bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Nitrate Application on Shoot and Root Development of Wheat Seedlings (Triticum aestivum L.)
Authors: Greef J. M. , Kullmann A.
Published: April 2008

The experiment was conducted to describe the effect of a varying nitrate level on shoot and root development of young wheat plants. The plants grew up under controlled condition of a growth chamber for a period of 15 days after germination. Nitrogen was applicated as nitrate in three levels of 0.5; 2.5 and 12.0 mM N. Seedlings were harvested in a three day interval beginning 72 d after germination. The plants were dissected into shoot and root. Root morphology is described by number, length and area of main and lateral root system. The shoot development is characterized by leaf area and chlorophyll concentration.

Especially the shoot growth was effected by varying nitrate application. The reaction of the root system on the nitrogen nutrition showed an indifferent situation. With higher N level the N uptake of all genotypes increased. Genotypic differences exists between the efficiency of nitrate uptake determined as N absorption per unit root parameter. The shoot is an important factor for the utilization and conversion of nitrate into dry matter.

Einfluß auf die Sproß‐ und Wurzelentwicklung verschiedener Weizengenotypen (Triti‐cum aestivum L.) in Abhängigkeit von der Nitratversorgung

Der Versuch wurde durchgeführt, um den Effekt einer variierten Nitratversorgung auf die Sproß‐ und Wurzelentwicklung von verschiedenen Weizengenotypen zu erfassen. Die Keimpflanzen wuchsen unter kontrollierten Bedingungen 15 Tage nach der Keimung in einer Wachstumskammer auf. Stickstoff als Nitrat wurde in den drei Konzentrationen 0,5, 2,5 und 12,0 mM N verabreicht. Die Pflanzen wurden in einem dreitägigen Intervall geerntet, beginnend 72 Stunden nach der Keimung. Die Pflanzen wurden in Sproß und Wurzel getrennt. Die Wurzelmorphologie wurde mit Hilfe der Parameter Anzahl, Länge und Oberfläche des Haupt‐ und Seitenwurzelsystems erfaßt. Zusätzlich wurden die Blattflächenentwicklung und die Chlorophyllkonzentrationen der einzelnen Blattstufen beschrieben. Besonders das Sproßwachstum ist durch die Nitratbehandlung deutlich beeinflußt worden. Das Wurzelsystem zeigte ein uneinheitliches Reaktionsmuster auf. Die Nitrataufnahme steigerte sich mit zunehmender Stickstoffversorgung. Genotypische Differenzen bestanden in der Leistungsfähigkeit, Nitrat aufzunehmen, ausgedrückt als Nitrataufnahme per Einheit Wurzelmerkmal. Der Sproß spielte in der Verwertung und Umsetzung von Stickstoff in Trok‐kenmasse eine entscheidende Rolle.
Description and Application of a Screening Method to Determine Root Morphology Traits of Cereal Cultivars*
Authors: Léon J. , Schwarz K.‐U.
Published: April 2008

Genotypic differences in root traits may be responsible for differences in yield especially under unfavourable growing conditions. This study was conducted to describe root morphology traits of oat and barley genotypes using a screening technique and to relate these root characteristics to the biomass accumulation of the genotypes in field tests. The described method permits the rapid quantification of morphological root parameters for large numbers of genotypes. Plants of oat and barley cukivars grew on filter‐paper which was soaked in a nutrient solution and was fixed on acryl‐glass plates. Genotypic differences in root morphology were measured periodically by counting the intersections between roots and horizontal lines of a grid. Oat and barley cultivar differences were detected for the sum of intersections (SIS) and for SIS of separated root zones. These cultivar differences showed no relationship to biomass and grain yield. However, regarding drought environments with low N fertilization supply the genotypic rank orders of grain yield and SIS were associated. Therefore it is stated that a selection for high SIS of deeper root zones may serve as an indirect selection for yield stability rather than for yield. Furthermore, the observed genotypic differences in SIS among high yielding cukivars provide the chance to select between actual breeding lines.

