Quantitative Trait Loci (QTL) of Seed Zn Accumulation in Barley Population Clipper X Sahara

There is little information regarding the chromosomal regions conferring zinc (Zn) accumulation in barley. With the aim of developing markers for Zn accumulation, 150 lines derived from cross between ‘Clipper’ (low-Zn-accumulator) and ‘Sahara’ (high-Zn-accumulator) were screened. In field-grown plants, two regions located on 2HS and 2HL were associated with seed Zn concentration and content. 2HS was flanked by Xbcd175 and Xpsr108; 2HL was flanked by vrs1 and XksuF15 markers. These two regions accounted for 45% of total variation in seed Zn concentration and 59% of total variation in seed Zn content. In a glasshouse experiment, 2HS and 2HL were also associated with seed Zn concentration and content, and explained 37% and 55% of the total variation in seed Zn concentration and content, respectively. The identification of these Quantitative Trait Loci (QTL) provides an important starting point for transferring and pyramiding genes that may contribute to the improvement of barley productivity and nutritional quality in Zn-deficient environments.     

Genetic diversity in wild barley (Hordeum spontaneum C. Koch) in the Near East: a molecular analysis using Random Amplified Polymorphic DNA (RAPD) markers

We analyzed the genetic diversity in 88 genotypes from 20 populations of wild barley (Hordeum spontaneum C. Koch) from Israel, Turkey and Iran, by randomly amplified polymorphic DNA (RAPD). Twenty two of the 33 primers used yielded scorable products with 1–11 polymorphic bands. No duplicate patterns were found except for four haplotypes.When the total genetic diversity was estimated, 75% of the variation detected was partitioned within the 88 genotypes and 25% among the populations. When variation between countries was assessed, no substantial differences were found, because most of the variation detected (97%) was partioned within the 20 populations and the remainder among countries. The results of this limited survey indicate that the extensive genetic diversity is present in natural stands of wild barley throughout the Fertile Crescent.     

Phenotypic variation in caryopsis dormancy and seedling salt tolerance in wild barley, Hordeum spontaneum, from different habitats in Israel

The phenotypic variation in caryopsis dormancy and seedling salt tolerance was investigated in 16 wild barley ecotypes in Israel. Depth of dormancy, as reflected by the time to maximum germination percentage, ranged from 15 to 103 days under dormancy-break treatment. Lower dormancy was characteristic of the mesic ecotypes, whereas deeper dormancy was characteristic of the xeric ecotypes. Dormancy-break patterns were revealed by growth curves: the xeric ecotype showed an S-shaped curve, whereas the mesic ecotype displayed a reverse L-shaped curve. Seedling salt tolerance was assessed by the ratio of root or coleoptile length in a seedling grown in 100 or 200 mM NaCl solution to that of a seedling grown in water. The root- and coleoptile-length ratios of mesic ecotypes were much higher than that of the xeric ecotypes, except that there was no observable difference in coleoptile-length ratio at 100 mM NaCl. The mesic ecotype was more tolerant to salt than the xeric ecotype at the young seedling stage, and seedling salt tolerance was negatively correlated with caryopsis dormancy depth. Thus evolutionary background environments have had a strong effect on the intensity of caryopsis dormancy in wild barley. Through natural selection, wild barley has adapted to dry and hot environments by increasing dormancy but not young seedling salt tolerance.     

Genetic studies on the powdery mildew resistance of winter barley lines derived from Hordeum spontaneum accessions collected in Israel

