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1.
Although seedling herbivory is an important selective filter in many plant communities, how and why seedlings are selected
is poorly understood. Here, we examined the putative role of herbivore olfaction in dictating seedling selection. Using a
Y-tube olfactometer we compared snail (Helix aspersa) preference for pellets derived from 14-day-old macerated seedlings of nine European grassland (‘Test’) species against standard
(‘Control’) pellets derived from lettuce. Snail movement towards ‘Test’ pellets was strongly correlated with seedling acceptability
(Pearson’s r
2 = 0.86, P > 0.01) and where snails exhibited a positive choice for the ‘Test’ species, the choice was made more quickly for highly
acceptable species (r
2 = 0.86, P > 0.01). In elucidating a link between seedling acceptability and olfactory response to macerated seedlings, our study suggests
that even from an early ontogenetic stage plant selection by snails may be governed by olfactory cues. This finding highlights
the need for research on the role of plant volatiles in plant–herbivore interactions to consider more fully interactions operating
at the seedling stage. 相似文献
2.
Seed and microsite limitations of recruitment and the impacts of post-dispersal seed predation at the within population level 总被引:1,自引:0,他引:1
María Calviño-Cancela 《Plant Ecology》2007,192(1):35-44
Seed predation may cause important seed losses in plant populations, but its impact on the dynamics of populations will depend
on the degree of seed or microsite limitations for recruitment. Seed losses will only affect recruitment if it is seed limited.
The nature of recruitment limitation (seeds or microsites) is usually ascribed to whole plant populations but it may vary
within populations among microhabitats and habitats. Thus, the potential impact of seed predation will also vary within the
population, being highest where recruitment is seed limited. The impact to the whole population will depend on the spatial
concordance between the intensity of seed predation and that of seed limitation. Recruitment limitations (with seed addition
experiments), seed predation (with seed removal experiments), and the dynamics of seed availability in the soil (with soil
samples taken both after seed dispersal and before the following dispersal event) of the shrub Corema album (Empetraceae) were investigated in dunes in NW Spain, at microhabitats ‘open ground’, ‘underneath C. album ♀’, and ‘underneath C. album ♂’ at two habitats, sparse and dense scrub. The nature of recruitment limitation (seeds vs. microsites) varied within the
population. It was seed limited in the microhabitat ‘open ground’ and microsite limited under shrub cover. The spatial patterns
of seedling recruitment were unrelated to seed availability but strongly affected by germination requirements. The spatial
discordance between seed availability and recruitment implies a crucial constraint for processes affecting seed availability
(seed predation but also e.g., dispersal) to impact recruitment. They will not affect its spatial pattern but only its quantity
as long as they act in those sites selected by seeds to germinate. Seed predation was highest underneath mother plants and lowest in open ground. Thus, its potential
impact is low, as it is centred where recruitment is not seed limited. This study shows that the analysis of seed predation
in relation to recruitment limitations at smaller spatial scales within the population provides more insight to understand
its impact. 相似文献
3.
J.-M. Lacape D. Dessauw M. Rajab J.-L. Noyer B. Hau 《Molecular breeding : new strategies in plant improvement》2007,19(1):45-58
A series of 320 mapped simple sequence repeats (SSRs) have been used to screen the allelic diversity of tetraploid Gossypium species. Fourty-seven genotypes were analyzed representing (i) the wide spectrum of diversity of the cultivated pool and
of the primitive landraces of species G. hirsutum (‘marie-galante’, ‘punctatum’, ‘richmondi’, ‘morrilli’, ‘palmeri’, and ‘latifolium’, and ‘yucatanense’), and (ii) species
G. barbadense, G. darwinii and G. tomentosum. The polymorphism of 201 SSR loci revealed 1128 allelic variants ranging from 3 to 17 per locus. Neighbor-joining (NJ) method
based on genetic dissimilarities produced groupings consistent with the assignments of accessions both at species and at race
level. Our data confirmed the proximity of the Galapagos endemic species G. darwinii to species G. barbadense. Within species G. hirsutum, and as compared to the other 6 races, race yucatanense appeared as the most distant from cultivated genotypes. Race yucatanense
also exhibited the highest number of unique alleles. The important informative heterogeneity of the 201 SSR loci was exploited
to select the most polymorphic ones that were assembled into three series of genome-wide (i.e. each homoeologous AD chromosome
pair being equally represented) and mutliplexable (× 3) SSRs. Using one of these ‘genotyping set’, consisting of 39 SSRs (one
3-plex for each of the 13 AD chromosomes pairs) or 45 loci, we were able to assess the relationships between accessions and
the topology in the genetic diversity sampled. Such genotyping set of highly informative SSR markers assembled in PCR-multiplex,
while increasing genotyping throughput, will be applicable for molecular genetic diversity studies of large germplasm collections.
Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
4.
Genetic analysis of adult plant,quantitative resistance to stripe rust in wheat cultivar ‘Stephens’ in multi-environment trials 总被引:1,自引:0,他引:1
Dolores Vazquez M James Peterson C Riera-Lizarazu O Chen X Heesacker A Ammar K Crossa J Mundt CC 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(1):1-11
The wheat (Triticum aestivum L.) cultivar ‘Stephens’ has been grown commercially in the USA Pacific Northwest for 30 years. The durable resistance of
‘Stephens’ to stripe rust (Puccinia striiformis f. sp. tritici) was believed to be due to a combination of seedling and adult plant resistance genes. Multilocation field trials, diversity
array technology (DArT), and simple sequence repeat (SSR) markers were used to identify quantitative trait loci (QTL) for
resistance. Recombinant inbred lines were assessed for stripe rust response in eight locations/years, five in 2008 and three
in 2009. The data from Mt. Vernon, WA, differed from all other environments, and composite interval mapping (CIM) identified
three QTL, QYrst.orr-1AL, QYrst.orr-4BS, and QYrpl.orr-6AL, which accounted for 12, 11, and 6% of the phenotypic variance, respectively. CIM across the remaining six environments identified
four main QTL. Two QTL, QYrst.orr-2BS.2 and QYrst.orr-7AS, were detected in five of six environments and explained 11 and 15% of the phenotypic variance, respectively. Two other QTL,
QYrst.orr-2AS and QYrpl.orr-4BL, were detected across four and three of six environments, and explained 19 and 9% of the phenotypic variance, respectively.
The susceptible parent ‘Platte’ contributed QYrpl.orr-4BL and QYrpl.orr-6AL, with the remaining QTL originating from ‘Stephens’. For each environment, additional minor QTL were detected, each accounting
for 6–10% of the phenotypic variance. Different QTL with moderate effects were identified in both ‘Stephens’ and ‘Platte’.
Significant QTL × environment interactions were evident, suggesting that specificity to plant stage, pathogen genotype, and/or
temperature was important. 相似文献
5.