Beschreibung und Anwendung einer Schnellmethode zur Bestimmung wurzelmorphologischer Merkmale bei Getreidesorten

Genetische Unterschiede in Wurzeleigenschaften können insbesondere unter ungünstigen Wachstumsbedingungen für Ertragsunterschiede verantwortlich sein. Ziel dieser Studie war es, Merkmale der Wurzelmorphologie von Hafer‐ und Gerstengenotypen mittels einer Serienmethode zu untersuchen und diese Merkmale mit der Biomassenbildung zu verknüpfen. Bei der Bestimmungsmethode wuchsen die Getreidepflanzen auf einem mit Nährlösung getränkten Filterpapier, welches sich auf einer um 15 Grad von der Vertikalen geneigten Acrylglasscheibe befand. Die Genotypunterschiede in der Wurzelmorphologie wurden periodisch durch Zählung der Schnittpunkte zwischen den Wurzeln und einem horizontalen

Raster gemessen. Sowohl die Hafer‐, als auch die Gerstensorten wiesen in der Summe der Schnittpunkte (SIS) Unterschiede auf. Diese Sortenunterschiede waren nicht mit Sortenunterschieden im Ertrag korreliert. Jedoch zeigte eine differenzierte Auswertung, daß für trok‐kene und schwach mit N‐Düngung versorgten Umwelten die Genotypenrangfolge zwischen Ertrag und SIS ähnlich waren. Eine Selektion auf hohe SIS der tieferen Wurzelschichten dürfte daher eher als Selektion auf höhere Ertragssicherheit als auf hohen Ertrag verstanden werden. Die Tatsache, daß auch zwischen hoch ertragreichen Sorten Unterschiede in der SIS gefunden wurden, bietet die Chance einer Selektion auf hohe SIS auch innerhalb des aktuellen Züchtungsmaterials.
Nitrogen Movement in an Arable Sandy Soil and Ways of Reducing Nitrogen Losses — Preliminary Results*
Authors: Herzog H. , Konrad R.
Published: April 2008

In order to reduce nitrogen leaching during the autumn‐winter period and to test methods for quantifying leaching processes, a field trial was performed on a sandy soil at the experimental station in Berlin‐Dahlem. Treatments comprised different tillage managements (10 cm rotary hoe vs. 25 cm plough), fallow vs. growing winter rape as a catch crop, and different nitrogen applications (0, 50, 100 kg/ha N). Effects were appraised by simple nitrogen balance, determination of Nmin and nitrate concentrations in the soil water. First attempts were made to assess water flows in the soil monitoring matric water potentials.

The catch crop took up about 55 kg/ha N and was by far most efficient in reducing Nmin and nitrate concentrations of the soil; moreover, the beginning of water movement in the soil was considerably delayed. The addition of 50 or 100 kg/ha N stimulated growth and N‐uptake by the catch crop, but revealed no obvious advantage in N‐conservation in the soil, besides a 3‐day‐retardation of leaching. Nmin in May as well as plant data of the following spring wheat indicated a poor efficiency of autumn‐applied nitrogen. Reduced tillage on the fallow decreased Nmin and nitrate concentrations, but such effect was hardly detectable in combination with the catch crop (due to its impact on growth and N‐uptake).

Stickstoffverlagerung auf einem sandigen Ackerboden und Möglichkeiten zur Minderung von Verlusten — vorläufige Ergebnisse

Mit dem Ziel N‐Verlagerung im Herbst— Winter zu verringern und Methoden der Quantifizierung des Verlagerungsprozesses zu testen, wurde ein erster Feldversuch auf einem Sandboden der Versuchsstation in Dahlem angelegt. Die Maßnahmen umfaßten Bodenbearbeitung (10 cm flaches Fräsen und 25 cm tiefes Pflügen), Brache und Zwischenfruchtanbau mit Winterraps sowie 0, 50 und 100 kg/ha N‐Düngung. Die Wirkungen wurden anhand einer vereinfachten N‐Bilanz, Bestimmungen von Nmin sowie Nitrat der Bodenlösung überprüft. Einen ersten Ansatz, den Wasserfluß im Boden zu erfassen, bildete die Ermittlung der matrikalen Wasserpotentiale.