The genetics of the powdery mildew resistance of 15 Hordeum spontaneum-derived winter barley lines were studied in testcrosses with selected cultivars carrying the MIa12 and MIa13 resistance alleles, in order to identify the inheritance of the resistance and to test for linkage with the MIa locus on chromosome 1H (5). A total of 27 genes were identified. Only one of these genes (in line 1–12 x Dura) could eventually be allelic to a gene previously identified in H. spontaneum Koch. A monofactorial dominant inheritance was identified in the majority of the lines. Three of the tested lines possessed recessively inherited genes and in one line a dominant and a recessive gene were identified. In respect to the reaction of the lines against European mildew cultures, lines with a bifactorially inherited resistance had a broader resistance spectrum than those with a monofactorial inheritance, while lines carrying recessive factors showed a moderately expressed resistance. In three cases a linkage with the MIa locus was found, while in two further lines a possible allelism to this locus was indicated by the absence of recombinant progeny plants. By using more than two isolates for linkage analysis, it was possible to identify additional genes for mildew resistance, reaching a maximum number of four genes in the same line. In some cases, a different inheritance was observed for the resistance of the same line against different isolates. It was assumed that different genes exist, each being effective against a different isolate.     

Inter-simple sequence repeat (ISSR) and RAPD variation among wild barley (Hordeum. vulgare subsp. spontaneum) populations from west Turkey

Inter-Simple Sequence Repeat (ISSR) and Randomly Amplified Polymorphic DNA (RAPD) markers were used to analyze genetic distance among H. vulgare subsp. spontaneum populations from west Turkey. Fifty-five RAPD and 10 ISSR primers were used to detect variation among sample. A total of 55 polymorphic loci were found using 65 primers. Two distinct cluster groups were clearly established among populations. The minimum variation was detected between Pinarbasi and Bornova (GD = 0.192) populations and the maximum was found between Icmeler and Aydin populations (GD = 0.926). As two dominant markers, RAPD and ISSRs are effective and promising marker systems for detecting genetic variation.     

Identification of new sources for resistance to powdery mildew in H. spontaneum-derived winter barley lines

Twenty four barley lines derived from the F ₇generation of crosses between two winter barley cultivars and different accessions of Hordeum spontaneum Koch collected in Israel were tested against a set of ten European and five Israeli powdery mildew cultures, possessing virulence genes which completely match the spectrum of known mildew resistance genes. The comparison of reaction patterns justified the conclusion that new genes for resistance have been conferred from H. spontaneum which also differ from genes previously identified in other wild barley accessions from Israel. Participation in the expression of the resistance reaction of one of the two barley cultivars used in the development of the lines is well documented in some cases. The majority of the lines was found to be highly resistant against all or almost all European isolates, while various kinds of reactions were observed against the Israeli cultures. The effective transfer of novel mildew resistance from H. spontaneum into winter barley confirms similar results with spring barley, indicating natural wild barley populations in Israel as a significant gene pool for yet unexploited mildew resistance in barley.     

Sources of Resistance to Whitefly (Bemisia spp.) in Wild Populations of Solanum lycopersicum var. Cerasiforme (Dunal) Spooner G.J. Anderson et R.K. Jansen in Northwestern Mexico

Genetic variability of wild populations, closely related to domesticated species, constitute important genetic resources for plant breeding programs. In this paper, we analysed the variation of eight wild populations of Solanum lycopersicum var. cerasiforme in a common garden experiment for levels of plant infestation by whitefly, leaf trichome density as a defensive character preventing infestation by whitefly, and the effect of whitefly incidence into vegetative and reproductive plant characters. Number of adults of whitefly was recorded in the eight wild populations of S. lycopersicum var. cerasiforme, one population of the wild species S. habrochaites (C-360), and one of a cultivated variety of S. lycopersicum (Rio Grande). There were significant differences among the wild populations of S. lycopersicum var. cerasiforme in the average level of whitefly incidence and trichome density. Cultivated tomatoes had the higher incidence of whiteflies ( = 7.50 ± 0.14) followed by plants of S. lycopersicum var. cerasiforme ( = 2.02 ± 0.92) and plants of S. habrochaites with the lowest incidence ( = 0.36 ± 0.35). Whitefly incidence was negatively correlated with trichome density (r = − 0.38, p < 0.0001), suggesting that trichomes deter or limit the establishment of whiteflies. Additionally, a significant negative effect of whitefly incidence along the growing season upon plant growth rate (number of branches and height) and fruit production was detected.     

Variability and Genetic Diversity for Gliadins in Natural Populations of Hordeum Chilense Roem. et Schult.

