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1.
Effects of Biomanipulation on Fish and Plankton Communities in Ten Eutrophic Lakes of Southern Finland 总被引:5,自引:0,他引:5
M. Olin M. Rask J. Ruuhijärvi J. Keskitalo J. Horppila P. Tallberg T. Taponen A. Lehtovaara I. Sammalkorpi 《Hydrobiologia》2006,553(1):67-88
The effects of biomanipulation were studied in ten Finnish lakes to determine responses in fish and plankton communities and
water quality after mass removal of cyprinids. From 1997 to 2001, the fish communities shifted from the dominance of large
cyprinids to an explosion of small cyprinids and a higher proportion of piscivores in effectively biomanipulated lakes (>200 kg ha−1 3 yr−1). The biomass of cyanobacteria decreased, and the duration of the blooms shortened and shifted towards the autumn. Decreased
concentrations and slower cycling of nutrients and increased grazing by cladocerans probably affected the declined biomass
of cyanobacteria. Less intensive sediment disturbance and increased phosphorus-retention in fast growing fish biomass may
have turned the role of the fish assemblage from ‘nutrient recycler’ to ‘nutrient storage’. Increased potential grazing pressure,
higher proportion of edible algae, and lower chlorophyll a:total phosphorus ratio indicated strengthened herbivore control. A high mass removal catch in relation to trophic state,
low background turbidity, and bearable external loading favoured the successful biomanipulation, whereas intensive cyprinid
reproduction, high nutrient loading and non-algal turbidity hindered the recovery. Three important issues should be noticed
before biomanipulation in Finland: (1) careful selection of target lake, (2) well-planned, effective and long-lasting biomanipulation
and (3) sustainable management of piscivores.
An erratum to this article is available at . 相似文献
2.
Mathematical modelling as a tool for management in eutrophication control of shallow lakes 总被引:2,自引:2,他引:0
The eutrophication model Delwaq-Bloom-Switch is developed to be a functional tool for water management. Therefore it includes nutrients, algal biomass and composition as well as water transparency. A module describing the interaction between water and bottom gives the model the flexibility to deal with measures, such as a decrease of the external phosphorus loading and flushing with water differing in composition from the lake water. This paper focuses on the functional aspects of the model, the results of an application on Lake Veluwe, The Netherlands, and the implications for water management.With one set of coefficients DBS reproduces the most important characteristics of Lake Veluwe for a period of two years before measures (reduction of the external loading and flushing during the winter months) and eight years after the measures. The phosphorus concentration decreased and became growth limiting for algae instead of nitrogen and light. Both in measurements and modelling results, the algal composition changed from blue-green algae dominance to green algae and diatom dominance. Lake Veluwe had a relatively short transient phase after reduction of external loading, because high nitrate concentrations in the flushing water inhibited a long period with high phosphorus releases from the bottom.Model calculations were carried out to investigate the effects of fish stock management and optimization of flushing. Both measures are promising. 相似文献
3.
Wilfried Scharf 《Hydrobiologia》2008,603(1):105-115
Only a combination of nutrient load abatement and food-web management proved efficient for the management of water quality
in the deep stratifying Wupper Reservoir. Reduction of nutrient loading, was completed in winter 1992/1993, but resulted only
in reduced winter/spring mixing of phosphorus concentrations. Since the capacity of the diatom spring bloom to remove nutrients
from the trophogenic layer of this slightly eutrophic water-body was never exhausted, the surplus of total phosphorus available
to support summer algal growth remained unchanged. Thus, nutrient reduction alone did not improve the water quality, as expected.
Subsequent replacement of the smaller Daphnia cucullata by the larger Daphnia galeata-hyalina complex that was attributable to successful food-web management did, however, result in a shift from a turbid to a clear
water regime in 1999. Clearly, the zooplankton community, and therefore food-web structure, played an integral role in nutrient
recycling and in the repartitioning of the phosphorus pool. As diatom settling and grazing became much more tightly linked
with the appearance of the larger-bodied Daphnia galeata-hyalina complex, which exploits lower-level food resources as early as May, daphnids increasingly acted as a sink for phosphorus.
This increased export fluxes out of the pelagic zone and leaves a smaller surplus of total phosphorus to support the accumulation
of summer algae. Consequently, water transparency and total chlorophyll concentrations in summer improved with food-web restructuring,
indicating real oligotrophication of Wupper Reservoir driven by internal feedbacks.
Handling editor: S. I. Dodson 相似文献
4.
