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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 99 (1987), S. 0 
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two sets of accessions were sampled, tram a natural population of Hordeum spontaneum at Shelomi, Israel, viz.: 100 ears along a transect at intervals of 1—1.5 m and 10 ring clusters of 10 ears each, circling each 10th plant of the transect. Single ear progenies were tested for banding patterns of 5 allozyme loci; in addition, hordein sanding; and field reaction against powdery mildew has been determined. 56 allozyme genotypes and 13 hordein patterns were determined. Most of the progenies showed susceptible to moderately susceptible infection types and high frequencies of low infection grade (slow mildewing). For all characters spatial grouping was found in plants derived from neighbouring transect parents. This was even more pronounced in the ring clusters. Reactions to mildew infection appeared to be closely correlated with hordein banding. In addition, accessions showing hypersensitive reactions carried excessive frequencies of a certain allele of the Est-1 locus.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 35 (1979), S. 1027-1029 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Genetic structure of populations ofHordeum spontaneum, the wild progenitor of barley, was studied electropho-retically in proteins encoded by 28 gene loci in 1179 individuals representing 28 populations covering the entire ecological range in Israel; for comparison, the same test was conducted in 100 random seeds of Composite Cross XXI (generation 17) of cultivated barley,Hordeum vulgare. The results indicate that: a)H. spontaneum in Israel is genetically highly polymorphic, b) clinal, regional and local genetic patterns are significantly correlated with and predictable by climatic and soil variables, suggesting the operation of natural selection, and c) natural populations are on the average more variable than the tested Composite Cross generation. This genetic variation awaits testing and exploitation in breeding programs.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 62 (1982), S. 241-254 
    ISSN: 1432-2242
    Keywords: Triticum dicoccoides ; Allozyme polymorphisms ; Genetic and ecological diversity ; Sampling and conservation strategies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Allozyme variation in the tetraploid wild progenitor of wheat, Triticum dicoccoides, was studied for the proteins encoded by about 50 gene loci in 457 individuals representing 12 populations from Israel. Six spikelet morphological traits were measured in the same populations. The results indicate that: (a) 16 loci (= 32%) were monomorphic in all 12 populations, 15 loci (= 30%) were locally polymorphic, and 19 loci (= 38%) were regionally polymorphic. All polymorphic loci (but one) displayed high levels of polymorphism (≧ 10%). In Israel, the proportion of polymorphic loci per population, P, in wild wheat averaged 0.25 (range, 0.16–0.38), and the genetic diversity index, He averaged 0.07, (range, 0.03 – 0.12). (b) Altogether there were 110 alleles at the 50 putative loci tested (c) Genetic differentiation of populations included regional and local patterns: (i) The coefficients of genetic distance between populations were high (mean D = 0.10 range, 0.02 – 0.25), and indicated sharp genetic differentiation over short distances, (ii) Common (≧ 10%) but sporadic and localized alleles were frequent (76%), and (iii) Rare alleles were few (only 5 alleles). (d) The patterns of allozyme and spikelet variation in the wild gene pool were significantly correlated with, and partly predictable by, water factors, including those of precipitation, evaporation, and relative humidity as well as of soil type, (e) All six spikelet characters showed statistically significant variation among localities and (f) Allozymic variation was correlated with spikelet variation. These results suggest in T. dicoccoides: (i) the operation of natural selection in population genetic structure, (ii) local adaptive genetic differentiation caused by diversifying selection through climate and soil, and (iii) the guidelines for sampling these resources for use in wheat breeding programs.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 45 (1974), S. 355-362 
    ISSN: 1432-2242
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The interspecific cytogenetic relationships among T. alexandrinum L., T. berytheum Boiss., T. salmoneum Mout., T. apertum Bobr., T. meironense Zoh. et Lern, and T. vavilovi Eig. were studied in several hundreds of intraspecific (WS) and interspecific (BS) F1 hybrids in all possible combinations, and in many of their progenies. Seed germination and development of F1 BS hybrids were normal, except in crosses involving T. vavilovi. Their pollen fertility and seed set was subnormal, with somewhat lower values in T. vavilovi progenies. No multivalents were observed in any F1 BS hybrid, but in some plants, four and also six chromosomes did not pair to form bivalents. B chromosomes were common in hybrids involving T. berytheum or T. salmoneum. Some BS F1 hybrids set ample seeds when selfed, and most of them originated from either one of two self-incompatible T. berytheum plants. The six taxa studied form three groups: (i) T. vavilovi, which is quite remote from the other five; (ii) T. meironense and T. apertum; and (iii) T. alexandrinum, T. berytheum and T. salmoneum. The two last species, especially T. salmoneum, seem to be the progenitors of the cultivated berseem.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-5060
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Transfer of stem rust resistance from diploid wild einkorn, Triticum boeoticum, to susceptible Mindum and Spelmar, varieties of cultivated T. durum, was achieved by means of a triploid hybrid bridge and subsequent backcrossing to the tetraploid parent. Seedlings of the second hybrid generation segregated for resistance to race 14 of Puccinia graminis f.sp. tritici which was used as test race in this investigation. The F3 and F4 progenies included segregants which displayed seedling resistance also to races 17, 19, 21, 40, 53, 194, 222, 315 and 322. Since these were the same races which proved avirulent to the T. boeoticum donor but virulent to the T. durum recipients, it was concluded that the full pattern of resistance determined in the wild diploid parent of this cross was transferred to the tetraploid durum-like hybrid derivatives.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 49 (1978), S. 97-108 
