F2 Plants Research Articles

APPLICATION OF SOME SELECTION PROCEDURES FOR IMPROVING OF SOME ECONOMIC CHARACTERS IN COTTON (G. BARBADENSE L.)

The main objective of this study was to estimate and compare the genetic gain obtained from Simith-Hazel index model of selection index with direct and indirect selection to enhance selection efficiency of superior promising families in early segregating generations of the cotton cross Giza 86 x Karshenky. The data revealed increase in mean values for all characters with advanced generations' from F2 to F4 except micronaire reading which showed lower values (desirable values). This shifting in mean values in desirable direction could largely be attributed to the possible accumulation of favorable alleles as a result of selection procedures adapted in this study. The range was comparatively wider in F2 generation as compared with the later generationsF3 and F4 for all studied characters. The advanced generations (F3 and F4 generations) showed reduction in PCV and GCV values as compared with F2, this may due to reduction in genetic variability and heterozygosity as a result of using different selection procedures which exhausted a major part of variability. Most characters showed high heritability values over 60% over generations indicating high magnitude of genetic variability. Significant desirable correlations between boll weight and each of seed/boll and seed index were existed over the three generations. The significant undesirable association existed between seed cotton yield with most traits in F2 generation were broken up and converted to desirable relation in later generations. Principal component analysis grouped estimates variables into six main components. In the first PC1 yield characters (lint yield followed by (x1) and seed cotton yield/plant showed negative loading and more contributed than the other fiber characters which gave negative loadings. The PC2 was great influenced by seed index followed by lint/seed and boll weight which had positive loadings, in same time micronaire reading and fiber strength showed negative loadings. Ten out eleven selection indices were more efficient than direct selection for improvement of lint yield in F2 population. The highest predicted genetic gain from F2 generation for lint yield/plant was observed when selecting for lint yield/plant with bolls/plant (IW1) followed by (I12) selecting for boll/plant with seed/boll and selection index in involving selection index involving lint yield/plant, bolls/plant, seeds/boll and lint/seed. The highest actual genetic gains from F3 generation for lint yield/plant occurred when selecting directly for lint yield/plant followed by selecting for boll/plant. However the indices IW12 (selection index involving lint yield/plant, bolls/plant and seeds/boll) followed by IW13 (selection index involving lint yield/plant, bolls/plant and lint/seed) and IW3 (selection index involving lint yield/plant and lint/seed) were superior to all selection procedures in amount of actual gain. Most indices showed high discrepancy between predicted and actual genetic gain as lint yield/plant, this was due to non-additive gene effect and large effect of environmental factor. However maximum actual genetic advance from F4 generation for lint yield/plant were achieved when selecting for lint yield/plant, seeds/boll and lint/seed followed by selection indices containing lint yield/plant, boll/plant, seed/boll. The direct selection for lint yield and pedigree selection for boll/plant followed by selection for lint/ seed gave desirable actual values and surpassed most indices. selection index involving lint yield/plant and boll/plant surpassed all selection procedures for predicted gain followed by Selection index involving lint yield/plant, bolls/plant, seeds/boll and lint/seed. However direct selection for lint yield followed by pedigree selection for boll/plant appeared to be most effective for the improvement lint yield and gives reasonable actual gains. The predicted and actual advances determine from F3 generation were higher than F4 generation for most selection procedures. On the basis of various selection procedures, six selected families were isolated from F4 generation by superiority of these families from better parents, F3 families and point start of F2 plants mean. The breeder may utilize such selected families in breeding programs aiming to improve yield and quality.

APPLICATION OF SOME SELECTION PROCEDURES FOR IMPROVING OF SOME ECONOMIC CHARACTERS IN COTTON (G. BARBADENSE L.)

