首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
Summary In a collaborative effort between the USDA-ARS and CAAS, 50 accessions each of perennial Triticeae held at the Forage and Range Research Laboratory, Logan, Utah, U.S.A. and the Institute of Crop Germplasm Resources, Beijing, People's Republic of China were exchanged. Eighty six and 85 accessions of these germplasms were screened for powdery mildew (caused by Erysiphe graminis DC) and barley yellow dwarf virus (BYDV) strain GPV, respectively. Fifty seven and 72 accessions had resistance to powdery mildew and BYDV, respectively. These materials are valuable genetic resources for breeding disease resistances in three of the major cereal crops — wheat, barley, and rye.Abbreviations BYDV barley yellow dwarf virus - ELISA enzyme-linked immunosorbent assay  相似文献   

2.
Abstract

The relative frequency of three viruses causing barley yellow dwarf disease (BYD) was assessed in spring cereals and pasture grasses at two regions in Latvia in 2000–2002. A total of 2589 leaf samples (367 from spring oats, 743 from spring barley, 1479 from predominant grass species) were collected from 44 fields of spring oats, 84 fields of spring barley, and 26 pastures. We found that isolates of barley yellow dwarf virus-PAV (BYDV-PAV), barley yellow dwarf virus-MAV (BYDV-MAV) and cereal yellow dwarf virus-RPV (CYDV-RPV) were present in these samples of spring cereals and pasture grasses. The most common isolates of barley yellow dwarf virus were BYDV-PAV and BYDV-MAV in both grasses and cereals, but there was a great difference between years and regions. The proportion of BYD symptomatic cereal samples that reacted positively in TAS-ELISA test was 9 to 15%. The overall BYDV/CYDV incidence in pasture grasses ranged from 2 to 19%. The incidence of BYDV/CYDV infection was higher in Festuca elatior than in other grass species. Isolates of CYDV-RPV were rather rare: only found in Lolium perenne and Dactylis glomerata among six grass species tested and more frequently in barley than oats. This paper reports the first quantitative survey of selected BYD-causing viruses in spring cereals and pasture grasses in Latvia and in the Baltic states. We conclude that three selected virus species are prevalent in spring cereals and pasture grasses in Latvia, although with great variation between years. Further studies are needed to obtain knowledge of the most critical factors that determine these fluctuations.  相似文献   

3.
Iwateyamanashi (Pyrus ussuriensis var. aromatica) is one of the Pyrus species which grows wild in Japan. The number of Iwateyamanashi trees has been decreasing, so conservation and evaluation is urgently needed. Over 500 accessions of Pyrus species collected from Iwate in northern Tohoku region are maintained at Kobe University as an Iwateyamanashi germplasm collection. In order to investigate the genetic diversity, five SSR (simple sequence repeat) markers, developed from Japanese and European pear were examined for 86 Pyrus individuals including 58 accessions from Iwate. These SSR loci could discriminate between all the Iwate accessions except for 10 that bear seedless fruit, as well as determine the genetic diversity in Iwateyamanashi germplasms. High levels of variation were detected in 41 alleles and the mean observed heterozygosity across 5 loci was 0.50 for the Iwate accessions. Seedless accessions sharing identical SSR genotype with the local pear variety “Iwatetanenashi” were supposed to have been propagated vegetatively via grafting. In an UPGMA phenogram, Japanese pear varieties (P. pyrifolia) were clustered into two groups with some Iwate accessions including seedless ones. Another 38 Iwate accessions were not clustered clearly, and there was no clear relationship between these accessions and geographical distribution or morphological characters. Allele frequency revealed that the Iwate accessions were genetically more divergent than the Japanese pear varieties. Most Japanese pears possessed a 219 bp deletion at a spacer region between the accD and psaI genes in the chloroplast DNA (cpDNA), but other Pyrus species and two Iwateyamanashi trees did not. In the Iwate accessions, 79.3% had a deletion type cpDNA and others had a standard type cpDNA without deletion. These results are indicative of the wide range of genetic diversity in the Iwate accessions which include Japanese pear varieties. A combination of SSR and cpDNA analyses revealed high heterogeneity in Iwateyamanashi and coexistence of Iwateyamanashi and hybrid progeny with P. pyrifolia. These could be reasons for the wide range of continuous morphological variation described previously.  相似文献   