Hordeum chilense Roem. et Schult. is wild diploid barley that has been used for the synthesis of the new cereal, tritordeum (× Tritordeum Ascherson et Graebner). This species is distributed in Chile and Argentina where it is possible to find in natural populations. In this work, the gliadin fraction of the seed storage protein have been used for evaluating the genetic diversity in nine natural populations of H. chilense. The total diversity (Ht) in the nine populations was 0.879 (ranging from 0.926 for the ω-gliadins to 0.795 for the β-gliadins). Data showed that the 71.3% of this genetic diversity was between populations, whereas the 28.7% was within populations. This species is considered as self-pollinating, where gene flow within populations was mainly attributed to seed dispersal because of these materials appear distributed in cattle zones where the pasturing could be an efficient mechanism of dispersion.     

Sources of Resistance to Anthracnose (Colletotrichum truncatum) in Wild Lens Species

Lentil anthracnose (Colletotrichum truncatum (Schwein.) Andrus et W.D. Moore is a potential threat in many lentil (Lens culinaris Medik.) production regions of North America. In the lentil germplasm maintained in Germany and North America, 16 lines were reported to have resistance to race Ct1, but none has resistance reported to race Ct0. The objective of this study was to examine accessions of wild Lens species for their resistance to races Ct1 and Ct0 of lentil anthracnose. Five hundred and seventy-four wild accessions of six species and control lines were screened in two replications under both field and greenhouse conditions using a 1–9 scoring scale (1, highly resistant; 2–3, resistant; 4–5, moderately resistant; 6–7, susceptible; and 8–9, highly susceptible). Indianhead and PI 320937 were resistant while Eston and Pardina were susceptible to race Ct1 as expected. However, none of the check lines were resistant to race Ct0. Among the six Lens wild species tested, accessions of Lens ervoides (Brign.) Grande had the highest level of resistance, 3–5 to race Ct1 and Ct0 followed by L. lamottei Czefr. in the field and greenhouse. Lens orientalis (Boiss.), L. odemensis L., L. nigricans (M. Bieb.) Godron and L. tomentosus L. were highly susceptible, 8–9 to race Ct0 in the greenhouse. The highest frequency of resistance, especially in L. ervoides (Brign.) Grande, was found in accessions originating from Syria and Turkey. The usefulness of these L. ervoides (Brign.) Grande accessions as sources of resistance to the more virulent race of anthracnose in a lentil breeding program is discussed.     

Assessment of Genetic Relationships between Wild and Cultivated Mulberry (Morus) Species using PCR Based Markers

In order to formulate appropriate strategies for the conservation and utilization of the wild mulberry genetic resources available in India, a study was undertaken with 20 mulberry genotypes from the four different species. Seventeen intersimple sequence repeat primers were used to generate a total of 114 markers, of which 98 (85.96%) were polymorphic. Seven unique bands for Morus serrata Roxb. and one for both M. serrata Roxb. and Morus macroura Miq. were identified, of which one fragment has been sequenced and deposited in the EMBL-GeneBank (AJ-585512). The genetic dissimilarity coefficients varied from 0.078 to 0.530 among these genotypes and from 0.168 to 0.465 among the species. The dendrograms realized from these markers clustered the genotypes into three groups. The outermost group was M. serrata Roxb., which was followed by the group of M. macroura Miq. and the innermost group contained genotypes of Morus indica L. and Morus alba L. This intermixing of genotypes of M. indica and M. alba supports the view that M. indica is merely a synonym of M. alba. Distribution of the genotypes on a two-dimensional figure upon multidimensional scaling with ALSCAL program, further, confirmed the genetic divergence between the cultivated and wild mulberry groups. On the basis of the results a few potential wild mulberry genotypes were identified for its conservation and utilization in breeding programs to confer the stress tolerance to the cultivated varieties of mulberry.     

