F1 Hybrid Plants Research Articles

The genetic study utility of a hexaploid wheat DH population with non-recombinant A- and B-genomes

To study the D-genome of the wild wheat relative Aegilops tauschii Cosson at the hexaploid level, we developed a synthetic doubled-haploid (DH) hexaploid wheat population, SynDH3. This population was derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from a cross between Triticum turgidum ssp. dicoccon PI377655 and A. tauschii ssp. strangulata AS66 × ssp. tauschii AS87. SynDH3 is a diploidization-hexaploid DH population containing recombinant D chromosomes from two different A. tauschii genotypes, with A and B chromosomes from T. turgidum being homogenous across the entire population. Using this population, we constructed a genetic map. Of the 440 markers used to construct the map, 421 (96%) were assigned to 12 linkage groups; these included 346 Diversity Arrays Technology (DArT) and 75 simple sequence repeat (SSR) markers. The total map length of the seven D chromosomes spanned 916.27 cM, with an average length of 130.90 cM per chromosome and an average distance between markers of 3.47 cM. Seven segregation distortion regions were detected on seven linkage groups. Out of 50 markers shared with those on a common wheat map, 37 showed a consistent order. The utility of the diploidization-hexaploid DH population for mapping qualitative trait genes was confirmed using the dominant glaucousness-inhibiting gene W2I as an example.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-131) contains supplementary material, which is available to authorized users.

Zygotic combinatorial process in plants

Experimental data that prove the existence of the zygotic combinatorial process occurring in an embryogenesis-entering zygote are presented in the paper. The zygotic combinatorial process is found when analyzing F1 hybrid plants obtained from crossing homozygous forms different, minimum, in two marker enzymes, and it is found in that hybrid plant which, with one marker enzyme heterozygous spectrum, has a homozygous spectrum of the other. The zygotic combinatorial process leads to F1 hybrids uniformity aberration. The zygotic combinatory process revealed in the study is supposed to be conditioned by chromosome polyteny in mother plant cells and diminution of chromatin excess from the embryogenesisentering zygote. An obligatory condition for combinatorial process is the presence of free exchange of chromatides among homological chromosomes in an embryogenesis-entering cell, i.e. the presence of crossing-over analogous to the one proceeding at meiosis.

Cross-Compatibility Between Some Cultivated Cowpea Varieties and a Wild Relative (Subsp. <i>Dekindtiana</i> Var <i>Pubescens</i>)

Four cultivated cowpea (Achi shuru, Ife Brown, Kanannado and Zebra bean) were crossed to their wild relative subsp. dekindtiana var. pubescens to ascertain their cross compatibility, reproductive potential and possible heterosis in the F1 generations. Results show that the cultivated varieties hybridized relatively well with their wild relative with pod set of 40.8% to 46.7%. F1 hybrid plants also showed high heterosis in plant height and number of leaves and produced viable seeds. These results are indications of a good reproductive potential of the hybrids thus making the wild, good candidate for transfer of important gene pool into the cultivated populations.© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.10761 J. Sci. Res. 5 (1), 195-200 (2013)

Outcrossing rates in two self‐compatible, hybridising Rhinanthus species: implications for hybrid formation

The congeners Rhinanthus angustifolius and Rhinanthus minor, two annual hemiparasites pollinated by bumblebees, are known to hybridise in the wild. Both species are self-compatible, but the capacity for autonomous selfing is higher in R.minor. This suggests a difference in realized outcrossing rates, which have not been determined before in these species. Using microsatellites, both species turned out to have mixed mating systems, but with a much lower multilocus outcrossing rate (0.13) for R.minor compared to R.angustifolius (0.76). We hypothesised that a higher outcrossing rate should lead to a higher chance of heterospecific pollination, and we therefore determined the rate of hybrid formation on each species in an artificial mixed population. Hybrid seeds were produced at low frequency (4.5%), and no significant difference was found between the species. It is therefore likely that post-pollination processes influence hybrid seed formation to counteract the expected difference in heterospecific pollen deposition. We checked fruit set, seed set and the rate of autonomous selfing in controlled crosses in the greenhouse in 2 years, and found that fruit set (2003) or seed set (2010) were lower in R.angustifolius × R.minor crosses relative to the reciprocal cross. Hybrid seeds produced on R.angustifolius also had a much lower germination rate, so most of the established F1 hybrid plants have the R.minor cytoplasm. The formation of advanced hybrids depends on pollinator preference, which is biased towards R.angustifolius if present in sufficient numbers, because it offers more rewards.

