Inferring geographic origin of barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L. subsp. <Emphasis Type="Italic">vulgare</Emphasis>) accessions using molecular markers

The USDA Agricultural Research Service (ARS) National Small Grains Collection (NSGC) has 207 landrace barleys obtained from a nursery grown in the Ukraine in 1930 by N.I. Vavilov, many of which have multiple resistance (MR) to disease similar to accessions from Ethiopia. The original collection locations of the accessions from the Vavilov nursery are unknown. The purpose of this study was to determine, using molecular markers, if the MR accessions of unknown origin from the Vavilov nursery are genetically related to MR accessions from Ethiopia. The genetic relatedness among susceptible accessions of unknown origin and among a selection of landrace accessions from the NSGC barley core subset was also assessed. Simple sequence repeat (SSR) and Diversity Array Technology PL (DArT) marker data were used to generate similarity matrices with Dice’s similarity coefficients. Cluster analysis from these results showed that the unknown-origin MR accessions grouped with accessions from Ethiopia. Susceptible accessions of unknown origin were genetically similar to accessions from western Asia, especially near the Caucasus, and from both southern and northern Europe. Based on similarity of marker profiles, some accessions from the core collection are likely duplicates. Future work will seek to identify the probable origin of the remainder of the unknown origin accessions and to more thoroughly characterize the genetic diversity within NSGC barley core subset.     

Molecular and phenotypic diversity of ICARDA spring barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) collection

Plant breeders are interested in using diverse genotypes in hybridization that can segregate for traits of importance with possibility of selection and genetic gain. Information on molecular and agro-morphological diversity helps the breeders reduce the effort for parental selection and helps the advancement of generations. A phenotypic and molecular diversity study, using 24 traits (agronomic and disease) and 6519 SNPs in a diverse collection of 336 spring barley genotypes, was carried out at Marchouch and Jemma Shiam research stations in Morocco. Based on structure and multivariate analyses, strong differentiation between the two- and six-row types were observed. The linkage disequilibrium (LD) decay of the current collection (for the combined population) was up to 3.58 cM (r ² = 0.15) while LD decay were estimated 3.91 and 2.36 cM for two- and six-row barley, respectively. PCA of agro-morphological traits revealed grain per spike, net form of net blotch (NFNB), spot form of net blotch (SFNB), and 1000 kernel weight were the most discriminatory traits in the current collection. Association mapping in the two independent populations will be ideal for identification of markers, and QTL related to traits. The generated information on relatedness between individuals will help identify diverse genotypes for breeding programs.     

Coleoptile length of barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) cultivars

Coleoptile length is related to maximum seeding depth. The coleoptile length of 44 spring barley cultivars (Hordeum vulgare L.) was determined by laying seeds on moistened filter paper and incubating at 15°C for 13 days. Significant differences in coleoptile length were noted between cultivars (P < 0.05). Most cultivars had a coleoptile length between 60 and 80 mm. Five cultivars (Buloke, Dash, Harrington, Morrell and Tallon) had a coleoptile length shorter than 60 mm. Seven cultivars (CM72, Doolup, Finniss, Fleet, Hannan, Haruna Nijo and Macumba) had a coleoptile length longer than 80 mm. No relationship was found between early growth habit or plant height and coleoptile length. The impact of different dwarfing genes on coleoptile length was discussed. Differences in coleoptile length observed should be exploited by breeders to improve the tolerance of barley to deep seeding and stubble retention. This would be a useful tool in managing climate variability and would assist barley growers to sow closer to the optimum sowing time in situations where moisture is present at depth but not on the soil surface.     

Phenotypic diversity in wild barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L. ssp. <Emphasis Type="Italic">spontaneum</Emphasis> (C. Koch) Thell.) accessions collected in Jordan

