Agronomic and genetic characterization of wild emmer wheat (<Emphasis Type="Italic">Triticum turgidum</Emphasis> subsp<Emphasis Type="Italic">. dicoccoides</Emphasis>) introgression lines in a bread wheat genetic background

During a long evolutionary history across a range of environmental conditions in the Near East Fertile Crescent, wild emmer wheat (Triticum turgidum subsp. dicoccoides) has accumulated a wealth of genetic diversity and adaptations to multiple biotic and abiotic stress conditions. The joint effects of the domestication and subsequent selection in man-made agro-ecosystems have considerably reduced the genetic variation in cultivated crop species as compared to their wild progenitors. The wild emmer gene pool harbors a rich allelic repertoire for improving numerous agronomically important traits. A set of advanced wild emmer wheat introgression lines (ILs) was previously established on a bread wheat genetic background. It combines genetic diversity from the wild progenitor as well as the genetic background of the cultigen. Based on field evaluations, the set of ILs (divided hierarchically into different families based on the genetic background) has exhibited high phenotypic variance in agronomically important traits. Analyses of variance ?(ANOVA) have shown that the effect of the hierarchical genetic factors was significant in the vast majority of the traits. Similarly, characterizations by molecular markers of known traits have shown that the genetic profile differs between ILs from different genetic backgrounds. Multivariate principal component analysis has revealed interesting associations between vegetative and reproductive traits and illustrated the impact of some of these traits on ILs distribution in the PC1 and PC2. The exploitation of the wild emmer wheat ILs as a tool for reintroduction of alleles that were lost during domestication and possible implications for wheat breeding are discussed.     

Geographic distribution and domestication of wild emmer wheat (<Emphasis Type="Italic">Triticum dicoccoides</Emphasis>)

The transition from hunting and gathering to agriculture had revolutionary consequences for the development of human societies. Crops such as wheat, barley, lentil, pea and chickpea played a crucial role in the establishment of complex civilizations in south west Asia. Wild emmer wheat (Triticum dicoccoides) was one of the first cereals to be domesticated in the Fertile Crescent between c. 12,000 and c. 10,000 years ago. This step provided the key for subsequent bread wheat evolution. Wild emmer is found today in the western Fertile Crescent in Jordan, Syria and Israel, the central part of southeastern Turkey and mountain areas in eastern Iraq and western Iran. In this review, we summarize issues concerning geography and domestication of wild emmer wheat based on published molecular and archaeobotanical data and on our recent findings. We suggest that modern domestic tetraploid wheats derived from wild emmer lines from southeast Turkey. However, our understanding of emmer domestication is not complete. The “dispersed-specific” domestication model proposed for einkorn might well be appropriate also for emmer.     

Variation in zinc efficiency among and within Aegilops species

Fifteen accessions of Aegilops tauschii (DD), 10 of Ae. speltoides (SS) and 8 of the tetraploid Aegilops species sharing the U genome were used to study the influence of varied zinc (Zn) supply on development of Zn-deficiency symptoms, and on shoot dry weight and Zn concentration. Plants were grown in a Zn-deficient calcareous soil under greenhouse conditions with (+Zn = 5 mg kg^—1 soil) and without (—Zn) Zn supply. Four accessions of wild tetraploid wheat, Triticum turgidum var. dicoccoides (BBAA), a group known for its high sensitivity to Zn-deficiency, were used in the experiments for comparison. As expected, the accessions of wild T. turgidum var. dicoccoides showed the highest sensitivity to Zn deficiency, and had more severe leaf symptoms of Zn deficiency (whitish-brown necrotic patches). Among the Aegilops species, leaf symptoms of Zn deficiency were, in general, more distinct in Ae. tauschii (DD) and least in Ae. speltoides (SS). Zinc efficiency, expressed as the percentage of shoot dry weight produced under conditions of Zn deficiency compared to Zn supply, averaged, 15% for T. turgidum, 32% for Ae. tauschii, 52% for Ae. speltoides and 61% for the tetraploid Aegilops species carrying the U genome. Differences in Zn efficiency among and within Aegilops species and T. turgidum were significantly correlated with the Zn amount per shoot, but not with the Zn amount per unit dry weight of shoots. The results show that Aegilops species can be exploited as an important genetic source for Zn efficiency genes, particularly Ae. speltoides var. ligustica (SS) and Ae. triuncialis (UUCC). Transfer of these genes to cultivated modern wheat may bring about a greater variation in Zn efficiency in wheat, and facilitate production of Zn-efficient modern wheat cultivars for Zn-deficient soil conditions.     

