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 687 毫秒
1.
Wild relatives of crops are an important source of resistance genes against insect pests. However, it is important to identify the accessions of wild relatives of crops with different mechanisms of resistance to broaden the basis and increase the levels of resistance to insect pests. Therefore, we studied the feeding behavior of pod borer, Helicoverpa armigera, which is the most damaging pest of pigeonpea, in relation to biochemical characteristics of the pod surface exudates in a diverse array of germplasm accessions belonging to 12 species of pigeonpea wild relatives. Feeding by H. armigera larvae was significantly lower on the unwashed or water-, methanol-, or hexane-washed pods of Canajus sericeus, C. scarabaeoides, Flemingia bracteata, F. stricta, and Rhynchosia aurea than those of C. acutifolius, C. albicans, C. cajanifolius, C. lineatus, D. ferruginea, P. scariosa, R. bracteata, and the cultivated pigeonpea, C. cajan genotypes, ICPL 87, and ICPL 332, although there were a few exceptions. The methanol-washed pods of wild relatives were less preferred for feeding by the H. armigera larvae than the unwashed pods, but the hexane-washed pods were preferred more than the unwashed pods. The results suggested that methanol extracted the phagostimulants from the pod surface, while hexane removed the antifeedants. The high-performance liquid chromatography (HPLC) finger printing of methanol and hexane pod surface extracts showed qualitative and quantitative differences in compounds present on the pod surface of different wild relatives of pigeonpea. Some of the peaks in HPLC profiles were associated with feeding preference of the third-instar larvae of H. armigera. There was considerable diversity in wild relatives of pigeonpea as revealed by principal component analysis based on HPLC fingerprints of pod surface extracts in methanol and hexane, and H. armigera feeding on the pods. Wild pigeonpea accessions with low amounts of phagostimulants and high amounts of antifeedants may be used for introgression of resistance genes into the cultivated pigeonpea to develop varieties with broad-based resistance to H. armigera. There is considerable diversity among the wild relatives of pigeonpea, and the accessions with resistance to pod borer. These can be used to broaden the basis and increase the levels of resistance to H. armigera.  相似文献   

2.

Premise

Domestication of plant species results in phenotypic modifications and changes in biotic interactions. Most studies have compared antagonistic plant-herbivore interactions of domesticated plants and their wild relatives, but little attention has been given to how domestication influences plant-pollinator interactions. Floral attributes and interactions of floral visitors were compared between sister taxa of the genus Cucurbita (Cucurbitaceae), the domesticated C. moschata, C. argyrosperma ssp. argyrosperma and its wild progenitor C. argyrosperma ssp. sororia in the place of origin.

Methods

We conducted univariate and multivariate analyses to compare floral morphological traits and analyzed floral reward (nectar and pollen) quantity and quality between flowers of wild and domesticated Cucurbita taxa. Staminate and pistillate flowers of all three taxa were video recorded, and visitation and behavior of floral visitors were registered and analyzed.

Results

Most floral morphological characteristics of flowers of domesticated taxa were larger in both staminate and pistillate flowers. Staminate and pistillate flowers presented distinct correlations between floral traits and integration indices between domesticated and wild species. Additionally, pollen quantity and protein to lipid ratio were greater in domesticated species. Cucurbit pollen specialists, Eucera spp., had the highest probability of visit for all Cucurbita taxa.

Conclusions

We provide evidence that floral traits of domesticated and wild Cucurbita species experienced different selection pressures. Domesticated Cucurbita species may have more resources invested towards floral traits, thereby increasing attractiveness to pollinators and potentially plant reproductive success. Wild ancestor plant populations should be conserved in their centers of origin to preserve plant-pollinator interactions.  相似文献   

