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1.
The host suitability of the oriental fruit fly, Bactrocera dorsalis (Hendel), for development of Biosteres arisanus (Sonan), a braconid parasitoid, was compared with three other fruit fly species, namely, Mediterranean fruit fly, Ceratitis capitata Weidemann, melon fly, Bactrocera cucurbitae Coquilett, and Malaysian fruit fly, Bactrocera latifrons (Hendel). In addition, effects of five different fruit species, namely, Carica papaya L. (solo papaya), Musa sapientum (L.) O. Ktze. (apple banana), Mangifera indica (L.) (Haden mango), Terminalia catappa (L.) (false kamani), and Citrus aurantiifolia (Christman) Swingle (common lime), on the parasitization rate of B. dorsalis and sex ratio of parasitoid progenies were evaluated. Effects of host egg to female B. arisanus ratios on parasitoid progeny yields were likewise determined. The host suitability of fruit flies for development of B. arisanus was ranked as: B. dorsalis>C. capitata=B. latifrons=B. cucurbitae. Based on percent parasitization of B. dorsalis, preference of B. arisanus females for host eggs varied with fruit species, however, preferential oviposition displayed by female parasitoids did not influence sex ratios of subsequent parasitoid progenies. Increases in host egg to female parasitoid ratios of 5:1, 10:1, 20:1, 25:1, and 30:1 corresponded with increases in parasitoid progeny yield reaching a plateau at 20:1. 相似文献
2.
Konrad Thorisson 《Environmental Biology of Fishes》1994,40(1):23-36
Synopsis Small volumes of food in ‘stomach’, large proportions of empty ‘stomachs’ and small maximum sizes of prey during metamorphosis
of cod,Gadus morhua, all point to an energy crisis during this developmental interval. The small size of the developing stomach of the 10–14
mm long cod may be partly responsible for the above mentioned difficulties during metamorphosis. A hypothesis based on Hjort's
‘critical stage theory’ is proposed, adding another critical interval at metamorphosis. Based on the presented data on cod
and reports on other species in the literature, the new critical interval is discussed for larvae of marine fish species in
general. 相似文献
3.
K. Thórarinsson 《BioControl》1990,35(1):107-118
Measurements of body length of cottony-cushion scales,Icerya purchasi Maskell, are presented. Although length increased markedly with developmental stage, the length distributions of successive
stages were found to overlap, making length an imperfect indicator of stage andvice versa. The likelihood of parasitism by the fly,Cryptochaetum iceryae (Williston), was found to increase with increasing scale size when scales of different sizes were concurrently made available
to the parasites under field conditions. Also, parasite loads (no. of parasites per parasitized host) were found to increase
with host size. The size ofC. iceryae pupae was found to depend on the developmental stage of the scale host in which pupation took place — the more developed
(larger) the host, the larger the pupa. This result suggests that parasite growth is food limited in the smaller hosts, and
that therefore its apparent preference for larger hosts is to the parasite's advantage.
相似文献
4.
Females of the larval parasitoidCotesia glomerata (L.) use plant-associated cues to locate their lepidopteran host,Pieris rapae L. In this study we investigated the influence of four host plant species,Brassica oleracea var.acephala (‘Vates’ kale),Tropaeolum majus (nasturtium),Lunaria annua (honesty), andCleome spinosa (spider flower), on two components of the host selection process inC. glomerata, namely, attraction and host acceptance. Choice tests in a flight tunnel showed that parasitoids were attracted to some host
plant species more than to others in the absence of host larvae.B. oleracea was the most attractive plant species, followed byL. annua, T. majus, andC. spinosa. In previous studies it was shown thatB. oleracea carries highly suitable hosts forC. glomerata and that, in the field, parasitization rates on this plant were the highest. When host larvae were reared on the four host
plant species and then transferred to a common substrate (B. oleracea var.capitata, cabbage), plant species that had served as diet for the hosts did not have a significant effect on acceptance for parasitization.