Drought-induced changes in nutrient concentrations and retention in two shallow Mediterranean lakes subjected to different degrees of management 总被引:3,自引:0,他引:3
Arda Özen Burcu Karapınar İsmail Kucuk Erik Jeppesen Meryem Beklioglu 《Hydrobiologia》2010,646(1):61-72
While extensive knowledge exists on the relationship between nutrient loading and nutrient concentrations in lakes in the
cold temperate region, few studies have been conducted in warm lakes, not least in warm arid lakes. This is unfortunate as
a larger proportion of the world’s lakes will be situated in arid climates in the future due to climate change and a larger
proportion will suffer from a higher frequency of intensive drought. We conducted a comprehensive 11–13 year mass balance
study in two interconnected shallow Mediterranean lakes in Turkey, covering a period with substantial changes in climate conditions.
The upstream lake was only affected by natural changes in nutrient loading, while the downstream lake was additionally influenced
by sewage diversion and restoration by fish removal. Contrasting to experience from north temperate lakes we found an increase
in in-lake concentrations of total phosphorus and inorganic nitrogen (ammonia as well as nitrate) in dry years despite lower
external nutrient loading, and submerged macrophytes did not increase the nitrogen retention capacity of the lakes. In contrast,
fish removal modulated the nitrogen concentration as in north temperate lakes, but the effect was not long-lasting. Our results
suggest that climate warming reduces the nutrient retention capacity of shallow lakes in the Mediterranean and exacerbates
eutrophication. Lower thresholds of nutrient loading for shifting turbid shallow lakes to a clear water state are therefore
to be expected in arid zones in a future warmer climate, with important management implications. 相似文献
5.
Gergely Boros Istvn Ttrai gnes Irma Gyrgy gnes Vri Alex Sndor Nagy 《International Review of Hydrobiology》2009,94(3):326-337
Impacts of internal nutrient loading and the role of biota in phosphorus (P) dynamics were studied in a shallow, hypertrophic, biomanipulated lake. Reduced fish stock resulted in clearing water and the development of a dense submerged vegetation by 2005. However, an abrupt shift occurred in 2007, seven years after the fish manipulation. Simultaneously, water quality deteriorated which became obvious in elevated chlorophyll‐a concentration in lake water, associated with increased biomass of fish and decay of a previously extended macrophyte cover. There were no significant differences in lake water P concentrations between the two periods (2005–2006 and 2007); however, peaks of different P forms were markedly higher in 2007 than in 2005–2006. At the same time, P content of sediment pore water declined considerably in 2007. Our mesocosm experiment, carried out in the manipulated lake, emphasize the positive role of the dominant fish species (roach) in P regeneration. We suggest that fish manipulation should be carried out every 5 year to maintain clear water conditions permanent, until the total removal of redundant nutrients accumulated in the lake ecosystem. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
C. H. D. Magadza 《Hydrobiologia》1992,232(1):73-77
A summary of current research on Lake Kariba is given. Lake Kariba is now a phosphorus limited oligotrophic lake, dependent
on annual nutrient input for the maintenance of production. Nitrogen fixation by cyanobacteria has become an important source
of nitrogen in the dry season and that fish harvesting is an important phosphorus sink. An up to date plankton composition
list has been produced and plankton biomass determined. Diving studies indicate large biomass of bivalves. The aquatic vegetation
displays both longitudinal as well as depth gradients, related to light regimes. Only preliminary data are available on mud/water
interactions, but the available data indicate considerable fluxes in the river mouth stations and shallow protected littoral
areas. The role of predatory birds and crocodiles in the fishery economy of the lake is evaluated and indicates no major conflict
between these predators and human fishing interests. The research also draws attention to pesticides in Lake Kariba as indicated
by work on fish eating birds and crocodile research. Since the publication of ‘Lake Kariba’ by Balon & Coche (1975) the research
project, THE ECOLOGY OF LAKE KARIBA, being undertaken by the University Lake Kariba Research Station constitutes the first
multidisciplinary study of the lake, 30 years after the Zambezi river was impounded at Kariba Gorge. It could have offered
a unique opportunity of comparing the lake now with what it was soon after impoundment. 相似文献
7.