The main objective of this study was to estimate and compare the genetic gain obtained from Simith-Hazel index model of selection index with direct and indirect selection to enhance selection efficiency of superior promising families in early segregating generations of the cotton cross Giza 86 x Karshenky. The data revealed increase in mean values for all characters with advanced generations' from F2 to F4 except micronaire reading which showed lower values (desirable values). This shifting in mean values in desirable direction could largely be attributed to the possible accumulation of favorable alleles as a result of selection procedures adapted in this study. The range was comparatively wider in F2 generation as compared with the later generationsF3 and F4 for all studied characters. The advanced generations (F3 and F4 generations) showed reduction in PCV and GCV values as compared with F2, this may due to reduction in genetic variability and heterozygosity as a result of using different selection procedures which exhausted a major part of variability. Most characters showed high heritability values over 60% over generations indicating high magnitude of genetic variability. Significant desirable correlations between boll weight and each of seed/boll and seed index were existed over the three generations. The significant undesirable association existed between seed cotton yield with most traits in F2 generation were broken up and converted to desirable relation in later generations. Principal component analysis grouped estimates variables into six main components. In the first PC1 yield characters (lint yield followed by (x1) and seed cotton yield/plant showed negative loading and more contributed than the other fiber characters which gave negative loadings. The PC2 was great influenced by seed index followed by lint/seed and boll weight which had positive loadings, in same time micronaire reading and fiber strength showed negative loadings. Ten out eleven selection indices were more efficient than direct selection for improvement of lint yield in F2 population. The highest predicted genetic gain from F2 generation for lint yield/plant was observed when selecting for lint yield/plant with bolls/plant (IW1) followed by (I12) selecting for boll/plant with seed/boll and selection index in involving selection index involving lint yield/plant, bolls/plant, seeds/boll and lint/seed. The highest actual genetic gains from F3 generation for lint yield/plant occurred when selecting directly for lint yield/plant followed by selecting for boll/plant. However the indices IW12 (selection index involving lint yield/plant, bolls/plant and seeds/boll) followed by IW13 (selection index involving lint yield/plant, bolls/plant and lint/seed) and IW3 (selection index involving lint yield/plant and lint/seed) were superior to all selection procedures in amount of actual gain. Most indices showed high discrepancy between predicted and actual genetic gain as lint yield/plant, this was due to non-additive gene effect and large effect of environmental factor. However maximum actual genetic advance from F4 generation for lint yield/plant were achieved when selecting for lint yield/plant, seeds/boll and lint/seed followed by selection indices containing lint yield/plant, boll/plant, seed/boll. The direct selection for lint yield and pedigree selection for boll/plant followed by selection for lint/ seed gave desirable actual values and surpassed most indices. selection index involving lint yield/plant and boll/plant surpassed all selection procedures for predicted gain followed by Selection index involving lint yield/plant, bolls/plant, seeds/boll and lint/seed. However direct selection for lint yield followed by pedigree selection for boll/plant appeared to be most effective for the improvement lint yield and gives reasonable actual gains. The predicted and actual advances determine from F3 generation were higher than F4 generation for most selection procedures. On the basis of various selection procedures, six selected families were isolated from F4 generation by superiority of these families from better parents, F3 families and point start of F2 plants mean. The breeder may utilize such selected families in breeding programs aiming to improve yield and quality.

Identification of modifiers of the plant height in wheat using an induced dwarf mutant controlled by RhtB4c allele.

In wheat, 25Rht genes for dwarfness are known, which include both, GA-insensitive and GA-responsive genes. The GA-insensitive Rht genes have been widely used, although, their suitability under abiotic stress conditions has been questioned. This necessitated a search for alternative GA-responsive, spontaneous and induced dwarfing genes. We earlier reported an induced dwarf mutant ('dwarf mutant-3'; 44cm), and the mutant allele was named Rht4c allele (2BL). This dwarf mutant was not suitable for cultivation due to its extra dwarf nature. Therefore, we searched for naturally occurring QTLs, which would modify the phenotype of 'dwarf-mutant-3' using 'mutant-assisted gene identification and characterization' (MAGIC) approach. For this purpose, the 'dwarf mutant-3' was crossed with a tall wheat cv. NP114 and homozygous mutant F2 plants (~ 25% of the progeny) were selected, which were phenotyped for plant height and genotyped using SSR markers. The data were utilized for QTL analysis andplant height. Six modifier QTLs were identified on chromosomes 2A, 2B and 4A. Two QTLs each on 2A and 2B were responsible for increase in plant height (described as 'enhancer modifiers'), whereas the remaining two QTLs located on 4A were responsible for reducing the plant height (described as 'suppressor modifiers'). It was hypothesized that the enhancer QTLs could be exploited for the development of semi-dwarf high yielding genotypes containing Rht4c allele. This is the first study of its kind in wheat demontsrating that the MAGIC approach could be used for identification of modifiers of the mutant phenotypes of other traits for wheat improvement.