Xingguo Zhang Chaozhi Ma Tingdong Fu Yuanyuan Li Tonghua Wang Qingfang Chen Jinxing Tu Jinxiong Shen 《Molecular breeding : new strategies in plant improvement》2008,21(3):305-315
‘SI1300’ is a self-incompatible Brassica napus line generated by introgressing an S haplotype from B. rapa ‘Xishuibai’ into a rapeseed cultivar ‘Huayou No. 1’. Five S-locus specific primer pairs were employed to develop cleaved amplified polymorphic sequences (CAPS) markers linked the S haplotype of ‘SI1300’. Two segregating populations (F2 and BC1) from the cross between ‘SI1300’ and self-compatible European spring cultivar ‘Defender’, were generated to verify the molecular
markers. CAPS analysis revealed no desirable polymorphism between self-incompatible and self-compatible plants. Twenty primer
pairs were designed based on the homology-based candidate gene method, and six dominant sequence characterized amplified region
(SCAR) markers linked with the S-locus were developed. Of the six markers, three were derived from the SRK and SP11 alleles of class II B. rapa
S haplotypes and linked with S haplotype of ‘SI1300’. The other three markers were designed from the SLG-A10 and co-segregated with S haplotype of ‘Defender’. We successfully combined two pairs of them and characterized two multiplex PCR markers which could
discriminate the homozygous and heterozygous genotypes. These markers were further validated in 24 F3 and 22 BC1F2 lines of ‘SI1300 × Defender’ and another two segregating populations from the cross ‘SI1300 × Yu No. 9’. Nucleotide sequences
of fragments linked with S-locus of ‘SI1300’ showed 99% identity to B. rapa class II S-60 haplotype, and fragments from ‘Defender’ were 97% and 94% identical to SLG and SRK of B. rapa class I S-47 haplotype, respectively. ‘SI1300’ was considered to carry two class II S haplotypes and the S haplotype on the A-genome derived from B. rapa ‘Xishuibai’ determines the SI phenotype, while ‘Defender’ carry a class I S haplotype derived from B. rapa and a class II S haplotype from B. oleracea. SCAR markers developed in this study will be helpful for improving SI lines and accelerating marker-assisted selection process
in rapeseed SI hybrid breeding program. 相似文献
6.
This study analyzed genetic differences of 19 cultivars selected from somaclonal variants of Syngonium podophyllum Schott along with their parents as well as seven additional Syngonium species and six other aroids using amplified fragment length polymorphism (AFLP) markers generated by 12 primer sets. Among the 19 somaclonal cultivars, ‘Pink Allusion’ was selected from ‘White Butterfly’. Tissue culture of ‘Pink Allusion’ through organogenesis resulted in the development of 13 additional cultivars. Self-pollination of ‘Pink Allusion’ obtained a cultivar, ‘Regina Red Allusion’, and tissue culture propagation of ‘Regina Red Allusion’ led to the release of five other cultivars. The 12 primer sets generated a total of 1,583 scorable fragments from all accessions, of which 1,284 were polymorphic (81.9%). The percentages of polymorphic fragments within ‘White Butterfly’ and ‘Regina Red Allusion’ groups, however, were only 1.2% and 0.4%, respectively. Jaccard's similarity coefficients among somaclonal cultivars derived from ‘White Butterfly’ and ‘Regina Red Allusion’, on average, were 0.98 and 0.99, respectively. Seven out of the 15 cultivars from the ‘White Butterfly’ group and three out of six from the ‘Regina Red Allusion’ group were clearly distinguished by AFLP analysis as unique fragments were associated with respective cultivars. The unsuccessful attempt to distinguish the remaining eight cultivars from the ‘White Butterfly’ group and three from the ‘Regina Red Allusion’ group was not attributed to experimental errors or the number of primer sets used; rather it is hypothesized to be caused by DNA methylation and/or some rare mutations. This study also calls for increased genetic diversity of cultivated Syngonium as they are largely derived from somaclonal variants. 相似文献
7.
Summary Anthers and ovaries of six grapevine cultivars (three Vitis vinifera L., two V × Labruscana L. H. Bailey, and one complex hybrid) were extracted from flower buds over 2 yr and cultured on three media reported to promote
somatic embryogenesis in Vitis tissues. The highest percent embryogenesis from the hybrid ‘Chancellor’ and V. vinifera ‘Chardonnay’, ‘Merlot’, and ‘Pinot Noir’ occurred on medium C [Nitsch and Nitsch, 1969, basal medium with 3.0% (w/v) sucrose,
0.01% (w/v) inositol. 0.3% (w/v) Phytagel, 2.5 μM 2.4-dichlorophenoxyacetic acid, 2.5μM β-naphthoxyacetic acid, 5.0μM N-(2-chloro-4-pyridyl)-N′-phenylurea, and 0.05% (w/v) glutamine]. Regardless of the media, the labrusca cultivars ‘Concord’ and ‘Niagara’ produced
soft non-embryogenic callus that was sometimes mixed with well-developed somatic embryos. Nine vinifera genotypes were further
tested for several different years on medium C. Embryogenic cultures suitable for transformation were obtained from all genotypes
in more than 1 yr. The average percent embryogenesis from ovaries was 7-fold higher than from anthers. There was significant
annual variation in percent embryogenesis, demonstrating the need for media comparisons to be replicated for more than one
season. Suspension cultures suitable for use in genetic transformation were initiated from ‘Chardonnay’, ‘Merlot,’ and ‘Pinot
Noir’ pro-embryogenic masses. ‘Chardonnay’ suspension cultures plated and grown under conditions developed for recovery of
plants after biolistic transformation yielded approximately 500 non-transformed embryos per plate after 4 mo. of culture,
with 68.6% of the embryos converting to plants. This is the first reported protocol for embryogenesis from ‘Concord,’ ‘Cabernet
Franc,’ and ‘Pinot Noir’ grapevines. 相似文献
8.