Thus, parasitoids were attracted to host plant species differentially, but they did not discriminate among host larvae based
on the dietary history of their hosts. ForC. glomerata, it appears that phytochemistry mediates host selection more by influencing parasitoid attraction than it does by affecting
host acceptance. 相似文献
5.
6.
Maculinea butterflies show social parasitism via obligatory myrmecophily as their larvae are adopted and raised to pupation by Myrmica ants. Suitable hosts differ for different Maculinea species, and host ant specificity can further differ at the population-level. Although early studies suggested single ant
species as main hosts for each Maculinea species, it has recently become clear that their host ant specificity is more complex. Maculinea alcon and Maculinea ‘rebeli’ have variously been separated according to adult and larval morphology, phenology, and their use of different ecosystems,
including host plant and host ant species. However, recent genetic evidence has questioned their separation as good species.
Here we compare the use of host ants by M. alcon and M. ‘rebeli’ at the regional scale in NE-Hungary and Transylvania (Romania), where molecular studies have found no species-level separation
between the two forms. We opened 778 nests of Myrmica ants and searched for Maculinea specimens (larvae, pupae and exuviae) shortly before imago emergence from the nest in seven M. alcon sites, six M. ‘rebeli’- sites and one site where both M. alcon and M. ‘rebeli’ are syntopic. In all, Maculinea caterpillars were found in the nests of seven different ant species (M. alcon was recorded mainly with Myrmica scabrinodis and occasionally with M. salina and M. vandeli; M. ‘rebeli’ used mainly M. scabrinodis, M. sabuleti and M. schencki and occasionally M. lonae and M. specioides). Myrmica scabrinodis was found to be a general host of both M. alcon and M. ‘rebeli’, which is the first record for a common host ant of these two closely related butterflies within the same region. However
there were also differences in host ant use patterns between the sites occupied by the two Maculinea taxa, which reflect differences in Myrmica communities between the two types of habitat. Possible explanations for the similar but not identical host use patterns of
M. alcon and M. ‘rebeli’, and their relevance for the question of whether they are separate species are discussed.
Received 27 November 2007; revised 28 May 2008; accepted 11 June 2008. 相似文献
7.
Fopius arisanus (Sonan) and Diachasmimorpha tryoni (Cameron) are two important solitary endoparasitoids of tephritid fruit flies. The former species attacks host eggs while the latter attacks host larvae, and both species emerge as adults from the host puparium. This study investigated intrinsic competition between these two parasitoids, as well as aspects of intraspecific competition within each species in the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Parasitization by F. arisanus resulted in direct mortality of host eggs and prolonged development of host eggs and larvae. Superparasitism by F. arisanus was uncommon when mean parasitism per host patch was <50%, but increased with rising rates of parasitism. Superparasitism by D. tryoni was more common. In superparasitized hosts, supernumerary individuals of F. arisanus were killed through physiological suppression, while supernumerary larvae of D. tryoni were killed mainly through physical attack. In multiparasitized hosts, dissections showed that 81.6% of D. tryoni eggs in the presence of F. arisanus larvae died within 3 days, indicating physiological inhibition of egg hatch. Rearing results further showed that F. arisanus won almost all competitions against D. tryoni. The ratio of D. tryoni stings to ovipositions was lower in hosts not previously parasitized by F. arisanus than in parasitized hosts, suggesting that D. tryoni can discriminate against parasitized hosts. The mechanism that F. arisanus employs to eliminate D. tryoni is similar to that it uses against all other larval fruit fly parasitoids so far reported. The results are discussed in relation to the competitive superiority of early acting species in fruit fly parasitoids, and to a possible competitive-mediated mechanism underlying host shift by D. tryoni to attack non-target flies following the successful introduction of F. arisanus in Hawaii. 相似文献
8.