Wild barley, Hordeum vulgare L. ssp. spontaneum (C. Koch) Thell., is the progenitor of cultivated barley. Almost unanimously the center of diversity is considered to be in the Fertile Crescent of the Near East, where wild barley grows under a wide range of environmental and climatic conditions. Jordanian wild barley is expected to harbor genes useful for the improvement of cultivated barley, particularly those associated with tolerance to drought. This study evaluated 103 wild barley accessions collected from different areas of Jordan along with 29 cultivated barley genotypes for several morphological and agronomical traits. The Hordeum vulgare ssp. spontaneum C. Koch accessions were grouped into six populations according to the longitude, latitude, altitude, and rainfall zone of the collection site, and the cultivated barley in one population. The evaluation was conducted during the 2004–2005 growing season under field conditions in three locations in Jordan; namely, Khanasri, Ramtha, and Maru with 123.0, 222.9, and 429.2 mm annual rainfall, respectively. We used an unreplicated design with two systematic checks (the cultivars Rum and Mu’ta) each repeated 15 times. The results showed the existence of high variability among the Hordeum vulgare ssp. spontaneum C. Koch accessions for most of the traits, especially for plant height, tiller number, days to heading, days to anthesis, peduncle length, and peduncle extrusion. Plant height, earliness, peduncle length, and peduncle extrusion were found to be adaptive traits under drought conditions and several superior genotypes for each trait were identified. Genetic variation within population was much higher than between populations. Clustering of populations was according to their ecological geographical pattern.     

Natural diversity of inflorescence architecture traces cryptic domestication genes in barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.)

Many-grained mutants occurring spontaneously among their less well-endowed field mates may have appeared to early farmers as fortunate twists of fate foreboding wealth and abundance. In domesticated barley, the number of kernel rows in spike can be tripled by recessive mutant alleles at the Six-rowed spike 1 (vrs1) locus that abolish the suppression of lateral spikelet fertility. In another barley row-type, so called intermedium-spike (int), lateral floret size is often intermediate between six-and two-rowed types. Phenotypic and sequence analyses of our intermedium-spike collection revealed that other genes can increase the size of florets and even stimulate occasional grain setting in lateral spikelets. Here, we show that a complete six-rowed phenotype occurs in a diverse panel of intermedium-spike barley carrying wildtype Vrs1 in the presence of the Int-c.a allele of the intermedium spike-c (int-c) gene, previously considered only as a modifier of lateral spikelet fertility. Int-c.a-type alleles had arisen before domestication and are associated with the enlargement of lateral florets in wild barley, suggesting that natural selection/evolution acts towards reduced lateral floret size. Since Int-c.a cannot overcome the suppression of lateral florets in the genomic background of wild barleys, we infer the existence of other gene loci, at which novel alleles or allelic combinations were selected for after domestication, to increase grain number of barley independently of Vrs1.     

Genotypic and phenotypic changes in wild barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> subsp. <Emphasis Type="Italic">spontaneum</Emphasis>) during a period of climate change in Jordan

Climate change and other anthropogenic disturbances can lead to the loss of genetic variation and thereby affect evolutionary potential and survival of plant populations in the wild. We examined these predictions in the primary wild relative of barley, Hordeum vulgare L. subsp. spontaneum (K. Koch) Thell., within its center of diversity, in Jordan. Changes in genotypic and phenotypic diversity were assessed using seed samples collected in 1981 and 2012 from the same 18 sites across Jordan. The overall population structure was conserved, but we observed an increase of within population genetic diversity and a reduction in population differentiation. Phenotypic variation differed among years and sites but the magnitude and direction of change variated among sites. While the sampled region became significantly hotter and drier during this period, simple correlation models did not support association between measures of climate change and the observed genetic and phenotypic changes. Agricultural activities that promote disturbance and demographic fluctuations may affect crop wild relatives that grow in agricultural landscapes, in unexpected ways. The observed increase in genetic diversity within populations might be explained by increased migration or by an advantage of increased genetic variation in the face of variable environmental conditions. This study provides a new perspective on the range of possible responses of crop wild relatives to environmental pressures.     

Genetic diversity of barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) landraces from the central highlands of Ethiopia: comparison between the <Emphasis Type="Italic">Belg</Emphasis> and <Emphasis Type="Italic">Meher</Emphasis> growing seasons using morphological traits

In Ethiopia, barley is generally grown in two different planting seasons per year: during the long rainy season (Meher) and the short rainy season (Belg). The aim of the present study was to assess for the first time the role of this ‘two-season system’ on the structure of the genetic diversity of the Ethiopian barley landraces. We characterised 3,170 individual genotypes from 106 landrace populations using eight morphological spike traits. The diversity within population was higher in the season where barley is more important (Belg), and in general, where its cultivation is in larger plots because of weaker ‘competition’ with others crops. This indicates that barley diversity has a complex relationship with variations in the surrounding agro-ecosystem. Overall, the divergence between the two seasons was quite small (3.4%), suggesting that seed flow does not occur independently across the years within the two seasons. This would affect the amount of mutations and historic recombination that have accumulated within these populations.     

