Variation in the Carbohydrate Composition of Wild Barley (Hordeum spontaneum) Grain

The carbohydrate content of Hordeum spotaneum lines collected from 23 diverse environments in Israel was investigated. The range in composition was sucrose: 0.83—1.15%; trisaccharides): 0.48—1.16% total free and combined fructose: 1.2—4.2%; pentosans: 4.2—9.9%; and fl→3), (1→4)-β-glucans: 4.5—13.2%. The high pentosan and β-glucan content in some lines would cause quality problems if found in malting barleys.     

Use of Isozyme-Marked Segments from Wild Barley (Hordeum spontaneum) in Barley Breeding

Fifty-six accessions of Hordeum spontaneum from various Israeli habitats were hybridized with, and their progeny backcrossed three times to H. vulgare cv. ‘Clipper’. Selected chromosome segments marked by one of 24 isozyme loci were transferred to form 84 backcross lines which were nearly isogenic with ‘Clipper’. Each line was made homozygous for a single isozyme-marked segment. These lines were evaluated in preliminary and advanced field trials. The yield, malt extract percentage and grain size of the lines approached or equalled, and sometimes significantly surpassed, that of ‘Clipper’ and more recent commercial cultivars. Three isozyme-marked segments were combined in pairs and the three resultant doubly-marked lines were compared with the reconstituted parental, singly-marked lines and with the ‘Clipper’ recombinant from the same F²-array. The additive effects of single segments on yield or gram size were not significant, whereas half of the six interactions were significant, but in the unfavorable direction. It was concluded that near-isogenic lines can identify segments of wild barley germplasm that are useful for improving yield, but that pairs of these from different habitats may interact unfavourably.     

Genetic Resources for Salt Tolerance in the Wild Progenitors of Wheat (Triticum dicoccoides) and Barley (Hordeum spontaneum) in Israel

Salt tolerance was tested in the progenitors of cultivated cereals, wild barley (Hordeum spontaneum) and wild emmer wheat (Triticum dicoccoides) from Israel. Plants from five selected populations of H. spontaneum from the Mediterranean Coastal Plain and northern Negev desert, were grown on 250 and 350 mM of NaCl. Likewise, five populations of T. dicoccoides from the eastern Samaria steppes, Mt. Hermon and Mt. Carmel, were grown on 175 and 250 mM of NaCl. Here we report on superior genotypes of H. spontaneum, ripening at 350 mM NaCl (= 60 % sea water), and of T. dicoccoides ripening at 250 mM (— 40 % sea water). We are proceeding now with both genetical and physiological studies aimed at chromosomally-locating salt tolerant genes and unravelling the mechanism(s) of salt resistance in these wild cereals.     

Allelopathic Effects of Black Mustard (Brassica nigra) on Germination and Growth of Wild Barley (Hordeum spontaneum)

Black mustard [Brassica nigra (L.) Koch.] contains water‐soluble allelochemicals that inhibit the germination and growth of other species. This characteristic could be used in weed management programmes. Greenhouse and laboratory experiments were conducted to determine the effects on wild barley (Hordeum spontaneum Koch.) germination and seedling growth of (i) preceding crops, (ii) fresh black mustard residue incorporation, and (iii) black mustard leaf, stem, flower and root water extract concentrations. Growth of wild barley, as indicated by plant height and weight, was significantly reduced when grown in soil previously cropped to black mustard compared with that cropped to wild barley. Soil incorporation of fresh black mustard roots and both roots and shoots reduced wild barley germination, plant height and weight when compared with a no‐residue control. In bioassays, black mustard extracts reduced wild barley hypocotyl length, hypocotyl weight, radicle weight, seed germination, and radicle length by as much as 44, 55, 57, 63 and 75 %, respectively, when compared with a water control. Increasing the water extract concentrations from 4 to 20 g per 100 ml of water of all black mustard parts significantly increased the inhibition of wild barley germination, seedling length and weight. Based on 8‐day‐old wild barley radicle length, averaged across all extract concentrations, the degree of toxicity of different black mustard plant parts can be ranked in the following order of inhibition: leaves > flowers > mixture of all plant parts > stems > roots.     

Genotypic Composition and Mildew Resistance in a Natural Population of Wild Barley, Hordeum spontaneum

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.     