Expression of Colorectal Cancer Antigenic Protein Fused to IgM Fc in Chinese Cabbage (Brassica rapa).

The epithelial cell adhesion molecule (EpCAM) is a tumor-associated antigen and a potential target for tumor vaccine. The EpCAM is a cell-surface glycoprotein highly expressed in colorectal carcinomas. The objective of the present study is to develop an edible vaccine system through Agrobacterium-mediated transformation in Chinese cabbage (Brassica rapa). For the transformation, two plant expression vectors containing genes encoding for the EpCAM recombinant protein along with the fragment crystallizable (Fc) region of immunoglobulin M (IgM) and Joining (J)-chain tagged with the KDEL endoplasmic reticulum retention motif (J-chain K) were constructed. The vectors were successfully transformed and expressed in the Chinese cabbage individually using Agrobacterium. The transgenic Chinese cabbages were screened using genomic polymerase chain reaction (PCR) in T0 transgenic plant lines generated from both transformants. Similarly, the immunoblot analysis revealed the expression of recombinant proteins in the transformants. Further, the T1 transgenic plants were generated by selfing the transgenic plants (T0) carrying EpCAM–IgM Fc and J-chain K proteins, respectively. Subsequently, the T1 plants generated from EpCAM–IgM Fc and J-chain K transformants were crossed to generate F1 plants carrying both transgenes. The presence of both transgenes was validated using PCR in the F1 plants. In addition, the expression of Chinese cabbage-derived EpCAM–IgM Fc × J-chain K was evaluated using immunoblot and ELISA analyses in the F1 plants. The outcomes of the present study can be utilized for the development of a potential anti-cancer vaccine candidate using Chinese cabbage.

Allelism Test between Crosses of High-O/L x High-O/L and Very High-O/L x Very High-O/L Peanut Genotypes

ABSTRACT Crosses were made between High-O/L x High-O/L and between Very High-O/L x Very High-O/L peanut genotypes. The High-O/L parental genotypes were F435-OL-2 and ‘Flavor Runner 458’ and ranged between 20 and 40:1 oleic (O) to linoleic (L) fatty acid methyl ester ratio. The Very High-O/L parental cultivars were ‘Georgia Hi-O/L' and ‘Georgia-11J' and consistently had O/L ratios ≥40:1 over four years at the Tifton, Georgia location when grown under maximum-input production practices with irrigation. F1 plants from the High-O/L x High-O/L cross combination had an average O/L ratio of 32.5:1; whereas, the F1 plants from the Very High-O/L x Very High-O/L crosses had an average O/L ratio of 50:1. Average O/L ratios of both F2 and F3 generation progeny also had similar O/L ratios within High-O/L x High-O/L and Very High-O/L x Very High-O/L crosses. The results from these test crosses suggest that there are at least two different high-oleic genotypes possibly associated with either multiple alleles or modifier genes.

Fine mapping of an anthracnose-resistance locus in Andean common bean cultivar Amendoim Cavalo.

Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum, is one of the world’s most destructive diseases of common bean. The use of resistant cultivars is the most cost-effective strategy to manage this disease; however, durable resistance is difficult to achieve due to the vast virulence diversity of the anthracnose pathogen. Finding new genes with broad-spectrum resistance increases the prospect of designing an effective anthracnose-management strategy. Genetic analysis confirmed the presence of a single, dominant anthracnose-resistance locus in AC, which we provisionally named Co-AC. Bulk segregant analysis and genetic mapping of two F2 populations from the crosses AC × PI207262 and AC × G 2333 were used to determine the position of the Co-AC locus in a 631 Kbp genomic region flanked by the SNP markers SS56 and SS92 on the lower arm of chromosome Pv01. By genotyping 77 F3 plants from the AC × PI207262 cross using nine additional markers, we fine-mapped the Co-AC locus to a significantly smaller genomic region (9.4 Kbp) flanked by the SNP markers SS102 and SS165. This 9.4 Kbp region harbors three predicted genes based on the common bean reference genome, notably including the gene model Phvul.001G244300, which encodes Clathrin heavy chain 1, a protein that supports specific stomatal regulation functions and might play a role in plant defense signaling. Because the Co-AC resistance locus is linked in cis, it can be selected with great efficiency using molecular markers. These results will be very useful for breeding programs aimed at developing bean cultivars with anthracnose resistance using marker-assisted selection. This study revealed the broad-spectrum resistance of AC to C. lindemuthianum and the existence of the Co-AC anthracnose-resistance locus. Fine mapping positioned this locus in a small genomic region on the lower end of chromosome Pv01 that contained three candidate genes for the Co-AC locus.