Die Zwischenfrucht nahm ca. 55 kg/ha N auf und minderte die Nmin‐ und Nitratwerte im Boden am effektivsten, darüber hinaus verzögerte sie den Beginn der Wasserbewegung im Herbst erheblich. Eine Düngung mit 50 oder 100 kg/ha N förderte Wachstum und N‐Aufnahme der Zwischenfrucht, aber bedingte außer einer 3tägigen Verzögerung der Verlagerung keine Vorteile bei der N‐Konser‐vierung. Nmin im Mai und Pflanzendaten der Nachfrucht wiesen auf eine schlechte Effizienz dieser N‐Düngung. Reduzierte Bodenbearbeitung senkte die Nmin‐ und Nitratkonzentration unter Brache leicht, nicht jedoch bei Zwischenfruchtanbau.
Effect of Low Night Temperatures on Photosynthetic Activity of the Maize Seedlings (Zea mays L.)
Authors: Kościelniak J.
Published: April 2008

Night chilling (5 °C) subsequently lowered photosynthetic intensity in the leaves of maize seedlings at 20 °C through an increase in leaf diffusive resistance brought on by lower tissue water content in morning hours. A more significant increase in leaf diffusion resistance was observed when soil temperature was lowered than in the case of lower air temperature.

The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.

An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm2 of leaf area.
Weed Competition in Soybeans (Glycine max L.)
Authors: Abusteit E. O.
Published: April 2008

The present investigation was conducted to determine the critical period of weed competition in soybeans at Giza, Egypt. Weed flora in the experimental site at Giza contained a wide range of species during both seasons of study (1990 and 1991). Total weed dry weight increased progressively with time up to 12 WAE (182.0 g/m2). Weed‐free and weedy periods exhibited significant effects on soybeans height, number of pods per plant, stand at harvest, biological and seed yields. Optimum seed yields were produced by weed‐free durations for 6 WAF up to all season (3.229–3.545 t/ha). Whereas, weedy periods for 2, 4, 6, 8, 10 and 12 WAF reduced seed yield by 14.9, 28.0, 35.3, 45.1, 48.1 and 51.1 %, respectively. Weed competition for the entire season caused 56.1 % reduction in soybean seed yield. The obtained results indicate that weed competition during the early stages of growth, adversely affected soybeans. At least 6 WAE of weed‐free period was required to insure optimum soybean growth and yield. However, oil and protein contents were not affected by weed competition.
Stickstoffdüngung und chemischer Pflanzenschutz in einem Dauerfeldversuch und die Ertragsgesetze von Liebig, L.iebscher, WOLLNY und MITSCHERLICH
Authors: Claupein W.
Published: April 2008

Nitrogen fertilization and chemical plant protection in a long‐term field experiment and the yield response laws of Liebig, Liebscher, Wollny and Mitscherlich

An interpretation of Liebig's “law of the minimum”, Liebscher's and Wollny's “law of the optimum” and Mitscherlich's “law of constant activity” for two growth factors is presented. With three‐quadrant diagrams (crop yield vs. N fertilization, crop yield vs. N uptake, N uptake vs. N fertilization) a long‐term field experiment in Göttingen (Ackerbau‐Systemversuch) is analyzed. This experiment started 1981 with the following treatments: 1. crop rotation (a: short rotation, sugar‐beet, winter‐wheat, winter‐barley/vetch‐green‐manure; b: long rotation, sugar‐beet, winter‐wheat, winter‐barley, lucerne, maize, faba beans); 2. chemical plant protection (a: with; b: without); 3. mineral nitrogen fertilization procedure (a: N‐fixed, cumulative effects; b: N‐rotating, one year's effects of different N fertilization); 4. mineral nitrogen fertilization (a: nil; b: suboptimal; c: optimal; d: hyper‐optimal doses).