3.
Seed pods of wild-type narrow-leafed lupins (Lupinus angustifolius L.) shatter upon maturity, dispersing their seeds. Recessive alleles of the genes Tardus and Lentus that confer reduced pod shattering have been incorporated into domesticated cultivars to facilitate harvesting. Tardus was mapped in an F8 recombinant inbred population of a cross between domesticated and wild lupins. A microsatellite–anchored fragment length polymorphism marker (TaM1), which mapped 2.1 cM from Tardus, was converted to a locus-specific PCR assay. Marker TaM2, a restriction fragment length polymorphism marker was converted to a PCR assay and mapped to 3.9 cM on the other side of Tardus. Marker TaM3, a cleaved amplified polymorphic sequence marker, was positioned along-side marker TaM1 at 3.9 cM from Tardus. One or more markers was polymorphic in 70% of possible pairwise crosses between Australian domesticated lines and wild accessions tested, indicating wide applicability of the markers in crosses between wild and domesticated germplasm.  相似文献   

4.
 The cowpea [Vigna unguiculata (L.) Walp.] is a morphologically and genetically variable species composed of wild perennial, wild annual, and cultivated forms that are mainly used for edible seeds and pods. In this study, genetic variation in 199 germplasm accessions of wild and cultivated cowpea was evaluated using an allozyme analysis. The results from this survey showed that wild cowpea exhibits genetic variation perfectly fitted with the existing morphological classification. The cowpea gene-pool is characterized by its unusually large size. It encompasses taxa (ranked as subspecies) that could be considered as different species considering the high genetic distances observed between accessions belonging to different taxa. These subspecies can be classified into three groups characterized by their breeding systems: perennial outcrossers, perennial out-inbreds, and inbred annuals. Allozyme data confirm this grouping. Perennial outcrossers look primitive and are more remote from each other and from perennial out-inbreds. Within this large gene-pool, mainly made of perennial taxa, cultivated cowpeas (ssp. unguiculata var. unguiculata) form a genetically coherent group and are closely related to annual cowpeas (ssp. unguiculata var. spontanea) which may include the most likely progenitor of cultivated cowpeas. Received: 15 June 1998 / Accepted: 29 September 1998  相似文献   

5.
Amplified fragment length polymorphisms (AFLPs) were used to evaluate genetic relationships within cowpea [Vigna unguiculata (L.) Walp.] and to assess the organization of its genetic diversity. Nei’s genetic distances were estimated for a total of 117 accessions including 47 domesticated cowpea (ssp. unguiculata var. unguiculata), 52 wild and weedy annuals (ssp. unguiculata var. spontanea), as well as 18 perennial accessions of the wild subspecies pubescens, tenuis and alba. AFLP variation was also used to study genetic variation among and within domesticated and wild accessions based on their geographical origin (western, eastern and southern Africa). Wild annual cowpea (var. spontanea) (H T =0.175) was more diverse than domesticated cowpea (H T =0.108). Wild cowpea was more diverse in eastern (H S =0.168) than in western Africa (H S =0.129), suggesting an eastern African origin for the wild taxon. The AFLP data were consistent with earlier findings of a unique domestication event in cowpea in the northern part of the continent and suggested that domestication in eastern or southern Africa was unlikely. It did not allow a more precise localization of domestication due to extensive gene flow between wild and domesticated forms that has led to a large crop-weed complex distributed over the entire African continent. In addition, wild materials from northeastern Africa are still lacking. Overall, the superiority of the AFLP technique over isozymes resided in its ability to uncover variation both within domesticated and wild cowpea, and should be a powerful tool once additional wild material becomes available. Received: 11 September 2000 / Accepted: 14 June 2001  相似文献   

6.
In the thousands of years of rice domestication in Asia, many useful genes have been lost from the gene pool. Wild rice is a key source of diversity for domesticated rice. Genome sequencing has suggested that the wild rice populations in northern Australia may include novel taxa, within the AA genome group of close (interfertile) wild relatives of domesticated rice that have evolved independently due to geographic separation and been isolated from the loss of diversity associated with gene flow from the large populations of domesticated rice in Asia. Australian wild rice was collected from 27 sites from Townsville to the northern tip of Cape York. Whole chloroplast genome sequences and 4,555 nuclear gene sequences (more than 8 Mbp) were used to explore genetic relationships between these populations and other wild and domesticated rices. Analysis of the chloroplast and nuclear data showed very clear evidence of distinctness from other AA genome Oryza species with significant divergence between Australian populations. Phylogenetic analysis suggested the Australian populations represent the earliest‐branching AA genome lineages and may be critical resources for global rice food security. Nuclear genome analysis demonstrated that the diverse O. meridionalis populations were sister to all other AA genome taxa while the Australian O. rufipogon‐like populations were associated with the clade that included domesticated rice. Populations of apparent hybrids between the taxa were also identified suggesting ongoing dynamic evolution of wild rice in Australia. These introgressions model events similar to those likely to have been involved in the domestication of rice.  相似文献   