Sources of Resistance to Powdery Mildew in Barley Lines Derived from Hordeum spontaneum Collected in Israel

Fourty two barley lines direved from the F₇ of crosses between barley cultivars and different accessions of Hordeum spontaneum collected in Israel and 30 lines or varieties with known genes for resistance to powdery mildew were included m this study. Eleven European and three Israeli powdery mildew cultures, possessing virulence genes corresponding to known resistance genes, were used to make comparisons between the varieties with known resistance genes and H. spontaneum derived lines. The reaction pattern of 39 H. spontaneum derived lines was clearly different from the reaction pattern o; any of the known genes for mildew resistance included in this study. Only two cases were observed in which the reaction pattern of H. spontaneum derived lines agreed with reaction patterns of known genes for mildew resistance viz. Ml-a9 and Ml-p. Trie Mildew resistance of one line apparently traces back to uncontrolled outcrossing with a Ml-a.6+Ml-g resistant cultivar. Since the majority of the 42 host genotypes tested showed distinctive variation in resistant reaction types against different mildew cultures, this study docs not support the assumption that differences in resistant infection types against distinct mildew cultures are sufficient to indicate the presence of supplementary genes for resistance in a given genotype of the host. The results justify the conclusion that the natural population of H. spontaneum in Israel forms a large gene pool for mildew resistance which is not yet used m cultivated barley.     

Linkage of Rust Resistance Genes from Wild Barley (Hordeum spontaneum) with Isozyme Markers

Eighty-three third backcross lines which comprise a set of near isogenic lines (NIL's) of the barley cultivar ‘Clipper’ but each carrying a different chromosomal segment from Hordeum spontaneum, marked with a distinct isozyme, were tested for resistance to three races of the barley leaf rust pathogen (Puccmia hordei). Fourteen lines showed resistance to at least one race and three showed resistance to all three races. The resistance in two of these lines was controlled by separate, single partially dominant genes. In one case the resistance gene named Rph1O was on chromosome 3 and linked (r = 0.15 ±0.05) with the isozyme locus Est2. In the second case, the gene (Rph11) was on barley chromosome 6 and linked (r = 0.07±0.02) with the isozyme locus Acp3 and (r = 0.11±0.02) with Dip2.     

Variation in vegetative parameters related to the nitrogen economy of wild barley,Hordeum spontaneum,in Israel

Summary Hordeum spontaneum, the wild progenitor of cultivated barley, has previously been examined in various studies as a germplasm resource in breeding for grain protein content and related nutritional traits.The nitrogen content and dry weight of leaf and stem (stem plus sheath) at anthesis, and the final grain size and grain protein content were measured in 33 H. spontaneum and two H. vulgare genotypes. H. spontaneum was generally higher in nitrogen content of leaves and stems, but lower in dry weight at anthesis. Consistent with previous reports, the H. spontaneum genotypes were considerably higher in grain protein than the cultivars. There was wide variation between and within populations of H. spontaneum suggesting that for breeding purposes lines combining high vegetative nitrogen content, dry weight and grain protein content can be selected.Incumbent of the Seagram Chair for Plant Science     

Genetical Studies of Resistance of Powdery Mildew in Barley Lines Derived from Hordeum spontaneum Collected from Israel

Genetical studies on mildew resistance were carried out with Hordem spontaneum derived lines. A total of 28 lines (66 %) showed monofactorial segregation for mildew resistance, For 14 lines, a bifactorial mode of inheritance was found. In total fifty six mildew resistance genes take part in the inheritance of mildew resistance of the H. spontaneum derived lines, while the presence of known genes for mildew resistance (i.e, Ml-a.9 and Ml-p) was established only in two cases. Independent segregation from the Ml-a locus was found in 10 mbnofaetorial segregating lines, The genes conditioning mildew resistance in barley lines derived from the accessions 1B-54B, RS 170-47, RS 20-1. 1B-86B, RS 145-39 and 1B–152B of H. spontaneum were closely linked or alleles to the Ml-a locus, but shown to be different from 15 previously identified Ml-a alleles. It is suggested that these genes should be designated Ml-a16, Ml-18, Ml-19 Ml-20 and Ml-a21 respectively. No recombinants were found in test crosses when both parents carried genes/alleles of the Ml-a locus. In addition, polymorphism has been observed also for the Ml-a locus. In 4 lines mildew resistance was conditioned by two dominant complementary genes. For one of the 2 genes, conditioning mildew resistance of line RS 42-8 × OrioL a new locus was found located near the centromere of the long arm of chromosome 5, and should be designated Ml-i The potential use of H. spontaneum genes for mildew resistance in barley breeding is discussed.     

野生大麦的抗旱性及其在大麦遗传改良中的应用

干旱是主要的非生物胁迫性灾害,极大地威胁到全球的粮食供应,是影响农业生产的最重要因素之一。因此,培育抗旱性植物是解决干旱危害和粮食危机的根本途径。野生大麦已经适应广泛的干旱环境并具有丰富的遗传多样性,它们的抗旱基因与抗旱相关数量性状位点(QTLs)已经确定,对改良大麦抗旱性有巨大的潜力。综述了野生大麦的抗旱性及其在大麦改良中的应用,并对大麦抗旱育种中存在的问题以及今后发展方向进行了展望。     

Milling Energy Polymorphism in Hordeum spontaneum Koch in Israel and its Potential Utilization in Breeding for Malting Quality

Variation for grain milling energy in Hordeum vulgare is associated with differences in grain size, shape and composition. Genetic polymorphisms within and between populations were found across the ecogeographical range of Hordeum spontaneum in Israel. Low milling energy estimates were positively correlated with and predictable by the aridity index. Milling energy in H. spontaneum, collected in Israel, ranged from the lowest values seen in making barley to twice the highest values seen in feed cultivars. It is concluded that H. spontaneum elite genotypes could be effectively identified by milling energy for use in the breeding of new cultivars.     