Without chemical plant protection resource use efficiency of applied nitrogen decreased according to Liebscher's and Wollny's “law of the optimum”. In most cases this “law of the optimum” was applicable to the empirical data. Liebig's “law of the minimum” and Mitscherlich's “law of constant activity” are exceptional cases, whereas Liebscher's and Wollny's “law of the optimum” has more general validity. For maximal resource use efficiency the growth factors have to be combined in optimal amounts.
Effects of Faba Bean Leaves in Different Positions on the Yield and Photosynthetic Compensation after Defoliation
Authors: Xia M. Z.
Published: April 2008

In a field experiment in the winter seasons of 1985/86 and 1988/89 at Xichang, China, the effects of defoliation on seed yield of Vicia faba and its photosynthetic compensation were investigated by removing all leaves, some leaves from different plant positions at the beginning of flowering and the beginning of pod formation. Seed yield decreased by 37.3–52.3 % in plants with upper leaves removed at the beginning of flowering. Removal of middle leaves at the beginning of pod formation had the most significant effect, followed by the of upper and lower leaves removed, causing yield decreases of 43.4–64.3 %, 18.6–24.7 % and 8.9–12.3 %, respectively. Removal of leaves at the beginning of pod formation resulted in a greater reduction in seed yield, total dry weight, harvest index, and number of pods and seeds per plant than leaf removal at the beginning of flowering.

The photosynthetic rate and export rate of photosynthate of upper leaves at the beginning of flowering, and middle leaves at the beginning of pod formation were the greatest during both years of the experiment. Photosynthetic rate increased and reached its maximum at 4–5 days after leaf removal, then decreased, but, yet greater than the control leaves at 9–11 days after leaf removal. In the meantime, transport of photosynthetic products was accelerated. In general, removal of leaves from the upper and middle third of the plant increased the export rate of photosynthate by ca. 20 %. Photosynthetic compensation could not fully make up the loss caused by leaf removal, so grain yield was decreased by all treatments. The full defoliation decreased yield by > 70 %.
Einfluß des Stickstoffangebotes auf Wasserverbrauch und Stoffproduktion der Zuckerrübe in Gefäßversuchen
Authors: Bürcky K.
Published: April 2008

Influence of nitrogen supply on water consumption and dry matter production of sugar beet in pot experiments

This paper describes the influence of nitrogen on water consumption, dry matter production and water use efficiency (WUE) of sugar beet.

The experiments, conducted in 1988 and 1989 using sand culture in pots, included five nitrogen levels from 2 to 16 g/pot.

Beet roots were heaviest where the N‐supply was 8 g/pot. Top weight increased considerably up to 16 g N/ pot. Therefore plant dry weight was greatest where the N‐supply was maximum. Overall, in 1989 dry matter production (g/pot) was 20 % greater than in 1988 because the beet roots were heavier.

Water consumption increased with nitrogen supply. At the largest N‐doses water consumption was 110 1 (1988) and 140 1 (1989). This was three times the amount used at the smallest N‐supply. Over the whole season WUE was greatest at 4 g N/pot and lower at both extremes of N‐supply. Independently of N‐supply, production of plant dry matter per litre of water consumed was between 4.9 and 6.0 g. For root dry matter, equivalent values were 3.7 and 4.6 g/l, and for white sugar yield they were 2.3 and 3.1 g/1
Differences in Root and Shoot Response to Limited N‐supply in Oat and Spring Barley
Authors: Górny A. G.
Published: April 2008

Oat and spring barley cultivars, varying in origin and date of release, were examined in soil boxes with sloped glass‐face. Considerable genotypic differences were found in shoot and root response to high and low nitrogen supply. Oat cultivars, representing a wider germplasm collection, exhibited a stronger and partially different shoot and root response to applied N‐levels than barley cultivars. Cultivar‐fertilization interaction effects were significant for seminal and adventitious root variation. Genotypic specificity (plasticity) in root response, as revealed in some oat and barley cultivars with a deeper penetration and more vigorous root growth under the low N‐supply, was recognized to be a valuable adaptive characteristic for breeding plants on light‐textured soils.
Synthesis of Osmotically Active Substances in Winter Wheat Leaves as Related to Drought Resistance of Different Genotypes1)
Authors: Martin M. , Miceli F. , Morgan J. A. , Scalet M. , Zerbi G.
Published: April 2008