Assessment of genetic diversity in Egyptian barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) genotypes using SSR and SNP markers

A barley core collection can be studied extensively and the derived information can be used to identify loci/genes for the genetic improvement of quantitative and qualitative traits. To assess genetic diversity, allelic variation and population structure of Egyptian barley, 134 barley genotypes collected from a different region along with 19 cultivated genotypes obtained from of the Egyptian Agricultural Research Center. All genotypes were analyzed with 261 polymorphic SSR and SNP alleles. The mean number of alleles per locus was 4 and PIC was 0.49, while the level of genetic diversity was 0.55 ranging from 0.03 to 0.82. The genotypes were assigned to three subpopulations that were consistent with their origins. The genetic variation within population was higher (51%) than among population at the molecular levels (F_ST =?0.491 when P?<?0.10). The level of polymorphic variation was highest in subpopulations-II, due to collected from different regions with different ear-types thus, expected to contain more diversity than local genotypes in subpopulations-I and subpopulations-III. The structured study found that the 153 barley genotypes are in harmony with clustering approaches using the SSR and SNP genotypic data in a neighbor-joining tree and principal components analysis, which identified three subpopulations. These results demonstrated genetic diversity among the Egyptian barley genotypes can be applied to suggest approaches, such as association analysis, classical mapping population development, and parental line selection in breeding programs. Therefore, it is necessary to use the exotic genotypes as the genetic resources for developing new barley cultivars in Egypt.     

A simple and effective ND-FISH probe design for identifying barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis>) chromosomes

Fluorescence in situ hybridization (FISH) has been widely used to analyze the physical mapping of chromosomes and study the chromosome rearrangements during evolution. The conventional FISH technique is time-consuming and labor-intensive as it involves many experimental steps including (1) PCR amplification of the target sequence, (2) recovery of the amplified product, (3) plasmid extraction, (4) fluorescence labeling, as well as (5) denaturing of chromosomes and probes. Here we report an effective method for the design of oligonucleotide probes and the development of a new oligonucleotide probe for non-denaturing FISH in barley. The probe Oligo-442A01 with 6133 copies in barley genome could be mapped to the subtelomeres of barley. However, there were significant differences in signal positions and strengths between Oligo-442A01 and the contrast probe Oligo-HvT01.1, especially on chromosome 3H. These oligonucleotide probes combinations (AGG)₅ and Oligo-442A01, (CTT)₅ and Oligo-HvT01.1 could effectively differentiate the barley chromosomes.     

Geographical distribution and diversity of maize (<Emphasis Type="Italic">Zea mays</Emphasis> L. subsp. <Emphasis Type="Italic">mays</Emphasis>) races in Mexico

The center of origin of maize is in Mexico and maize diversity is very high in many parts of the country. Here we describe and analyze the geographic distribution and diversity of maize using a database of 18,176 georeferenced observations of maize races. The number of observations by race follows the common “hollow curve” distribution, with six races comprising 54 % of the records and 37 races only 10 %. Few races are widespread, and some have a highly localized distribution. The average maximum distance (D _max) between two records of the same race was 1169 km, but seven races had a D _max lower than 200 km. The average circular area range size (CA₂₅) was 51, but 14 races had a CA₂₅ lower than 10. Some races have very few observations but were found over a large area. These races may not be valid and their classification should be reviewed. Areas of high race richness and diversity are in mountainous northwest, south central, and southern Mexico in the states of Oaxaca, Jalisco, Michoacán and Chiapas. Six contiguous maize regions were defined using hierarchical clustering. Despite the high sample size, further sampling could improve estimates of race diversity in several regions.     

Genetic structure and history of Swiss maize (<Emphasis Type="Italic">Zea mays</Emphasis> L. ssp. <Emphasis Type="Italic">mays</Emphasis>) landraces

Between 1930 and 2003 with emphasis on the 1940s maize landraces (Zea mays L. ssp. mays) from all over Switzerland were collected for maintenance and further use in a new Swiss breeding program. The genetic relationship and diversity among these accessions stored in the Swiss gene bank is largely unknown. Our hypothesis was that due to the unique geographic, climatic, and cultural diversity in Switzerland a diverse population of maize landraces had developed over the past three centuries. The aims were to characterize the genetic diversity of the Swiss landraces and their genetic relationship with accessions from neighbouring regions as well as reviewing their history, collection, and maintenance. The characterization and grouping was based on analyses with ten microsatellite markers. Geographic, cultural, and climatic conditions explained a division in two distinct groups of accessions. One group consisted of landraces collected in the southern parts of Switzerland. This group was related to the Italian Orange Flints. The other group contained accessions from northern Switzerland which were related to Northern European Flints in particular German Flints. Historic evidence was found for a frequent exchange of landraces within the country resulting in a lack of region-specific or landrace-specific genetic groups. The relatively large separation between the accessions, indicated by high F _ST (0.42), might be explained partly by a bottleneck during the collection and maintenance phase as well as by geographical and cultural separation of north and south of the country. Due to the high genetic diversity, the accessions here are a potential resource for broadening the European flint pool.     