Many areas of blanket mire in Britain display apparently degraded vegetation, having a limited range of ericaceous and Sphagnum species. Data are presented here from Wales from the upland locality of Drygarn Fawr (Elenydd SSSI), which is dominated overwhelmingly
by Molinia caerulea. Palaeoecological techniques were used to chronicle vegetation history and to determine the nature and timing of vegetation
changes, as an aid to devising conservation management and restoration strategies. Although for the past 2000 years the pollen
and plant macrofossil data indicate some evidence for cyclic vegetation change, they demonstrate that here the major vegetation
change post-dated the start of the industrial revolution. The palaeoecological data show a greater proportion of Sphagnum than currently. Local extinction of some species (e.g., Myrica gale) apparently took place in Medieval times, but most of the degradation and floral impoverishment apparently occurred during
the 20th Century. The implications for conservation management are far-reaching. The overwhelming dominance of Molinia is clearly unprecedented. While it was locally present for hundreds of years, some factor(s)—possibly a change in grazer
and grazing regime—encouraged its recent ascendancy in the 20th Century. Consequently, any management attempts to reduce the
pre-eminence of Molinia would not be countering an ingrained, long-established dominance. It is suggested that investigation of degraded blanket
mires elsewhere by historical and multi-proxy palaeoecological techniques—through multiple, dated cores to track species extinctions
and directional vegetation changes—would help ascertain previous mire floras and so indicate a range of restoration targets
for mire vegetation. 相似文献
8.
Tiia Pedusaar Ilkka Sammalkorpi Arto Hautala Jaana Salujõe Ain Järvalt Margus Pihlak 《Hydrobiologia》2010,649(1):95-106
Lake ülemiste, the drinking water reservoir of Estonia’s capital city Tallinn, was biomanipulated by manual removal of cyprinids
in 2004–2006 and its impact on water quality in the vegetation period was studied. A total biomass of 156 tonnes corresponding
to 160 kg ha−1 of fish, predominantly cyprinids, were removed. A decline in the unit catches of fishing was observed. The removed fish biomass
versus phosphorus concentration of the lake was considered sufficient to reduce the impact of cyprinids on water quality.
The phosphorus removed within fish biomass corresponded to 38 μg l−1 and 21% of the external phosphorus load of the fishing period. The mean total phosphorus concentration dropped from >50 to
≤36 μg l−1. However, the densities of planktivorous young-of-the-year percids remained high and the role of zooplankton grazing in improving
water quality was found non-significant or transient. The cladocerans biomass decreased and the small-sized Daphnia cucullata remained almost the only daphnid in Lake ülemiste during and after the manipulation. Predomination of filamentous cyanobacteria
was replaced by a more diverse phytoplankton composition and co-domination of micro- and pico-sized colonial cyanobacteria
during summer. Mean phytoplankton biomass decreased from 15 to 6 mg l−1 primarily as a result of decreased in-lake TP availability. The Secchi disc transparency increased only in May 2005–2007.
The effects of coincidental events, a decline of external loading of phosphorus and a simultaneous flushing induced by heavy
rainfall, on lake water quality are discussed with some implications to the future management of the reservoir. 相似文献
9.
Stochastic modelling of nutrient loading and lake ecosystem response in relation to submerged macrophytes and benthivorous fish 总被引:3,自引:0,他引:3
SUMMARY 1. The strong stabilising effect of increased submerged macrophytes (charophytes) and benthivorous fish reduction on the clear water state was shown for shallow Lake Veluwe and Lake Wolderwijd. 2. The first two links in the chain of relationships from external phosphorus (P) loading to in‐lake total‐P concentrations to chlorophyll a concentrations to water transparency, showed a significant correlation with the areal fraction of coverage with charophytes. Higher coverages lead to (i) lower ratios of the in‐lake total‐P concentration compared with the volume weighted average concentration in the inlet water, indicating a higher retention of P in the presence of charophytes (ii) lower chlorophyll a to total‐P ratios, indicating a positive effect of charophytes on top‐down control of algae, and (iii) higher water transparency because of lower algal turbidity. Transparency further improved as a result of benthivorous fish reduction and a significant positive correlation between non‐algal turbidity and benthivorous fish biomass. 3. A model was developed taking into account the inherent variability in precipitation and uncertainties in the empirical relationships determining phosphorus export from stream catchments and other sources and eutrophication variables in the receiving lakes. The model was used to compute (i) probability distributions for in‐lake total‐P, chlorophyll a and Secchi Disc transparency in relation to the coverage with charophytes and benthivorous fish biomass, and (ii) exceedence probabilities with respect to critical values for in‐lake total‐P and water transparency for several management scenarios. 4. The effects of an expected rise in external nutrient loading on the in‐lake total‐P and chlorophyll a concentrations and on water transparency can be compensated for by two proposed control measures: (i) extended treatment at a waste water treatment plant directly discharging into Lake Veluwe, and (ii) diverting the outlet of a stream draining a catchment with high fertilisation. The minimal internal charophyte coverage needed to sufficiently stabilise the clear water state and to meet with the objective of a summer mean water transparency of at least 1 m was estimated at well over 30% of the lake area, while the benthivorous fish stock should be maintained at the present level of c. 20 kg ha?1. 相似文献
10.