Water stress increased mono‐saccharides and decreased di‐saccharides concentration in four field grown genotypes, regardless of their different drought susceptibility. Sandy, a USA genotype known for giving satisfying yields in droughty environments, outstood the other cultivars in terms of betaine and proline concentration in leaf tissues; these aminoacids are therefore considered responsible for the most negative Ψs perceived in this cultivar.

PV‐curve technique revealed for Tullio, the drought susceptible Italian genotype, an osmotic adjustment of –0.63 MPa, four times greater than in Pandas, though this drought resistant cultivar showed a similar content in osmotically active substances; the authors therefore hypothesize an alternative mechanism in the response to water shortage in Tullio.
Yield Formation in Modern and Old Oat Cultivars under High and Low Nitrogen Regimes
Authors: Peltonen‐Sainio P. , Granqvist M. , Säynäjärvi A.
Published: April 2008

Contribution of nitrogen (N) and plant breeding to yield formation of oats (Avena sativa L.) was evaluated with two years'field experiments. These consisted of four Finnish oat cultivars released between 1935 and 1988 and one breeding line. Three rates of N application were used (0, 90, and 120 kg N ha−1) and 19 morpho‐physiological traits, including maturity class, plant structure and plant stand structure, were assessed.

The modern cultivar out‐yielded the old one under low and high N, indicating that return of old varieties into cultivation under low‐input conditions is unlikely to be feasible. An oat ideotype for low productivity conditions must be characterized. Furthermore, N contributed more than oat breeding to several traits studies. However, in some cases N appeared to affect the traits measured in a negative manner. Use of N increased production of both above‐ground vegetative biomass and panicle weight without changing HI significantly. However, plant breeding slightly reduced the production of vegetative phytomass and increased the grain: straw ratio by 10 %. Moreover, genetic gains in shortening straw length, increasing lodging resistance, and improving BYDV tolerance were partly lost when high rates of N application were used. The contribution of N and oat breeding to other morpho‐physiological traits is discussed.
Growth and Development of Soybean (Glycine max [L.] Merr.) Cultivars under Shade in Coconut Garden
Authors: Babu R. Chandra , Nagarajan M.
Published: April 2008

The growth and development of seven soybean cultivars were studied under shade in a coconut garden. Higher shoot height, internodal elongation and lower leaf area index were the most significant growth changes noticed under shade. Leaf net photosynthesis, crop growth rate and seed yield were also reduced under shade. The cultivars CO 1, UGM 30 and UGM 37 recorded higher yield under shade when compared to other cultivars tested.
Carbon Isotope Discrimination and Productivity in Winter Wheat1)
Authors: Morgan J. A. , Zerbi G. , Martin M. , Mujahid M. Y. , Quick. J. S.
Published: April 2008

The recent discovery that carbon isotope discrimination (Δ) relates negatively to leaf transpiration efficiency (CER/gs, defined as leaf CO2 exchange rate/leaf conductance) has led to suggest the trait may be useful in breeding programs. However, the tendency of wheat yields to relate positively to Δ has raised the question as to whether plant scientists should be selecting for more negative (i.e., greater transpiration use efficiency) or more positive (greater yield potential) Δ. Two studies were undertaken, one to examine how Δ relates to yield and yield components in 15 winter wheat genotypes, and the other to study how Δ varies among two wheat genotypes from the USA and two from Italy known to differ in drought resistance.