Patrick H. Brown Steven A. Weinbaum Geno A. Picchioni 《Trees - Structure and Function》1995,9(3):158-164
The influence of alternate bearing on nutrient utilization and total tree nutrient content was investigated in mature pistachio
(Pistacia vera L. cv Kerman trees). Removal of N, P and Zn in fruit and abscised leaves of cropping (‘on’) trees averaged 5, 6, and 2 times,
respectively, the removal in abscised leaflets of the non-fruiting, ‘off’ year trees. One hundred and thirty-five kg N, 131
kg K, 86 kg Ca, 39 kg Mg and 18 kg P per hectare were removed in fruits and abscised leaves in ‘on’ year trees. Tree nutrient
contents and, presumably, the size of nutrient storage pools in dormant trees varied between ‘on’ and ‘off’ years. There was
22% and 14% more N and P, respectively, in dormant trees following ‘off’ than ‘on’ years. The greater N and P accumulation
in ‘off’ year trees is depleted in support of the large fruit demand for N and P during ‘on’ years. In contrast to N and P,
there was greater K and Ca accumulation in perennial tree parts during ‘on’ years than during ‘off’ years. The greater K accumulation
in perennial tree parts and approximately 30% greater removal of K in annual organs during ‘on’ than ‘off’ years suggests
that K uptake could be 4 times higher in ‘on’ year trees than in (non-cropping), ‘off’ year trees. 相似文献
9.
Larger male Caribbean fruit flies are more likely to be chosen as mates and defeat rivals in territorial contests. Yet males are smaller than females. Adaptive explanations for relatively small male size include (1) acceleration of male development to maximize female encounter rates, (2) selection for greater female size to increase fecundity, and (3) selection for body sizes most suitable for sexually dimorphic degrees of mobility, speed, and distance flight. None of these unambiguously accounts for the degree of sexual dimorphism. Male development is not accelerated relative to that of females. On average, males remain inside fruit longer than females and those males with extended development periods are smaller than more rapidly developing individuals. There is no evidence that female enlargement alone, presumably for greater fecundity, has generated the degree of dimorphism in the Caribbean fruit fly or other fruit flies. The relationship between dimorphism and mean female body size in 27 species of Tephritidae is the opposite of what would be predicted if differences in dimorphism were due to differences in unilateral female enlargement. Larger size in a species or in one sex of a species may be an adaptation for extensive flight. In general, among 32 species of fruit flies, as body size increases, wing shape becomes progressively more suited for distance flight. However, there are important exceptions to this correlation. Both sexual selection and nonadaptive allometries may contribute to the range of dimorphisms within the family. 相似文献
10.
We tested the efficacy of synthetic host marking pheromone (HMP) of the European cherry fruit fly (R. cerasi) as a fruit-infestation-reducing-agent in an experimental cherry orchard. Two different pheromone deployment strategies were compared: covering entire tree canopies with synthetic HMP or treating only one half (top to bottom or lower half) of the tree canopy. Pheromone application caused a tenfold reduction in fruit infestation if the entire tree canopy was covered (0.226 vs 0.021 pupae/fruit in untreated and treated trees, respectively). Results show, nevertheless, that a significant reduction in fruit infestation can be achieved by treating only one half of tree canopies (top to bottom) (0.021 vs 0.048 pupae/fruit when comparing totally vs partially treated trees). We conclude that synthetic cherry fruit fly HMP has potential as a fruit fly management tool, especially in cases where organically grown fruit reaches high market values. 相似文献
11.
Jeyasankar Alagarmalai Mor Grinberg Rafael Perl-Treves Victoria Soroker 《Journal of Insect Behavior》2009,22(5):375-387
This study examined the host-selection ability of the broad mite Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae). To make long-distance-shifts from one host plant patch to another, broad mites largely depend
on phoretic association with whiteflies. However, the host plants of whiteflies and broad mites are not necessarily the same.
We determined the host-preference and acceptance of free-moving and phoretic broad mites using two behavioral bioassays. We
used a choice test to monitor host selection by free-moving mites. In the case of phoretic mites, we compared their rate of
detachment from the phoretic vector Bemisia tabaci placed on leaves taken from various host plants. The suitability of the plant was further determined by monitoring mite’s
fecundity and its offspring development. We compared the mites’ responses to young and old cucumber (Cucumis sativus cv. ‘Kfir’) leaves (3rd and 8–9th leaf from the apex, respectively), and two tomato (Solanum lycopersicum cvs. ‘M82’ and ‘Moneymaker’). Free-moving mites of all stages and both sexes preferred young cucumber leaves to old cucumber leaves and preferred young
cucumber rather than young tomato leaves, demonstrating for the first time that broad mites are able to choose their host
actively. As for phoretic mated females, although eventually most of the mites abandoned the phoretic vector, the rate of
detachment from the whitefly vector was host dependent and correlated with the mites’ fitness on the particular host. In general,
host preference of phoretic female mites resembled that of the free-moving female. Cues used by mites for host selection remain
to be explored. 相似文献
12.