Inheritance of rhizobitoxine‐induced chlorosis in soybean

AbstractThere are two species of Bradyrhizobium that nodulate soybean [Glycine max (L.) Merr.] and fix nitrogen (N): B. japonicum and B. elkanii. Bradyrhizobium elkanii is endemic to soils in the southeastern region of the United States. Some strains of B. elkanii produce rhizobitoxine (RT), a toxin that causes chlorosis on newly developing trifoliates of some field‐grown soybean, in root nodules. Some soybean genotypes are resistant to rhizobitoxine‐induced (RI) chlorosis. The objective of this research was to determine the inheritance of soybean resistance to RI chlorosis. Crosses were made between resistant and susceptible cultivars. Progeny were identified as susceptible, resistant, or segregating in the first, second, and third self‐pollinated generations. All F1 hybrids from crosses between resistant and susceptible soybean exhibited seedling chlorosis, indicating that genes for resistance to chlorosis are recessive. The F2 progeny segregated in a ratio of nine susceptible to seven resistant, indicating that there are two genes responsible for the soybean resistance to RI chlorosis. This ratio was confirmed in F2:3 population screening. One hundred forty‐one simple sequence repeat (SSR) markers polymorphic in both a susceptible parent and a resistant parent were used to locate the genes responsible for resistance to chlorosis. A gene found near marker Satt 657 on linkage group (LG) F (chromosome 13) explained a statistically significant 32% of the phenotypic variation among F2 plants based on the p‐value and R2 of a single factor ANOVA. The second gene was not located.

Genomic and chemical evidence for local adaptation in resistance to different herbivores in Datura stramonium.

Because most species are collections of genetically variable populations distributed to habitats differing in their abiotic/biotic environmental factors and community composition, the pattern and strength of natural selection imposed by species on each other's traits are also expected to be highly spatially variable. Here, we used genomic and quantitative genetic approaches to understand how spatially variable selection operates on the genetic basis of plant defenses to herbivores. To this end, an F2 progeny was generated by crossing Datura stramonium (Solanaceae) parents from two populations differing in their level of chemical defense. This F2 progeny was reciprocally transplanted into the parental plants' habitats and by measuring the identity by descent (IBD) relationship of each F2 plant to each parent, we were able to elucidate how spatially variable selection imposed by herbivores operated on the genetic background (IBD) of resistance to herbivory, promoting local adaptation. The results highlight that plants possessing the highest total alkaloid concentrations (sum of all alkaloid classes) were not the most well-defended or fit. Instead, specific alkaloids and their linked loci/alleles were favored by selection imposed by different herbivores. This has led to population differentiation in plant defenses and thus, to local adaptation driven by plant-herbivore interactions.

R2R3-MYB genes control petal pigmentation patterning in Clarkia gracilis ssp. sonomensis (Onagraceae).

Petal pigmentation patterning is widespread in flowering plants. The genetics of these pattern elements has been of great interest for understanding the evolution of phenotypic diversification. Here, we investigate the genetic changes responsible for the evolution of an unpigmented petal element on a colored background. We used transcriptome analysis, gene expression assays, cosegregation in F2 plants and functional tests to identify the gene(s) involved in petal coloration in Clarkia gracilis ssp. sonomensis. We identified an R2R3-MYB transcription factor (CgsMYB12) responsible for anthocyanin pigmentation of the basal region ('cup') in the petal of C. gracilis ssp. sonomensis. A functional mutation in CgsMYB12 creates a white cup on a pink petal background. Additionally, we found that two R2R3-MYB genes (CgsMYB6 and CgsMYB11) are also involved in petal background pigmentation. Each of these three R2R3-MYB genes exhibits a different spatiotemporal expression pattern. The functionality of these R2R3-MYB genes was confirmed through stable transformation of Arabidopsis. Distinct spatial patterns of R2R3-MYB expression have created the possibility that pigmentation in different sections of the petal can evolve independently. This finding suggests that recent gene duplication has been central to the evolution of petal pigmentation patterning in C. gracilis ssp. sonomensis.