Fisheries management as an additional lake restoration measure: biomanipulation scaling-up problems 总被引:4,自引:4,他引:0
Restoration of the highly eutrophic Reeuwijk lakes (ca. 700 ha) started in 1986 by reducing the external phosphorus loading. As an additional measure to improve the quality of the lake water, the structure of the fish population in Lake Klein Vogelenzang (18 ha) was altered in 1989 by the removal of ca. 100 kg ha–1 bream from the lake in April and December. This constituted about 50% of the total bream biomass in the lake.The fish-stock reduction in April, 1989, was initially followed by high phosphorus concentrations, probably the result of considerable phosphorus release from the sediments. The resulting heavy algal blooms that occurred reduced the transparency to very low values. During the summer the zooplankton population increased markedly in numbers coinciding with reductions in total suspended matter including (blue-green) algae. A great improvement in Secchi-disc transparency was observed and by the end of December, 1989, the bottom of the lake (1.5–2.0 m) was visible. After heavy storms in January and February 1990, transparency dropped to < 1 m as a result of resuspension of high concentrations of suspended matter from the bottom sediments. Although transparency over the rest of 1990 was higher than in 1988, i.e. the year preceding the removal of fish (biomanipulation), it was lower than expected, based on the results of 1989. The study shows that technical and biological factors can cause serious management problems for the implementation of biomanipulation in larger water bodies. 相似文献
11.
Katsumasa Yamada Masakazu Hori Yoshiyuki Tanaka Natsuki Hasegawa Masahiro Nakaoka 《Hydrobiologia》2007,583(1):345-358
Changes in water clarity (secchi disc transparency) in relation to the presence/absence of introduced, exotic fish, including
rudd (Scardinius erythrophthalmus), tench (Tinca tinca), perch (Perca fluviatilis), brown bullhead catfish (Ameiurus nebulosus), goldfish (Carassius auratus), and koi carp (Cyprinus carpio) were determined for 49 small, North Island, New Zealand lakes. There was a negative association between water clarity and
the presence of exotic fish independent of lake depth. Moreover, a ‘before-and-after’ comparison and examination of case-studies
indicated that introductions of exotic fish reduce water clarity. The number of species introduced affected the relationship
between lake depth and water clarity but the specific role of each species could not be distinguished because most of the
lakes (83%) contained more than one exotic fish species. A model incorporating the known mechanisms by which planktivorous,
benthivorous and herbivorous fish can influence water clarity in lakes showed that control over just one species or feeding
guild may not result in an improvement in water clarity because of the additive and synergistic effects of different species
on lake trophic processes.
Handling editor J. Cambray 相似文献
12.
The effects of water deficit on photochemical parameters and activities of superoxide dismutase, catalase, ascorbate peroxidase
and glutathione reductase were investigated in two olive cultivars differing in drought tolerance — ‘Chemlali’ and ‘Chetoui’.
After 30 days without irrigation, leaf water potential fell to −5.5 MPa that was accompanied by a marked decrease in net photosynthesis
in ‘Chetoui’ olive cultivar. Maximal efficiency of PSII photochemistry (Fv/Fm) decreased slightly in ‘Chemlali’ (28 %) and substantially in ‘Chétoui’ (47 %). Both cultivars showed a similar decline (about
25 %) in the photochemical quenching coefficient, but only the drought-sensitive olive cultivar exhibited an enhancement (31
%) of non-photochemical fluorescence quenching under water deficit conditions. The quantum yield of electron transport decreased
in both olive cultivars. ‘Chemlali’ showed a higher protection against oxidative stress, as judged from the lower levels of
the malondialdehyde production. Catalase activity was higher in ‘Chetoui’. Glutathione reductase activity was increased similarly
in both olive cultivars under water stress. Ascorbate peroxidase activity was enhanced in ‘Chemlali’ under water stress, but
was unaffected in ‘Chetoui’. While, superoxide dismutase activity was inhibited in both cultivars under water stress, but
higher activity was detected in ‘Chemlali’. Thus, the ability to increase ascorbate peroxidase and a higher superoxide dismutase
activity might be an important attribute linked to the drought tolerance in ‘Chemlali’ olive cultivar. 相似文献
13.