4.
The conservation and utilization of allied gene resources is vital for the improvement of crop species. Rubber has been an undeniably beneficial commodity for the past 100 years. Progress in yield improvement over 70 years resulted in primary and hybrid clones with exceptional yielding abilities. The extension of Hevea to marginal areas necessitated breeding of new clones with resistance to environmental constraints. India, China, Brazil, Thailand, Côte d'Ivoire and Vietnam have marginal environments with single or multiple constraints such as low temperature, wind, higher altitude, moisture deficit and diseases. Allied species and accessions from the Brazil Amazonia can be integrated into such breeding programmes. Many of these clones are resultant of natural interspecific hybridizations. Also, allied species are excellent resources of timber. Molecular interventions revealed mtDNA of modern clones are highly conserved contributed by only two clones (PB 56 and Tjir 1). Nuclear DNA is highly divergent due to breeding and selection under varied geo-climates. The adaptation of allied species and wild accessions under a wide range of environments of Brazil is promising as a source of variation for breeding, and enables selection of clones for specific marginal areas.  相似文献   

5.
The Colorado Potato Beetle is a serious pest of the cultivated potato. Natural resistance has been found in a few wild species, including Solanum chacoense Bitter, in which the resistance is attributed to the presence of leptine glycoalkaloids. Production and accumulation of these compounds within S. chacoense varies widely and appears to be inherited in a quantitative fashion, but high leptine-producing clones occur rarely. In the present study, 15 different accessions from various locations and altitudes of origin within central to northern Argentina and Paraguay were analyzed for foliar glycoalkaloid (leptine, leptinine, solanine, chaconine) content. The objective was to infer the frequency of leptine production in ecogeographically distinct S. chacoense accessions, and to ascertain any possible association between leptine levels/concentrations and ecogeographical location. Leptines were detected in 8 of the 15 accessions, and the amounts within each accession varied widely. Most of the leptine-containing accessions originated from western Argentina except two in province Córdoba in central Argentina. There was no relationship between elevational level and leptine, but there was a negative trend with total glycoalkaloids (TGA) and elevation, due to solanine and chaconine levels which decreased with increasing elevation. In addition, nine unidentified, putative glycoalkaloids were detected, in very high proportions in some individuals and accessions. This study raises interesting questions about glycoalkaloid distribution, helps provide direction for new avenues of leptine and glycoalkaloid research, and proposes a systematic, ecogeographically based method for bioprospecting genes controlling rare plant secondary compounds.  相似文献   

6.
The collection, identification and maintenance of genebank accessions of the genus Trifolium is a major task because of the large number of genera and their occasional morphological similarity. We investigated whether the measurement of nuclear DNA content can serve as an additional criterion for identification of mislabeled accessions. Relative nuclear DNA content was determined by flow cytometry measurements for a total of 151 genebank accessions of 23 Trifolium species with notable agronomical value. Among 23 species analyzed, 15 were found to possess a uniform relative nuclear DNA content, with intraspecific variability of the majority of analyzed species lower than 5%. Within six Trifolium species, 1–2 atypical accessions with outstanding differences in relative DNA content, chromosome number and morphological features were found. In T. hybridum and partially in T. ambiguum these outstanding differences could be ascribed to variations in accession ploidy level. For the remaining atypical accessions, the determined nuclear DNA content, chromosome number and morphological features were not related to those characteristic of the species. Additionally taxonomic identity of atypical accessions was determined using ITS region sequencing and morphological observations. We propose flow cytometric measurements of nuclear DNA content as simple and reliable technique which can be used at seedling stage to verify identity and genetic stability of Trifolium genebank accessions.  相似文献   