Study on reproductive barriers in 4x–2x crosses in Dianthus caryophyllus L

Reproductive barriers often exist in 4x–2x crosses in Dianthus caryophyllus L. and seriously lead to low seed set and breeding efficiency. In this study, we inspected pre-fertilization and post-fertilization barriers in crosses between ‘butterfly’ (2n = 4x = 60) and the fertile breeding line ‘NH10’ (2n = 2x = 30) and ‘NH14’ (2n = 2x = 30) using fluorescence microscopy and paraffin section. The growth of the pollen tubes up to the ovary was observed in crosses of ‘butterfly’ × ‘NH10’ and ‘butterfly’ × ‘NH14’. However, abnormalities of pollen tube including coiled and spiky and callose deposition in incompatible tubes has also been detected. In the cross ‘butterfly’ and ‘NH10’, the number of pollen tubes at the base of the style reached the highest value, 67.2 ± 10.8 at 48 h after pollination, but the number of ovules with micropylar penetration was low, 19 ± 4.5. Similarly, in the cross between ‘butterfly’ and ‘NH14’, pollen tubes at the base of the style at 48 h after pollination was 51 ± 6.2 and the ovules with penetrated micropyles per ovary at 48 h after pollination was 11 ± 2.4. It indicated the pollen tubes difficultly penetrated into the ovules in 4x–2x crosses. In addition, it was observed that non-fused of egg and sperm or non-fused polar nucleus resulted in endosperm without embryos, and embryos without endosperm. Embryos aborted at different developmental stages (prembryo to cotyledon embryo, main globular embryo), which might be related to a deficient endosperm development in reciprocal crosses. The results suggested that pre-fertilization and post-fertilization barriers were detected in these combinations. Due to the post-fertilization barriers in 4x–2x crosses, the embryo rescue might be contributed to obtain hybrid F1 plants.

Genetic map of Triticum turgidumbased on a hexaploid wheat population without genetic recombination for D genome

BackgroundA synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed. SynDH1 is a tetraploidization-hexaploid doubled haploid (DH) population because it contains recombinant A and B chromosomes from two different T. turgidum genotypes, while all the D chromosomes from Ae. tauschii are homogenous across the whole population. This paper reports the construction of a genetic map using this population.ResultsOf the 606 markers used to assemble the genetic map, 588 (97%) were assigned to linkage groups. These included 513 Diversity Arrays Technology (DArT) markers, 72 simple sequence repeat (SSR), one insertion site-based polymorphism (ISBP), and two high-molecular-weight glutenin subunit (HMW-GS) markers. These markers were assigned to the 14 chromosomes, covering 2048.79 cM, with a mean distance of 3.48 cM between adjacent markers. This map showed good coverage of the A and B genome chromosomes, apart from 3A, 5A, 6A, and 4B. Compared with previously reported maps, most shared markers showed highly consistent orders. This map was successfully used to identify five quantitative trait loci (QTL), including two for spikelet number on chromosomes 7A and 5B, two for spike length on 7A and 3B, and one for 1000-grain weight on 4B. However, differences in crossability QTL between the two T. turgidum parents may explain the segregation distortion regions on chromosomes 1A, 3B, and 6B.ConclusionsA genetic map of T. turgidum including 588 markers was constructed using a synthetic doubled haploid (SynDH) hexaploid wheat population. Five QTLs for three agronomic traits were identified from this population. However, more markers are needed to increase the density and resolution of this map in the future study.

EST-SSR Marker Sets for Practical Authentication of All Nine Registered Ginseng Cultivars in Korea

Panax ginseng has been cultivated for centuries, and nine commercial cultivars have been registered in Korea. However, these nine elite cultivars are grown in less than 10% of ginseng fields, and there is no clear authentication system for each cultivar even though their values are higher than those of local landraces. Here, we have developed 19 microsatellite markers using expressed gene sequences and established an authentication system for all nine cultivars. Five cultivars, ‘Chunpoong’, ‘Sunpoong’, ‘Gumpoong’, ‘Sunun’, and ‘Sunone’, can each be identified by one cultivar-unique allele, gm47n-a, gm47n-c, gm104-a, gm184-a (or gm129-a), and gm175-c, respectively. ‘Yunpoong’ can be identified by the co-appearance of gm47n-b and gm129-c. ‘Sunhyang’ can be distinguished from the other eight cultivars by the co-appearance of gm47n-b, gm129-b, and gm175-a. The two other cultivars, ‘Gopoong’ and ‘Cheongsun’, can be identified by their specific combinations of five marker alleles. This marker set was successfully utilized to identify the cultivars among 70 ginseng individuals and to select true F1 hybrid plants between two cultivars. We further analyzed the homogeneity of each cultivar and phylogenetic relationships among cultivars using these markers. This marker system will be useful to the seed industry and for breeding of ginseng.

