Die Variabilität einiger Komponenten der Allogamieneigung bei der Kulturgerste (Hordeum vulgare L. s. l.)

Zusammenfassung Zur Einschätzung der Allogamieneigung der Gerste wurde die Variabilität der für die Anemophilie bedeutenden Merkmale Stigmatagröße, Antherenlänge und Antherenejektion geprüft. In Voruntersuchungen an 5000 Sommer- und 1000 Wintergersten konnten 155 Sippen gefunden werden, die zur Chasmogamie neigen. Bei der autogamen Kulturgerste sind die Anemophiliemerkmale gegenüber den allogamenHordeum-Species meist deutlich reduziert. Das betrifft besonders die Antherenlänge und die Antherenejektion, während die Stigmatagröße, die auch bei Autogamen den Ansatz und damit die Anzahl der Nachkommen beeinflußt, relativ wenig vermindert ist. In allen Merkmalen wurde eine große Variabilität der Komponenten der Anemophilie gefunden, auch bei der im allgemeinen strenger autogamen Sommergerste.

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Some aspects of the tendency to allogamy and their variability in barley (Hordeum vulgare L. s. l.)

Summary The variability of stigma size, anther length, and anther extrusion as important characters of anemophily was examined in barley to estimate its tendency to allogamy. 5000 spring and 1000 winter barleys were examined, 155 of which exhibited a tendency to chasmogamy. The characters of anemophily are reduced for the most part of autogamous cultivated barleys compared with allogamousHordeum species, especially as to anther length (table 4) and anther extrusion (table 5). There is a relatively little reduction of stigma size (table 3), because this character influences the seed set and with this the number of offspring in autogamous species too. A comparatively high variability could be found for all characters of anemophily even in spring barley, which is in general stronger autogamous than winter barley.

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(Hordeum vulgare L. s. 1.)

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Nonlinear increasing axial gap stiffness in type II external skeletal fixation: a mechanical study

OBJECTIVE: To quantify the effect on gap stiffness and cranial to caudal bending stiffness of conversion of the 6 distal clamps of planar bilateral fixator models to sliding clamps and the effect of attachment of composite beams to the sliding clamp models. STUDY DESIGN: Mdash;Mechanical testing performed on models. SAMPLE POPULATION: Five models using birch dowels and a commercially available external skeletal fixator system. METHODS: A segmentally comminuted, middiaphyseal fracture was simulated with the use of wooden dowels, and a bilateral 6-pin fixator was applied to create each of 5 models. The models were mechanically tested with all fixed clamps, with the 6 distal clamps converted to sliding clamps and with composite beams attached to the sliding clamp models. Testing was carried out in axial loading with physiologically relevant loads for a canine model, and in bending in the cranial to caudal plane. RESULTS: Sliding clamp fixators with composite beams attached exhibited a nonlinear increase in axial loading gap stiffness as load increased. The composite beam group also exhibited an increase in cranial to caudal bending stiffness as compared with fixed clamp and sliding clamp models. CONCLUSIONS: Using composite beam elements, planar bilateral external fixators can be constructed such that the fracture site would undergo controlled amounts of displacement at low loads and lessening displacement at higher loads. CLINICAL RELEVANCE: The nonlinear stiffness profile attained by the addition of composite beam elements to a planar external fixator allows controlled axial micromotion at the fracture site. Because controlled axial micromotion appears to stimulate fracture healing, a nonlinear stiffness profile of this type should enhance fracture healing.     