7.
Soybean (Glycine max (L.) Merr.) has a long planting history in both China and Japan. In order to investigate the genetic relationship between Chinese and Japanese soybeans, 205 Chinese soybean accessions, that represent the seven different soybean ecotypes, and 39 Japanese soybean accessions from various regions were analyzed by using 46 SSR loci. In total 745 alleles were detected with an average allele number of 16.2 per locus. The allelic frequencies varied from 0.002 to 0.554 with an average of 0.06. Cluster analysis with UPGMA separated the Chinese accessions from Japanese accessions, suggesting that soybean in these two countries form different gene pools. When comparing the Japanese soybean with that from seven different Chinese soybean ecotypes, 164–200 alleles were specific to the Chinese accessions and 64–112 specific to the Japanese accessions. The comparison of SSRs diversity revealed that accessions from China exhibited more genetic diversity than those from Japan. The data were analyzed to resolve the genetic structure and to interpret the evolutionary relationships between groups. Three distinct groups were identified, corresponding to Japanese soybean, Northern China soybean, Southern China soybean and a mixed group in which most accessions were from central China. The results indicate that accessions from Japan are distinct from Chinese ones, and Japanese accessions had more close relationship with Chinese northeast spring and southern spring ecotypes. We further analyzed five agronomic trait-related SSR loci and found that the preponderant alleles are different in Chinese and Japanese soybean. Our study provides important insights into further utilization of Japanese soybean in Chinese soybean breeding.  相似文献   

8.
Radix Campanumoeae (C. javanica Bl.) has been used in Miao herbal medicine to treat neurasthenia and consumptive disease for hundreds of years. Though Radix Campanumoeae shows great potential for utilization in medical studies, this herb crop has not been cultivated industrially in China. Many species in the Campanumoea genus are similar in phenotype; therefore, a karyotypic study would prove useful for clearly distinguishing Radix Campanumoeae from related species within the same genus, for germplasm preservation and for breeding Radix Campanumoeae. 10 accessions of four species in this genus and 5 accessions in 5 relative genera from SCSB were used for karyotype determination. The results showed a karyotype of 2n = 16 = 2m + 12sm + 1st in Campanumoea, and a karyotype of 2n = 18 = 6 m + 12sm in Cyclocodon. Based on the chromosome number and the karyotypic formula, we suggest that the Campanumoea genus can be divided into two genera, which is in agreement with results observed from pollen morphology and from homological usage in Chinese herbal medicine. The chromosome length in C. javanica subsp. javanica and C. javanica subsp. japonica Makino, ranged from 2.24 to 1.38 μm and 2.04 to 1.31 μm, respectively; and their haploid sets were almost identical (13.15 and 13.16 μm, respectively). This indicates that chromosomal rearrangements occur within chromosomes IV, V and VII without a net gain or loss of genetic material.  相似文献   

9.
The identification of seedling resistance to white rust of crucifers was performed in a screening of a B. oleracea core collection with 400 accessions representing the genetic and geographic diversity of the species. Fifty seedlings per accession were tested against the Portuguese isolate Ac502 using the methodology and evaluation procedures developed by and . The percentage of resistant seedlings (%R) and the conventional rating criteria of the mean Disease Index (DI) based on the two different evaluation procedures of disease expression used, were compared and adopted as the criteria to rank the accessions for their interest as sources of resistance. A great variability of reactions was found between and within accessions of the core collection, ranging from complete resistance to full susceptibility. Sources of resistance were found namely among the cauliflowers, broccoli and tronchuda cabbages gene pools. Forty-seven accessions presented at least 20% of resistant seedlings. Nine accessions (the kales INRA18 and INRA62, the cauliflowers HRI4856, HRI4866 and HRI5424, the loose-head cabbage HRI11555, the savoy cabbage BRA848, the black broccoli HRI6318 and the Portuguese tronchuda cabbage ISA207) presented 50–78% of resistant seedlings and so they should be considered as potential and useful sources for direct use in breeding programs for white rust resistance. Fourteen inbred lines, representing the full range of disease expression, derived from resistant accessions of the core collection were also tested for resistance to other two Portuguese isolates (Ac503 and Ac504) and to a UK isolate. The results provided no evidence of differential reaction to the A. candida isolates tested.  相似文献   

