Spontaneum Populations Research Articles

The Occurrence of Barley (Hordeum vulgare) and Wild Barley (H. spontaneum) Leaf Diseases in Batman Province and Surrounding Areas of Turkey

Barley ( Hordeum vulgare ) is an important crop in Turkey. In this study, 37 barley fields in Batman central district and Beşiri (Batman), Gercüş (Batman), Hasankeyf (Batman), Kozluk (Batman), Sason (Batman), Kocaköy (Diyarbakır), Kurtalan (Siirt), and Midyat (Mardin) districts were examined for the presence of leaf diseases. In addition, 24 naturally grown wild barley ( H. spontaneum ) populations in Batman central district and Beşiri, Hasankeyf, Kurtalan and Midyat districts were inspected for the presence of leaf diseases. In barley fields, scald caused by the Rhynchosporium commune was the most common diseases followed by spot form of net blotch caused by Drechslera teres f. maculata , barley stripe caused by Drechslera graminea , net form of net blotch caused by Drechslera teres f. teres , spot blotch caused by Cochliobolus sativus , powdery mildew caused by Blumeria graminis f. sp. hordei and brown rust caused by Puccinia hordei . Among the Hordeum spontaneum populations the most common disease was scald, followed by spot form of net blotch, net form of net blotch, powdery mildew, and brown rust.

WILD SUGARCANE - SACCHARUM SP. GERMPLASM COLLECTION IN THE STATES OF PUNJAB AND HARYANA, INDIA

The Indian sub-continent harbours a great wealth of diversity of Saccharum and its related genera. Several targeted expeditions were conducted to collect the range of diversity present in Saccharum complex from diverse parts of the country. But the north western states of Punjab and Haryana were hitherto unexplored. A targeted exploration was conducted during 2016 to collect the entire range of variability present in Saccharum complex. Collections were made from a wide range of habitats and altitudes. The Saccharum spontaneum was present mostly along the river banks and river beds and showed considerable variability for morphological characteristics. S. spontaneum was distributed throughout both the states and collections could be made from all the districts and union territory of Chandigarh. A total of 104 accessions comprising of 100 Saccharum spontaneum and four Erinathus sp. have been collected. They were occurring mostly as small population except in the canal bunds where larger population was noticed. Plant height ranged from 0.46 m to 4.5 m. Variation for leaf and stem characters were observed from the collections. Statistical analysis of altitude of the collection sites with plant characters showed no significant association. Correlation analysis among plant characters showed the highest correlation coefficient between plant height and internode thickness. Clustering of Haryana, Chandigarh and Punjab Saccharum spontaneum collections through complete linkage clustering resulted in five clear clusters among the collections. Geographic distance and environmental factors including local climates interplay in the formation of the genetic structure and geographic patterns of the native S. spontaneum populations. Haryana and Punjab state were not much explored during earlier period and hence the collection would add more diversity to the germplasm maintained. In addition to the 100 S. spontaneum, four Erianthus sp. were collected during the exploration which will enrich the gene pool.

SRAP analysis of genetic diversity of nine native populations of wild sugarcane, Saccharum spontaneum, from Sichuan, China

Saccharum spontaneum is a wild sugarcane species that is native to and widely distributed in China. It has been extensively used in sugarcane breeding programs, and is being tested for the development of bioenergy cultivars. In order to provide basic information for the exploitation of this species, we analyzed genetic variation among and within native S. spontaneum populations collected from Sichuan, China. Eighty plants from nine native populations were sampled. Twenty-one sequence-related amplified polymorphism primer pairs generated 235 clearly scorable bands, of which 185 were polymorphic (78.7%). Nei's genetic diversity was 0.2801 and Shannon's information index was 0.4155 across the populations. Genetic diversity parameters, G(ST) value (0.2088) and N(m) value (1.8944), showed that the genetic variation within populations was greater than that among populations. In the cluster analysis, one major grouping was formed by populations from Ya'an and another one by populations from Sichuan basin; a population from Baoxing formed a single cluster. In order to fully comprehend the genetic diversity of cold-tolerant local germplasm in this species, germplasm should be collected from the heterogeneous environments along the northern regions of this species' distribution. The germplasm that we collected should be a valuable resource for Saccharum breeding.