The effect of heat stress on sugar beet recombination

Meiotic recombination plays a crucial role in plant breeding through the creation of new allelic combinations. Therefore, lack of recombination in some genomic regions constitutes a constraint for breeding programmes. In sugar beet, one of the major crops in Europe, recombination occurs mainly in the distal portions of the chromosomes, and so the development of simple approaches to change this pattern is of considerable interest for future breeding and genetics. In the present study, the effect of heat stress on recombination in sugar beet was studied by treating F1 plants at 28 °C/25 °C (day/night) and genotyping the progeny. F1 plants were reciprocally backcrossed allowing the study of male and female meiosis separately. Genotypic data indicated an overall increase in crossover frequency of approximately one extra crossover per meiosis, with an associated increase in pericentromeric recombination under heat treatment. Our data indicate that the changes were mainly induced by alterations in female meiosis only, showing that heterochiasmy in sugar beet is reduced under heat stress. Overall, despite the associated decrease in fertility, these data support the potential use of heat stress to foster recombination in sugar beet breeding programmes.

Characterization of Pm68, a new powdery mildew resistance gene on chromosome 2BS of Greek durum wheat TRI 1796.

New powdery mildew resistance gene Pm68 was found in the terminal region of chromosome 2BS of Greek durum wheat TRI 1796. The co-segregated molecular markers could be used for MAS. Durum wheat (Triticum turgidum L. var. durum Desf.) is not only an important cereal crop for pasta making, but also a genetic resource for common wheat improvement. In the present study, a Greek durum wheat TRI 1796 was found to confer high resistance to all 22 tested isolates of Blumeria graminis f. sp. tritici (Bgt). Inheritance study on the F1 plants and the F2 population derived from the cross TRI 1796/PI 584832 revealed that the resistance in TRI 1796 was controlled by a single dominant gene, herein designated Pm68. Using the bulked segregant RNA-Seq (BSR-Seq) analysis combined with molecular analysis, Pm68 was mapped to the terminal part of the short arm of chromosome 2B and flanked by markers Xdw04 and Xdw12/Xdw13 with genetic distances of 0.22cM each. According to the reference genome of durum wheat cv. Svevo, the corresponding physical region spanned the Pm68 locus was about 1.78-Mb, in which a number of disease resistance-related genes were annotated. This study reports the new powdery mildew resistance gene Pm68 that would be a valuable resource for improvement of both common wheat and durum wheat. The co-segregated markers (Xdw05-Xdw11) developed here would be useful tools for marker-assisted selection (MAS) in breeding.

Development of Mapping Population and Validation of Molecular Markers Associated with MYMV Resistance in Mungbean

Background: Mungbean yellow mosaic virus disease is the most devastating disease on Mungbean production. The virus is transmitted by whitefly and can cause yield losses from 75 to 100 per cent. The development of mungbean cultivars resistant to both virus and its vector is considered as one of the most desirable means of managing the disease as it is environmentally safe and highly efficient. The selection of resistant genotypes in conventional methods is complex and time consuming. Hence, the use of molecular markers linked with resistance genes is powerful as it hastens the breeding programmes. The current study was aimed to develop mapping population and to validate molecular markers associated with Mungbean yellow mosaic virus (MYMV). Methods: The present investigation was carried out with 260 F2 individuals that were derived from crossing DGGV-2 and IPM 2-14 during Kharif-2017 at Main Agril Research Station, UAS, Dharwad. Hybrid seeds of this cross were harvested individually and sown during rabi 2017 along with the two parents, as checks for distinguishing the true hybrids. Hybridity of F1s was confirmed through molecular marker analysis and the true F1s were selfed to raise the F2 generation. Result: Of the 24 previously reported simple sequence repeat markers used for detecting the polymorphism, two markers viz., CEDG305 and CEDG115 were found to be polymorphic between DGGV-2 and IPM-2-14. Two hundred and sixty F2 plants segregated in the ratio of 3 S:1 R (202 susceptible: 58 resistant) as phenotypic and 1: 2 :1 as genotypic ratio implying that single recessive gene controlled resistance. Single marker analysis revealed that the molecular markers CEDG305 and CEDG115 were associated with MYMV resistance with a phenotypic variance of 24.5 and 10.3 per cent respectively.