9.
N. Friesen R. Fritsch K. Bachmann 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(8):1229-1238
Random amplified polymorphic DNA (RAPD) and genomic in situ hybridization (GISH) methods have been used to verify the hybridogenic
origin and to identify the parental species of some ornamental cultivars in the subgenus Melanocrommyum of the genus Allium. The cultivars had been selected from seed obtained after uncontrolled pollination in breeders’ fields. The combination of
GISH analysis with RAPD markers is very suitable for testing the hybridogenic origin of plants and to ascertain the parental
species of the hybrids in such cases. As suspected, A. macleanii and A. cristophii are the parental species of ‘Globemaster’. The parental species of cultivar ‘Globus’ are A. karataviense and A. stipitatum, and not A. cristophii and A. giganteum as has been assumed on morphological grounds. Cultivars ‘Lucy Ball’ and ‘Gladiator’ are of hybrid origin, though only one
of the parental species, A. hollandicum, could be confirmed. The cultivars ‘Purple Sensation’, ‘Mount Everest’, ‘White Giant’, ‘Michael H. Hoog’ and ‘Mars’ are not
hybrids since neither GISH nor RAPD suggest the presence of a second genome. ‘Purple Sensation’ belongs to A. hollandicum, ‘Mount Everest’, ‘White Giant’ and ‘Mars’ to A. stipitatum,‘Michael H. Hoog’ to A. rosenorum.
Received: 3 July 1997 / Accepted: 9 October 1997 相似文献
10.
On the Spectrum of Prebiotic Chemical Systems 总被引:1,自引:1,他引:0
Rodrick Wallace Robert G. Wallace 《Origins of life and evolution of the biosphere》2008,38(5):419-455
We reexamine Eigen’s paradox using the asymptotic limit theorems of information theory. Applying the homology between information
source uncertainty and free energy density, under rate distortion constraints, the error catastrophe emerges as the lowest
energy state for simple prebiotic systems without error correction. Invoking the usual compartmentalization – i.e., ‘vesicles’
– and using a Red Queen argument, suggests that information crosstalk between two or more properly interacting structures
can initiate a coevolutionary dynamic having at least two quasi-stable states. The first is a low energy realm near the error
threshold, and, depending on available energy, the second can approach zero error as a limit. A large deviations argument
produces jet-like global transitions which, over sufficient time, may enable shifts between the many quasi-stable modes available
to more complicated structures, ‘locking in’ to some subset of the various possible low error rate chemical systems, which
become subject to development by selection and chance extinction. Energy availability, according to the model, is thus a powerful
necessary condition for low error rate replication, suggesting that some fundamental prebiotic ecosystem transformation entrained
reproductive fidelity. This work, then, supports speculation that our RNA/DNA world may indeed be only the chance result of
a very broad prebiotic evolutionary phenomenon. Processes in vitro, or ex planeta, might have other outcomes. 相似文献
11.