Natural Variation in Grain Selenium Concentration of Wild Barley, Hordeum spontaneum, Populations from Israel

Wild barley (Hordeum spontaneum), the progenitor of cultivated barley, is an important genetic resource for cereal improvement. Selenium (Se) is an essential trace mineral for humans and animals with antioxidant, anticancer, antiarthropathy, and antiviral effects. In the current study, the grain Se concentration (GSeC) of 92 H. spontaneum genotypes collected from nine populations representing different habitats in Israel was investigated in the central area of Guizhou Province, China. Remarkable variations in GSeC were found between and within populations, ranging from 0 to 0.387 mg kg−1 among the 92 genotypes with an average of 0.047 mg kg−1. Genotype 20_C from the Sede Boqer population had the highest GSeC, while genotype 25_1 from the Atlit population had the lowest. The mean value of GSeC in each population varied from 0.010 to 0.105 mg kg−1. The coefficient of variation for each population ranged from 12% to 163%. Significant correlations were found between GSeC and 12 ecogeographical factors out of 14 studied. Habitat soil type also significantly affected GSeC. The wild barley exhibited wider GSeC ranges and greater diversity than its cultivated counterparts. The higher Se grain concentrations found in H. spontaneum populations suggest that wild barley germplasm confer higher abilities for Se uptake and accumulation, which can be used for genetic studies of barley nutritional value and for further improvement of domesticated cereals.

Genetic relationships among South-East Turkey wild barley populations and sampling strategies of Hordeum spontaneum

To assess the genetic diversity and the genetic structure of Turkish wild barley (Hordeum spontaneum Tell.) populations, 76 genotypes from ten ecologically and geographically different locations were analyzed by means of amplified fragment length polymorphism (AFLP) markers. Five primer combinations produced 187 scorable bands, of which 117 (62.6%) were polymorphic. Several population-specific and genotype-specific bands were identified, which differentiate populations or genotypes. Genetic distance, determined by Nei's distance coefficient, varied from 0.07 to 0.21 with an average of 0.13. In the UPGMA dendrogram based on Nei genetic distances, the Hordeum spontaneum populations were separated into two major clusters. Genetic diversity was larger among (68%) than within (32%) populations. Eight AFLP bands were strongly correlated to the altitude of the collecting site, while no clear trend was detected between geographical origin and genetic diversity. Our results strongly suggest the need for a change in Hordeum spontaneum sampling strategy: more populations, rather then more individuals within population, should be sampled to appraise and safeguard genetic diversity in the wild barley gene pool.

Genomic microsatellite adaptive divergence of wild barley by microclimatic stress in ‘Evolution Canyon’, Israel

We examined diversity levels and patterns of 19 nuclear microsatellites and four chloroplast microsatellites in 275 genotypes of wild barley Hordeum spontaneum, in seven stations at the ‘Evolution Canyon’ (EC) microsite, Lower Nahal Oren, Mt. Carmel, Israel. EC is sharply subdivided ecologically into a tropical savannoid, ‘African’, xeric, south-facing slope (SFS) abutting the temperate, dense, liveoak, brushwood, ‘European’, mesic, north-facing slope (NFS). We found the following. (i) 17 of 19 (89.5%) nuDNA simple sequence repeats (SSRs) were polymorphic across all seven subpopulations and three chDNA SSRs were polymorphic. (ii) A total of 216 nuDNA SSR alleles, with a maximum of 23 alleles in a nuclear locus, and ten chDNA SSRs, with a maximum of four alleles in a locus, were registered. (iii) There were striking and significant inter- and intraslope diversities, based on the 19 nuDNA SSRs, climaxing with a remarkable genetic distance between the mid-slope stations on opposite slopes (DA = 0.481), across a distance of 200 m. This genetic distance is as large as that between the H. spontaneum populations of Jerusalem and Sede Boqer, which are separated by 100 km (× 500 larger in transect length). (iv) Slope-unique alleles (103 = 45.6%) were higher on the ‘European’ than on the ‘African’ slope. Slope-specific (predominant) alleles (17) were equal on opposite slopes. (v) nuDNA SSR gene diversity was higher on the ‘European’ slope and the opposite was found for the chDNA SSR. (vi) nuDNA SSR genic differentiation was very high between opposite slopes, with Gst = 0.187; for chDNA SSR this value was 0.127. Our results are inexplicable by stochastic processes and suggest that: (i) microclimatic diversifying selection is the major evolutionary, fast-acting, interslope force, overriding migration and drift, and (ii) ecological stress can generate local, regional and global adaptive patterns, suggesting that natural selection is a major differentiating force of both coding and noncoding SSRs linking micro- and macroevolutionary processes. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 84, 205–224.