Grain Quality of Emmer Wheat Derived Synthetic Hexaploid Wheats

The wild diploid goat grass (Aegilops tauschii Cosson), and the cultivated tetraploid emmer wheat (Triticum turgidum L. subsp. dicoccon (Schrank) Thell.) may be important sources of genetic diversity for improving hexaploid bread wheat (Triticum aestivum L.). Through interspecific hybridization of emmer wheat and Ae. tauschii, followed by chromosome doubling, it is possible to produce homozygous synthetic hexaploid wheat. Fifty-eight such synthetic hexaploids were evaluated for grain quality parameters: grain weight, length, and plumpness, grain hardness, total protein content, and protein quality (SDS-Sedimentation volume, SDS-S). Most synthetics showed semi-hard to hard grain texture. Results showed significant genetic variation among the synthetic hexaploids for protein content, SDS-S values, and grain weight and plumpness. Quality measurement values of synthetic hexaploids were regressed on corresponding values of the emmer wheat parents. With this offspring-parent regression, protein content and SDS-S values explained 8.7 and 28.8%, respectively, of the variation among synthetics, indicating a significant contribution from the emmer wheat parents for these traits. The synthetic hexaploids, in general, had significantly higher protein content (15.5%, on average) and longer grains than ‘Seri M82’, the bread wheat control (13.1% protein content). Synthetics with SDS-S values and grain weights higher than those of ‘Seri M82’ were also identified. Protein content among synthetics showed significantly negative correlations with grain weight and plumpness, but no correlation with SDS-S values. Despite these negative correlations, 10 superior synthetic hexaploid wheats, derived from nine different emmer wheat parents and with above average levels of protein content, SDS-S values, and either grain weight or plumpness, were identified. This study shows that genetic variation for quality in tetraploid emmer wheat can be transferred to synthetic hexaploid wheats and combined with plump grains and high grain weight, to be used for bread wheat breeding.     

Comparison of the genetic structure of populations of wild emmer wheat, <Emphasis Type="Italic">Triticum turgidum</Emphasis> ssp. <Emphasis Type="Italic">dicoccoides</Emphasis>, from Israel and Turkey revealed by AFLP analysis

The aim of the present study was to assess the genetic variation in several Israeli and Turkish populations of wild emmer wheat, Triticum turgidum ssp. dicoccoides, the progenitor of most domesticated wheat. Single spikes were collected in 2002 from 60 plants that grew in six different habitats in Ammiad, northeastern Israel (8–12 plants from each habitat), and in 1998 from 56 plants that grew in seven different habitats in Diyarbakir, southeastern Turkey (8 plants from each habitat). Seeds were planted in a nursery and DNA was extracted from every plant and analyzed by the fluorescent-based amplified fragment length polymorphism (AFLP) method. Seven primer combinations produced 788 discernible loci of which 48.6% were polymorphic in Israel and 40.5% in Turkey. The genetic diversity estimates P (frequency of polymorphic loci) and He (gene diversity) were higher in Ammiad than in Diyarbakir (means of P = 0.34 and He = 0.13 in Ammiad vs. P = 0.20 and He = 0.08 in Diyarbakir). Ammiad populations contained more unique alleles than Diyarbakir populations. The relative genetic diversity estimates (θ) values were 0.188 in Ammiad and 0.407 in Diyarbakir, suggesting better differentiation of the populations in Turkey. Genetic distance was larger between Israeli and Turkish populations than between populations of each country. The data indicate that the Israeli and Turkish populations are considerably diverged and that the Israeli populations are more polymorphic than the Turkish ones, having a larger within-populations genetic variation than among-populations one. The significance of the results in relation to the differentiation pattern of wild emmer in the Near East is discussed.     

