Non-abscised aborted sweet cherry fruits are vulnerable to fruit decaying fungi and may be sources of infection for healthy fruits

During three growing seasons (1999–2001), disease incidence of non-abscised aborted and normally developing (sound) sweet cherry fruits were investigated in a research orchard at Ullensvang, western Norway. To reveal possible fungal infections, aborted and sound fruits of two cultivars (cv. Van for three years and cv. Lapins for two years) were harvested over four to seven weeks in an experimental orchard during the green fruit phase and incubated at 20°C in moisture saturated air for 7 days. The most frequently observed fungal pathogens were Monilinia laxa, Colletotrichum gloeosporioides, and Botrytis cinerea. The mean of all observations (±standard deviation) over three years, showed that aborted and sound fruits had a disease incidence of 51.9% (±31.8) and 5.2% (±9.7), respectively, after seven days incubation. In 24 of 25 trials aborted fruits had significantly higher disease incidence than sound fruits after incubation. In one season, when fruits were collected from two commercial orchards, aborted fruits had much higher disease incidence than sound fruits (a mean of 6.5 and 4.5 times higher incidence for the two orchards, respectively). Time of fruit abortion varied with the years (two years observation) and the two cultivars, but the major abortion took place between the fourth and eighth week after anthesis. A higher disease incidence and more rapid disease development in non-abscised aborted fruits indicate that they are more vulnerable to fungal colonisation than sound fruits and may thus be potential incoulum sources for neighbouring, healthy fruits.     

温室土壤食物网静态和动态结构特征

Soil food web structure is fundamental to ecosystem process and function; most studies on soil food web structure have focused on agro-ecosystems under different management practices and natural terrestrial ecosystems, but seldom on greenhouses. This study explored the static and temporal variability of soil food structure in two greenhouses of Shandong Province, North China over a two-year period. The static properties were measured directly by surveying functional group composition and a series of parameters portraying the species properties, link properties, chain properties and omnivory properties of the web, as well as indirectly through calculation of nematode indices, enrichment index （EI）, structure index （SI）, and channel index （CI）. The dynamic variability of greenhouse soil food structure was described by the dynamics of functional groups, Bray-Curtis （BC） similarity and cluster analysis. The results showed that the greenhouse soil food web contained 14 functional groups, with microbes having the highest mean biomass, followed by protozoa. Of the three functional groups of protozoa, flagellates were the dominant group on most sampling dates, amoebae only became the dominant group during the summer, while ciliates were the least prevalent group. All nematodes were assigned into one of the four functional groups, bacterivorous, fungivorous, herbivorous and omnivorous, and the fungivorous nematodes had the lowest mean biomass. Mites were assigned into three functional groups and the omnivorous noncryptostigmatic mites were the dominant group. All the functional groups showed significant seasonal changes. The soil food web connectance was 0.15, the maximum food chain length was 5, and the average food chain length was 3.6. The profiles of the EI and SI showed that the food web was resource- depleted with minimal structure. The results of CI indicated that the bacterial decomposition pathway was the dominant pathway in the food web of the greenhouse soils studied and the results of BC similarity showed that the soil food web had higher variability and instability over time. The cluster analysis showed that the functional groups located at high trophic levels with low biomass were in a cluster, whereas those at low trophic levels with high biomass were closer. Compared with the food web structure of agroecosystem and natural terrestrial ecosystem soils, the structure of greenhouse soil food web was simple and unstable, which was likely driven by high agricultural intensification, particularly over application of fertilizers.     

The Characterization of Heavy Metals in the Grapevine (Vitis vinifera) Cultivar Rkatsiteli and Wild Blackberry (Rubus fruticosus) from East Serbia by ICP-OES and BAFs

Inductively coupled plasma optical emission spectroscopy, in combination with calculation of various biological factors, was used in this study not only for a simple illustration of the present status of some essential and non-essential metals such as copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), arsenic (As), and cadmium (Cd) in the grapevine cultivar Rkatsiteli and wild blackberry from East Serbia but also for the estimation of plant bioaccumulation potentials. Great majority of detected metal concentrations were in normal ranges except in few cases: Zn concentrations were at the level of deficiency in almost all plant parts, and some Cu and As concentrations were at the levels that could be considered phytotoxic. Biological accumulation factors provided very informative data on metal accumulation and translocation in both plants and pointed to low accumulation rates of metals except in the case of Cu, Zn, and As in some wild blackberry tissues.     

Influence of water potential on nitrification and structure of nitrifying bacterial communities in semiarid soils

The objective of this study was to examine the relationship between soil water potential, nitrifier community structure and nitrification activity in semiarid soils. Soils were collected after a 5-month dry period (end of summer) and subsequently rewetted to specific water potentials and incubated for 7 days prior to analysis of nitrification activity and nitrifier community structure. The approach used in this study targeted a 491bp segment of the amoA gene which encodes the active site of the ammonia monooxygenase enzyme, which is the key enzyme for all aerobic ammonia oxidisers. amoA serves as a useful target for environmental studies since it is both specific and universal for all ammonia oxidisers and reflects the phylogeny of the ammonia oxidisers. Our results suggest that in semiarid soils water potential plays a key role in determining the structure of ammonia oxidising bacteria (AOB), and that additionally AOB community structure is correlated to potential nitrification rate in these soils.     