Accumulation of additive effects generates a strong photoperiod sensitivity in the extremely late-heading rice cultivar ‘Nona Bokra’ 总被引:1,自引:0,他引:1
Uga Y Nonoue Y Liang ZW Lin HX Yamamoto S Yamanouchi U Yano M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(8):1457-1466
Many rice cultivars that originated from lower-latitude regions exhibit a strong photoperiod sensitivity (PS) and show extremely
late heading under long-day conditions. Under natural day-length conditions during the cropping season in Japan, the indica rice cultivar ‘Nona Bokra’ from India showed extremely late heading (202 days to heading) compared to the japonica cultivar ‘Koshihikari’ (105 days), from Japan. To elucidate the genetic factors associated with such extremely late heading,
we performed quantitative trait locus (QTL) analyses of heading date using an F2 population and seven advanced backcross progeny (one BC1F2 and six BC2F2) derived from a cross between ‘Nona Bokra’ and ‘Koshihikari’. The analyses revealed 12 QTLs on seven chromosomes. The ‘Nona
Bokra’ alleles of all QTLs contributed to an increase in heading date. Digenic interactions were rarely observed between QTLs.
Based on the genetic parameters of the QTLs, such as additive effects and percentage of phenotypic variance explained, these
12 QTLs are likely generate a large proportion of the phenotypic variation observed in the heading dates between ‘Nona Bokra’
and ‘Koshihikari’. Comparison of chromosomal locations between heading date QTLs detected in this study and QTLs previously
identified in ‘Nipponbare’ × ‘Kasalath’ populations revealed that eight of the heading date QTLs were recognized nearby the
Hd1, Hd2, Hd3a, Hd4, Hd5, Hd6, Hd9, and Hd13. These results suggest that the strong PS in ‘Nona Bokra’ was generated mainly by the accumulation of additive effects of
particular alleles at previously identified QTLs. 相似文献
12.
Yves Hingrat Michel Saint Jalme Frédéric Ysnel Eric Le Nuz Frédéric Lacroix 《Journal of Ornithology》2007,148(1):39-52
Studies of the movements and home-ranges of houbara bustards (Chlamydotis undulata undulata) showed sexual and seasonal differences in the use of space, with a polygynous mating system similar to an ‘exploded-lek’
or a ‘resource-defence-polygyny’, that remains undefined. We used the arthropod biomass as an index of the trophic quality
of six defined habitats and we radio-tracked 7 females and 13 males to test whether sexual and seasonal variations in habitat
use were related to resource availability, and to verify if critical resources for breeding females were monopolised by males.
We analysed habitat selection in both sexes separately. We used the habitat type composition of buffer zones around radio-locations
to study annual and seasonal habitat selection and to identify preferred habitats, using the chi-square goodness-of-fit test.
Habitat use between sexes and between seasons were compared using MANOVA based on log-ratios of habitat proportions. During
the year, and in each season, both sexes appeared to be significantly selective for habitats in comparison to their availability.
But males avoided esparto grass, while females used all habitats. Habitat use differed between sexes in the breeding season,
but not in the non-breeding season. In spring, when food resources were abundant and uniformly distributed in space, males
preferred ‘temporarily flooded areas’ and females preferred ‘reg with tall perennials’ that offered both food and cover for
brooding. Critical resources were not monopolised by males and the mating system fulfilled the definition of the ‘exploded-lek’.
Leks are key sites for reproduction and should be considered as priority areas in further conservation plans. 相似文献
13.