Evolution of tetraploid wheat based on variations in 5′ UTR regions of Ppd-A1: evidence of gene flow between emmer and timopheevi wheat

Previous study showed that tetraploid wheat was divided into two groups (Type AI and Type AII) based on sequences around Ppd-A1 gene (Takenaka and Kawahara in Theor Appl Genet 125(5):999–1014, 2012). That study focused on domesticated emmer wheat and used only 19 wild emmer wheats, so could not be clear the evolutional relationship between Type AI and Type AII. Here, a total of 669 accessions comprising 65 einkorn wheats, 185 wild emmer wheats, 107 hulled emmer wheats, 204 free-threshing (FT) emmer wheats, and 108 timopheevii wheats were studied by PCR assay and DNA sequencing for Type AI/AII. Type AII was an older type than Type AI because all einkorn accessions had Type AII. In wild emmer, Type AI was distributed in the northeast regions of its distribution and Type AII was found to be centered on Israel. A total of 37.4 % of hulled emmer accessions were Type AI, while 92.2 % of FT emmer accessions were Type AI. Differences in the proportion of Type AI/AII in domesticated emmer suggested a strong bottle-neck effect. We also found two MITE-like sequence deletion patterns from a part of Type AII accessions (dic-del and ara-del). Dic-del was found from only Israeli wild emmer accessions and ara-del was found from almost all timopheevii wheat accessions. Only three timopheevii accessions did not have ara-del, and one wild emmer accession and ten hulled emmer accessions had ara-del. These accessions suggested gene flow between emmer and timopheevii wheat.     

Genetic variation for phenolic acids concentration and composition in a tetraploid wheat (<Emphasis Type="Italic">Triticum turgidum</Emphasis> L.) collection

Phenolic acid intake through the consumption of whole-wheat foods provides important health benefits associated with reduced risks of cardiovascular diseases and colon cancer. The genetic variation for phenolic acids was extensively studied in common wheat, but a comprehensive survey in tetraploid wheat is lacking. In this study we evaluated the genetic variability for individual and total phenolic acids concentration existing in a large collection of tetraploid wheat (Triticum turgidum L.). A 2-year evaluation was undertaken on the whole-meal flour of 111 genotypes belonging to seven T. turgidum subspecies including cultivars, landraces and wild accessions. Durum cultivars [T. turgidum subsp. durum (Desf.) MacKey], had the highest average concentration of total phenolic acids (828.7 μg g^?1 dm in 2012; 834.5 μg g^?1 dm in 2013) with amounts varying from 550.9 μg g^?1 dm to 1701.2 μg g^?1 dm, indicating a variation of greater than threefold fold. The lowest concentration of phenolic acids was found in T. turgidum subsp. dicoccum (Schrank ex Schübler) Thell. Rivet wheat (T. turgidum L. subsp. turgidum) had phenolic acid concentrations similar to those in durum, but less variation was noted among the accessions. On the other hand, the accessions of the four remaining subspecies showed lower phenolic acid concentrations and variation among the accessions as compared to durum. A total of six phenolic acids were identified across the wheat genotypes. The effects of genotype, year and year × genotype were estimated by ANOVA and resulted significant for all phenolic acids. The ratio of genotypic variance to total variance suggested the possibility of improving phenolic acid content in elite wheat germplasm through appropriate breeding programs. Moreover, significant correlations between phenolic acids and other quality characteristics of the grain were detected.     

