitaya genome was 1.41 Gb, with a scaffold N50 of ~127.15 Mb. In total, 27,753 protein-coding genes and 896.31 Mb of repetitive sequences in the H. undatus genome were annotated. Pitaya has undergone a WGT (whole-genome triplication), and a recent WGD (whole-genome duplication) occurred after the gamma event, which is common to the other species in Cactaceae. A total of 29,328 intact LTR-RTs (~696.45 Mb) were obtained in H. undatus, of which two significantly expanded lineages, Ty1/copia and Ty3/gypsy, were the main drivers of the expanded genome. A high-density genetic map of F1 hybrid populations of ‘GHB’ × ‘Dahong’ pitayas (H. monacanthus) and their parents were constructed, and a total of 20,872 bin markers were identified (56,380 SNPs) for 11 linkage groups. More importantly, through transcriptomic and WGCNA (weighted gene coexpression network analysis), a global view of the gene regulatory network, including structural genes and the transcription factors involved in pitaya fruit betalain biosynthesis, was presented. Our data present a valuable resource for facilitating molecular breeding programs of pitaya and shed novel light on its genomic evolution, as well as the modulation of betalain biosynthesis in edible fruits.

Heredity of leaf apparatus features in F2 of soft winter wheat

The aim of the research was to study the heredity nature of flag (first top) and sub-flag (second top) leaves of F2 hybrid populations obtained from the crossbred varieties and lines of soft winter wheat of different morphophysiological types. The research was conducted in the experimental field of KhNAU named after V.V. Dokuchaiev in 2015 – 2016. The vegetation period of 2015 – 2016 turned out to be abnormally warm with a lot of precipitation. The amount of precipitation during the wheat vegetation period in 2015 – 2016 was 597,8 mm, which was significantly higher than the long-term average (456,0 mm). Such weather conditions affected the course of vernalization and wintering of plants, contributed to the development of diseases and pests, complicated and stretched the harvest period, its quantity and quality. 14 F2 hybrid populations, obtained by crossbreeding 16 varieties and lines were used as a starting material. The selection of the parent pairs was performed on a set of the morphological and anatomical productivity features. Based on cluster analysis (K-average method), the set of the studied genotypes of soft winter wheat was divided into four clusters. The genotypes of the first cluster had a high level of ear productivity and the maximum level of development of the anatomical structure features of the stem and ear. The genotypes of the second and third clusters are two “opposite” types of variability of the productivity features, leaf apparatus and anatomical structure of the stem and ear. Thus, the genotypes of the second cluster are characterized by a relatively high level of development of the features of ear productivity, but minimal – the features of anatomical structure, and for the third vice versa. The genotypes of the third cluster can be a donor of the anatomical structure features, and the second – ear productivity. The genotypes of the fourth cluster had the maximum level of development of the group of the features of the leaf apparatus, productivity and a fairly high level of the development of the anatomical structure features. The varieties from the first cluster were used for crossing: Smuhlianka, Izolda, Prestizh, Kharkivska 105; from the second one: Odeska 267, Venera, Ebi, Statna, Dobirna, KIU line – 7; from the third one: KIU lines – 40, L 80 – III / 7, Patriot variety; from the fourth one: Pereiaslavka, Lehenda, line L 89 – I/2. The hybrids were sown in a block with the parental forms, the area of the plot for the parental forms made up 1 m2, the area of the hybrid populations plots depended on the number of seeds and was equal to 1 – 2 m2. The level of heredity according to the characteristics of the leaf apparatus of F2 hybrids of soft winter wheat was determined, namely the frequency (Tf) and the degree of transgressions (Td) and the heredity coefficient in the “broad sense”. The frequency of transgressions of the hybrids on the basis of the area of the flag leaf varied from 3,00% to 40,00%, and the degree of transgressions varied from 3,30% to 52,90%, but in three combinations the transgression was zero. The heredity coefficient in the “broad sense” ranged from 0,07 to 0,99. According to the total area of the two upper leaves (flag and sub-flag), the frequency of transgressions varied from 6,70% to 50,00%, and the degree of transgressions – from 3,60% to 45,20%. In two combinations, the transgression was zero. High and medium heredity coefficients, exceeding 0,50, and a high manifestation of transgressions were observed in the combinations: KIU-7 / Smuhlianka (Tf – 33,3 and Td – 45,2%), Kharkivska 105 / Smuhlianka (Tf – 30,00 and Td – 45,23%) Izolda / Prestige (Tf – 30,00 and Td– 12,60%), Ebi / L 89 – I / 2 (Tf – 23,30 and Td – 31,50%). These combinations can predict the effective plant selection, starting with F2 and F3. Key words: soft winter wheat, F2 hybrids, heredity coefficient in the “broad sense”, frequency and degree of transgression.