Variation in Δ among the fifteen genotypes was positively associated (r = 0.71**) with grain yield under irrigated conditions, but only weakly associated (r = 0.43) under non‐irrigated conditions. Δ was not significantly associated with shoot weight under both irrigated and non‐irrigated conditions. Significant correlations of Δ with tiller number and grains per spike under both irrigated and non‐irrigated environments suggest Δ influences wheat yields primarily through variations in grain number per land area. Variation in Δ among drought resistant and susceptible genotypes from the USA and Italy, grown in Northern Italy, did not relate simply to drought susceptibility, but appeared more related to the apparent improved adaptation of the Italian genotypes in their native environment. Δ of grain tissue was lower than in peduncle tissue, reflecting the improved water use efficiency of the later‐formed grain tissue which developed in a more dessicating environment. Lower Δ in grain tissue from non‐irrigated compared to irrigated environments was also attributed to increased transpiration use efficiency.
Variation in Salt Tolerance Among Some Wheat and Triticale Genotypes
Authors: Shalaby Essam E. , Epstein E. , Qualset C. O.
Published: April 2008

The identification of genotypes having potential salt tolerance is an effective approach to solve the problems of saline soils.

Seed germination and seedling establishment are limiting factors in crop production. Seven wheat (Triticum aestivum L.) and one Triticale (X Triticosecale Wittmak) genotypes were evaluated for salt tolerance at emergence and early seedling growth in solution culture with NaCl salinities up to 300 mM L−1 (electrical conductivity equals 27.6 dS m−1).

Seedling emergence was delayed by increasing NaCl in nutrient media. At 200 mM L−1 NaCl, the emergence percentages of wheat genotypes ranged between 68.7 % and 91.3 % after 7 days and 79.3 % and 98.7 % after 15 days. While at 300 mM L−1, the emergence percentages of the wheat genotypes were 0.0 % after 7 days. After 15 days the emergence percent ranged between 24 % and 72 %. The emergence percent of the Triticale line was 88.7 after 7 days and 89.3 after 15 days at 200 mM L−1, while it was 25.3 % and 84 % after 7 and 15 days, at 300 mM L−1, respectively. Root and shoot dry weight were greatly reduced by increasing NaCl, however, the Triticale line showed less reduction in growth compared to the wheat genotypes. K+, Ca2+ and Mg2+ were decreased with increasing salinity levels while Na+ content was decreased in the shoot tissues of wheat and Triticale genotypes.
The Effect of Cold and Sucrose Concentration on its Uptake and on the Respiration Rate of Isolated Embryos of Winter Wheat
Authors: Dubert F. , Biesaga‐Kościelniak J. , Marcińska I. , Skoczowski A.
Published: April 2008

Both at 5°C and 20°C the sucrose concentrations between 8–14 % appear to be optimal from the point of view of dry mass accumulation by the seedling. The metabolic efficiency was also the highest for these concentrations of sucrose.

At both temperatures the hydration of the seedlings was strongly dependent on sucrose concentration in the nutrient, diminishing, respectively, from about 6 to about 2 and from about 10 to about 2 mg H2O × mg DW−1 Such low values of the seedling hydration, however, caused only a 10–20 % decrease of their dry weight. Within the range of the applied sucrose concentration (2–20 %) its beneficial – trophic interaction prevails over the negative – osmotic interaction.

At 5°C, as compared with 20°C, a drop in the seedlings hydration was observed, which appears to be the general response of plants to low temperature of growth.

An analysis of the 24‐hour respiration rate of the seedlings when grown at 5°C seems to reveal the occurrence of a process requiring additional metabolic energy and, probably, associated with the vernalization process.

A method of leveling the temperature dependent hydration of the seedling is proposed to enable the selection of high‐temperature control in the investigations of the biochemical mechanism of frost hardening and vernalization.
Influence of Barley Scald Disease on Yield and Competition in Barley‐Oat Mixtures
Authors: Karjalainen R. , Jokinen K.
Published: April 2008