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The association of ecological factors and allozyme markers with genotypes of tetraploid wild emmer wheat,Triticum dicoccoides, varying in resistance to four cultures of the pathogenErysiphe graminis tritici, and to one culture ofPuccinia recondita tritici, which incite the diseases powdery mildew and leaf rust respectively, were explored theoretically and practically. The study involved 233 accessions comprising 10 populations representing the ecological range ofT. diococcoides in Israel. Our results indicate that genetic polymorphism for resistance to both pathogens is structured geographically, and is predictable by climatic as well as allozymmc markers. Three variable combinations of water factors and temperature differentials significantly explain 0.27 and 0.14 of the spatial variance for resistance to powdery mildew and leaf rust, respectively, suggesting the involvement of natural selection. Several allozyme genotypes, singly, or in combination, are significantly associated with disease resistance. We conclude thatT. dicoccoides populations in Israel, which grow in the center of diversity of the species, contain large amounts of unexploited disease resistant genotypes. The populations could be effectively screened and utilized for producing resistant cultivars by means of ecological factors and allozyme markers as predictive guidelines.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic variability within and between populations of the wild progenitor of barley was studied electrophoretically. Thirty enzyme loci were assayed in 437 individuals representing 11 populations ofH. spontaneum in Turkey. The results indicated that: (a)H. spontaneum in Turkey is genetically rich in allozyme variation, but because of predominant self-pollination the variation is maintained as different homozygotes in the population; (b) genetic differentiation of populations includes clinal, regional, and local patterns, sometimes displaying sharp geographic differentiation over short distances; (c) overall indices of allozymic diversity and some allele frequencies of wild barley are significantly correlated with the environment and are predictable ecologically, chiefly by combinations of temperature and humidity variables; (d) a high percentage of alleles (66%) occur in local areas or are distributed sporadically rather than widespread; (e) Wright Fixation index was very high, F=0.995; (f) genetic distance was high (D=0.11, ranging from 0.031 to 0.288) between populations, and (g) average relative genetic differentiation was high among populations (Gst=0.47, ranging from 0.02 to 0.66). The spatial patterns and environmental correlates and predictors of genetic variation ofH. spontaneum in Turkey, indicated that genetic variation in wild barley populations is not only common, but also at least partly, adaptive. Therefore, a much fuller exploitation of these genetic resources by breeding is warranted.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 20 (1971), S. 380-395 
    ISSN: 1573-5060
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary On the combined evidence from morphology, ecology, and cytogenetics, seven species are recognized in the genus Avena L. 1. A. clauda Dur., 2. A. ventricosa Bal. 3. A. longiglumis Dur, 4. A. strigosa Schreb., 5. A. magna Murphy et Terr., 6. A. murphyi Ladiz. and 7. A. sativa L. The first three species are wild diploids. The fourth is a diploid-tetraploid complex of wild forms, weeds and cultivars. The fifth and sixth are wild tetraploids and the seventh constitutes a hexaploid aggregate of wild forms, weeds and cultivated forms. A short morphological and ecological characterization is given to each species. The cytogenetic, ecological and morphological evidence available on the evolutionary divergence and on the genetic affinities between the seven species is reviewed and discussed. The conclusion in drawn that in Avena there are two independent developments of polyploidy: 1. strigosa tetraploids, where the diploid background is well known; 2. the tetraploid-hexaploid of A. magna, A. murphyi and A. sativa (series Denticulatae). Here the first two species apparently represent the general tetraploid background from which hexaploid A. sativa evolved. It is also argued that it is impossible to explain the morphology, ecology and cytology of series Denticulatae in terms of the known diploid species of Avena, and a yet missing hypothetical diploid ancestor was extrapolated.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-5060
    Keywords: Truticum dicoccoides ; wild emmer wheat ; Erysiphe graminis tritici ; powdery mildew ; resistance ; Israel ; germplasm ; wheat ; collection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The reactions of 233 Triticum dicoccoides acessions, collected at 10 sites in Israel and elsewhere, to infection with cultures of Erysiphe graminis tritici, were determined. The reactions indicated that the number of sources of resistance to E. graminis tritici which can be obtained from T. dicoccoides plants growing wild in Israel and elsewhere is almost unlimited. One hundred and fourteen or 49% of the accessions were resistant, and 137 or 59% of the accessions were resistant or moderately resistant to infection with four cultures of E. graminis tritici which possess the virulence genes corresponding to most of the identified resistance genes in wheat. Accessions collected at sites with marginal habitats where T. dicoccoides grows poorly and has lower grain weight, were more susceptible than were accessions collected at sites with an optimal habitat for growth of T. dicoccoides. The results agreed with those in a previous study with Hordeum spontaneum, and indicate that to obtain H. spontaneum or T. dicoccoides accessions with the highest level of resistance to the powdery mildew pathogens, plants should be collected at sites in ecological and geographic regions where those two species occupy optimum habitats and are exposed to the powdery mildew pathogens.
    Type of Medium: Electronic Resource
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