Introgession of powdery mildew resistance into cultural pea from wild accession of P. fulvum

Wildlife pea specimen P. fulvum i-609881 of the UIP collection (Saint Petersburg, Russia) in a greenhouse box has demonstrated full resistance to powdery mildew. As a result of crossing with cultivated peas, interspecific hybrids of Stabil × i-6098881 were obtained. In populations of interspecific hybrids, the BC2F3 Stabil × i-609881 line of the leafless morphotype (af), resistant to the powdery mildew pathogen, was isolated as a result of backcrossing. As a result of crossing plants of this line with susceptible plants of the leafy (Af) variety Temp, the following series of pea hybrids was obtained. Analysis of F1 hybrids showed that all plants were characterized by resistance to the pathogen powdery mildew. In the population of F2 hybrids, a splitting analysis was performed on the basis of resistance to powdery mildew. The analysis revealed that the hybrid population consisted of 66 resistant and 20 affected plants. The actual splitting corresponded to the expected one for monogenic inheritance with a phenotype ratio of 3: 1 phenotype ratio (η05 2 test, p=0.7087438). Based on the analysis of populations of F1 and F2 hybrids, it is concluded that resistance to powdery mildew is the result of introgression of the genetic resistance factor from the genome of the P. fulvum i-609881 sample and is encoded by the dominant allele of a single gene.

Whole-genome resequencing reveals loci with allelic transmission ratio distortion in F1 chicken population.

Allelic transmission ratio distortion (TRD) is the significant deviation from the expected ratio under Mendelian inheritance theory, which may be resulted from multiple disrupted biological processes, including germline selection, meiotic drive, gametic competition, imprint error, and embryo lethality. However, it is less known that whether or what extent the allelic TRD is present in farm animals. In this study, whole-genome resequencing technology was applied to reveal TRD loci in chicken by constructing a full-sib F1 hybrid population. Through the whole-genome resequencing data of two parents (30×) and 38 offspring (5×), we detected a total of 2850 TRD SNPs (p-adj < 0.05) located within 400 genes showing TRD, and all of them were unevenly distributed on macrochromosomes and microchromosomes. Our findings suggested that TRD in the chicken chromosome 16 might play an important role in chicken immunity and disease resistance and the MYH1F with significant TRD and allele-specific expression could play a key role in the fast muscle development. In addition, functional enrichment analyses revealed that many genes (e.g., TGFBR2, TGFBR3, NOTCH1, and NCOA1) with TRD were found in the significantly enriched biological process and InterPro terms in relation to embryonic lethality and germline selection. Our results suggested that TRD is considerably prevalent in the chicken genome and has functional implications.

Multivariate linear mixed model enhanced the power of identifying genome-wide association to poplar tree heights in a randomized complete block design.

With the advances in high-throughput sequencing technologies, it is not difficult to extract tens of thousands of single-nucleotide polymorphisms (SNPs) across many individuals in a fast and cheap way, making it possible to perform genome-wide association studies (GWAS) of quantitative traits in outbred forest trees. It is very valuable to apply traditional breeding experiments in GWAS for identifying genome variants associated with ecologically and economically important traits in Populus. Here, we reported a GWAS of tree height measured at multiple time points from a randomized complete block design (RCBD), which was established with clones from an F1 hybrid population of Populus deltoides and Populus simonii. A total of 22,670 SNPs across 172 clones in the RCBD were obtained with restriction site-associated DNA sequencing (RADseq) technology. The multivariate mixed linear model was applied by incorporating the pedigree relationship matrix of individuals to test the association of each SNP to the tree heights over 8 time points. Consequently, 41 SNPs were identified significantly associated with the tree height under the P-value threshold determined by Bonferroni correction at the significant level of 0.01. These SNPs were distributed on all but two chromosomes (Chr02 and Chr18) and explained the phenotypic variance ranged from 0.26% to 2.64%, amounting to 63.68% in total. Comparison with previous mapping studies for poplar height as well as the candidate genes of these detected SNPs were also investigated. We therefore showed that the application of multivariate linear mixed model to the longitudinal phenotypic data from the traditional breeding experimental design facilitated to identify far more genome-wide variants for tree height in poplar. The significant SNPs identified in this study would enhance understanding of molecular mechanism for growth traits and would accelerate marker-assisted breeding programs in Populus.