Modeled Effects of Dissolved Organic Carbon and Solar Spectra on Photobleaching in Lake Ecosystems 总被引:1,自引:0,他引:1
Dissolved organic matter (DOM) contains molecules that absorb light at various wavelengths. This chromophoric DOM (CDOM) influences
the transmission of both visible and ultraviolet energy through water. The absorption of light by CDOM often causes structural
changes that reduce its capacity to further absorb light, a process termed ‘photobleaching‘. A model was designed to assess
photobleaching through the entire water column of lake ecosystems. The model uses lake morphometry and dissolved organic carbon
(DOC) concentration in conjunction with a defined solar spectrum and experimentally measured photobleaching rates to compute
the total water columm photobleaching. The model was initially applied to a theoretical ‘average‘ lake using solar spectra
for both the north (N) and south (S) temperate western hemispheres and variable DOC from 0.3 to 30 mg L−1. The consequences of varying waveband-specific photobleaching coefficients and lake morphometry were explored in a second
set of simulations. Finally, the model was also applied to four temperate northern lakes for which we had prior measurements
of CDOM photobleaching rates. The model demonstrates that all three wavebands of solar radiation (UVB, UVA, and PAR) contribute
significantly to total water column photobleaching, with UVA being most important. The relative contributions of the three
wavebands were invariant for DOC more than 3 mg L−1. Total water column photobleaching at 440 nm was three to five times faster under the UV-enriched solar spectrum of the southern
hemisphere. Increasing the lake’s mean depth (from 0.37 to 9.39 m) resulted in five- or 15-fold slower rates of total water
column photobleaching for DOC concentrations of 1 or 10 mg L−1, respectively. Varying the waveband-specific photobleaching coefficients by 10-fold resulted in a similar change in total
water column photobleaching rates. Applying the model to four specific lakes revealed that photobleaching for the entire water
column would reduce CDOM light absorption by 50% in 18–44 days under summer conditions.
Received 17 November 1998; accepted 27 June 2000. 相似文献
14.
Phosphorus reference concentrations in European lakes 总被引:7,自引:5,他引:2
A. C. Cardoso A. Solimini G. Premazzi L. Carvalho A. Lyche S. Rekolainen 《Hydrobiologia》2007,584(1):3-12
15.
A study was conducted to determine which bud (terminal or lateral) breaks first, and thereby exerts primigenic dominance,
on ‘Granny Smith’ and ‘Golden Delicious’, 1-year-old apple (Malus × domestica Borkh.) shoots grown in two locations in the Western Cape, South Africa, with differing degrees of chilling. Primigenic dominance
of laterals was more common in a warm area than a cool area, and more common in ‘Granny Smith’ than ‘Golden Delicious’. Laterals
rarely broke before the terminal in ‘Golden Delicious’, and so differences in lateral development due to position of first
bud to break were only analyzed in ‘Granny Smith’ shoots from this point on in the study. In ‘Granny Smith’, lateral budbreak
and growth was influenced by the position of the first bud to break on the shoot, but did not differ between locations. On
‘Granny Smith’ shoots with primigenic dominance of the terminal, lateral budbreak and growth was suppressed, in accordance
with the typical ‘delayed foliation’ commonly observed in warm winter climates. However, when at least one lateral broke before
the terminal, lateral budbreak and growth were similar to previous observations in cold winter areas. 相似文献
16.
For more than 20 years scientists of the ‘Food-chain studies’ Group of the former Limnological Institute have been studying
interactions within the pelagic food web. Purpose of research was to explain the structure and dynamics of the zooplankton
and fish communities in lakes and reservoirs in relation to biotic and abiotic environmental factors. A so-called multi-species
approach was used, in which all common and abundant species within a specific ecosystem were studied on the individual and
population level with the same degree of detail. The recent results and the scientific approach used are evaluated and the
main gaps in knowledge about food-web dynamics in shallow eutrophic lakes are identified and discussed. It is concluded that
instead of the purely functional approach used so far, future studies should also include evolutionary aspects which determine
the success of an organism in a given environment and that more attention should be paid to central questions in ‘community
ecology’.