Exploration of glaucous variation in a collection of wild diploid wheat Triticum urartu Thumanjan ex Gandilyan

Glaucousness is the visible opaque-white or bluish-green wax which appears in plant cuticles. Although W1 and Iw1 loci on chromosome 2B mainly play a role to determine glaucousness/non-glaucousness trait in polyploid wheat, in the chromosome 2A of polyploid wheat, the non-glaucous inhibitor locus has not been reported. We explored the glaucous phenotypes for leaf, spike and stem in 274 accessions of Triticum urartu Thumanjan ex Gandilyan (2n?=?2x?=?14, genome A^uA^u), the A genome progenitor of polyploid wheat. The 272 accessions of T. urartu were non-glaucous for leaf, spike and stem. It was thought that non-glaucousness of T. urartu played an important role for plant adaptation throughout the Fertile Crescent. However, PI 662236 was glaucous in leaves, leaf sheaths and spikes, whereas PI 662271 was glaucous on the leaves and leaf sheaths, but non-glaucous in the spikes. Prior to heading PI 662236 and PI 662271 mimicked T. urartu by showing glaucous leaves and leaf sheaths. The plant form and somatic chromosome number indicated that PI 662236 and PI 662271 were tetraploid Triticum dicoccoides (Körn. ex Asch. & Graebn.) Schweinf. (2n?=?4x?=?28, BBA^uA^u genome). The occurrence of T. dicoccoides in the collections of T. urartu demonstrated that even famous botanists can make mistakes in identifying grasses. However, these mistakes lead to finding two rare types of T. dicoccoides with occurrence of glaucousness. The majority of T. dicoccoides that are non-glaucous. The genotype of PI 662236 was assigned as iw1iw1iw3iw3 for glaucousness and that of PI 662271 was iw1iw1Iw3Iw3 for the inhibitors for non-glaucous spikes.

     

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.     

Estimating Gliadin and Albumin Variation at Intra‐ and Interaccession Level in USDA Oriental Wheat (Triticum turgidum L. subsp. turanicum (Jakubz.) (A. Lőve & D. Lőve) Collection Using Capillary Zone Electrophoresis

Interest in so‐called ancient wheats (einkorn, emmer, oriental wheat, and spelt) has increased steadily in the last few decades. Oriental wheat (Triticum turgidum L. subsp. turanicum (Jakubz.) (A. Lőve & D. Lőve) is a neglected and underutilized tetraploid species that has survived over the centuries in some areas of the Near East and central Asia. Very little attention has been devoted by researchers to the evaluation and characterization of the oriental wheat germplasm. Knowledge of the variation of seed storage proteins within a germplasm collection is very useful for breeders interested in increasing the genetic bases of modern wheat cultivars. In this study, capillary zone electrophoresis (CZE) was used to analyze the gliadin and albumin extracts relative to 74 accessions belonging to the oriental wheat collection maintained at the USDA gene bank. Fourteen gliadin patterns were observed. Among the six most frequent patterns, one was widely predominant, being observed in 29 accessions, whereas eight were single types. Two profiles showing similar frequencies within the collection together with six single types were recognized for the albumins. The combination of the observed gliadin and albumin profiles gave rise to 25 combinations. In general, accessions collected in the same country shared the same combinations. This suggests that some accessions could be duplicates of the same genetic stock. Accessions collected in Iran and Turkey, which are indicated as the countries in which oriental wheat originated, were characterized by a higher degree of polymorphism.     

Whole-genome analysis with SNPs from BOPA1 shows clearly defined groupings of Western Mediterranean, Ethiopian, and Fertile Crescent barleys

The discovery of Hordeum spontaneum C. Koch, a wild ancestor of cultivated barley, in Morocco in 1978 led to the proposal of a multicentric origin for this crop, as an alternative to the widely accepted theory of a single centre of domestication in the Fertile Crescent. Since this discovery, we have tested this hypothesis using the most advanced genetic techniques available at the time, from CM-proteins to RFLP and DNA-chloroplast markers. Nowadays, the availability of single nucleotide polymorphism (SNP) markers that are spread densely over the barley genome provides us with another powerful tool to give further support for the above. We have used 1,536 SNPs from the Barley Oligo Pool Assay 1 (BOPA1) of Illumina to characterize 107 wild and cultivated barley accessions from the Western Mediterranean, Fertile Crescent, Ethiopia, and Tibet. The results have confirmed that each location of the above-mentioned germplasm groups clusters separately. Analysis of molecular variance enabled us to focus on the chromosomal regions and loci that differentiated these groups of barley germplasm. Some of these regions contain vernalization and photoperiod response genes, some of the so-called domestication genes, as well as the most important quantitative trait locus for flowering time in the Mediterranean region. We have combined these results with other genetic evidence, and interpreted them in the framework of current theories on the onset of the Neolithic revolution in the Mediterranean region, to conclude that neither Ethiopia nor the Western Mediterranean can be ruled out as centres of barley domestication, together with the Fertile Crescent.     