Generation and Characterization of Interspecific Hybrids of Lotus uliginosus × Lotus corniculatus

ABSTRACTA method is described for obtaining interspecific hybrids between commercial lines of Lotus uliginosus Schkuhr and Lotus corniculatus L. Hybridization was possible between these species using embryo rescue. Two strategies were used to confirm 40 F1 hybrids, that is, flow cytometry and microsatellite simple sequence repeats (SSRs). The L. uliginosus and L. corniculatus parents have significantly different genome size (2.5 ± 0.02 and 2.22 ± 0.02 pg, respectively) and the offspring from the cross had intermediate values. Two SSR primers were polymorphic between the genotypes tested, TM1150 and EH380069. Maternal effect was detected in L. uliginosus genotypes, as determined by greater frequency of F1 hybrids. Recombinant traits were observed in the F1 hybrid progeny. Ninety F1 hybrids resulting from L. uliginosus × L. corniculatus crosses showed different levels of fertility in the polycross; <3% F1 plants produced more than 1000 seeds without embryo rescue while 10% of plants did not flower the first year. The F1 hybrid plants grown under greenhouse conditions exhibited shoot phenotypes similar to L. uliginosus (maternal) whereas F2 phenotypes were similar to L. corniculatus (paternal) in field trials. Rhizome presence was observed in 60% of F2 hybrid plants. The diameters of the root crowns of these plants, however, were similar to that of L. corniculatus.

Exceptionally high fertility observed in three F1 hybrids between Lolium multiflorum Lam. and L. temulentum L.

AbstractThe pollen fertility and seed set of three F1 hybrid plants derived from a cross between a darnel ryegrass (Lolium temulentum L.) line (Ba3081) and a genotype of Italian ryegrass (L. multiflorum Lam.) were evaluated in field and greenhouse experiments under different temperatures. In the field where the daily mean temperature for 3 weeks prior to pollen dispersal was 16.5°C, the mean pollen fertility of the F1 plants was 42.8%, which was lower than the value observed in the parental species (96.0–98.1%). In two greenhouses with a daily mean temperature of 20.4 and 15.8°C, the mean pollen fertility of the F1 plants was 53.1% and 44.0%, respectively, which were higher than the values reported previously for the hybrids between L. temulentum × L. multiflorum (maximum of about 20%). The seed set of the F1 plants was 24% under open‐pollinated conditions in the field compared with 4.2–8.8% under self‐pollinated conditions in the two greenhouses. These results indicated that the F1 plants were self‐fertile and able to set F2 seed, with a significant reduction in pollen fertility occurring with a decrease in the daily mean temperature (2.15% decrease in fertility per unit decrease in temperature). The germination rate of the F2 seeds was approximately 57%, indicating the possibility of producing an F2 population for future genetic analysis. This is the first report of F1 plants from L. temulentum × L. multiflorum with fertile pollen and with the ability to produce progeny by self‐pollination. These findings suggest a possibility of developing recombinant inbred lines between L. temulentum and L. multiflorum.

Comparative proteome analysis of drought-sensitive and drought-tolerant rapeseed roots and their hybrid F1 line under drought stress