Evaluation of Genetic Diversity of Wild Rice (Oryza rufipogon Griff.) in Myanmar using Simple Sequence Repeats (SSRs)

As a part of an in situ survey of wild rice (Oryza rufipogon Griff.) in Myanmar (Burma), 16 strains of wild rice were collected, and analyzed for allelic diversity over 74 loci with simple sequence repeat (SSR) markers to obtain a basic information for their conservation. Three each of indica and japonica cultivars were added for a comparison. In the six cultivars and 16 strains of wild rice, three to 15 alleles were detected per locus with an average of 7.9. The wild rice revealed a large number of unique alleles throughout their chromosomes with much wider ranges of variation than those detected in the six cultivars of O. sativa L.. The alleles found in the wild rice were classified into those specific to wild rice, common to wild rice and cultivars, and those similar to indica or japonica cultivars. According to the classification, the genotype of each of the 16 strains of wild rice was schematically depicted. The genetic variation among individual strains within a collection site was larger than the variation among the collection sites.     

Powdery Mildew Resistance in a Collection of Chinese Barley Varieties

One hundred and forty-seven Chinese barley varieties maintained at the Gene Bank of the National Barley Improvement Centre, Zhejiang, and 84 progenies from these varieties were tested at the seedling stage for their reaction to 32 selected pathotypes of Blumeria graminis f. sp. hordei. Eighteen resistance spectra were identified comprising single or combined resistances from eight known (Ml(Bw), Ml(Ch), Mla7, Mla8, Mla9, Mla13, MlaRu4 and Mlg) and six unknown resistance genes. The most frequent gene was Ml(Bw), which was found in 69 varieties and previously detected in only a few European winter barley varieties. The genes Mla8 and Ml(Ch) were also often present, but other resistance genes were rare. After inoculation, considerably fewer pathogen colonies were observed in ‘Aiganqi’ and one line of ‘Tong5’. Twenty varieties were composed of lines with different resistance genes. China is likely to be a region of origin of the genes Ml(Bw), Mla7, as well as three unknown genes found in original landraces and perhaps another three unknown genes detected in cultivars bred in China. The resistances of varieties from the Zhejiang province and those originating from 11 other Chinese provinces were quite different. Unfortunately, none of the varieties are promising sources of resistance to powdery mildew and China does not seem to be a region suitable for identifying such sources.     

Vigna vexillata (L.) A. Rich. Cultivated as a Root Crop in Bali and Timor

Vigna vexillata is considered as a pantropical distributed wild species closely related to the cowpea (Vigna uniculata) and adapted to infertile soils. The species is occasionally used for its storage roots as well as forage and erosion control plant. The objective of this study was to pursue personal communications that V. vexillata has be transformed into a cultivar in Indonesia. Seven Indonesian islands were visited (Java, Bali, Sumba, Flores, Timor, Kalimantan and Sulawesi). Wild V. vexillata was found in Java, Bali, Sumba, Flores and Timor, occasionally used as wild ‘forest food’, and cultivated V. vexillata was found in Bali and Timor, Seven cultivars were collected and two of these were made available for the National Botanic Garden of Belgium. The cultivars were primarily cultivated for their storage roots, propagated by seeds, required no scarified seeds for good germination and formed non-dehiscent pods. On-farm root yields of 18–30 t ha⁻¹ and seed yields of 0.7–1.2 t ha⁻¹ were estimated. A brief discussion about the common names of wild V. vexillata is given and it is proposed to use the name ‘tuber cowpea’ for V. vexillata accessions which are cultivated for their storage roots. The material may be of interest for regions, where the growing season is too short or the rainfall too low for sweet potato and cassava as well as to incorporate cultivar characteristics into wild V. vexillata accessions which are used for their storage roots.     

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.     