High-Quality SNP Linkage Maps Improved QTL Mapping and Genome Assembly in Populus.

With the advances in high-throughput sequencing technologies and the development of new software for extracting single nucleotide polymorphisms (SNPs) across a mapping population, it is possible to construct high-quality genetic maps with thousands of SNPs in outbred forest trees. Two parent-specific linkage maps were constructed with restriction site-associated DNA sequencing data from an F1 hybrid population derived from Populus deltoides and Populus simonii, and applied in QTL mapping and genome assembly. The female P. deltoides map contained 4018 SNPs, which were divided into 19 linkage groups under a wide range of LOD thresholds from 7 to 55. The male P. simonii map showed similar characteristics, consisting of 2097 SNPs, which also belonged to 19 linkage groups under LOD thresholds of 7 to 29. The SNP order of each linkage group was optimal among different ordering results from several available software. Moreover, the linkage maps allowed the detection of 39 QTLs underlying tree height and 47 for diameter at breast height. In addition, the linkage maps improved the anchoring of 689 contigs of P. simonii to chromosomes. The 2 parental genetic maps of Populus are of high quality, especially in terms of SNP data quality, the SNP order within linkage groups, and the perfect match between the number of linkage groups and the karyotype of Populus, as well as the excellent performances in QTL mapping and genome assembly. Both approaches for extracting and ordering SNPs could be applied to other species for constructing high-quality genetic maps.

The testing of haploproduction ability of soft winter wheat different hybrids in anther culture in vitro

Aim. Study the the efficiency of androgenesis in vitro in anther culture of different genotyps winter wheat. Methods. Obtaining of soft winter wheat double haploid lines by anther culture in vitro. The statistical methods. Results The ability to androgenesis in an in vitro anthers culture of 30 soft winter wheat genotypes was tested. The differences in the frequency of callus induction and the ability to regenerate plants in the process of androgenesiss in vitro of winter soft wheat were detected. The range of variation haploproduction activiti (from % of implanted anthers) was broad. The sign of "the formation of callus" was in limited from 0 to 13.2 % and on the sign of "regeneration of green plants" – from 0 to 1.8 %. The 126 green plants-regenerants were received. Conclusions. Genotype-specific of microspores morphogenetic reactions of soft winter wheat in the process of androgenesis in vitro were revealed. It is advisable to use the anthers from the F2 hybrid population plant as a donor material to create an effective technology for producing double haploids of soft winter wheat was shown.&#x0D; Keywords: wheat hybrid, anther culture in vitro, callus, regeneration.

Comparative analysis of full-length transcriptomes based on hybrid population reveals regulatory mechanisms of anthocyanin biosynthesis in sweet potato (Ipomoea batatas (L.) Lam)

BackgroundSweet potato (Ipomoea batatas (L.) Lam.) is a highly heterozygous autohexaploid crop with high yield and high anthocyanin content. Purple sweet potato is the main source of anthocyanins, and the mechanism of anthocyanin biosynthesis in storage roots has not been fully revealed.ResultsIn order to reveal the mechanism of anthocyanin biosynthesis and identify new homologous genes involved in anthocyanin biosynthesis in the storage roots of sweet potato, we used Ningzishu 1 and Jizishu 2 as parents to construct a F1 hybrid population. Seven anthocyanin-containing lines and three anthocyanin-free lines were selected for full-length and second-generation transcriptome analyses. A total of 598,375 circular consensus sequencing reads were identified from full-length transcriptome sequencing. After analysis and correction of second-generation transcriptome data, 41,356 transcripts and 18,176 unigenes were obtained. Through a comparative analysis between anthocyanin-containing and anthocyanin-free groups 2329 unigenes were found to be significantly differentially expressed, of which 1235 were significantly up-regulated and 1094 were significantly down-regulated. GO enrichment analysis showed that the differentially expressed unigenes were significantly enriched in molecular function and biological process. KEGG enrichment analysis showed that the up-regulated unigenes were significantly enriched in the flavonoid biosynthesis and phenylpropanoid biosynthesis pathways, and the down-regulated unigenes were significantly enriched in the plant hormone signal transduction pathway. Weighted gene co-expression network analysis of differentially expressed unigenes revealed that anthocyanin biosynthesis genes were co-expressed with transcription factors such as MYB, bHLH and WRKY at the transcription level.ConclusionsOur study will shed light on the regulatory mechanism of anthocyanin biosynthesis in sweet potato storage roots at the transcriptome level.