Localization of the rice stripe disease resistance gene, Stv-bi, by graphical genotyping and linkage analyses with molecular markers 总被引:4,自引:0,他引:4
Y. Hayano-Saito T. Tsuji K. Fujii K. Saito M. Iwasaki A. Saito 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(8):1044-1049
We used graphical genotyping and linkage analyses with molecular markers to determine the chromosomal location of the rice
stripe disease resistance gene, Stv-b
i
. The stripe resistance gene from the indica rice (Oryza sativa) cv ‘Modan’ was introgressed into several Japanese rice varieties. We found 4 RFLP markers in ‘Modan’, five susceptible parental
rice varieties (‘Norin No. 8’, ‘Sachihikari’, ‘Kanto No. 98’, ‘Hokuriku No.103’ and ‘Koganebare’) and four resistant progeny
varieties (‘St. No. 1’, ‘Aichi No. 6’, ‘Aoisora’ and ‘Asanohikari’). Graphical genotyping of the resistant progeny revealed
a chromosomal segment ascribable to ‘Modan’ and associated with stripe resistance. The chromosomal segment from ‘Modan’ was
located at 35.85 cM on chromosome 11. Linkage analysis using 120 F2 individuals from a cross between ‘Koshihikari’ (susceptible) and ‘Asanohikari’ (resistant) revealed another 8 RFLP markers
in the same chromosome. We performed a bioassay for rice stripe resistance in F3 lines of the F2 individuals using infective small brown planthoppers and identified an 1.8-cM segment harboring the rice stripe disease resistance
gene, Stv-b
i
, between XNpb220 and XNpb257/ XNpb254. Furthermore, Stv-b
i
was linked by 0.0 cM to a RFLP marker, ST10, which was developed on the basis of the results of RAPD analysis. These DNA
markers near the Stv-b
i
locus may be useful in marker-assisted selection and map-based cloning of the Stv-b
i
gene.
Received: 26 September 1997 / Accepted: 4 November 1997 相似文献
14.
Fotini G. Skiada Katerina Grigoriadou Eleftherios P. Eleftheriou 《Central European Journal of Biology》2010,5(6):839-852
The effects of six basal media on in vitro shoot proliferation of the greek grapevines Vitis vinifera L. cv. ‘Malagouzia’ and ‘Xinomavro’ were investigated. Galzy and Zlenco proved to be the most effective for ‘Malagouzia’
and ‘Xinomavro’, respectively. If only BA was present in the medium, shoot development was poor and the plantlets were chlorotic.
When the medium was supplemented with BA and NAA, growth was enhanced. The best ratio (in μM) of growth regulators was 0.5/0.3
for ‘Malagouzia’, and 0.1/0.03 for ‘Xinomavro’, which resulted in the highest number of microshoots per explant and greatest
proliferation rate. The development of ‘Malagouzia’ and ‘Xinomavro’ explants at 21±2 and 26±2°C was also investigated, revealing
the higher temperature to be more effective. Regarding rooting, 0.5 μM IBA improved root formation at 26°C for ‘Malagouzia’
and 0.5 μM IBA at 21°C for ‘Xinomavro’. Moreover, 0.5 μM IBA resulted in a higher rooting percentage (>95%) and proved to
be more beneficial for the overall morphological appearance of the plantlets of ‘Malagouzia’. After acclimatization, survival
of microshoots cultivated in media with IBA was higher than those in NAA. 相似文献
15.
Comparative microhabitat use of cyprinid larvae and juveniles in a lotic floodplain channel 总被引:1,自引:0,他引:1
Gordon H. Copp 《Environmental Biology of Fishes》1992,33(1-2):181-193
Synopsis The microhabitat of six cyprinids in a braided side-channel of the Upper Rhône River, France, was studied June to September 1985, using point abundance sampling by electrofishing. Correspondence analysis of the samples-by-species data and Jacob&s electivity index (calculated from the availability and exploitation of eight environmental variables) revealed three groups of species: (1) Leuciscus cephalus and Alburnus alburnus, which used relatively similar microhabitat during both larval and 0 + juvenile development; (2) Rutilus rutilus, Leuciscus leuciscus and Chondrostoma nasus, which used different microhabitats as larvae but whose microhabitat overlapped notably during 0 + juvenile development; (3) and Gobio gobio, whose juvenile microhabitat overlapped only marginally with that of other 0 + juveniles (no data were available on larvae). Overlap in microhabitat use by 0 + juveniles increased notably during a period of reduced discharge, when the amount of available vegetal and ligneous structures decreased; while most species exploited the increased area of shallow waters, juvenile A. alburnus appeared to be the only species that exploited the deeper waters off the channel&s steeper banks. Although not quantified, numerous field observations of predation threat, particularly during the period of reduced discharge (which reduced the amount of cover), suggest that predation risk may influence the microhabitat use of young fishes. Compared with similar species in European lakes, the overlap in microhabitat use of these fluvial cyprinids appears to be more intensive. 相似文献
16.