Daniel R. Papaj Susan B. Opp Ronald J. Prokopy Timothy T. Y. Wong 《Journal of Insect Behavior》1989,2(2):241-254
Groups of female Mediterranean fruit flies, Ceratitis capitata(Wiedemann), were exposed for several days to one of three host fruit species. Oviposition-site acceptance behavior was subsequently assayed on five fruit species. Females accepted most often the fruit to which they were exposed. Females exposed to a small fruit, mock orange, accepted other fruit species less often as the size of the fruit increased; females exposed to a large fruit, sweet orange, accepted other fruit species more often as the size of the fruit increased. This tendency for experience with one host fruit species to alter differentially behavioral responses to alternative host fruit species has been defined as cross-induction. In contrast, females exposed to a medium fruit, kumquat, were not cross-induced: females accepted the medium fruit very often and rejected all other fruit species to approximately the same degree regardless of size. When females were exposed to small, medium, or large fruit and tested on spherical wax fruit models of a variety of sizes, patterns similar to those with real fruit were observed. Whereas naive females generally accepted a given model as frequently as real fruit of a similar size, experienced females generally accepted models much less frequently than real fruit. In a final experiment, females were exposed to different fruits and tested on spherical wax models treated with fruit chemicals. Experienced females generally accepted fruit-treated spheres more often than untreated spheres. In addition, females usually accepted most often models treated with chemicals from the fruit to which they were exposed. Two hypotheses about the mechanism by which experience alters fruit acceptance— termed the sliding template and closing window hypotheses— are presented. Results of fruit and model acceptance by naive and experienced females support the latter hypothesis. 相似文献
13.
Zhentu Ying Thomas L. Davenport Taifang Zhang Raymond J. Schnell Cecile L. Tondo 《Plant Molecular Biology Reporter》2009,27(3):374-380
‘Hass’ is the most popular avocado (Persea americana Mill.) cultivar in the world. It has been characterized as a crop requiring cross-pollination. However, the potential extent
of self-pollination and the most effective pollen donors (best cross-pollinizing cultivars) have not been determined. In this
study, 56 markers were screened against ‘Hass’ and nine commonly used pollinizing cultivars grown in southern California:
‘Bacon,’ ‘Ettinger,’ ‘Fuerte,’ ‘Harvest,’ ‘Lamb Hass,’ ‘Marvel,’ ‘Nobel,’ ‘Sir Prize,’ and ‘Zutano.’ Seventeen microsatellite,
i.e., simple sequence repeat (SSR) markers, were found to be very promising for paternity analysis. Four highly informative
SSR markers were selected to accurately and unequivocally identify pollen parents of ‘Hass’ fruit from an orchard interplanted
with these pollinizing cultivars. From 2003 to 2006, 7,984 ‘Hass’ fruit were analyzed for their paternity. Overall, the pollen
parents of 99.55% of the analyzed fruit could be unequivocally identified with a single multiplex polymerase chain reaction
(PCR). Only 36 fruits (<0.45%) required a second PCR reaction to reach unequivocal identification of the pollen parents. 相似文献
14.