Can a Genetic Correlation with Seed Mass Constrain Adaptive Evolution of Seedling Desiccation Tolerance in Wild Barley?

Very young seedlings of wild barley Hordeum spontaneum have the ability to survive extended periods of severe drought. This desiccation tolerance is considered an adaptation to the rain‐limited and unpredictable habitats that the species occupies. Genetic variation has been observed for this trait, but the limited evidence to date does not consistently show that genotypes from more xeric populations have better desiccation tolerance. As large seed endosperm volume may buffer the desiccating seedling from drought stress, we explored the hypothesis that tolerance to temporary but severe drought is affected by seed mass. We crossed a big‐seeded with a small‐seeded H. spontaneum genotype and measured seed mass and seedling survival rates after 6‐ddesiccation in 140 F4 progeny families. A positive correlation was observed between family mean scores of the two traits. At the genetic level, this indicated that at least some genes underlying variation in the two traits overlapped (or show close chromosomal linkage), which is inevitable if seed mass causally affects desiccation tolerance. Quantitative Trait Loci (QTL) analysis, which can identify chromosome regions responsible for trait variation by exploring associations between trait expression and genetic markers dispersed over the genome, did not confirm this hypothesis of shared genetic control. Despite the lack of QTL evidence, the observed genetic association between seed mass and desiccation tolerance indicates that the two traits are not fully independent, implying that selection targeting one trait will cause a correlated response in the other. We discuss this finding in the context of adaptive differentiation of H. spontaneum populations, which is thought to involve selection of increasingly smaller seeds along a gradient of decreasing predictability and amount of annual precipitation.

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.

Microsatellite diversity associated with ecological factors in Hordeum spontaneum populations in Israel.

Microsatellite diversity at 18 loci was analysed in 94 individual plants of 10 wild barley, Hordeum spontaneum (C. Koch) Thell., populations sampled from Israel across a southward transect of increasing aridity. Allelic distribution in populations was not distributed randomly. Estimates of mean gene diversity were highest in stressful arid-hot environments. Sixty-four per cent of the genetic variation was partitioned within populations and 36% between populations. Associations between ecogeographical variables and gene diversity, H(e), were established in nine microsatellite loci. By employing principle component analysis we reduced the number of ecogeographical variables to three principal components including water factors, temperature and geography. At three loci, stepwise multiple regression analysis explained significantly the gene diversity by a single principal component (water factors). Based on these observations it is suggested that simple sequence repeats are not necessarily biologically neutral.

Detection and analysis of genetic variation in Hordeum spontaneum populations from Israel using RAPD markers

Randomly amplified polymorphic DNA (RAPD) markers were used to analyse genetic diversity within and between Hordeum spontaneum populations sampled from Israel. Nei's index of genetic differentiation was used to partition diversity into within and between population components. Fifty-seven per cent of the variation detected was partitioned within 10 H. spontaneum populations. Using principal component and multiple regression analysis, part of the variation detected between populations was seen to be associated with certain ecogeographical factors. Fifty-eight per cent of the distribution of the phenotypic frequencies of three RAPD phenotypes detected using a single primer in 20 H. spontaneum populations could be accounted for by four ecogeographical variables, suggesting adaptive variation at certain RAPD loci.