Field experiments with mixtures of barley and oats in southern Finland demonstrated a reduction in barley scald disease caused by Rhynchosporium secalis on upper leaves compared with that on pure barley stands. Mixtures lowered disease‐induced yield reductions only slightly. In general, barley was not less competitive in the presence of disease than in its absence. Competitive relationships between the species were more important for yield determination than the direct influence of the disease. Over three years the yield increase of the mixtures compared with the means of pure components was close to 5%, whereas extreme conditions in one year led to a decrease of 11%. The role of competition for yield determination in barley‐oats mixtures under disease conditions is emphasized.
Influence of Solar Radiation and Vapour Pressure Deficit on Transpiration Efficiency of Rainfed Sorghum
Authors: Subramanian V. Bala , Venkateswarlu S. , Maheswari M. , Reddy M. Narayana
Published: April 2008

Besides assimilation, plant water relations are important aspects of physiological basis of productivity of crops in water limited environment. The relationships of photosynthesis rate, transpiration rate, leaf water potential and stomatal conductance with photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) during pre‐flowering (panicle initiation to ear emergence) and grain filling (from anthesis to maturity) stages of a sorghum hybrid (cv.CSH‐6) grown under rainfed conditions were studied. Photosynthesis rate declined when PAR was above 1300 μmol m−2s−1. during both the growth stages. Higher transpiration rate during grain filling stage at higher PAR caused the transpiration efficiency to be lower than during pre‐flowering stage when PAR was above 1200 μmol m−2s−1.Leaf water potential and stomatal conductance decreased with increase in PAR. Leaf water potential was higher during pre‐flowering than during grain filling stage but maximum photosynthesis rate was similar during both the growth stages. Changes in VPD did not qualitatively alter the relationships of the physiological variables with PAR.

Decreasing photosynthesis rate and LWP at high PAR suggest that photosynthesis rate was limited by low leaf water potential when PAR was optimal, and by low PAR even when leaf water potential was high in rainfed sorghum during rainy season.
Growth and Yields of Intercropped Sorghum and Sunflower (Helianthus annuus L.) in Semi‐arid Nigeria
Authors: Adetunji I. A.
Published: April 2008

Effect of five planting patterns on the growth, yield and yield components of intercropped sunflower and sorghum was studied during 1989–90 planting seasons at University of Maiduguri, Nigeria. Generally, intercropping depressed the performance of sorghum more than sunflower. Sorghum plants grown in alternate hills with sunflower had the shortest stems, the least dry matter and total seed yields per hectare, while the highest dry matter and seed yields were obtained from sorghum planted in five alternating rows with sunflower. Similarly, in sunflower, plants grown in five alternating rows with sorghum had the highest yields compared with other planting patterns, but there were no significant differences in the dry matter and total seed yields of sorghum and sunflower intercropped in three and five alternating rows. Light transmission, leaf area index and yields of both crops followed similar trends under the various planting patterns. Interplanting in five alternating rows that allowed the highest leaf area also allowed the lowest light transmission and produced the highest yields. Land use efficiency was highly improved under three and five rows interplanting by 52 and 74 % respectively.
Senescence of Flag Leaf and Glume in Rice: Role of Grains during Source‐Sink Modification by Physical and Chemical Means
Authors: Biswas A. K. , Mandal S. K.
Published: April 2008

Senescence of flag leaf and glume of rice (Oryza sativa L. cv. Ratna) at different source sink ratios, through manipulating the plants by physical and chemical means, were analyzed. As judged from the chlorophyll retention capacity, induction of sterility deferred senescence of flag leaf and glume at both grain filling and post grain maturation period. Senescence of the glumes was promoted in the plants whose panicles were darkened. The time needed for achieving maximum 1000 grain dry weight was quickened, the harvest index (HI) was lowered and the flag leaf senescence was delayed by such manipulation. Spraying of urea deferred senescence of the flag leaf as well as increased 1000 grain dry weight and HI. The time taken for achieving maximum 1000 grain dry weight was, however, delayed. Senescence of glumes was promoted by α‐HPMS spray, while the same was delayed by PMA spray on the whole plant. Both the chemicals deferred flag leaf senescence and decreased 1000 grain dry weight and HI. Senescence of the flag leaf at post grain filling period was also delayed by the above physical and chemical manipulations compared to that of control, the highest delaying effect was recorded in the flag leaf of sterile plant.