Genetic diversity changes and relationships in spring barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) germplasm of Nordic and Baltic areas as shown by SSR markers

To examine changes in the level of and pattern in variability in 197 Nordic and Baltic spring barley cultivars over time we used 21 mapped barley simple sequence repeats (SSRs). A total number of 191 alleles were found from 22 SSR loci. The number of alleles per locus ranged from 2 to 23, with average of 8.63 107 alleles were rare (frequency <0.05) among the cultivars and only one allele was frequently observed (frequency >0.95). The gene diversity between loci in Nordic and Baltic material varied between 0.033 and 0.891. Average gene diversity was 0.623. The SSR data separated two-rowed and six-rowed cultivars. According to analysis of molecular variance (AMOVA) differentiation in two-rowed vs six-rowed accounted for 23.6% of the total variation. Overall no significant decrease of average gene diversity over time could be found. However, differences were observed when spring barleys from northern (north of ∼58°) and southern (south of ∼58°) parts of the Nordic and Baltic area were compared. For the southern ecogeographical region significant decrease of genetic diversity was observed in the middle of the 20th century, whereas no significant changes in the northern part were found. We found larger differentiation between modern and old cultivars in the South compared to the ones in North parts of the region. The magnitude of changes in genetic diversity differed also with the country of origin. Danish cultivars had a significant decrease in diversity in the middle of century, whereas changes in Finland, Norway and Sweden were not significant.     

EST-SSR based estimates on functional genetic variation in a barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) collection from Egypt

Genetic diversity was investigated in a set of 27 barley genotypes, originated from Egypt, using 23 expressed sequence tag (EST)-derived simple sequence repeats (eSSRs), representatives of the seven barley chromosomes. Ninety-five alleles were detected among all the barley accessions. For 22 polymorphic eSSRs, the number of alleles per locus varied from 2 to 12, with a mean of 4.318 alleles per locus. The lowest and the largest number of alleles per locus among the seven homeologous groups was observed in homeologous group 5H and 4H with 3.00 and 6.33, respectively. The gene diversity increased as the number of alleles increased. Gene diversity for 22 ESTs loci varied from 0.137 for GBM1404 to 0.896 for GBM1015 with an average of 0.563. A significant correlation coefficient between gene diversity and the number of alleles was high, r = 0.741 (P < 0.01). Cluster analysis was conducted based on eSSRs data to group the barley genotypes and to construct a dendrogram. Four groups can be distinguished by truncating the dendrogram at gs value of 0.77.     

Genetic diversity and spatial structure in a new distinct <Emphasis Type="Italic">Theobroma cacao</Emphasis> L. population in Bolivia

Cacao (Theobroma cacao L.) is an important economic crop in the Bolivian Amazon. Bolivian farmers both cultivate cacao, and extract fruits from wild stands in the Beni River region and in valleys of the Andes foothills. The germplasm group traditionally used is presently referred to as “Cacao Nacional Boliviano” (CNB). Using DNA fingerprinting technology based on microsatellite markers, we genotyped 164 Bolivian cacao accessions, including both cultivated and wild CNB accessions sampled from the Amazonian regions of La Paz and Beni, and compared their SSR profiles with 78 reference Forastero accessions from Amazonian cacao populations, including germplasm from the Ucayali region of Peru. Results of multivariate ordination and analysis of molecular variance show that CNB cacao has a unique genetic profile that is significantly different from the known cacao germplasm groups in South America. The results also show that cultivated CNB and wild CNB populations in the Beni River share a similar genetic profile, suggesting that the cultivated CNB is of indigenous origin in Bolivia. The level of genetic diversity, measured by allele richness and gene diversity in the Bolivian cacao, is moderately high, but was significantly lower than gene diversity in the other Amazonian cacao populations. Significant spatial genetic structure was detected in the wild CNB population, using analysis of autocorrelation (rc = 0.232; P < 0.001) and Mantel tests (Rxy = 0.276; P < 0.001). This finding is also highly valuable to support in situ conservation and sustainable use of CNB genetic diversity in Bolivia.     