10.
Thailand is a center of diversity for section Angulares of the Asian Vigna (genus Vigna subgenus Ceratotropis) and 4 Vigna species are cultivated in Thailand. Using newly collected wild and cultivated germplasm of Vigna from Thailand and outgroup accessions AFLP analysis was conducted to clarify genetic diversity and relationships. The results suggest that cultivated V. umbellata and V. mungo evolved from wild relatives in a single domestication event. Vigna umbellata is poorly differentiated from its wild and weedy relatives compared to V. mungo. Results suggest northern Thailand and the neighboring Shan state, Myanmar, is the probable center of domestication for V. umbellata as wild accessions from this area and cultivated rice bean from a wide area in Asia are not greatly diverged. Vigna minima, V. tenuicaulis and V. exilis accessions in Thailand are well differentiated with considerable intra-specific variation. Vigna hirtella consists of two well differentiated subgroups, suggesting taxonomic revision may be necessary. Close genetic relationships between V. radiata and V. grandiflora, and between V. mungo and V. trinervia are confirmed. Naturally growing V. mungo populations in northern Thailand appear to be true wild species as they are well differentiated from Indian wild and Thai cultivated populations. The origin of naturally growing cowpea in Thailand needs to be further studied using a more comprehensive set of materials. This study clarifies inter and intra-specific genetic diversity and inter species relationships of Thai Vigna species.  相似文献   

11.
Choix, a plant in the tribe Maydeae of the grass family, has been cultivated in Asia for several thousand years. It is a potential gene resource for improvement of other cereal crops because of its nutritional value and tolerance to stress. Genetic variation and relationships among 21 Choix lachryma-jobi L. accessions were characterized by random amplified polymorphic DNA (RAPD) markers. A total of 205 DNA fragments across all materials were amplified with 31 random primers, averaging 6.61 per primer. Among amplified fragments, 115 showed polymorphism averaging 3.71 per primer. Of amplified markers, 56.1% were polymorphic, indicating considerable variation at the DNA level among these accessions. Some fragments were accession-specific. Pair-wise genetic similarity (GS) among 21 accessions ranged from 0.809 to 0.301. The 21 accessions clustered into two major groups. Three exotic Choix accessions clustered together. Three other Choix accessions, collected from Guangxi, China, clustered into a cohesive subgroup. Four wild types of Choix clustered into the same subgroup. These results indicated that the classification by RAPD data reflected the differences in geographic origins and evolution in Choix.  相似文献   

12.
The seed oil composition and content in a number of accessions from species of the genera Barbarea and Lepidium were analysed. The oil from most accessions of B. verna contained more than 50% erucic acid, while the oil from B. vulgaris contained ～ 30% erucic acid, and 22% each of oleic and linoleic acid. The oil from B. intermedia resembled that of B. verna. The oil content was ～ 30% in all three species. The oil composition of L. campestre and L. heterophyllum is ～ 35% linolenic acid and 23% erucic acid. Other Lepidium species had up to 47% linolenic acid in the oil. The oil content of L. campestre and L. heterophylhim was just below 20%, but other species had more than 30% oil in their seeds. The variation in oil composition found within and between species is considered sufficient for the breeding of valuable oil qualities in both genera.  相似文献   

13.
Several Lathyrus species have a considerable potential as alternative pulses in sustainable dryland farming systems mainly due to their high tolerance to drought and disease resistance. Powdery mildew is a serious disease affecting several Lathyrus species. Little is known on the availability of resistance and the underlying resistance mechanisms against powdery mildew in the Lathyrus genus. The present study assessed and characterized the resistance reaction to powdery mildew, Erysiphe pisi, in a collection of Iberian Lathyrus cicera accessions. In general, a compatible reaction with no macroscopically visible necrosis was observed but accessions with reduced disease severity despite of a high infection type have also been identified. This Partial Resistance was in some accessions only expressed in the adult plant stage. The controlling genes of the Lathyrus resistance mechanisms can be of great interest not only for the Lathyrus improvement per se but also for related legume species, like field pea.  相似文献   