Rapeseed (Brassica napus L.), which is the third leading source of vegetable oil, is sensitive to drought stress during the early vegetative growth stage. To investigate the initial response of rapeseed to drought stress, changes in the protein expression profiles of drought-sensitive (RGS-003) and drought-tolerant lines (SLM-003), and their F1 hybrid, were analyzed using a proteomics approach. Seven-day-old rapeseed seedlings were treated with drought stress by restricting water for 7 days, and proteins were extracted from roots and separated by two-dimensional polyacrylamide gel electrophoresis. In the sensitive rapeseed line, 35 protein spots were differentially expressed under drought stress, and proteins related to metabolism, energy, disease/defense, and transport were decreased. In the tolerant line, 32 protein spots were differentially expressed under drought stress, and proteins involved in metabolism, disease/defense, and transport were increased, while energy-related proteins were decreased. Six protein spots in F1 hybrid were common among expressed proteins in the drought-sensitive and -tolerant lines. Notably, tubulin beta-2 and heat shock protein 70 were decreased in the drought-sensitive line and hybrid F1 plants, while jasmonate-inducible protein and 20S proteasome subunit PAF1 were increased in the F1 hybrids and drought-tolerant line. These results indicate that (1) V-type H(+) ATPase, plasma-membrane associated cation-binding protein, HSP 90, and elongation factor EF-2 have a role in the drought tolerance of rapeseed; (2) The decreased levels of heat shock protein 70 and tubulin beta-2 in the drought-sensitive and hybrid F1 lines might explain the reduced growth of these lines in drought conditions.

Physiological and Biochemical Characterization of Intergeneric Hybrids of Papaya

Successful intergeneric crosses have been achieved between Carica papaya and Vasconcellea cauliflora and break the intergeneric hybridization barrier by using various nutrients. Among the nutrients used, sucrose 5 per cent, sucrose 5 per cent + boron 0.5 per cent and sucrose 5 per cent + CaCl2 0.5 per cent improved the fruit set and seed set percentage. A total number of 1197 flowers were pollinated resulted in 308 fruits. On extraction, 721 seeds were obtained from CO 7, Pusa Nanha and CP 50. Out of twenty nine F1 hybrid plants of CO 7 x Vasconcellea cauliflora, only six plants namely CO 7V1 to CO 7V6 were found free from PRSV symptoms. Similarly, out of fifty five F1 hybrid plants of Pusa Nanha x Vasconcellea cauliflora only twenty three plants namely PNV1 to PNV23 were found free from the symptoms and seventy plants namely CPV1 to CPV70 out of 335 plants of CP50 x Vasconcellea cauliflora were found free from PRSV symptoms. Physiological and biochemical characters were found to be higher in the male parent Vasconcellea cauliflora and also the cross combination involving Pusa Nanha x Vasconcellea cauliflora recorded the highest chlorophyll content and the enzymes like peroxidase and polyphenol oxidase also played a major role in plant productivity and resistance to PRSV at the time of harvest.

Analysis of Papaya Intergeneric Hybrids for Morphological Traits

Successful crosses have been achieved in intergeneric hybridization between Carica papaya and wild Vasconcellea cauliflora, to break post zygotic barriers by using various nutrients. Among the nutrients used, sucrose 5 per cent, sucrose 5 per cent + boron 0.5 per cent and sucrose 5 per cent + CaCl2 0.5 per cent improved the fruit set and seed set percentage. A total of 1197 flowers were pollinated resulted 308 fruits. On extraction, 721 seeds were obtained from CO 7, Pusa Nanha and CP 50. Out of twenty nine F1 hybrid plants of CO 7 x Vasconcellea cauliflora, only six plants namely CO7V1 to CO7V6 were found free from PRSV symptoms. Similarly, out of fifty five F1 hybrid plants of Pusa Nanha x Vasconcellea cauliflora only twenty three plants namely PNV1 to PNV23 were found free from the symptoms and seventy plants namely CPV1 to CPV70 out of 335 plants of CP50 x Vasconcellea cauliflora were found free from PRSV symptoms. F1 hybrids exhibited very clear morphological marker in the form of pink vein colour. The number of days for first flowering, first flowering height (cm), plant height (cm), stem girth (cm), number of leaves, first fruiting height (cm), fruit set (%), days to first harvest, fruit yield per tree (kg), were intermediate between the two parents.

Reduced sexual compatibility between cultivated and wild chicory and their F1 hybrids

Crops were domesticated from wild plants not too long ago and have subsequently diverged from the wild ones, especially in traits used by humans. Whether divergence between the cultigen and wild forms has also lead to reduced reproductive compatibility is unknown for many species. Chicory (Cichorium intybus L.) has been bred as a crop at least since Roman times. To test if this has led to a loss in reproductive compatibility with wild chicory, we planted cultivar, wild, and F1 hybrid plants into two field plots, and let them pollinate freely. On 2 days, in the beginning and middle of the flowering season, we counted the numbers of flowering capitula and open flowers per capitulum, which in combination with counts of viable pollen per flower were used to estimate the expected proportion of seeds fathered by cultivar, wild, and hybrid plants. Open capitula on wild and hybrid plants were marked, and when seeds were ripe we determined whether cultivar, wild or hybrid plants had pollinated the seeds, using AFLP markers. Cultivar plants fathered much fewer seeds than expected, both on wild and hybrid plants, suggesting that some degree of incompatibility has evolved between cultivar and wild chicory. Hybrid plants fathered more seeds than expected on some of the hybrid plants, indicating that hybrids do not suffer much from outbreeding depression. Our study thus suggests that cultivated and wild chicory, even though they belong to the same species, have diverged to an extent where reproduction between them is somewhat impaired.