Genetic diversity in wild cereals: regional and local studies and their bearing on conservation ex situ and in situ

The current alarming global crisis and extinction of biodiversity affect negatively the planet's biosphere. Conservation of biodiversity is one attempt to alleviate the pending extinction of the biosphere by humans. Genetic diversity, the basis of evolution by natural selection, is gravely threatened in the progenitors of cultivated plants and its exploration, evaluation, conservation in situ and ex situ is imperative to guarantee sustainable development. This is illustrated by the population genetics and ecology of two important progenitors of cereals wild, wheat and barley. The wild cereals are rich in adaptive genetic diversity in the Fertile Crescent, primarily in Israel, which is their center of origin and diversity. The 40–55% intrapopulation diversity level in the wild cereals contrasts sharply with the average of 80% in outbreeders. Genetic diversity in wild wheat and barley is structured, particularly in wild emmer wheat, as an 'archipelago' ecological and genetic structure. These include central, semi-isolated and ecologically peripheral and marginal isolated populations, where specific alleles and allele combinations predominate as coadapted blocks of genes, adaptive to diverse ecological stresses. These involve both physical (climatic and edaphic) and biotic (pathogens and parasites) stresses at macro- and microgeographical scales. Complementary in situ and ex situ conservation is imperative across the geographic range of these species, to safeguard their immensely important genetic resources for crop improvement.     

Evaluation of Wild Lens Taxa for Agro-Morphological Traits, Fungal Diseases and Moisture Stress in North Western Indian Hills

Exploitation of wild gene pool for breeding is a common practice in an increasing number of cultivated plants. The cultivated lentil could not attain the substantial improvement in the yield potential due to loss of genes for higher productivity and lack of resistance against biotic and abiotic stresses. The absence of evaluation data of wild lentils for characters of economic importance, besides biotic and abiotic stresses, is one of the constraints in their use in lentil breeding programme. In the present study, 70 wild accessions from four wild Lens subsp./sp. (L. culinaris subsp. orientalis, L. odomensis, L. ervoides and L. nigricans) along with 3 checks (Precoz, PL-406 and PL-639) were evaluated for phenological and agro-morphological characters, for their reaction to three fungal diseases (wilt, powdery mildew and rust) and screened for tolerance to moisture stress. The wild accessions showed higher performance for branches/plant as compared to cultivated genotypes. Similarly, a few accessions of L. culinaris subsp. orientalis were earlier to flower and had higher seeds and seed yield/plant as compared to cultivated lentil. However, some were comparable with cultivated genotypes for flowers/peduncle, peduncle length and plant height. The mean performance for flowers per peduncle, leaflets per leaf, plant height, seeds and seed yield per plant increased, while decreased for days to flowering and maturity, and branches per plant during the evolution of cultivated lentil from the wild Lens taxa. Of Lens taxa, L. nigricans had the maximum resistant accessions for biotic and tolerance to abiotic stresses. The valuable variation existing among wild accessions can be exploited following introgression with cultivated lentils. It will help in the flow of useful genes from wild to cultivated lentil for generating wide spectrum of variability and its subsequent use in genetic restructuring of lentil.     