Leaf K/Na ratio predicts salinity induced yield loss in irrigated rice

Salinity is a major constraint to irrigated rice production, particularly in semi-arid and arid climates. Irrigated rice is a well suited crop to controlling and even decreasing soil salinity, but rice is a salt-susceptible crop and yield losses due to salinity can be substantial. The objective of this study was to develop a highly predictive screening tool for the vegetative growth stage of rice to estimate salinity-induced yield losses. Twenty-one rice genotypes were grown over seven seasons in a field trials in Ndiaye, Senegal, between 1991 and 1995 and were subjected to irrigation with moderately saline water (3.5 mS cm^-1, electrical conductivity) or irrigation with fresh water. Potassium/sodium ratios of the youngest three leaves (K/Na_Leaves) were determined by flame photometry at the late vegetative stage. Grain yield was determined at maturity. All cultivars showed strong log-linear correlations between K/Na_Leaves and grain yield, but intercept and slope of those correlations differed between seasons for a given genotype and between genotypes. The K/Na_Leaves under salinity was related to grain yield under salinity relative to freshwater controls. There was a highly significant correlation (p < 0.001) between K/Na_Leaves and salinity-induced grain yield reduction: the most susceptible cultivars had lowest K/Na_Leaves and the strongest yield reductions. Although there were major differences in the effects of salinity on crops in both the hot dry season (HDS) and the wet season, the correlation was equally significant across cropping seasons. The earliest possible time to establish the relationship between K/Na_Leaves under salinity and grain yield reduction due to salinity was investigated in an additional trial in the HDS 1998. About 60 days after sowing, salinity-induced yield loss could be predicted through K/Na_Leaves with a high degree of confidence (p < 0.01). A screening system for salinity resistance of rice, particularly in arid and semi-arid climates, is proposed based on the correlation between K/Na_Leaves under salinity and salinity-induced yield losses. This revised version was published online in July 2006 with corrections to the Cover Date.     

A gamma‐ray spectrometry approach to field separation of illuviation‐type WRB reference soil groups in northern Thailand

According to the World Reference Base for Soil Resources (IUSS Working Group WRB, 2006), the differentiation of Acrisols and Alisols is based on the cation‐exchange capacity of clay, which cannot be directly determined in the field, but needs expensive and time‐consuming soil‐chemical analyses. This is an unsatisfactory situation for pedologists, who urgently require a rapid field method to distinguish illuviation‐type reference soil groups (Alisols, Acrisols, Luvisols, Lixisols). In this study, we tested the ability of gamma‐ray spectrometry to separate major WRB reference soil groups in the field. The underlying hypothesis is that Alisols and Acrisols are distinguished by their clay mineral composition, which should be reflected by geochemistry and consequently gamma‐ray radiation (i.e., K‐containing illite vs. K‐free kaolinite). Highly significant differences in their gamma‐ray spectrum for K, Th, and U were found for limestone and its soils. Especially the K and Th signatures allowed a clear separation of Acrisols and Alisols. In general, the surface radiation was sufficient to separate these soils. Best results were revealed considering parent rock and the whole soil profile. This means by using a portable radiometer and a pH meter, all illuviation‐type reference soil groups could be distinguished in this case. If applicable at other sites, this approach could enormously reduce expenditures for soil‐chemical analysis needed to assist soil classification.     

Literarische Berichte

Ohne Zusammenfassung     

Human-wildlife conflict in the Kingdom of Bhutan: Patterns of livestock predation by large mammalian carnivores

We examined predation activity throughout Bhutan by tiger (Panthera tigris), common leopard (Panthera pardus), snow leopard (Uncia uncia) and Himalayan black bear (Ursus thibetanus) on a variety of livestock types using data gathered over the first two years (2003-2005) of a compensation scheme for livestock losses. One thousand three hundred and seventy five kills were documented, with leopards killing significantly more livestock (70% of all kills), than tigers (19%), bears (8%) and snow leopards (2%). About 50% of livestock killing were of cattle, and about 33% were of horses, with tigers, leopards and snow leopards killing a significantly greater proportion of horses than predicted from availability. Examination of cattle kills showed that leopards killed a significantly greater proportion of smaller prey (e.g., calves), whereas tigers killed a significantly greater proportion of larger prey (e.g., bulls). Overall, livestock predation was greatest in summer and autumn which corresponded with a peak in cropping agriculture; livestock are turned out to pasture and forest during the cropping season, and subsequently, are less well guarded than at other times. Across Bhutan, high horse density and low cattle and yak density were associated with high rates of livestock attack, but no relationship was found with forest cover or human population density. Several northern districts were identified as ‘predation hotspots’, where proportions of livestock lost to predation were considerable, and the ratio of reported kills to relative abundance of livestock was high. Implications of our findings for mitigating livestock losses and for conserving large carnivores in Bhutan are discussed.     