7.
AFLP analysis of relationships among cassava and other Manihot species   总被引:4,自引:0,他引:4  
 Despite the worldwide importance of cultivated cassava (M. esculenta Crantz) its origin and taxonomic relationships with other species in the genus have not been clearly established. We evaluated a representative sample of the crop’s diversity and six wild taxa with AFLPs to estimate genetic relationships within the genus. Groupings of accessions of each species by data analysis corresponded largely with their previous taxonomic classifications. A mixed group, consisting of Manihot esculenta subsp. flabellifolia and M. esculenta subsp. peruviana, was most similar to cassava, while M. aesculifolia, M. brachyloba, and M. carthaginensis were more distant. Species-specific markers, which may be useful in germ-plasm classification or introgression studies, were suggested by the unique presence of AFLP products in samples of each of the three wild species. Heterogeneity of similarities among individuals of certain species suggested the existence of intraspecific gene pools, a hypothesis that was supported by morphological or ecogeographic evidence with varying degrees of success. Quantitative assessment of genetic diversity revealed greater homogeneity among cassava accessions than among itsclosest wild relatives. The demonstration of unique genetic diversity in the two M. esculenta subspecies and their genetic similarity to the crop supports the hypothesis that these materials may be the ancestors of cassava. Received: 4 November 1996 / Accepted: 20 December 1996  相似文献   

8.
Host plant resistance is an important component for minimizing the losses due to the pod borer, Helicoverpa armigera, which is the most devastating pest of pigeonpea. An understanding of different morphological and biochemical components of resistance is essential for developing strategies to breed for resistance to insect pests. Therefore, we studied the morphological and biochemical components associated with expression of resistance to H. armigera in wild relatives of pigeonpea to identify accessions with a diverse combination of characteristics associated with resistance to this pest. Among the wild relatives, oviposition non-preference was an important component of resistance in Cajanus scarabaeoides, while heavy egg-laying was recorded on C. cajanifolius (ICPW 28) and Rhynchosia bracteata (ICPW 214). Accessions belonging to R. aurea, C. scarabaeoides, C. sericeus, C. acutifolius, and Flemingia bracteata showed high levels of resistance to H. armigera, while C. cajanifolius was as susceptible as the susceptible check, ICPL 87. Glandular trichomes (type A) on the calyxes and pods were associated with susceptibility to H. armigera, while the non-glandular trichomes (trichome type C and D) were associated with resistance to this insect. Expression of resistance to H. armigera was also associated with low amounts of sugars and high amounts of tannins and polyphenols. Accessions of wild relatives of pigeonpea with non-glandular trichomes (type C and D) or low densities of glandular trichomes (type A), and high amounts of polyphenols and tannins may be used in wide hybridization to develop pigeonpea cultivars with resistance to H. armigera. Handling editor: Robert Glinwood  相似文献   

9.
 DNA fingerprinting verified hybrid plants obtained by crossing Eastern gamagrass, Tripsacum dactyloides L., and perennial teosinte, Zea diploperennis Iltis, Doebley & R. Guzmán. Pistillate inflorescences on these hybrids exhibit characteristics intermediate to the key morphological traits that differentiate domesticated maize from its wild relatives: (1) a pair of female spikelets in each cupule; (2) exposed kernels not completely covered by the cupule and outer glumes; (3) a rigid, non-shattering rachis; (4) a polystichous ear. RFLP analysis was employed to investigate the possibility that traits of domesticated maize were derived from hybridization between perennial teosinte and Tripsacum. Southern blots of restriction digested genomic DNA of parent plants, F1, and F2 progeny from two different crosses were probed with RFLP markers specifically associated with changes in pistillate inflorescence architecture that signal maize domestication. Pairwise analysis of restriction patterns showed traits considered missing links in the origin of maize correlate with alleles derived from Tripsacum, and the same alleles are stably inherited in second generation progeny from crosses between Tripsacum and perennial teosinte. Received: 11 October 1996/Accepted:8 November 1996  相似文献   