This paper is based on a lecture given by the first author for the Netherlands Society of Aquatic Ecology on May 12th, 1992,
in Amsterdam, The Netherlands. 相似文献
17.
Variation in abundance and survival of fish larvae in shallow eutrophic lake Tjeukemeer 总被引:2,自引:0,他引:2
Wolf M. Mooij 《Environmental Biology of Fishes》1996,46(3):265-279
Synopsis Variations in abundance and survival of larvae of the major fish species, bream, roach, pikeperch, perch and smelt were studied in shallow eutrophic lake Tjeukemeer (1986–1988). Except for smelt, the size of the spawning stock and the abundance of larvae were not related. Both the timing of appearance of larvae and their growth rate were determined by water temperature as was shown by a growth model developed earlier for Tjeukemeer fishes. In cyprinids and percids the survival of the larvae was hypothesized to be negatively related to the duration of the earliest stages. Except in cyprinids, the abundance of 0+ juvenile fish could be explained by the number of larvae. In cyprinids 0+ juvenile abundance at the end of the year was not related to the number of larvae in May and June. The cyprinid juvenile survival rates are hypothesized to be related to the size of the main cyprinid predator, 0+ pikeperch. 相似文献
18.
19.
Water-filled treeholes are temporally and spatially variable habitats that consist of communities of a limited number of insect
orders, namely dipterans and beetles. Since these systems are largely heterotrophic, treeholes are dependent on the surrounding
terrestrial ecosystem for their basal energy input. In this study, we observed a cyclic succession of three system states
in a water-filled Fagus grandifolia treehole: ‘connected’ during rainfall; ‘isolated’ during periods without rain; and ‘dry’ when no freestanding water was present.
During the isolated phase, a rapid, microbially mediated turn-over of nitrogen and sulphate took place, coincident with an
accumulation of orthophosphate. Ammonium was the dominant form of nitrogen in the treehole water, and a net decrease in its
concentration was observed when the water volume decreased. Normally, nitrate concentration showed only minor fluctuations
(0.3–1.3 mg l−1) and concentrations of nitrite were very low (3–18 μg l−1). Concentration of sulphate showed a net decrease, coincident with an increase in sulphide. During the connected phase, the
effect of stemflow and throughfall on the nutrient concentrations in the treehole water proved to be variable. Over time,
both dilution of, and increase in, treehole water nutrient concentrations were observed. Dissolved organic carbon (DOC) concentration
showed a net decrease during the isolated phase. Spring coarse particulate organic matter input into the treehole was variable
(0.20–1.74 mg cm−2 week−1). The observed variability in precipitation inputs as well as fall-in of organic matter underlines the pulsed character of
basal energy entering the treehole food-web. DOC concentrations varied mainly with depth (15–57.4 mg l−1) as concentrations were almost three times greater within the detritus than within the water column. Bacterial abundances
ranged from 7.3 × 105 to 9.3 × 106 cells ml−1 and did not appear to vary within the water column or in the detrital sediment. Rates of bacterial production increased 24 h
after rain events, suggesting that the combined nutrient fluxes due to increased stemflow stimulate the microbial community.
Handling editor: J. Cole 相似文献
20.
A. H. Price A. D. Tomos D. S. Virk 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(1-2):132-142
Root growth is an important component of the adaptation of rice to drought-prone environments. A hydroponic screen was used
to study root growth of 28 rice varieties. Both maximum root length and adventitious root thickness varied widely between
varieties. In general, japonica varieties had larger root systems than indica varieties. Two F2 populations involving the thick- and long-rooted upland japonica variety ‘Azucena’ and two poor-rooting varieties, namely the upland indica‘Bala’ and the Italian japonica‘Maratelli’, were made and screened in hydroponics. Generation means analysis revealed significant additive and dominance
main effects for the root length traits with a prevalence of dominance gene effects in both crosses. The dominance×dominance
type of non-allelic interactions were important for maximum root length from day 7 to day 28, root volume, root thickness
and root cell length in the cross ‘Bala’בAzucena’. The heritability (broad-sense) estimates varied from low to high for the
traits and displayed differences between populations. This suggested that recombinant lines with improved root traits can
be developed from the two crosses with selection methods that involve some form of progeny evaluation. In a companion paper,
we report the mapping of quantitative trait loci (QTLs) for root growth traits in the ‘Bala’בAzucena’ population using restriction
fragment length polymorphisms (RFLPs).
Received: 5 May 1996 / Accepted: 14 February 1997 相似文献