Genetic structure and differentiation among oregano [<Emphasis Type="Italic">Origanum vulgare</Emphasis> subsp. <Emphasis Type="Italic">glandulosum</Emphasis> (Desf.) Ietswaart] provenances from North Africa: bioinformatic approaches cause systematic bias

Thirteen simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs) of essential oil glands of Origanum vulgare were previously evaluated. These EST-SSR loci were analyzed to study the genetic diversity and differentiation of Origanum vulgare subsp. glandulosum, an endemic species of Tunisia. The study was performed on five natural populations from the Maghreb regions (North Africa) from northern Tunisia (Sejnane, Krib, Bargou, Zaghouan and Nefza). Two other subspecies of O. vulgare were used as out-group. These are O. vulgare subsp. hirtum (from USA) and O. vulgare subsp. vulgare (from Italy). A total of 60 alleles were detected in the seven populations studied. The number of alleles per locus ranged from 2 to 9. This analysis revealed that the unbiased expected heterozygosity (0.327) is higher than the observed heterozygosity (0.242), reflecting a deficit in heterozygosity in the total population. Only the Sejnane population has an excess of heterozygosity. The differentiation between Tunisian populations is highly significant and indicates the presence of a structure between these populations. However, the indexes of genetic differentiation (FST) values are low and vary between 0.048 and 0.115 which indicate the presence of a weak structure. The value of the FST between Nefza and Krib is not significant, reflecting the absence of genetic structure between them. The value of gene flow between these two populations is the most important (27.34), showing a substantial exchange of genes or genomic regions between them. The migration of genes is less important among the other Tunisian populations. Genetic structuring according to the geographical origin of Tunisian populations is low but still exists, which allows concluding the presence of a single complex gene pool.     

Genetic diversity of the D-genome in <Emphasis Type="Italic">T. aestivum</Emphasis> and <Emphasis Type="Italic">Aegilops</Emphasis> species using SSR markers

Simple sequence repeats (SSRs), highly dispersed nucleotide sequences in genomes, were used for germplasm analysis and estimation of the genetic relationship of the D-genome among 52 accessions of T. aestivum (AABBDD), Ae. tauschii (D^tD^t), Ae. cylindrica (CCD^cD^c) and Ae. crassa (MMD^cr1D^cr1), collected from 13 different sites in Iran. A set of 21 microsatellite primers, from various locations on the seven D-genome chromosomes, revealed a high level of polymorphism. A total of 273 alleles were detected across all four species and the number of alleles per each microsatellite marker varied from 3 to 27. The highest genetic diversity occurred in Ae. tauschii followed by Ae. crassa, and the genetic distance was the smallest between Ae. tauschii and Ae. cylindrica. Data obtained in this study supports the view that genetic variability in the D-genome of hexaploid wheat is less than in Ae. tauschii. The highest number of unique alleles was observed within Ae. crassa accessions, indicating this species as a great potential source of novel genes for bread wheat improvement. Knowledge of genetic diversity in Aegilops species provides different levels of information which is important in the management of germplasm resources.     

Salt tolerance in <Emphasis Type="Italic">Zea mays</Emphasis> (L). following inoculation with <Emphasis Type="Italic">Rhizobium</Emphasis> and <Emphasis Type="Italic">Pseudomonas</Emphasis>

This study aimed to investigate the effect of inoculation with plant growth-promoting Rhizobium and Pseudomonas species on NaCl-affected maize. Two cultivars of maize (cv. Agaiti 2002 and cv. Av 4001) selected on the basis of their yield potential were grown in pots outdoors under natural conditions during July. Microorganisms were applied at seedling stage and salt stress was induced 21 days after sowing and maintained up to 50% flowering after 120 days of stress. The salt treatment caused a detrimental effect on growth and development of plants. Co-inoculation resulted in some positive adaptative responses of maize plants under salinity. The salt tolerance from inoculation was generally mediated by decreases in electrolyte leakage and in osmotic potential, an increase in osmoregulant (proline) production, maintenance of relative water content of leaves, and selective uptake of K ions. Generally, the microbial strain acted synergistically. However, under unstressed conditions, Rhizobium was more effective than Pseudomonas but under salt stress the favorable effect was observed even if some exceptions were also observed. The maize cv. Agaiti 2002 appeared to be more responsive to inoculation and was relatively less tolerant to salt compared to that of cv. Av 4001.     