Loss of C‐genome‐specific markers during transgene introgression from Brassica napus to wild Brassica juncea

Transgene flow from engineered Brassica napus to wild weed relatives could potentially have an environmental effect. To evaluate the introgression of transgenic B. napus into wild Brassica juncea, the hybrid F1 and backcross progenies derived from B. juncea (genome constitution AABB) and transgenic B. napus (AACC) crosses were investigated. C‐genome‐specific simple sequence repeat (SSR) markers corresponding to linkage groups N11–N19 in B. napus were screened and used to estimate the marker frequency in hybrid F1 and backcross progenies. C‐genome‐specific markers could be stably detected in hybrid F1 and backcross BC1 plants, but were only rarely found in the BC2–BC5 generations. For example, a specific SSR marker for linkage group N12 segregated in BC2 generation but were completely lost in BC3–BC5, while a specific SSR marker of linkage group N15 segregated in BC1, BC2 and BC3 generations and was absent in more advanced backcrossed generations (BC4 and BC5). The results indicate that a certain gene regions in Brassica napus plants are transmitted at a relatively lower frequency to wild relatives, and more rapidly disappeared in subsequent backcross generations. We propose that a foreign gene or transgene that is integrated in the C‐chromosome of Brassica napus could reduce the risk of introgression in nature.

Seleksi Generasi Awal untuk Toleransi terhadap Suhu Tinggi pada Padi

The impacts of high-temperature stress on rice growth and productivity can be mitigated by growing tolerant varieties. This research was conducted to estimate the genetic parameters and to select the best genotypes based on the susceptibility stress index (SSI) values. This research was conducted from August 2016 to February 2017. Half of the five weeks seedling tiller of each F3 plant was transferred to new pot culture so that each genotype of the F3 rice population grown in two pots. At the maximum vegetative phase, the parental and F3 populations were treated under two different temperatures: in the open ground area and inside a greenhouse with daily mean temperatures of 38.89/22.67 °C dan 41.62/23.32 °C, respectively. The traits observed were yield and yield components. The results showed that the grain yield of the parents and the F3 population were lower when grown inside the greenhouse. The filled grain number per panicle was controlled by additive gene action in these two environments, and is suggested to be a selection character. Selection based on SSI index obtained 13 genotypes tolerant to heat stress and had higher yield compared to their parents. SSD method combined with shuttle breeding is recommended as a breeding method to produce tolerant and high yielding lines.
 Keywords: heat stress, heritability, segregating population, SSI

Genetic analysis of morphological traits of the spike and reproductivity elements of speltoid chemomutant Triticum aestivum