Grain isozyme and ribosomal DNA variability in Hordeum spontaneum populations from Israel

Grain isozyme and ribosomal DNA (rDNA) variability was examined in Hordeum spontaneum populations sampled from 27 geographical sites in Israel. Considerable phenotypic variability was observed with variants of ADH1, EST3, EST10, BMY1 and WSP detected, which are not available in the H. vulgare gene pool. Seven new rDNA phenotypes were detected in the H. spontaneum populations. Shannon's index of diversity was used to partition the total phenotypic variation into between and within population components. Most of the variation occurred between H. spontaneum populations. The distribution of both grain isozyme and rDNA phenotypes was non-random and correlated with a range of ecogeographical factors. In particular, the G phenotype of BMY1 was restricted to the Negev Desert and Dead Sea regions of Israel. Over 78% of the variation in the frequency of this particular phenotype could be explained by the number of rainy days per year and mean temperature in January. This suggests that variation at this locus or at loci linked to it may be of adaptive significance and of value in the introgression of genes controlling abiotic stress tolerance from H. spontaneum into the H. vulgare gene pool.

Lactate Dehydrogenase lsozymes in Barley: Polymorphism and Genetic Basis

Hypoxia induces a set of five lactate dehydrogenase (LDH) isozymes in roots of barley (Hordeum vulgare) and most lines of H. spontaneum, the wild progenitor. Barley LDH isozymes are tetramers. A survey of 30 diverse H. spontaneum lines identified three electrophoretic LDH variants; in two variants the five isozymes were displaced as a group (fast or slow) relative to the normal set, whereas in the third there was only one major lsozyme. Immunoblot analysis established that the latter variant lacked LDH protein as well as enzyme activity from the normal band positions. All variants bred true for LDH phenotype. In crosses among variants, the F1 banding patterns were consistent with those predicted by a model in which the products of two Ldh loci associate freely in all possible combinations. However, no recombinants were found in the F2 progenies, and F2 ratios of parental to F1-hybrid phenotypes were 1:2:1. These data indicate that barley has two closely linked Ldh genes, each with several alleles that have been fixed in particular combinations in natural H. spontaneum populations.

Correlation of ecological factors and allozymic variations with resistance toErysiphe graminis hordei inHordeum spontaneum in Israel: Patterns and application

The association of ecological factors and allozymic markers of wild barley,Hordeum spontaneum, with genotypes varying in resistance to 3 cultures of the pathogenErysiphe graminis hordei, which incites the disease powdery mildew of barley, were explored theoretically and practically. The study involved 275 accessions comprising 16 populations largely representing the ecological range ofH. spontaneum in Israel. From earlier studies of allozymic variation and disease resistance it now becomes apparent that genetic polymorphisms for resistance toE. graminis hordei are structured geographically, and are predictable by climatic as well as allozymic variables. Three-variable combinations of temperature and water factors explain significantly 0.32 of the spatial variance in disease resistance between localities. Also, several allozyme genotypes, singly or in combination, are significantly associated with disease resistance. A high correlation was found between the standard deviation of infection types of the culture of the pathogen from Israel, and allozymic polymorphism,P (rs = 0.86, p < 0.001). Consequently, the IsraelH. spontaneum populations, growing in the center of diversity of the species, contain large amounts of unexploited disease resistance polymorphism. These could be effectively screened and utilized for producing resistant barley varieties by using ecological factors and allozymic variants as guidelines.

Cytoplasmic male sterility in barley

The associations between seedling reactions to three fungal pathogens (Puccinia hordei, Pyrenophora teres, and Rhynchosporium secalis) or between adult plant reaction to Rh. secalis and the male fertility restoration ability of msml cytoplasm were studied in about 100 accessions of Hordeum spontaneum. Significant differences in the severity of infection between classes of restoration ability were observed with two cultures of P. hordei (751 and 7,649) and with Rh. secalis on adult plants in the field. The cultures 7,432, 751 and 7,649 of P. hordei showed significant positive correlations between infection severity and restoration percentage. The culture 7,620 of P. hordei displayed a significant negative correlation. Rh. secalis (cultures 492A and 531 combined) on seedlings and the natural field infection in the 1978 season showed significant positive correlations. The accession class with the partial restoration ability of 0.1 to 5.0% of the four arbitrary classes (0.0, 0.1-5.0, 5.1-55.0, and 90.1-100%), displayed the lowest mean severity of infection in six of the eleven tests. Some frequently appearing races of these pathogens may operate as selective agents in the maintenance of restoration ability in the original spontaneum populations.