10.
 The annual sunflower (Helianthus annuus L.) is a morphologically and genetically variable species composed of wild, weedy, and domesticated forms that are used for ornament, oilseed, and edible seeds. In this study, we evaluated genetic variation in 146 germplasm accessions of wild and domesticated sunflowers using allozyme analysis. Results from this survey showed that wild sunflower exhibits geographically structured genetic variation, as samples from the Great Plains region of the central United States were genetically divergent from accessions from California and the southwestern United States. Sunflower populations from the Great Plains harbored greater allelic diversity than did wild sunflower from the western United States. Comparison of genetic variability in wild and domesticated sunflower by principal coordinate analysis showed these groups to be genetically divergent, in large part due to differences in the frequency of common alleles. Neighbor-Joining analyses of domesticated H. annuus, wild H. annuus and two closely related wild species (H. argophyllus T. & G. and H. petiolaris Nutt.) showed that domesticated sunflowers form a genetically coherent group and that wild sunflowers from the Great Plains may include the most likely progenitor of domesticated sunflowers. Received: 2 December 1996/Accepted: 4 April 1997  相似文献   

11.
The Pre-potteryNeolithic A (PPNA) site of Jerf el Ahmar, Syria, dated to the 10th millennium uncal B.P., has produced over 657 flotation samples which are now under study. The results described in this article were obtained from the analysis of 32 samples of charred plant remains taken from a room of 2.5 × 3 m, which had been destroyed by fire. The room contained three saddle querns, two flat polished stone plates (each of 60 cm in diameter), one hearth, and three limestone "basins". These objects were in situ and the room appeared to represent a food preparation area (kitchen). On one of the querns two charred seed cakes were found. The finely ground seeds have been identified as Brassica/Sinapis, a rare taxon for this period. The major taxa, which are morphologically wild, have distinct spatial distributions, which provide evidence for plant processing activities. Hordeum spontaneum and Triticum/Secale were processed separately. The association of H. spontaneum with stone basins suggests soaking of this grain. Received August 10, 2001 / Accepted January 7, 2002  相似文献   

12.
13.
Through the process of domestication, bean varieties have beenselected from their wild ancestors for various anthropocentrically-importantcharacteristics. In order to compare some agronomic and morphologicaltraits of a wild population and a modern variety (cv. Bayo Mecentral),the following variables were evaluated: growth habit; numberof nodes on the main stem; number of branches and pods per plant;flower and pod colours; stem length; days to initiation of flowering;days to physiological maturity and duration of flowering. Variationin each trait was recorded, particularly in the wild population.The growth habits of the wild population were very diverse andthere were positive and significant correlations between 13pairs of variables, including the number of nodes on the mainstem, pods per plant, days to flowering and duration of flowering,whereas domesticated beans gave only a few significant correlations.The analysis of principal components indicated that the linearcombination of agronomic and morphological variables, involvingthe first three principal components, accounted for 70% of thetotal variability of the data, and the populations were clearlyseparated as two biological entities by the first principalcomponent. This study confirms that the process of domesticationhas acted to reduce variation in a range of characters. Growth; growth habit; Phaseolus vulgaris ; domestication  相似文献   