Identification of New Genes for Mildew Resistance of Barley at the Mia Locus in Lines Derived from Hordeum spontaneum

Genetical studies have been conducted with lines derived from H. spontaneum showing that these lines carry dominant mildew resistance genes located at or near the Mla, locus. The resistance spectra of the lines ‘RS170—10 × Piccolo A’, ‘Diamant × 1B-20’, ‘RS1—8 × Piccolo E’ and ‘Diamant × 1B-151’ obtained from 10 European and Israeli isolates differ from previously-identified Mia alleles. Therefore, it is suggested that these genes should be designated as Mla 25, Mla 26, Mla.27 and Mla 28, respectively. In addition, the RFLP-patterns of these lines and their crossing parents were studied by hybridization with probes MWG 1H036, MWG 1H060 and MWG 1H068, which are very closely linked to the Mia locus. Two double crossover events have been identified. The use of RFLP markers for the identification of mildew resistance genes is discussed.     

Salinity tolerance of wild barley Hordeum vulgare ssp. spontaneum

Salinity tolerance of 47 wild barley genotypes and six barley cultivars was evaluated under control and salinity stress (300 mM NaCl) conditions. Shoot and root dry weight (DW), plant height, membrane stability index (MSI), relative water content, survival rate, leaf malondialdehyde (MDA) and proline contents, root and leaf Na, K, Ca and K/Na ratio, and chlorophyll a fluorescence were measured. Salinity stress caused significant increase in the MDA, proline content, Na and Ca concentrations of the roots and leaves, but resulted in a decrease in the other traits. H. spontaneum genotypes were considerably less affected by the salinity than the genotypes of H. vulgare. Plant survivability was negatively correlated with the Na concentration (r =−.66) but positively correlated with the leaf K/Na ratio (r = .67) and MSI (r = .68). Tolerance mechanisms such as ion exclusion (Na) were likely to be present in the wild barley causing K/Na homeostasis as well as the much lower root and shoot Na, resulting in the higher survival rate.     

Genetic analysis of powdery-mildew (Erysiphe graminis f.sp. hordei) resistance derived from wild barley (Hordeum vulgare ssp. spontaneum)

The inheritance of resistance to powdery mildew was investigated in 20 accessions of Hordeum spontaneum and in 20 F₄ lines derived from crosses between the variety ‘Aramir’ and 13 accessions of H. spontaneum. Two resistance genes were detected in 17 accessions, and three resistance genes in one accession. In two accessions, only one resistance gene was present. The 20 breeding lines showed a large variation in infection type and infection level. The genetic relationship between the resistance genes detected was investigated in the seven most resistant F₄ lines. These F₄ lines were divided into three groups which carried different resistance genes. In two lines, the detected resistance gene was shown to be race-specific.     

Genetic resources of wild cereals in Israel and vicinity. II. Phenotypic variation within and between populations of wild barley,Hordeum spontaneum

Summary Populations of wild barley, Hordeum spontaneum, in Israel, originating from diverse habitats, and tested earlier for allozyme (Nevo et al., 1979a) and disease resistance polymorphisms (Moseman et al., 1984; Nevo et al., 1984a), were compared and contrasted for performance in agronomically important phenotypic traits. The traits compared involved 10 variables comparing germination, earliness, numerical and weight variables of biomass and yield. The field experiments were conducted in 1980, 1981 and 1982 in two relatively standardized and contrasting environments: mesic (Mount Carmel, Haifa) and xeric Avedat farm, and Sede Boqer (both in the northen Negev desert). The experimental design involved 26 population quadrangles at Avedat farm (1980), and rows of randomized plants of 11 populations in both Haifa and Sede Boqer (1981 and 1982).The results indicate that the characters studied are partly genetically determined. Striking genetic variation was found between and within populations in each site, whereas remarkable environmental variation including genetic environmental interaction was found between the mesic and the xeric sites, as well as between populations and years. We conclude that natural populations of wild barley in Israel vary not only in genetic polymorphisms of allozymes and disease resistance, but also in quantitative traits of agronomie importance. These traits are economically significant and should be conserved and utilized in barley crop improvement.     