Long use of the methods of direct intraspecies hybridization in the selective breeding of varieties of Triticum aestivum L. has led to narrowing of their gene fund and close similarity of the genetic potential of their selective breeding traits. Using the method of experimental mutagenesis, one can induce systemic mutants with features of other hexaploid Triticum species which can freely cross-breed with other hybridization offspring, contributing to extension of genetic potential of cultivated wheat and creation of varieties with new levels of manifestation of economically beneficial traits. We studied the pattern of inheritance of morphological traits of the ear, length of the stem and the elements of productivity of speltoid chemomutant of T. aestivum. For the genetic analysis we used hybrids F1 and F2 of soft wheat obtained by cross-breeding speltoid macromutant (Smuhlianka speltoid), induced by the impact of aqueous solution of N-nitroso-N-methylurea (NMU) in the concentration of 0.025% on the seeds of Smuhlianka variety, with plants of Smuhlianka variety (Erythrospermum variety) and Podoloanka (Lutescens variety). To determine the pattern of inheritance the spike morphology, length of the stem and the elements of productivity in F1 hybrids, we calculated the extent of phenotype domination. In populations of F2, we examined plants with different combinations of phenotype manifestation of ear morphology. In F1 hybrids, the speltoid shape of the ear, absence of awns and red colour of the glumes indicated the dominant pattern of inheritance. The high level of phenotype domination of length of the stem and ear, number of spikelets in the main ear indicates the inheritance of the features according to intermediate, partly dominant and over-dominant types. Taking into account the segregation according to the features of spike morphology, awnedness and colour of glumes, the plants of F2 population were divided into phenotype classes, that is 12 and 6 in the combinations of respectively Smuhlianka speltoid × Smuhlianka and Smuhlianka speltoid × Podolianka. We determined that the obtained results are the consequences of dihybrid linkage which corresponds to the theoretical proportion of 12 : 3 : 1. Segregation into non-aristate and aristate plants corresponds to the proportion of monogene segregation of 3 : 1. Within separately distinguished phenotype classes, no independent inheritance of the shape of the ear and awnedness was observed. Dihybrid segregation of F2 plants into speltoid, squarehead and varieties Lutescence/Erythrospermum with quantitative superiority of speltoid plants suggests the control of the trait by two non-allele genes with epistatic interaction. The red colour of the glumes indicates the dominant monogenic pattern of inheritance. Absence of independent inheritance of the shape of the ear and awnedness indicates localization of genes which determine these features in one chromosome.

Mapping a Partial Andromonoecy Locus in Citrullus lanatus Using BSA-Seq and GWAS Approaches.

The sexual expression of watermelon plants is the result of the distribution and occurrence of male, female, bisexual and hermaphrodite flowers on the main and secondary stems. Plants can be monoecious (producing male and female flowers), andromonoecious (producing male and hermaphrodite flowers), or partially andromonoecious (producing male, female, bisexual, and hermaphrodite flowers) within the same plant. Sex determination of individual floral buds and the distribution of the different flower types on the plant, are both controlled by ethylene. A single missense mutation in the ethylene biosynthesis gene CitACS4, is able to promote the conversion of female into hermaphrodite flowers, and therefore of monoecy (genotype MM) into partial andromonoecy (genotype Mm) or andromonoecy (genotype mm). We phenotyped and genotyped, for the M/m locus, a panel of 207 C. lanatus accessions, including five inbreds and hybrids, and found several accessions that were repeatedly phenotyped as PA (partially andromonoecious) in several locations and different years, despite being MM. A cosegregation analysis between a SNV in CitACS4 and the PA phenotype, demonstrated that the occurrence of bisexual and hermaphrodite flowers in a PA line is not dependent on CitACS4, but conferred by an unlinked recessive gene which we called pa. Two different approaches were performed to map the pa gene in the genome of C. lanatus: bulk segregant analysis sequencing (BSA-seq) and genome wide association analysis studies (GWAS). The BSA-seq study was performed using two contrasting bulks, the monoecious M-bulk and the partially andromonoecious PA-bulk, each one generated by pooling DNA from 20 F2 plants. For GWAS, 122 accessions from USDA gene bank, already re-sequenced by genotyping by sequencing (GBS), were used. The combination of the two approaches indicates that pa maps onto a genomic region expanding across 32.24–36.44 Mb in chromosome 1 of watermelon. Fine mapping narrowed down the pa locus to a 867 Kb genomic region containing 101 genes. A number of candidate genes were selected, not only for their function in ethylene biosynthesis and signalling as well as their role in flower development and sex determination, but also by the impact of the SNPs and indels differentially detected in the two sequenced bulks.

Identification and genetic analysis of EMS-mutagenized wheat mutants conferring lesion-mimic premature aging