14.
Summary Flower pigment compositions of 43 accessions of Tulipa species, 6 species hybrids and 494 tulip cultivars were analysed with respect to the amount of carotenoids, and the anthocyanidins pelargonidin, cyanidin and delphinidin. After principal component analysis, the different pigment compositions appeared to be correlated with flower color. Hybrids were not intermediate between the parents in all cases. The variation found in T. gesneriana extends that of the whole rest of the genus. The biosynthetic pathway as described in Petunia, Anthirrinum and other genera can also be postulated for the genus Tulipa, but additive effects of multiple genes may be assumed, since several levels of concentration were found. Flavonoid synthesis has biological relevance in view of co-evolution with insect pollinators and male sterility.  相似文献   

15.
Aegilops tauschii Coss., the D-genome progenitor of common wheat (Triticum aestivum L.) includes two subspecies, tauschii and strangulata (Eig) Tzvel. Subspecies tauschii has a wide geographic distribution spreading westwards to Turkey and eastwards to Afghanistan and China, while ssp. strangulata has a narrower distribution occurring only in two disjoined regions, southeastern Caspian Iran and Transcaucasia. A collection of 56 Ae. tauschii accessions was screened at adult stage against a mixture of pathotypes of stripe rust prevalent in the current wheat production in China. The results for three crop seasons indicated that among the 38 ssp. tauschii accessions, 37 were susceptible and only one was resistant, while all the 18 ssp. strangulata accessions were resistant. These results indicated that stripe rust resistance was related to taxonomic origin. Further genetic analysis revealed the resistance of stripe rust in ssp. strangulata accession AS2388 was conferred by a single dominant gene.  相似文献   

16.
Sequence variation of nuclear internal transcribed spacer regions of ribosomal DNA (ITS1, 5.8S rRNA and ITS2) from Chinese vegetable mustards (AB-genome) and its putative parents Brassica rapa (the A-genome) and Brassica nigra (the B-genome) were used to investigate the molecular phylogeny and the probable evolutional pattern of this amphidiploid species that uniquely formed in China. Totally, 16 accessions of Chinese vegetable mustard those covering nearly all the diverse variations were included in this study, and together with three accessions of B. rapa and one accession of B. nigra. The results disclosed two strongly supported clades, one containing four accessions of vegetable mustard which have closer relationship with B-genome species “B.nigra” lineage and the other containing 12 accessions of B. juncea and three A-genome accessions. This classification was in disagreement with the evidence from chloroplast DNA, mitochondrial DNA, nuclear DNA restriction fragment length polymorphism (RFLP), which suggested that B. juncea was closely related to the A-genome type. For the incongruence, we speculated that the B. juncea crops derived from Chinese have evolved through different recombined events of the diploid morphutypes and evolved unidirectional concerted evolution. The traditional phenotypic classification of B. juncea was not wholly supported by ITS results, and hence the phylogenetic relationships among these subspecies need to be reconsidered on molecular level.  相似文献   

17.
The wild lettuce, Lactuca aculeata Boiss. et Ky., is closely related and fully interfertile with cultivated lettuce, Lactuca sativa L. Altogether, 155 accessions of this wild species, which is rare conserved within the world’s germplasm collections, were collected from 12 localities throughout northeastern Israel. Ten of these localities represent different sites across the Golan Heights, while two, high-density populations were suprisingly found at the Hula Plain (first report of this species in this region). Lactuca aculeata was recorded at various elevations (222–968 m a.s.l.) and habitats. The taxonomic status of 30 L. aculeata accessions was morphologically validated during ex situ seed regeneration of 31 random accessions representing all 12 localities. Characterization of 12 traits showed that the Israeli populations of L. aculeata do not exhibit broad morphological variability, but more great levels of variation were obtained for developmental traits. Relatively little variability was observed in the morphology of cauline leaves or in the distribution of anthocyanin pigmentation in bracteae. In two cases, L. aculeata plants lacked trichomes in the inflorescence, a typical feature in the majority of plants. These unique collections of wild lettuce may carry novel sources of genetic variation for a wide range of traits and, thus, should be of interest for careful evaluation and exploitation in lettuce breeding.  相似文献   