14.
Hypotheses of evolutionary relationships among the Australian wild perennial relatives of soybean (Glycine subgenus Glycine) are based largely on patterns of meiotic pairing in intra- and interspecific experimental hybrids. This evidence has indicated a number of genome groupings within the subgenus but has not resolved most phylogenetic relationships. Restriction-endonuclease site variation of chloroplast DNA (cpDNA) within the perennial subgenus is reported here, representing a sampling of approximately 3% of the approximately 150-kilobase plastome. Seven hundred twenty-one unique restriction sites were compared within Glycine using 29 restriction endonucleases; 157 sites varied within the genus. Distance and parsimony methods using these data yielded congruent results, recognizing the existence of three major groups within subgenus Glycine: the species-rich and geographically diverse A clade consisting of G. canescens and related taxa; the B clade, which includes the stoloniferous species; and the C group, containing two species with distinctive curved pods. These results are in general agreement with hypotheses based on genome analysis; inconsistencies involve the inclusion of genetically divergent taxa such as G. falcata in well-supported plastome clades comprised of otherwise interfertile species. Such findings are not unexpected if crossing barriers are considered to be unique features of such anomalous species, paralleling their often numerous morphological and cpDNA autapomorphies. Consideration of cpDNA divergence within the three major clades of subgenus Glycine indicates that the rate of plastome evolution is uncoupled from rates of morphological or ecological diversification.  相似文献   

15.
Fungal endophytes were isolated from healthy stems and pods of Theobroma gileri, an alternative host of the frosty pod rot pathogen of cacao. Non-sporulating isolates were grouped into 46 different morphological species according to their colony morphology. Many of these morphospecies were assumed to be basidiomycetes and, therefore, were of particular interest. Basidiomycetous endophytes have received far less attention than ascomycetes and also have potential as biological control agents of the basidiomycetous pathogens of T. cacao: Moniliophthora roreri (frosty pod rot pathogen) and M. perniciosa (witches' broom disease). The morphospecies were further characterised by molecular analyses. Amplification of the nuLSU was undertaken for phylogenetic placement of these non-sporulating cultures and revealed a total of 31 different taxa of which 15 were basidiomycetes belonging to the class Agaricomycetes, and 16 ascomycetes primarily belonging to the Sordariomycetes.  相似文献   

16.
Teucrium montanum L. and T. polium L. are the two closest Teucrium L. species from sect. Polium (Mill.) Schreb in Turkey. In addition, they are sympatric for some part of their range in Turkey. In this study, comparative anatomical and micromorphological studies of the two species are carried out. They have been investigated by their leaf and stem anatomical features, as well as nutlet micromorphological characteristics. The results of anatomical studies show that the anatomical characters of both taxa are observed to be similar to the general features of the family Lamiaceae anatomy, except for lacking rich collenchyma at the corners. Both taxa are similar in stem anatomy and their leaves exhibit xeromorphy. However, trichome morphology on the stems and the leaves appear to have a taxonomic value in segregation of the two taxa. Light and scanning electron microscope studies on the nutlets also show that nutlet shapes, measures and surface micromorphologies are different in the two species. Whereas nutlet surfaces are bireticulate in both species, the nutlets are larger and primary sculpturing is more distinct in T. polium than in T. montanum. Moreover, the nutlets are oblong to oblong-ovoid and larger in T. polium, but ovoid and smaller in T. montanum.  相似文献   

17.
 Genetic variation and structure of ten wild, three domesticated and one wild-cultivated populations of pepper (Capsicum annuum) from northwestern Mexico were studied in order to find out if the domestication process has reduced the genetic variation of the modern cultivars of this species. The analysis was based on 12 polymorphic loci from nine isozymes. Wild populations were sampled in different habitats along a latitudinal gradient of ca. 500 km. All populations had high genetic variation (i.e. wild: A = 2.72, P = 90.8%, He = 0.445; wild-cultivated: A = 2.50, P = 92.3%, He = 0.461; domesticated: A = 2.60, P = 84.6%, He = 0.408), indicating little genetic erosion in modern cultivars of pepper. Genetic diversity estimated by Nei's method showed that most genetic variation is found within, rather than among populations. However, genetic differentiation is greater among cultivated (G ST=0.167) than among wild (G ST=0.056) populations. Wild populations had an average genetic identity (I) of 0.952, indicating little differentiation and high gene flow (Nm=4.21) among these populations. Average genetic identity between wild and domesticated populations was of I=0.818, revealing that the domestication process has modified the genetic composition of commercial varieties of pepper. Changes in genetic composition among commercial varieties seem to have occurred in different directions, as indicated by the average value of I = 0.817 among these populations. The high level of diversity found in wild populations of C. annuum suggests that the wild relatives of cultivated peppers are a valuable genetic resource which must be conserved. Received May 5, 1999 Accepted October 30, 2000  相似文献   