C. M. Felland L. A. Hull B. A. Barrett A. L. Knight J. W. Jenkins P. A. Kirsch D. R. Thomson 《Entomologia Experimentalis et Applicata》1995,74(2):105-114
Mating disruption treatments for the tufted apple bud moth (TABM),Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and
by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component
isomeric blend ofE-11-tetradecen-1-ol (E11-14:OH) andE-11-tetradecenyl acetate (E11-14:Ac). A 50∶50 ratio of these two components was used in standard monitoring septa and in mating
disruption treatments released from either hollow fibers (‘fiber’) or PVC tubes (‘PVC’). Other pheromone blends tested included
a 90∶10 ratio of E11-14: Ac and E11-14:OH (‘EAc’) and its reverse (‘EOH’), mixture ‘EAc’ with 30% of the Z-isomers (‘low AEc’),
and a blend similar to the preceding with 2% Z9-12:Ac (‘generic’). These other blends were released from multi tube tape (‘tape’)
or Shin-Etsu type rope (‘rope’) dispensers. Seasonal dispenser release rate in mg ha−1 h−1 was ca. 30 for the ‘rope’ dispensers, 14 for ‘PVC’ and 6 for ‘fiber’. ‘EAc-tape’ and ‘EOH-tape’ were equally effective in
reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also
reduced fruit injury. ‘EAc-rope’, ‘fiber’ and ‘PVC’ also were generally effective; whereas, the ‘low EAc’ and ‘generic’ treatments
reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction
in trap capture for the ‘low EAc-rope’ and ‘genericrope’ treatments. Traps loaded with ‘fiber’ dispensers captured more male
TABM than the other treatments in non-pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone
treatments. ‘EAc-rope’ and the ‘TABM’ treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9
(10.1), respectively, for the redbanded leafroller,Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller,Choristoneura rosaceana (Harris). 相似文献
15.
Samira A. Mohamed Robert A. Wharton Georg von Mrey Fritz Schulthess 《Biological Control》2006,39(3):262-271
Tetrastichus giffardii Silvestri is a gregarious eulophid endoparasitoid of several tephritid fruit fly species. Host stage suitability was studied using nine age groups of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), namely, eggs less than 24 h and between 24 and 48 h old, and 1- to 7-day-old larvae. Life table studies for T. giffardii using C. capitata as host were done at 26 ± 5 °C and 55–60% RH. Egg load in relation to age of the female parasitoid was also assessed as was the effect of host deprivation on adult longevity. Host acceptance and suitability were examined with respect to eight species of tephritids. Potential hosts so tested were five Ceratitis species, the Medfly, C. capitata, the mango fruit fly, Ceratitis cosyra (Walker), the Natal fruit fly, Ceratitis rosa Karsch, Ceratitis fasciventris (Bezzi), and Ceratitis anonae Graham; two Bactrocera species, the melon fruit fly, Bactrocera cucurbitae (Coquillett) and the newly invasive Bactrocera invadens Drew, Tsuruta, and White; and one Dacus species, the lesser pumpkin fly, Dacus ciliatus Loew. No parasitoids were obtained from eggs while all larval stages were suitable though at varying degrees. Parasitism and number of progeny was related to host age in a curvilinear manner with maxima at 4- to 5-day-old larvae. By contrast, development time decreased with age of host larvae while sex ratio was not affected. The intrinsic rate of increase was 0.17 ± 0.01; gross and net reproductive rates were 64.9 ± 4.3 and 44.9 ± 3.8, respectively. Non-ovipositing females lived significantly longer than ovipositing ones. The females accepted all host species tested, but only C. capitata, D. ciliatus and, to a much lesser extent, C. cosyra were suitable. In the remaining host species, most eggs were encapsulated. In C. capitata and D. ciliatus, percent parasitism was similar, but number of progeny was lower and the sex ratio, as the proportion of females, was higher when the parasitoid was reared on D. ciliatus. Progeny per puparium were also similar for the two hosts. In the light of these results it can be concluded that T. giffardii has a narrow host range, but it attacks and successfully develops in larvae representing a wide range of ages. 相似文献
16.