Genetic Analysis of Leaf Traits in Small-Flower Chrysanthemum (Chrysanthemum × morifolium Ramat.)

Leaf shape is an important quality trait of agronomic crops, and to control the law of genetic variation of leaf shape is of practical significance for improving the early identification and selection of agronomic crops. Variations in the leaf morphology of chrysanthemum cultivars are abundant, and previous studies have quantitatively defined and classified the leaf morphology of chrysanthemum; however, the genetic architecture of chrysanthemum leaves has not been elucidated to date. In this study, two pairs of F1 hybrid populations were constructed by using small-flower chrysanthemum varieties with differences in leaf traits, and the genetic variation rules of these important quantitative traits were further discussed based on the major gene and polygene mixed inheritance analyses. The results showed that the leaves in blade shape (LBS), leaf length/width is controlled by two pairs of additive-dominant major genes (B-1), the widest part length/leaf length is controlled by two completely dominant genes (B-5); in leaf lobe shape (LLS), the lobe length/vein length is controlled by one pair of additive dominant major genes (A-1); and the lobe length/lobe width is controlled by two pairs of additive dominant major genes (B-2). The heritability of major genes was greater than 30%. For the leaf petiole shape (LPS), the petiole length is controlled by a pair of additive-dominant major genes (A-1). The results showed that the leaf traits were mainly controlled by genetic factors. In addition, based on the high-density genetic map of one F1 hybrid population, it was found that 51 quantitative trait loci (QTL) were used to control the leaf traits, including two QTLs that controlled the LBS. There were 18 QTLs that controlled LLS. Moreover, the primary QTLs that controlled leaf width and lobe length were obtained. The results of this study may establish a theoretical foundation for the in-depth exploration of leaf-shape-related genes in chrysanthemum and may provide a reference for future research investigating leaf-shape genetics in other agronomic crops.

Oral shelling within an adaptive radiation of pupfishes: Testing the adaptive function of a novel nasal protrusion and behavioural preference.

Dietary specialization on hard prey items, such as mollusks and crustaceans, is commonly observed in a diverse array of fish species. Many fish consume these types of prey by crushing the shell to consume the soft tissue within, but a few fishes extricate the soft tissue without breaking the shell using a method known as oral shelling. Oral shelling involves pulling a mollusc from its shell and it may be a way to subvert an otherwise insurmountable shell defence. However, the biomechanical requirements and potential adaptations for oral shelling are unknown. Here, we test the hypothesis that a novel nasal protrusion is an adaptation for oral shelling in the durophagous pupfish (Cyprinodon brontotheroides). We first demonstrate oral shelling in this species and then predict that a larger nasal protrusion would allow pupfish to consume larger snails. Durophagous pupfish are found within an endemic radiation of pupfish on San Salvador Island, Bahamas. We took advantage of closely related sympatric species and outgroups to test: (a) whether durophagous pupfish shell and consume more snails than other species, (b) if F1 and F2 durophagous hybrids consume similar amounts of snails as purebred durophagous pupfish, and (c) if nasal protrusion size in parental and hybrid populations increases the maximum size of consumed snails. We found that durophagous pupfish and their hybrids consumed the most snails, but did not find a strong association between nasal protrusion size and maximum snail size consumed within the parental or F2 hybrid population, suggesting that the size of their novel nasal protrusion does not provide a major benefit in oral shelling. Instead, we suggest that the nasal protrusion may increase feeding efficiency, act as a sensory organ, or is a sexually selected trait, and that a strong feeding preference may be most important for oral shelling.