Genetic diversity of Swiss maize (<Emphasis Type="Italic">Zea mays</Emphasis> L. ssp. <Emphasis Type="Italic">mays</Emphasis>) assessed with individuals and bulks on agarose gels

About 65 years ago, more than 150 Swiss maize landraces (Zea mays L. ssp. mays) of the flint type were collected and conserved ex situ. Due to the climatically and culturally diverse environment of the Alps, a considerable genetic diversity of this material was assumed. To prove this, an efficient method was required to carry out genetic profiling of all the accessions in the Swiss Gene Bank. Simple sequence repeat marker (SSR) profiling in combination with the visualization of the polymerase chain reaction (PCR) products on agarose gels was chosen. Here a set of 19 different landrace accessions was analyzed to: (i) investigate their genetic diversity, (ii) investigate and display the population structure and (iii) determine whether DNA bulks rather than single plants can be used for such analyses. Four repeated samples of one accession were found to be much closer to one another than to the rest of accessions. Furthermore, specific alleles were identified for several accessions. The PCR products of the bulked DNA samples represented only a small part of the variation revealed by the analysis of individuals. Loci with four base repeat motifs performed better in the analysis of bulks than loci with other repeat motifs. The correlation between genetic distance matrices, based on the analysis of individuals and bulks, respectively, was significant. Thus, the single plant approach allowed for sufficient differentiation of accessions, and DNA bulks visualized on agarose gels led to correlated genetic distances although a limited number of alleles were detected. Although the limited resolution of agarose gels likely causes some bias, profiling of larger sets with the individual plant approach appears feasible and more informative compared to the bulk analysis we conducted.     

Genetic Characterization of Brazilian Annual <Emphasis Type="Italic">Arachis</Emphasis> Species from Sections <Emphasis Type="Italic">Arachis</Emphasis> and <Emphasis Type="Italic">Heteranthae</Emphasis> using RAPD Markers

The genus Arachis is divided into nine taxonomic sections. Section Arachis is composed of annual and perennial species, while section Heteranthae has only annual species. The objective of this study was to investigate the genetic relationships among 15 Brazilian annual accessions from Arachis and Heteranthae using RAPD markers. Twenty-seven primers were tested, of which nine produced unique fingerprintings for all the accessions studied. A total of 88 polymorphic fragments were scored and the number of fragments per primer varied from 6 to 17 with a mean of 9.8. Two specific markers were identified for species with 2n = 18 chromosomes. The phenogram derived from the RAPD data corroborated the morphological classification. The bootstrap analysis divided the genotypes into two significant clusters. The first cluster contained all the section Arachis species, and the accessions within it were grouped based upon the presence or absence of the ‘A’ pair and the number of chromosomes. The second cluster grouped all accessions belonging to section Heteranthae.     

Production and cytogenetics of trigeneric hybrid involving <Emphasis Type="Italic">Triticum</Emphasis>, <Emphasis Type="Italic">Psathyrostachys</Emphasis> and <Emphasis Type="Italic">Secale</Emphasis>

Trigeneric hybrids may help establish evolutionary relationships among different genomes present in the same cellular-genetic background, and also offers the possibility to transfer different alien characters into cultivated wheat. In this study, a new trigeneric hybrid involving species from the Triticum, Psathyrostachys and Secale was synthesized by crossing wheat-P. huashanica amphiploid (PHW-SA) with wheat-S. cereale amphiploid (Zhongsi 828). The crossability of F₁ hybrid was high with 35.13%, and the fertility was 41.95%. The morphological characteristics of F₁ plants resembled the parent Zhongsi 828. The trigeneric hybrids pollen mother cells (PMCs) regularly revealed averagely 19.88 univalents, 9.63 ring bivalents, 3.97 rod bivalents, 0.60 trivalents and 0.03 tetravalents per cell. Multivalents consisted of trivalents and tetravalents can be observed in 52.7% of cells. A variation of abnormal lagging chromosome, micronuclei and chromosome bridge were formed at anaphase I and telophase II. The mean chromosomes number of F₂ progenies was 2n = 46.13, and the distribution range was 42–53. GISH results revealed that most F₂ plants had 6–12 S. cereale chromosomes, and only 0–2 P. huashanica chromosomes were detected. The results indicated that S. cereale chromosomes can be preferentially transmitted in the F₂ progenies of trigeneric hybrid than P. huashanica chromosomes. A survey of disease resistances revealed that the stripe rust resistance from the PHW-SA were completely expressed in the F₁ and some F₂ plants. The trigeneric hybrid could be a useful bridge for the transference of P. huashanica and S. cereale chromatins to common wheat.