18.
Tiedemann J  Neubohn B  Müntz K 《Planta》2000,211(1):1-12
The temporal and spatial patterns of storage-globulin mobilization were immunohistochemically pursued in the embryonic axis and cotyledons of vetch seed (Vicia sativa L.) during germination and early seedling growth. Embryonic axes as well as cotyledons of mature seeds contain protein bodies with stored globulins. Prevascular strands of axes and cotyledons, the radicle and epidermal layers of axis organs were nearly exclusively stained by vicilin antibodies whereas the cotyledonous storage mesophyll gave similar staining for vicilin and legumin. Globulin breakdown started locally where growth and differentiation commenced in the axis. There, vicilin mobilization preceded legumin mobilization. Thus vicilin represents the initial source of amino acids for early growth and differentiation processes in vetch. Legumin presumably only serves as a bulk amino acid source for subsequent seedling growth during postgerminative globulin degradation. During the first 2–3 d after the start of imbibition the axis was depleted of globulins whereas no decrease in immunostainability was detected in the cotyledons except in their vascular strands where immunostainability was almost completely lost at this time. Continuous vascular strands were established at the third day when globulin breakdown was finished in the axis but had just started in the cotyledon mesophyll. Protein mobilization proceeded in a small zone from the epidermis towards the vascular strands in the center of the cotyledons. In this zone the storage cells, which initially appeared densely packed with starch grains and protein bodies, concomitantly transformed into cells with a large central vacuole and only a thin cytoplasmic layer attached to the cell wall. These results agree well with the hypothesis that during the first 2 d after imbibition the axis is autonomous in amino acid provision. After the endogenous reserves of the axis are depleted and the conductive tissue has differentiated, globulins are mobilized in the cotyledons, suggesting that then the amino acid supply is taken over by the cotyledons. For comparison with other degradation patterns we used garden bean (Phaseolus vulgaris L) and rape (Brassica napus L.) as reference plants. Received: 3 August 1999 / Accepted: 11 December 1999  相似文献   

19.
The effects of secondary metabolites in different Vigna species on the development of Clavigralla tomentosicollis were investigated in an artificial seed system using different fractions of crude pod extracts, while the orientation response of this pod‐bug to volatile extracts was studied using a dual‐choice olfactometer. Feeding on the neutral fraction extracts, in contrast to the basic and acidic fractions, resulted in significantly higher mortalities, longer total developmental time, and lower growth index of the insects in comparison with controls. All volatile extracts elicited an avoidance reaction by C. tomentosicollis, except the volatile from the susceptible genotype IT84S‐2246 which generally attracted as many insects as controls. Extracts from wild Vigna species showed higher activity than those from their cultivated relatives. The present study which has established that most secondary metabolites in cowpea pods were localized in the neutral fraction of the crude extract, could facilitate experiments on the separation and characterization of the toxic factors involved.  相似文献   

20.
This paper presents archaeobotanical results from Sardinia, an island in the western Mediterranean. The starting point is the material excavated at Duos Nuraghes near Borore, but remains provided by other sites are taken into account as well. Naked wheat, presumably a tetraploid wheat such as Triticum durum Desf. (macaroni wheat), and Hordeum vulgare L. (barley) are the most common finds from the Neolithic up to the Medieval period. Triticum dicoccum Schübl. (emmer), Lens culinaris Medik. (lentil), Pisum sativum L. (pea) and Vicia faba L. var. minor (horse bean) have been grown as well. A medieval context revealed Beta vulgaris L. (beet). The most common find in the category of fruits is Vitis vinifera L. (grape). The overall picture is one of continuity in agricultural practices. Nevertheless this picture may be false. In the early Bronze Age the cultivation of barley may have shifted from the naked variety towards the hulled variety. The Phoenicians may have introduced new cultivars of grapevine, although the native grapevine was not replaced by these. The weed taxa suggest some change in agriculture from Punic or Roman times onwards. Received August 10, 2001 / Accepted January 15, 2002  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