Hoffmann S Di Gaspero G Kovács L Howard S Kiss E Galbács Z Testolin R Kozma P 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(3):427-438
Vitis vinifera ‘Kishmish vatkana’, a cultivated grapevine from Central Asia, does not produce visible symptoms in response to natural or
artificial inoculation with the fungus Erysiphe necator Schwein., the casual agent of powdery mildew. ‘Kishmish vatkana’ allowed pathogen entry into epidermal cells at a rate comparable
to that in the susceptible control Vitis vinifera ‘Nimrang’, but was able to limit subsequent hyphal proliferation. Density of conidiophores was significantly lower in ‘Kishmish
vatkana’ (33.6 ± 8.7 conidiophores mm−2) than in ‘Nimrang’ (310.5 ± 24.0 conidiophores mm−2) by 120 h after inoculation. A progeny of 310 plants from a ‘Nimrang’ × ‘Kishmish vatkana’ cross were scored for the presence
or absence of visible conidiophores throughout two successive seasons. Phenotypic segregation revealed the presence of a single
dominant allele termed Resistance to Erysiphe necator 1 (REN1), which was heterozygous in ‘Kishmish vatkana’. A bulked segregant analysis was carried out using 195 microsatellite markers
uniformly distributed across the entire genome. For each marker, association with the resistance trait was inferred by measuring
in the bulks the ratio of peak intensities of the two alleles inherited from ‘Kishmish vatkana’. The phenotypic locus was
assigned to linkage group 13, a genomic region in which no disease resistance had been reported previously. The REN1 position was restricted to a 7.4 cM interval by analyzing the 310 offspring for the segregation of markers that surrounded
the target region. The closest markers, VMC9H4-2, VMCNG4E10-1 and UDV-020, were located 0.9 cM away from the REN1 locus.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Monica Santa-Maria Kenneth V. Pecota Craig G. Yencho George Allen Bryon Sosinski 《Plant Cell, Tissue and Organ Culture》2009,97(1):109-117
Sweetpotato (Ipomoea batatas L.) is an important crop in North Carolina with annual production of 0.33 million tons, accounting for 37% of total US supply
(USDA, Louisiana Farm Reporter 8(12), August 2008). To target industrial use, novel high-starch industrial-type varieties that contain more than 30% dry matter were developed
by conventional breeding methods. In vitro cultures from selected genotypes were established using meristem culture. To establish
regeneration procedures that could be coupled with transformation experiments, conditions for the induction of rapid shoot-organogenesis
in leaf explants were compared using varying concentrations of the auxins ‘NAA’, ‘IAA’, ‘2,4-D’, and ‘4-FA’ either alone or
in combination with zeatin riboside. Regeneration efficiencies, defined as the number of explants developing shoots out of
the total number tested, were as high as 57% for the best genotypes, with a significant genotype-dependent response observed
in all the hormone regimes evaluated. In all treatments, shoot regeneration was observed within 2 months. Our results led
to the establishment of optimized in vitro regeneration procedures for the novel high-starch sweetpotato (SP) genotypes ‘DM01-158’,
‘FTA94’, ‘FT489’, and ‘PDM P4’ that are rapid and reliable. 相似文献
18.