The larvae of Dacus (Leptoxyda) persicus (aak fruit fly) are key predispersal seed predators in Calotropis procera (Asclepiadaceae). Based on fruit characteristics, two morphs are distinguishable in C. procera viz., the soft-fruited morph (SF morph) and the hard-fruited morph (HF morph). The work reported here examined whether the
fruit characteristics influenced the infestation by the aak fruit fly and, if so, what mechanism(s) were operative. Fruits
in the SF morph were significantly more acceptable to the aak fruit fly than those of the HF morph irrespective of their size
class and availability or fly population density. A general ranking of fruit acceptability for oviposition by the aak fruit
fly within the fruit size class was: size class III ≥ size class II > size class I and IV. The negative relationship between
fruit infestation and pericarp toughness, which is suggestive of trade-offs between the fly’s oviposition obligation and energy/time
(predation risk) constraint, was found to correlate with the requirement of greater force to puncture the pericarp in the
hard fruits. Lower penetrability of the pericarp in the hard fruits appeared to be primarily due to the thickness of pericarp
and secondarily on account of the thickened walls of endocarpic–mesocarpic cells in the inner pericarpic layer. The present
data point to the existence of two fruit morphs in C. procera differing in the acceptability of fruits for oviposition by the aak fruit fly primarily on account of toughness and internal
structure of the pericarp. 相似文献
17.
Breeding for fruit quality traits is complex due to the polygenic (quantitative) nature of the genetic control of these traits.
Therefore, to improve the speed and efficiency of genotype selection, attention in recent years has focused on the identification
of quantitative trait loci (QTLs) and molecular markers associated with these QTLs. However, despite the huge potential of
molecular markers in breeding programmes, their implementation in practice has been limited by the lack of information on
the stability of QTLs across different environments and within different genetic backgrounds. Here, we present the results
from a comprehensive analysis of the inheritance of fruit quality traits within a population derived from a cross between
the apple cultivars ‘Telamon’ and ‘Braeburn’ over two successive seasons. A total of 74 different QTLs were identified for
all the major fruit physiological traits including fruit height, diameter, weight and stiffness, flesh firmness, rate of flesh
browning, acidity, the oBrix content and harvest date. Seventeen of these QTLs were ‘major’ QTLs, accounting for over 20%
of the observed population variance of the trait. However, only one third (26) of the identified QTLs were stable over both
harvest years, and of these year-stable QTLs only one was a major QTL. A direct comparison with published QTL results obtained
using other populations (King et al., Theor Appl Genet 102:1227–1235, 2001; Liebhard et al., Plant Mol Biol 52:511–526, 2003)
is difficult because the linkage maps do not share a sufficient number of common markers and due to differences in the trait
evaluation protocols. Nonetheless, our results suggest that for the six fruit quality traits which were measured in all populations,
nine out of a total of 45 QTLs were common or stable across all population × environments combinations. These results are
discussed in the framework of the development and application of molecular markers for fruit quality trait improvement. 相似文献
18.
The behaviour of female cabbage root flies during host plant selection was studied in the laboratory using brassica plants
growing in backgrounds of bare soil, clover, grass, peas and four non-living materials. Gravid females landed about twice
as often on brassica plants growing in bare soil than on comparable plants growing amongst non-host plants. Once a receptive
female landed on a brassica plant, the female made, on average, four ‘spiral flights’ and two jumps on and off the plant before
laying alongside the plant. Surrounding a brassica plant with a diverse background altered the behaviour of the flies, so
that the spiral flights around the host plant were replaced by short hops between nearby vertical objects. The loss of contact
and recontact with the host plant then prevented the females from accumulating sufficient contacts with the host plant to
be stimulated to lay. Spiral flights around host plants appear to determine whether or not flies will lay alongside host plants.
Flies in mixed plantings have a reduced rate of settling on the host plant, and a higher rate of locomotion, because they
land frequently on non-host plants. Hence, visual stimuli appeared to have greater effects than, chemical or mechanical barriers
in deterring flies from laying alongside brassica plants in diverse backgrounds. In ‘choice’ situations, backgrounds of real
plants reduced oviposition alongside brassica plants by at least 50%. In ‘no-choice’ situations, flies laid similar numbers
of eggs alongside all brassica plants irrespective of plant background or plant size. If numbers of fly eggs are to be reduced
on commercial brassica crops by undersowing the crops with clover, plants growing in bare soil may also have to be included
to provide the flies with sites preferred for oviposition. 相似文献
19.