Sources of Resistance to Stem Rust (<Emphasis Type="Italic">Puccinia graminis</Emphasis> f. sp. <Emphasis Type="Italic">tritici</Emphasis>) in Ethiopian Tetraploid Wheat Accessions

Seedlings of 41 emmer (Triticum dicoccon Schrank) and 56 durum (T. durum Desf.) wheat accessions were evaluated for their response to stem rust (Puccinia graminis f. sp. tritici) infection under greenhouse condition at Kulumsa Agricultural Research Center, Ethiopia. The objectives were to identify tetraploid wheat accessions that could serve as sources of resistance to stem rust, and postulate the stem rust (Sr) resistance genes through multipatotype testing. The test included screening of accessions for stem rust resistance and multipatotype testing. To ensure vigorous screening, a mixture of six isolates (Si-1a, Am-2, Ku-3, Dz-4a, Ro-4 and Na-22) that were collected from severely infected emmer, durum, and bread wheat (Triticum aestivum L.) varieties of major wheat growing areas of Ethiopia was used as inocula. Out of the tested accessions, 18 emmer and 6 durum accessions exhibited low infection types (0–2) response and hence selected as a source of resistance to stem rust infection. Multipatotype testing was done to postulate Sr genes in the selected accessions. In the test, 10 different stem rust races (A2, A9, A11, A14, A16, A17, B3, B7, B15, and B21), 33 stem rust differential lines, and a universal susceptible check variety, Morocco were used, The high (3–4) and low infection type reaction patterns of the tested accessions and differential lines were used to postulate the genes that exhibit gene-for-gene relationship. The presence of Sr 7b, 8b, 9a, 9b, 10, 14, 24, 27, 28, 29, 30, 31, 32 and Tt-3+10 genes were postulated in 16 selected emmer and 5 durum wheat accessions. Efforts to transfer these valuable Sr genes from cultivated tetraploid wheats could be rewarding to get stem rust resistant varieties and boost wheat production.     

Characterisation and Variation of Morphological Traits and Storage Proteins in Spanish Emmer Wheat Germplasm (<Emphasis Type="Italic">Triticum Dicoccon</Emphasis>)

Emmer wheat is hulled wheat that was wide cultivated in Spain at the past. Actually, the most of this germplasm is conserved in Germplasm Banks, and only two small populations have been found in Asturias (North of Spain) in a recent collecting mission. In this work, a collection of 31 Spanish emmer lines developed from identical number of accessions of two Germplasm Banks was analysed for morphological spike traits and seed storage protein composition. Up to seven different botanical varieties were detected, which suggest the presence of a wide diversity, although lower than the historically described 10 botanical varieties. At level of seed storage proteins, the lines showed a high diversity, although the new alleles were present with low frequency in materials with scarce agronomic interest for the farmers (var. atratum, var. lagascae or var. pycnurum). This last circumstance could translate in a lost of variability by genetic drift.     

Genetic variation among populations of wild safflower, <Emphasis Type="Italic">Carthamus oxyacanthus</Emphasis> analyzed by agro-morphological traits and ISSR markers

Wild species of safflower, Carthamus oxyacanthus Bieb., is highly crossable with cultivated species, C. tinctorius L. and could be directly exploited in broadening safflower gene pool and improving the crop for biotic and abiotic stress environments. In this study, genetic diversity among accessions of C. oxyacanthus and their relationships with cultivated safflower were evaluated using agro-morphological traits and polymorphic inter-simple sequence repeats (ISSR) markers. Significant variation was observed among accessions particularly for seeds per capitulum, seed yield per plant, harvest index and capitula per plant. Cluster analysis based on agro-morphological traits classified the wild accessions in two groups according to their geographical regions, and separated them from the cultivated genotypes. ISSR marker also revealed a high genetic variation among the accessions, and cluster analysis based on this marker divided genotypes into four groups, with cultivated ones in a separate clade. Genetic variation observed among the wild safflower germplasm at the DNA level was higher than the agro-morphological traits, indicating that ISSR is an effective marker system for detecting diversity among safflower genotypes and their genetic relationships. Accessions of C. oxyacanthus with high genetic relationship to cultivated species could be used for interspecific hybridization in breeding programs of safflower.     