Increased sacral screw purchase minimizes screw loosening in canine triple pelvic osteotomy

OBJECTIVE: To determine if screw loosening in triple pelvic osteotomies (TPO) is minimized when screws cranial to the ilial osteotomy had maximal sacral purchase. STUDY DESIGN: Prospective study. ANIMALS: Forty-six dogs with decreased acetabular coverage of the femoral head and minimal degenerative joint changes. METHODS: TPOs were performed where screws cranial to the ilial osteotomy were inserted to maximally engage sacral bone. Data collected were: use of ilial and ischial cerclage wire, screw length, ventrodorsal radiographic sacral width (most caudal aspect), pelvic canal diameter, and sacral penetration of the 3 cranial screws. On all subsequent radiographs, changes in screw position, pelvic canal diameter, and sacral purchase were noted. RESULTS: For 69 TPOs, 414 screws were used. Mean radiographic cranial screw length was 34.54 mm. Combined sacral depth of all 3 screws was 93.3% of sacral width. All osteotomies healed uneventfully. Twenty-four screws (6%) loosened with 12 being in the most cranial positions. Use of ischial or ilial cerclage wires did not statistically influence screw loosening. Pelvic diameter decreased by a mean of 7.79% from postoperative radiographs to the last radiographic recheck. CONCLUSIONS: By sufficiently engaging the sacrum with screws cranial to the ilial osteotomy, implant failures can be avoided and screw loosening minimized when a 6-hole TPO plate is used. CLINICAL RELEVANCE: To minimize screw-loosening in TPO, screws inserted cranial to the ilial osteotomy should be inserted to maximum sacral depth without penetrating the vertebral canal.     

Report on a travel to the Socialist People's Libyan Arab Jamahiriya 1983 for the collection of indigenous taxa of cultivated plants

Summary The mission was carried out within the Mediterranean Programme of the IBPGR in April/May 1983 with participants from the Socialist People's Libyan Arab Jamahiriya (Agricultural Research Centre, Tarabulus), the Istituto del Germoplasma, Bari, and the Zentralinstitut für Genetik und Kulturpflanzenforschung, Gatersleben. In Tripolitania, the Fezzan- and Ghadmis-areas 316 samples, mostly cereals and vegetables, have been collected. In Tripolitania and the Ghadmis-area the land-races have been nearly completely replaced by new varieties. In the Fezzan genetic erosion is in progress. There, several cereal- and vegetable-land-races could still be collected. The land-races may be useful for breeding programmes.

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Bericht über eine Reise in die Sozialistische Libysche Arabische Volksjamahiriya 1983 zur Sammlung autochthoner Sippen von Kulturpflanzen

Zusammenfassung Die Reise erfolgte im Rahmen des Mediterranean Programme des IBPGR im April/Mai 1983 mit Teilnehmern aus der Sozialistischen Libyschen Arabischen Volksjamahiriya (Agricultural Research Centre, Tarbulus), des Istituto del Germoplasma, Bari, und des Zentralinstituts für Genetik und Kulturpflanzenforschung, Gatersleben. In Tripolitanien, dem Fezzan und dem Gebiet von Ghadmis wurden 316 Proben, meist von Getrieden und Gemüsen, gesammelt. In Tripolitanien und dem Gebiet von Ghadmis sind die Landsorten fast vollständig von neueren Sorten verdrängt worden. Im Fezzan schreitet die Generosion fort. Hier konnten noch zahlreiche Getreide- und Gemüselandsorten gesammelt werden. Die Landsorten können für Züchtungsprogramme nützlich sein.

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1983 .

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