QTL mapping of aroma compounds analysed by headspace solid-phase microextraction gas chromatography in the apple progeny ‘Discovery’ × ‘Prima’ 总被引:2,自引:0,他引:2
F. Dunemann D. Ulrich A. Boudichevskaia C. Grafe W. E. Weber 《Molecular breeding : new strategies in plant improvement》2009,23(3):501-521
Improving fruit quality of apple varieties is an important but complex breeding goal. Flavour is among the key factors of
apple fruit quality but in spite of the analytical and biochemical knowledge about volatiles little is known about the genetic
and molecular bases of apple aroma. The aim of this study was to use a saturated molecular linkage map of apple to identify
QTLs for aroma compounds such as alcohols, esters and terpenes, but also for a number of unidentified volatile compounds (non-targeted
analysis approach). Two parental genetic maps were constructed for the apple cultivars ‘Discovery’ and ‘Prima’ by using mainly
AFLP and SSR markers. ‘Discovery’ and ‘Prima’ showed very different volatile patterns, and ‘Discovery’ mostly had the higher
volatile concentrations in comparison with the Vf-scab resistant ‘Prima’ which has its origin in the small-fruited apple species Malus floribunda. About 50 putative QTLs for a total of 27 different apple fruit volatiles were detected through interval mapping by using
genotypic data of 150 F1 individuals of the mapping population ‘C3’ together with phenotypic data obtained by head-space solid phase microextraction
gas chromatography. QTLs for volatile compounds putatively involved in apple aroma were found on 12 out of the 17 apple chromosomes,
but they were not evenly dispersed. QTLs were mainly clustered on linkage groups LG 2, 3 and 9. In a first attempt, a LOX
(lipoxygenase) candidate gene, putatively involved in volatile metabolism, was mapped on LG 9, genetically associated with
a cluster of QTLs for ester-type volatiles. Implications for aroma breeding in apple are discussed. 相似文献
20.
B. Viertel 《Hydrobiologia》1992,234(3):151-173
The influence of particle size, initial particle concentration and larval stage on the ingestion rate, ‘retention efficiency’,
and filtering rate of anuran larvae with varying filter apparatus anatomy and different life histories was investigated for
four species. Larvae of premetamorphic Stages 28 and 32 and prometamorphic Stage 40 were selected for filtering experiments
on the basis of their different growth rates. Three different sizes of silica gel particles were offered as mock food. Particle
concentration was measured photometrically. The Michaelis-Menten model was used to describe the dependency of ingestion rate,
filtering rate, and ‘retention efficiency’ upon initial particle concentration, and to calculate maximum ingestion rate, threshold
concentration, and the half-saturation constant.
(1) The highest ingestion rates, filtering rates and ‘retention efficiencies’ were achieved by Xenopus laevis larvae, followed by Bufo calamita larvae. Bufo bufo larvae lay at the opposite end of the scale. Rana temporaria larvae were placed between B. calamita and B. bufo larvae. This order is attributed to differences in life histories, especially the different breeding environments in which
these larvae occur. (2) The larger the particle size and the older the stage, the greater the tendency toward saturation of
the ingestion rate, filtering rate and ‘retention efficiency’. These filtration parameters are graded according to particle
size. The ingestion rate (number of particles), filtration rate and ‘retention efficiency’ are greatest for PS3. Ingestion
volume is greatest for PS 1. The difference between PS3 and PS2 on the one hand, and PS1 on the other, is often great; for
Stage 28 X. laevis it is very great. This shows that larvae ingest large particles more effectively, and that the most effective ingestion takes
place at Stages 28 and 32, owing to the growth function of these stages. The ability of larvae to ingest large particles effectively
is possibly a very basic phylogenetic characteristic. (3) The threshold concentration is lowest when the particles are at
their largest. In accordance with conclusions drawn by other authors, threshold feeding is attributed to regulation by buccal
pumping and mucus production. Considerable importance is attributed to threshold feeding with respect to larval adaptation
to oligotrophic environments. 相似文献