BackgroundLesion-mimic and premature aging (lmpa) mutant lmpa1 was identified from the ethyl methane sulfonate (EMS) mutant library in the bread wheat variety Keda 527 (KD527) background. To reveal the genetic basis of lmpa1 mutant, phenotypic observations and analyses of chlorophyll content and photosynthesis were carried out in lmpa1, KD527 and their F1 and F2 derivatives. Further, bulked segregation analysis (BSA) in combination with a 660 K SNP array were conducted on the F2 segregation population of lmpa1/Chinese spring (CS) to locate the lmpa1 gene.ResultsMost agronomic traits of lmpa1 were similar to those of KD527 before lesion-like spots appeared. Genetic analysis indicated that the F1 plants from the crossing of lmpa1 and KD527 exhibited the lmpa phenotype and the F2 progenies showed a segregation of normal (wild type, WT) and lmpa, with the ratios of lmpa: WT = 124:36(χ2 = 1.008 < =3.841), indicating that lmpa is a dominant mutation. The combination of BSA and the SNP array analysis of CS, lmpa1 and lmpa1/CS F2 WT pool (50 plants) and lmpa pool (50 plants) showed that polymorphic SNPs were enriched on chromosome 5A, within a region of 30–40 Mb, indicating that the wheat premature aging gene Lmpa1 was probably located on the short arm of chromosome 5A.ConclusionsEMS-mutagenized mutant lmpa1 deriving from elite wheat line KD527 conferred lmpa. Lmpa phenotype of lmpa1 mutant is controlled by a single dominant allele designated as Lmpa1, which affected wheat growth and development and reduced the thousand grain weight (tgw) of single plant in wheat. The gene Lmpa1 was tentatively located within the region of 30–40 Mb near to the short arm of chromosome 5A.

Molecular mapping of stripe rust resistance gene YrH921 in a wheat introgression line H921‐11‐1

AbstractSeveral novel stripe rust pathogen races emerging in the wheat‐planting regions of China in recent years were virulent to a majority of the designated wheat seedling resistance genes. Therefore, it is of great significance to continuously select more new and valuable materials for enriching resistant sources diversity, pyramiding different excellent resistance genes and achieving durable resistance. In this study, a resistance gene, temporarily designated as YrH921, was identified from wheat–Psathyrostachys huashanica introgression line H921‐11‐1. Two hybrid populations, 160 F2 plants and corresponding derived F2:3 families, of the two parents about Mingxian169 as female and H921‐11‐1 as male, were used to evaluate stripe rust resistance in seedling stage and as a mapping population. At last, a genetic map which comprises of four simple sequence repeat (SSR) markers and six expressed sequence tag (EST) markers was constructed. YrH921 was located on the long arm of chromosome 5A. Two closely linked EST‐STS markers (BF483937 and BF484913) were screened, and the genetic distance linked to YrH921 was 3.0 and 4.3 cM, respectively. There was great value in research and production if the two closest markers were effectively used for marker‐assisted selection of YrH921 in breeding.

Development of Kunitz Trypsin inhibitor free vegetable soybean genotypes through marker-assisted selection

ABSTRACT Genetic elimination of Kunitz trypsin inhibitor (KTI) from vegetable soybean (VSB) (Glycine max L. Merrill.) is important as inactivation of this anti-nutritional factor requires 15–20 min. boiling. The F2 plants carrying the null allele of KTI were identified using gene-specific markers in two populations generated by crossing two (VSB) genotypes with a null KTI grain-type genotype. Deployment of gene-specific and Ti-linked simple sequence repeat (SSR) markers led to identification of homozygous recessive (titi) lines in the F6 generation. Across both populations, 21 F6 KTI free lines exhibiting 100-fresh seed weight >45 g, sucrose content >7%, and morphologically similar to VSB were selected. Moisture content and pod yield, at R6, selected lines were 64–74.1% and 7.0−9.5 t∙ha−1, respectively. This is the first report on development of KTI-free VSB which may be suitable for direct consumption.

A Plant-Derived Antigen-Antibody Complex Induces Anti-Cancer Immune Responses by Forming a Large Quaternary Structure.

The antigen–antibody complex (AAC) has novel functions for immunomodulation, encouraging the application of diverse quaternary protein structures for vaccination. In this study, GA733 antigen and anti-GA733 antibody proteins were both co-expressed to obtain the AAC protein structures in a F1 plant obtained by crossing the plants expressing each protein. In F1 plant, the antigen and antibody assembled to form a large quaternary circular ACC structure (~30 nm). The large quaternary protein structures induced immune response to produce anticancer immunoglobulins G (IgGs) that are specific to the corresponding antigens in mouse. The serum containing the anticancer IgGs inhibited the human colorectal cancer cell growth in the xenograft nude mouse. Taken together, antigens and antibodies can be assembled to form AAC protein structures in plants. Plant crossing represents an alternative strategy for the formation of AAC vaccines that efficiently increases anticancer antibody production.