Effectiveness of combining resistance to Thielaviopsis basicola and Tomato spotted wilt virus in haploid tobacco genotypes.

Black root rot (BRR) caused by Thielaviopsis basicola as well as Tomato spotted wilt virus (TSWV) are the most serious problems in tobacco growing regions. We crossed the breeding line WGL 3 carrying BRR resistance derived from N.glauca with the line PW-834 the resistance of which to TSWV was transferred from cultivar Polalta. Anthers obtained from F1 hybrid plants were cultured to induce haploids combining resistance to Th. basicola and TSWV. Flow cytometry analysis revealed 242 haploids and 2 spontaneous doubled haploids among regenerants. All haploids were cloned and then evaluated for BRR as well as TSWV resistance. The presence of pathogens was detected by microscopic evaluation of roots or using DAS-ELISA test. Microscopic assessment showed that, 132 haploids had no symptoms of Th. basicola which, together with the absence of symptoms in the F1 hybrids, indicated a dominant monogenic mode of inheritance. At the same time only 30 haploids demonstrated resistance to TSWV. SCAR markers associated with TSWV resistance gene detection was applied. The results indicate that small proportion of TSWV-resistant haploids is probably due to the influence of deleterious genes flanking the resistance factor that reduced vitality of gametophytes. Altogether, 24 haploids showed multiple resistance to Th. basicola and TSWV.

Nonadditive Protein Accumulation Patterns in Maize (Zea mays L.) Hybrids during Embryo Development

Heterosis describes the superior performance of heterozygous F(1)-hybrid plants compared to their homozygous parental inbred lines. In the present study, heterosis was detected for length, weight, and the time point of seminal root primordia initiation in maize (Zea mays L.) embryos of the reciprocal F(1)-hybrids UH005xUH250 and UH250xUH005. A two-dimensional gel electrophoresis (2-DE) proteome survey of the most abundant proteins of the reciprocal hybrids and their parental inbred lines 25 and 35 days after pollination revealed that 141 of 597 detected proteins (24%) exhibited nonadditive accumulation in at least one hybrid. Approximately 44% of all nonadditively accumulated proteins displayed an expression pattern that was not distinguishable from the low parent value. Electrospray ionization-tandem mass spectrometry (ESI-MS/MS) analyses and subsequent functional classification of the 141 proteins revealed that development, protein metabolism, redox-regulation, glycolysis, and amino acid metabolism were the most prominent functional classes among nonadditively accumulated proteins. In 35-day-old embryos of the hybrid UH250xUH005, a significant up-regulation of enzymes related to glucose metabolism which often exceeded the best parent values was observed. A comparison of nonadditive protein accumulation between rice and maize embryo data sets revealed a significant overlap of nonadditively accumulated proteins suggesting conserved organ- or tissue-specific regulatory mechanisms in monocots related to heterosis.

Instability of chromosome number and DNA methylation variation induced by hybridization and amphidiploid formation between Raphanus sativus L. and Brassica alboglabraBailey

BackgroundDistant hybridization can result genome duplication and allopolyploid formation which may play a significant role in the origin and evolution of many plant species. It is unclear how the two or more divergent genomes coordinate in one nucleus with a single parental cytoplasm within allopolyploids. We used cytological and molecular methods to investigate the genetic and epigenetic instabilities associated with the process of distant hybridization and allopolyploid formation, measuring changes in chromosome number and DNA methylation across multiple generations.ResultsF1 plants from intergeneric hybridization between Raphanus sativus L. (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) were obtained by hand crosses and subsequent embryo rescue. Random amplification of polymorphic DNA (RAPD) markers were used to identify the F1 hybrid plants. The RAPD data indicated that the hybrids produced specific bands similar to those of parents and new bands that were not present in either parent. Chromosome number variation of somatic cells from allotetraploids in the F4 to F10 generations showed that intensive genetic changes occurred in the early generations of distant hybridization, leading to the formation of mixopolyploids with different chromosome numbers. DNA methylation variation was revealed using MSAP (methylation-sensitive amplification polymorphism), which showed that cytosine methylation patterns changed markedly in the process of hybridization and amphidiploid formation. Differences in cytosine methylation levels demonstrated an epigenetic instability of the allopolyploid of Raphanobrassica between the genetically stable and unstable generations.ConclusionsOur results showed that chromosome instability occurred in the early generations of allopolyploidy and then the plants were reverted to largely euploidy in later generations. During this process, DNA methylation changed markedly. These results suggest that, epigenetic mechanisms play an important role in intergeneric distant hybridization, probably by maintaining a genetic balance through the modification of existing genetic materials.