Environmental, phenotypic and genetic variation of wild barley (Hordeum spontaneum) from Israel

Wild relatives of crop plants offer an attractive gene pool for cultivar improvement. We evaluated genetic and phenotypic variation for a set of 72 Israeli accessions of wild barley from 21 populations. These populations were grouped further into four ecotypes. In addition, environmental variables describing the local conditions for the populations were used to infer the environmental divergence. Genetic, phenotypic and environmental distances were estimated from the data and UPGMA dendrograms constructed. The results showed that genetic variation was larger between populations than within them, whereas for phenotypic measurements variation was larger within populations than between them. No significant correlation was found between genetic and phenotypic similarities, or between phenotypic and environmental similarities, whereas a weak correlation between genetic and environmental similarities was detected. Twenty-three AFLP-markers were identified to be ecotype specific. Chromosomal location was known for five of these markers. Four of the five ecotype specific markers were correlated with both phenotypic traits and environmental variables.     

Cryopreservation of Embryogenic Callus Cultures from Barley (Hordeum vulgare L.)

Embryogenic callus cultures of barley (Hordeum vulgare L.) were frozen in the presence of a cryoprotector and subsequentjy stored in liquid nitrogen. After thawing, a high percentage of cultures resumed growth after a lag-period of 2–4 weeks. Plant regeneration was achieved at a frequency comparable to that observed in control cultures.     

Genetic characterization of wild barley populations (Hordeum vulgare ssp. spontaneum) from Kazakhstan based on genome wide SNP analysis

The wild ancestral form of barley, Hordeum vulgare ssp. spontaneum, is a valuable source for gene enrichment of cultivated barley. The purpose of this work was to study the area of distribution as well as the extent and structure of genetic variation of wild barley populations grown in Kazakhstan. It was found that distribution of wild barley populations in Kazakhstan is restricted to the most southern province. A genome wide single nucleotide polymorphism (SNP) analysis was performed in order to study the level of the genetic diversity in 96 accessions representing 14 wild barley populations from Kazakhstan and 25 accessions from the Middle East which is the center of diversity of this subspecies. The oligonucleotide pooled assay was used to genotype 384 SNPs distributed throughout the genome. In total 233 polymorphic SNPs were selected for further statistical analysis. The level of genetic diversity of wild barley populations from Kazakhstan was predictably narrower (He = 0.19 ± 0.01) in comparison with wild barley samples from the Middle East (He = 0.29 ± 0.01). The results suggested that H. vulgare ssp. spontaneum populations in Kazakhstan probably represent a recent spread of a limited number of plants from the primary distribution area and might be well adapted to winter low temperature.     

Reactions of Hordeum spontaneum to infection with two cultures of Puccinia hordei from Israel and United States

Summary The reactions to infection with two cultures of Puccinia hordei were determined for 292 Hordeum spontaneum (syn. H. vulgare ssp. spontaneum) accessions, collected at 16 sites which encompassed the ecological range of H. spontaneum in Israel. Culture Tel-Aviv was from Israel and culture 57.19 was from the United States. Fifty-two percent of the accessions were resistant to culture Tel-Aviv and 67% were resistant to culture 57.19. Forty-three percent of the accessions were resistant to both cultures. The average infection type (IT) of accessions within sites ranged from 2.7 to 7.5 on a 0–9 rating scale. The results showed that the presence of Ornithogalum species, the alternate hosts of P. hordei, may increase the percentage of H. spontaneoum accessions resistant to P. hordei. More accessions were resistant at sites where humidity at 1400 was higher, the annual evaporation was lower, and where the glumes were shorter. Kernel weight and annual rainfall was not correlated with resistance. A lower percentage of H. spontaneum accessions were resistant to P. hordei culture Tel-Aviv from Israel than to culture 57.19 from the United States. In a previous study a lower percentage of H. spontaneum accessions also was found to be resistant to a culture of Erysiphe graminis hordei from Israel than to cultures from other countries. Previous studies also have shown that cultures of P. hordei and E. graminis hordei from Israel have many genes for virulence on barley, and that H. spontaneum accessions from Israel have many genes for resistance to these two pathogens. Previous results and the results reported in this paper support the hypothesis of coevolution of resistant host genes and virulent pathogen genes where hosts and pathogens have coexisted for many thousand years.     

Grain Protein Accumulation During Grain Development in Barley (Hordeum vulgare L.)

Grain protein accumulation during grain development was studied as a function of defoliation at anthesis in barley ( Hordeum vulgare L.) genotypes grown under pot culture and non limiting nitrogen conditions. The data indicates that per cent grain protein did not decrease proportionally despite 50 % or more decrease in grain yield per plant. These data support the contention that shrivelling need not result in proportional increase in grain protein %. The data also suggests that accumulation of grain protein and carbohydrate during the grain development may not be negatively associated. The data also brings about the importance of grain protein yield per plant as a useful parameter for breeding high grain protein genotypes.