Characteristics of the root system in the diploid genome donors of hexaploid wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Wild crop relatives are of considerable interest in plant breeding and significant efforts have been made to transfer their genetic variation into modern crops. Of the three diploid progenitors of bread wheat (Triticum aestivum L.), only Aegilops tauschii Coss. has been explored and exploited and only for some above ground characteristics. The three wild progenitors (Aegilops speltoides Tausch., Triticum urartu Tumanian ex Gandilyan, and Aegilops tauschii) have never been assayed for root traits. Here we report such a root study, and include Triticum monococcum L. subsp. boeoticum (Boiss.) Hayek and T. turgidum L. subsp. dicoccoides (Koern. ex Asch. et Graebn.) Thell. Fifteen accessions were selected from the above wild species and tested in the presence of one bread wheat cultivar Pavon F76. Significant variation was observed between and within the taxa. Of all accessions tested, cv. Pavon F76 had the smallest root system at maturity while A. speltoides had the largest root system. Moreover, Aegilops spp. had larger mean values for root biomass when compared with Triticum spp. These results suggest there is significant unexplored potential for the use of wheat wild relatives in wheat breeding to improve the root system, or to develop synthetic mapping populations to study root traits.     

Changes in seed Morphology, Dormancy and Germination from wild to Cultivated Hyacinth bean Germplasm (Lablab purpureus: Papilionoideae)

Morphological and physiological seed characteristics of the hyacinth bean (Lablab purpureus) were investigated in a set of 18 different germplasm accessions, from wild over semi-domesticated forms to landraces and current cultivars. The objective of this study was to improve the understanding of the domestication of this tropical legume crop. Wild accessions were easily distinguished by morphological characters, such as small, greyish-brown, mottled seeds. Cultivated or semi-domesticated forms showed a much wider variation in size, colour and shape. Seed mass of cultivated accessions reached up to almost 10 times that of wild accessions. Most wild accessions showed a greater spread of germination and larger proportions of hard seeds, up to about 70%, than most cultivated and so-called semi-domesticated accessions. Cluster analysis applied separately to morphological and germination data and a subsequent discriminant analysis did not help integrating the morphological variability observed. The presumed occurrence of semi-domesticated accessions within the germplasm tested as well as the crop's origin from Africa alone or both Africa and Asia are debated on the basis of seed germination and hard seed coat dormancy.     

Introgression from Durum Wheat Landraces in Wild Emmer Wheat (Triticum Dicoccoides (Körn. ex Asch. et Graebner) Schweinf)

Introgression was detected within wild emmer wheat population in Jordan during the year 2000. Wild emmer wheat was found to occur in non-disturbed habitat, very close to cultivated durum wheat in northern parts of Jordan, and it was found in cultivated durum wheat in southern parts of Jordan. Random Amplified Polymorphic DNA (RAPD) test was constructed to assess natural introgression occurrence within wild emmer wheat population. Associated durum wheat land races from the vicinity of durum wheat fields were also collected. Shannon Diversity Index for wild emmer wheat populations was 0.46 and for durum wheat landraces was 0.45. The percentage of polymorphic loci for wild emmer wheat populations was 92.6. The close genetic distance between certain wild emmer wheat populations and durum wheat landraces provided proofs that massive introgression has occurred.     

Genetic diversity and intra-specific phylogeny of Triticum turgidum L. subsp. dicoccon (Schrank) Thell. revealed by RFLPs and SSRs

Today, emmer wheat, T. turgidum subsp. dicoccon, widely grown in the past is a candidate crop for sustainable agriculture in Italy. As part of a research project aimed at the enhanced use of the hulled wheat germplasm, molecular characterization was carried out to understand the genetic structure of the crop and to identify accessions of interest. A collection of 194 accessions was analyzed with 15 microsatellite loci (SSRs), while only a sample of 38 accessions was tested with 19 RFLP probes. The marker loci were selected on the basis of their independent genomic distribution. Genetic distances and allelic frequencies were calculated for each marker class. The genetic relationships were visualized with dendrograms. RFLP loci were, on average, less polymorphic than SSRs. An average Dice's genetic distance of 0.22 for RFLPs vs 0.38 for SSRs was detected, while an expected average heterozygosity per locus of 0.23 for RFLPs vs 0.26 for SSRs was also estimated. With a least number of 10 loci per marker class it was possible to identify each genotype. The most diverse accessions had different geographic origins. Germplasms from Italy and Ethiopia appear to belong to a more primitive genepool, given that a group of accessions from these countries were genetically differentiated from a Russian-Iranian group.