Vertical distribution of nematodes in arable soil under grass (Festuca pratensis) and barley (Hordeum distichum)

Summary The connection between faunal composition and soil factors is discussed in this study on vertical distribution of soil nematodes under grass and barley. The investigation was undertaken on the field site of a Swedish integrated research project Ecology of Arable Land. The Role of Organisms in Nitrogen Cycling. Higher nematode number (7.6 × 10⁶ m^–2) and biomass (340 mg dry wt. m^–2) were found under a 4-year-old grass ley than under barley (5.0 × 10⁶ m^–2; biomass, 136 mg dry wt. m^–2). Plant feeders dominated under the grass ley (3.2 × 10⁶ m^–2 whereas under barley the bacterial feeders (2.4 × 10⁶ m^–2) were the most abundant feeding group. Number, biomass, mean individual size and various community parameters indicated a much better nutritive situation for the nematodes under grass than under barley. The vertical changes in the various parameters, including proportion of egg-carrying females, indicated an increasing food shortage for the nematode populations towards greater depths. In the top soil, predation could be an important factor in regulating nematode number.Dedicated to the late Prof. Dr. M.S. Ghilarov     

Variation of Agro-morphological Characters in Moroccan Barley Landraces Under Near Optimal and Drought Conditions

In many areas of North Africa, barley is often the only possible rainfed crop. In these regions water deficit is the primary constraint affecting crop production. Twenty barley landraces collected from different localities in south Morocco and four modern varieties were characterized in two field experiments, one under well-irrigated and one under limited-irrigated conditions. Nine agro-morphological characters were evaluated: Plant height, tiller number per plant, number of grains per spike, number of spikes per plant, spike weight, spike length, plant weight (PW), number of internodes of rachis (NIR), and length of the last internode of rachis. The correlation coefficients among characters were nearly the same in the well- and limited-irrigated experiment. Under limited-irrigated conditions, plant growth was significantly decreased as measured by all characters except NIR, which was unaffected. The percentage of reduction, ranging from 80.08% to 5.82%, was recorded on PW and NIR, respectively. The injury index ranging from 4.02 to 0.06 was recorded on PW and NIR, respectively. Using discriminant analysis the genotypes were arranged in three, clearly separated groups that varied in their tolerance to drought stress.     

利用三重测交群体剖析玉米苗期性状杂种优势的遗传学基础

为了探讨玉米苗期性状及其杂种优势形成的遗传学基础,以强优势玉米(Zea maysL.)杂交种组合豫玉22及其重组近交系为基础材料,采用三重测交(triple testcross,TTC)遗传交配设计,组配了包含312个测交后代的TTC群体,通过复合区间作图法检测到了30个控制发芽后第4天的最长根长、苗高、初生根数、根干重及叶干重的QTLs,并且在第2、3和7染色体上存在4个同时控制不同苗期性状的QTL区域。分析发现,在利用Z1和Z2数据定位出的22个QTLs中,以超显性位点最多(11个),加性(5个)和部分显性较少(5个),而显性最少(1个)。另外,还检测到8个QTLs与遗传背景之间的互作和16对不同标记间的互作。据此,我们提出超显性和上位性是玉米苗期性状及其杂种优势形成的主要遗传学基础。关键词玉米,苗期性状,三重测交,杂种优势,QTL定位     

Inheritance of Seed Shattering in Lolium temulentum and L. persicum Hybrids

Lolium temulentum and L. persicum are non-crop species found in wheat and barley fields. L. temulentum has non-shattering seeds like the associated grain crops, whereas L. persicum seeds shatter after maturity. We analyzed the inheritance mode of shattering tendency by comparing the F₂ of L. temulentum and L. persicum hybrids. The selfed progeny of L. temulentum and L. persicum exhibited typical non-shattering (1.6% shattering) and shattering phenotypes (70.8%), respectively. F₁ hybrids of L. temulentum×L. persicum and its reciprocals were of the shattering phenotype (71.4% and 63.8%, respectively), indicating that shattering is dominant to non-shattering. When the phenotype ratio was assumed to be 15 shattering: 1 non-shattering, the χ² value for F₂ segregation was not significant at the 5% level, and the reciprocal effect was not detected. This indicates that the non-shattering tendency is controlled by two recessive genes. The two-gene inheritance model of shattering tendency suggests that harvest is the selector for seed shattering in cultivated fields, thus the alternative tendency for non-shattering seeds of L. temulentum or shattering of L. persicum would be better adapted to cultivated fields.