Meiotic behaviour of <i>Eragrostis tef </i>and,i> Eragrostis Pilosa</i>

Tef (Eragrostis tef (Zucc.) Trotter) is major cereal crop cultivated in Ethiopia. It occupies approximately two million hectares of land each year. However, little has been done on meiotic chromosome study of the interspes hybrid. So, studies were conducted to examine meiotic behavior and pollen fertility of the F1-hybrid (E. tef x E. pilosa) and parental lines at Addis Ababa, Ethiopia in 200 7/08. The F1-hybrid plant showed regular meiotic cell division and high level of pollen fertility (94.3%). It also produced better seed and biomass yield and number of tillers than the parental lines which are the manifestation of meiotic stability in the hybrid and the subsequent generations. Pollen fertility test of the parental lines and selected recombinant inbred lines of E. tef and E. pilosa cross was also high (90 - 95%), which are an indication of regular meiotic chromosome division. The resultdemonstrated chromosome stability of the hybrid plant, which is important for widening the genetic pool of tef germplasm through conventional crossing with E. pilosa. The study further strengthen the view that the two species are very closely related.

Inheritance of Morphological and Quantitative Characteristics of F1 after Crossing Winter Rye (Secale cereale) Donors with Distinct Breeding Characteristics (Secale cereale).

In first time it is used the marker genes’ donor of dominant stem shortness, recession erective leaf and absence of waxen plants’ cover for the receipt of F1 hybrid plants of winter rye. It is certain the parameters and character of intercommunications for ten quantitative signs at F1 hybrids from crossing of rye standards with distinctive morphological signs.

Identification of differentially expressed genes related to aberrant phenotypes in Brassica oleracea var. botrytis

AbstractThe aberrant phenotype is characterized by the progressive expression of abnormal traits during vegetative growth affecting leaf thickness, shape and/or plant vigour. These striking morphological abnormalities do not appear to be caused by agronomical practices or pathogen infections. Furthermore, the aberrant phenotype, which is observed in 3–20% of cultivated cauliflowers, is not linked to DNA sequence or structural polymorphisms. To detect candidate genes related to the aberrant phenotype, we used amplified fragment length polymorphism on cDNA approach, sampling normal and aberrant F1 hybrid plants several times before and after the expression of the aberrant phenotype. This screen led to the detection of 51 differentially expressed transcripts. Twenty‐nine of these were homologous to annotated genes in genomic databases. We identified transcripts, which were differentially expressed before the expression of the aberrant trait with homology to genes involved in various abiotic stress responses. A non‐specific lipid transfer protein homologue was also identified and given the role that these proteins play in epicuticular wax formation and leaf morphology, it may be implicated in the abnormal leaf shape phenotypes.

Spontaneous wheat-Aegilops biuncialis, Ae. geniculata and Ae. triuncialis amphiploid production, a potential way of gene transference

Some F1 hybrid plants between three species of the Aegilops genus and different hexaploid wheat Triticum aestivum cultivars show certain self-fertility, with averages of F1 hybrids bearing F2 seeds of 8.17%, 5.12% and 48.14% for Aegilops biuncialis, Aegilops geniculata and Aegilops triuncialis respectively. In the Ae. triuncialis-wheat combination with ";Astral" wheat cultivar, the fertility was higher than that found in the other combinations. All the F2 seeds studied were spontaneous amphiploids (2n=10x=70). The present study evidences the possibility of spontaneous formation of amphiploids between these three Aegilops species and hexaploid wheat and discusses their relevance for gene transference. Future risk assessment of transgenic wheat cultivars needs to evaluate the importance of amphiploids as a bridge for transgene introgression and for gene escape to the wild.