Site-Specific Nitrogen Management in Rice Using Remote Sensing and Geostatistics

Proper doses of nitrogenous fertilizer are most important for rice production system because a large part of the nitrogen may be lost if it is not applied judiciously. A study was conducted covering five blocks of Balasore and two blocks of Bhadrak districts. Soil samples were collected randomly, and field visit was conducted during peak vegetative stage of rice. Two approaches have been used in this study for estimating the site-specific nitrogen (N) requirement in the study area. In one approach, geostatisical analysis and kriging was used to develop the soil test–based N recommendation map by which a minimum of 72 kg N ha^?1 and maximum of 94 kg N ha^?1 were recommended. In a second approach, remote sensing was used and N recommendation map was developed using the moderate-resolution imaging spectroradiometer (MODIS) leaf area index (LAI) and normalized difference vegetation index (NDVI) satellite data, and a minimum requirement of 60 kg N ha^?1 and maximum of 120 kg N ha^?1 was estimated through this approach.     

Soils of mountainous forest-steppe in the southwestern part of Khentei Ridge (Mongolia)

The study of soil cover in the mountainous forest-steppe on the southwestern macroslope of Khentei Ridge has shown that the spatial distribution of soils is controlled by the ruggedness of topography, slope aspects, geocryological conditions, and the thickness of loose deposits. The soils belong to the orders of lithozems and organo-accumulative soils (Mollic Leptosols) of the postlithogenic trunk of pedogenesis. Dark-humus and mucky–dark-humus horizons of the organic matter accumulation are characteristic features of these soils. The investigated area is differentiated according to the soil moistening conditions on the slopes of different aspects. Favorable growth conditions for dwarf birch and Siberian larch at the southern boundary of the boreal forests in Mongolia are explained by the relatively high moistening of mucky–darkhumus lithozems and mucky–dark-humus soils developed on windward northern slopes and on mountain terraces in places of the local snow accumulation by wind. An important role in preservation of forest vegetation belongs to permafrost in small cirque-like depressions.     

Stable resistance against the leaf miner <Emphasis Type="Italic">Leucoptera coffeella</Emphasis> expressed by genetically transformed <Emphasis Type="Italic">Coffea canephora</Emphasis> in a pluriannual field experiment in French Guiana

Summary A pluriannual field trial of transgenic clones of Coffea canephora (the Robusta coffee tree) transformed for resistance to the lepidopteran coffee leaf miner Leucoptera coffeella was installed in French Guiana. Fifty-eight transformed clones produced by transformation of the C. canephora clone 126 were planted. They were harbouring the pEF1α constitutive promoter of Arabidopsis thaliana controlling either the Bacillus thuringiensis native gene for the cry1Ac insecticidal protein (eight clones) or a synthetic cry1Ac gene (53 clones). The vectors for the transformation were a strain of the bacterium Agrobacterium tumefaciens and one of Agrobacterium rhizogenes. The transformed clones were generally independent, presenting different integration patterns of the genetic construct. Four randomly distributed groups of five plants per transformed clone were planted along with 60 untransformed control trees. Over a 4-year period after plantation six releases of L. coffeella were performed. Mines on the leaves are the marks of larvae development and were counted on plants. A majority of the independent transformed clones harbouring the synthetic gene and transformed by the strain of A. tumefaciens displayed constantly much less mines than the control, therefore expressing a stable resistance. The need for complementary research is presented.     

Current status and future strategy in breeding grasspea (Lathyrus sativus)

Efforts in grasspea (Lathyrus sativus) improvement have increased since the development of lines that are very low in the neurotoxin Beta-N-oxalyl-L-alpha-beta-diamino propionic acid (ODAP); also referred to as Beta-N oxalyl-amino-L-alanine (BOAA). Many programs now address several related aspects of improvement simultaneously. These include reduced ODAP concentrations, insect and disease resistance, nitrogen fixation, agronomic practices, fodder and forage production, and components for increased yielding ability. The coordinated, multidisciplinary approach now being applied to the genetic improvement of grasspea should allow the potential of this largely neglected grain legume to be fully realized.     

The Optimization for Crop Planning and Some Advances for Water-Saving Crop Planning in the Semiarid Loess Plateau of China

The establishment of water-saving crop planning is an inevitable choice of the water-saving agriculture for the water-deficiency region in the arid and semiarid Loess Plateau of China and the world. The water-saving crop planning refers to the planting structure that centres the adjustment of the crop's adaptation to water, the optimization of temporal and spatial layout for crops, the local natural resources, marketing resources, human resources and financial input to enable region or basin with limited water resources to achieve the maximum economic, social and ecological benefits of planting industry under certain technology and economy. After the analysis on the research progress of optimization theory, optimization goals, optimization methods of water-saving cultivation structure and macro-control measures, it is pointed out that the main deficiencies of the current research of water-saving cultivation pattern optimization are lacking of a strong theoretical basis, and the immaturity of optimization technologies. The future crucial research direction will focus on five aspects such as the special optimization theory system, the division methods by studying the watershed unit and using 3S technology, optimization model based on multi-objective evolutionary algorithm, evaluation of rationality and macro-control measures on the basis of the public participation.     

Genetic mapping of loci determining long glumes in the genus Triticum

Elongated glumes are present in thetetraploid wheat species T.polonicum, T. turanicum, T.durum convar. falcatum and in thehexaploid species T. petropavlovskyi.Inheritance of glume length was studiedwith the aim to map the respective lociusing wheat microsatellite markers. In T. polonicum and T. petropavlovskyiloci conferring long glume were mapped nearthe centromere on chromosome 7A. These twoloci are designated P-A ^pol 1 andP-A ^pet 1, respectively. It isshown that both are probably homoeoallelicto each other and to the P gene ofT. ispahanicum on chromosome 7B. The loci determining elongated glumes in T. turanicum and T. durum conv. falcatum are not homoeologous to the P loci in the centromeric region of thegroup 7 chromosomes.