18.
The Hessian fly, Mayetiola destructor (Say), is a major pest of wheat in North Africa, southern Europe, North America, and northern Kazakhstan. It is believed this pest (like wheat) originated in West Asia. The Syrian Hessian fly biotype has been found to be the most virulent worldwide, and has been used at the International Center for Agricultural Research in the Dry Areas (ICARDA) for screening wheat and its wild relatives to identify new sources of resistance. The screening was conducted in an insect rearing room set at 20°C and 70% RH using a Hessian fly population collected from Lattakia region, Syria. The experimental design was a randomized complete block with four replications. ‘Nasma’ (bread wheat) and ‘Cando’ (durum wheat) were used as susceptible and resistant checks, respectively. A total of 623 lines/accessions of wheat and its wild relatives (Aegilops and Triticum) were evaluated. Twenty-nine Aegilops accessions and four synthetic derived bread wheat lines were found resistant. The presence of dead first instars confirmed the resistance reaction and also showed that antibiosis is the major mechanism of resistance in these materials. These sources of resistance are used in ICARDA’s wheat breeding programs for the development of Hessian fly-resistant germplasm/varieties.  相似文献   

19.
Genetic Diversity in AA and CC Genome Oryza Species in Southern South Asia   总被引：3，自引：0，他引：3  
The CC genome of Oryza is found in nine species of Oryza that are distributed on all continents having a tropical climate. Three diploid Oryza species with CC genome are found in Africa and Asia to Papua New Guinea. In southern South Asia these three CC genome diploid species can be found, O. eichingeri and O. rhizomatis in Sri Lanka and O. officinalis in India. AA genome wild relatives of rice are also found in the same geographic region. Germplasm of both diploid CC and AA genome Oryza germplasm has recently been collected from Sri Lanka. AFLP analysis was used to compare the genetic diversity of the two Oryza genomes from a similar geographic region in southern South Asia. In addition, the diploid CC Oryza germplasm was also analyzed by RAPD and SSR methodologies and the combined results were analyzed. The results show that in southern South Asia the diploid CC genome species have a high level of genetic diversity compared to the diploid AA genome species. Molecular marker analysis revealed that populations of O. rhizomatis from northern and southeastern Sri Lanka are genetically differentiated. One accession of O. rhizomatis was aligned with O. eichingeri. This accession was collected from the site of O. rhizomatis that is the closest to a population of O. eichingeri. O. eichingeri showed lower genetic diversity than the other two diploid Oryza CC genome species. O. officinalis accessions from Assam, India, and China were genetically less diverged from O. eichingeri and O. rhizomatis than two accessions of O. officinalis from Kerala state, India. The first two authors contributed equally to this research  相似文献   

20.
Cherimoya (Anonna cherimola Mill.) is a fruit tree which originated in Peru and Ecuador and is now cultivated in several subtropical areas of the world. The characterization of cherimoya cultivars at allozyme level has been previously reported, but the geographic distribution and organization of this variation have not been fully characterized. In this study, we assessed the relationships among 206 cherimoya and four atemoya (A. cherimola ×A. squamosa) cultivars based on allozyme polymorphism. We have confirmed the genetic differences between atemoya and cherimoya cultivars, and showed that cherimoya accessions from Madeira, Bolivia and Spain form homogeneous groups of cultivars. Accessions from Chile and California form heterogeneous groups, probably due to their mixed origins. Cultivars from Peru and Ecuador showed a wide range of allelic variation, as is expected for accessions from the center of origin of this species.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号