Pedro Francisco Quintana-Ascencio Idoia Caballero José Miguel Olano Adrián Escudero Maria José Albert 《Population Ecology》2009,51(2):317-328
Habitat heterogeneity may influence plant demography because conditions for survival, growth, and reproduction vary within
a species’ range. We assessed the role of microhabitat spatial structure on the demography of Helianthemum squamatum, a shrubby gypsum specialist endemic to the Iberian Peninsula. We evaluated the demographic effect of microhabitat spatial
variation using an approach that combined cellular automata with matrix population models, and included environmental and
demographic stochasticty. We collected data on seed bank (2003–2005), seedling emergence (2003–2006), and adult survivorship
(2004–2007) for H. squamatum in two independent blocks with different grazing intensity in Belinchón (Cuenca, Spain). We built spatial scenarios for each
block based on field data of cover and spatial pattern of four microhabitats: lichenic crust, litter, H. squamatum, and shrub. Seedling survivorship was affected by year, block, and microhabitat, with individuals emerging under conspecifics
having the highest survival rate and on litter the lowest in both blocks, whereas the effect of crust and other shrubs differed
across blocks. Our models indicated population increase in the block with low grazing, but population decline in the block
with intense grazing. We hypothesize that higher pressure of livestock grazing and trampling leads to a shift in relative
microhabitat suitability for crust and shrub. This potential effect of grazing on spatial demographic variation opens interesting
questions for future research. We emphasize the importance of considering microhabitat spatial structure when evaluating management
and conservation strategies.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
20.
Costello MJ 《Experimental & applied acarology》2007,42(3):197-208
Sulfur is the oldest and most widely used fungicide in the vineyards of California, where it is used for control of powdery
mildew (Uncinula necator [Schw.] Burr). For decades, sulfur use has been associated with outbreaks of Tetranychus pacificus McGregor (Acari: Tetranychidae) on cultivated grapes in the San Joaquin Valley. I undertook large-scale field studies to
test this association, to evaluate the impact of sulfur on Galendromus occidentalis (Nesbit) (Acari: Phytoseiidae), a major predator of T. pacificus, and to determine if timing of sulfur applications with respect to grape bloom has an impact on T. pacificus density. The studies took place in a 32 ha vineyard in Fresno County, and all fungicide applications were made with commercial-scale
equipment. In 1998 a ‘high sulfur’ treatment, a combination of wettable sulfur and sulfur dust, was compared to ‘low sulfur,’
in which demethylation inhibitor (DMI) fungicides partially substituted for sulfur. In 1999 treatments were ‘sulfur,’ ‘DMI,’
‘sulfur pre-bloom’ (here sulfur was applied prior to grape bloom, in late May, and then DMIs were applied until mid-season)
and ‘sulfur post-bloom’ (the reverse of ‘sulfur pre-bloom’). In each year, the T. pacificus population increase came after the end of fungicide applications, and results clearly show a relationship between sulfur
use and T. pacificus density. In 1998, mean T. pacificus density was 2.7 times higher and mean G. occidentalis density 2.5 times higher in ‘high sulfur’ compared to ‘low sulfur.’ In 1999, the highest T. pacificus counts were in the ‘sulfur’ and ‘sulfur pre-bloom’ treatments, 4.8 times higher than ‘sulfur post-bloom’ and 2 times higher
than ‘DMIs.’ Density of G. occidentalis was 2.3 times as high in ‘sulfur’ or ‘sulfur pre-bloom’ than ‘DMIs.’ The predator/prey ratio was not significantly different
among treatments in 1998, but in 1999 it was highest in the ‘sulfur pre-bloom’ treatment. In 1999, density of Homeopronematus anconai (Baker) (Acari: Tydeidae) was 2.7 times higher in ‘sulfur pre-bloom’ compared to ‘sulfur,’ and higher by 2.7 times in ‘DMI’
compared to ‘sulfur post-bloom,’ suggesting a negative effect of sulfur on this tydeid. These results do not support the hypotheses
that the cause of the increase in T. pacificus density is due to negative effects of sulfur on phytoseiids or tydeids. Rather, it appears that a plant-based explanation
is likely, first, because of the differences in pre-bloom versus post-bloom sulfuring, and second, because of the long lag
time between the end of the sulfur applications and the corresponding increase in spider mite density. 相似文献