It is concluded that nutrient drainage is the primary cause of nonsequential senescence of the flag leaf of rice (cv. Ratna). The involvement of senescence signal if any, is perhaps of secondary importance.
Nitrogen Fixation and Nitrate Assimilation of Determinate, Semi‐determinate and Undeterminate Soybeans (Glycine max L.)
Authors: Serraj R. , Obaton M. , Vidal V.
Published: April 2008

Soybean (Glycine max L.) nitrogen nutrition is ensured by both symbiotic nitrogen fixation and mineral nitrogen assimilation. The relationship between these two modes of N nutrition was analysed in 3 growth types (determinate, semi‐determinate and undeterminate) of soybean. The nitrate reductase activity and nitrogenase activity (acetylene reduction) of plants grown in the field and greenhouse showed that these enzymatic activity acted simultaneously or successively during the growth cycle, depending on the availability of inorganic nitrogen in the growing medium. Undeterminate soybean types had a higher potential nitrate reductase activities than determinate types.

The proportion of N2 fixed as measured by 15N labelling or stem ureide content indicated that determinate soybeans derived a higher proportion of their N from N2 fixation than the undeterminates.
Development of Stripe and Leaf Rusts in Wheat Cultivar Mixtures
Authors: Aslam M. , Fischbeck G.
Published: April 2008

Development of stripe and leaf rusts was studied for a two year period, from 1988 to 1990, in four cultivars of bread wheat planted in pure stands as well as in mixtures of different compositions in trials conducted at two different locations in Pakistan. The relative rate of disease development appeared to be slower in plots planted to cultivar mixtures as compared to that with pure stands of the same cultivars. Similarly, the area under the disease progress curve in cultivar mixtures was reduced, the reduction being proportional to the amount of the resistant component in the composite. Frequency of individual virulences in the parasite population also remained constant during the period of these studies. Differences in yield between plots with mixed populations and those with pure stands were also found to be statistically significant.
Effects of Thiourea, Thiamine and Ascorbic Acid on Growth and Yield of Maize (Zea mays L.)
Authors: Sahu M. P. , Solanki N. S. , Dashora L. N.
Published: April 2008

Three chemicals, viz., thiourea, thiamine and ascorbic acid capable of potentiating‐SH turnover, were tested with the objective to improve growth and productivity of maize. Thiourea was tested as seed‐soaking and foliar‐applied treatments as also in combination. Thiamine and ascorbic acid were tested as foliar sprays alone. Foliar treatments were applied at vegetative stage (30 and 45 days after sowing).

The results of the field experiment showed that seed soaking with thiourea (500 ppm) tended to improve grain yield (13.4 per cent over control), but improvement in biological yield was significant. However, seed soaking plus foliar treatment of thiourea significantly increased both biological and grain yields, besides causing significant improvement in leaf area index and number of green leaves plant‐1. The increase in grain yield ha‐1 was of the order of 34.6 per cent over control.

It was further noted that foliar sprays of thiourea (1000 ppm), thiamine (100 ppm) and ascorbic acid (100 ppm) significantly increased leaf area index, number of green leaves plant‐1 and biological yield ha‐1. These treatments also significantly increased grain yield ha‐1 by 40.6, 20.2 and 26.3 per cent, respectively over control. Improvement in maize yield with thiourea, thiamine and ascorbic acid treatments appeared to have resulted from increased photosynthetic efficiency and canopy photosynthesis on account of the biological activity of ‐SH group. It was also apparent that leaf senescence was delayed under the influence of these chemicals. It is therefore suggested that thiourea, thiamine and ascorbic acid are the potential bioregulators for improving photosynthetic efficiency and grain yield of maize and possibly other cereals, and that thiourea, a sulphydryl compound, holds considerable promise in this context.
Multivariate Analysis of Relations between Mineral Element Concentrations in Grain and Baking Quality of Wheat
Authors: Schnug E. , Evans E. , Haneklaus S.
Published: April 2008

Research work on the investigation of multivariate relations between mineral element concentrations in wheat grain and parameters of baking quality were carried out on grain samples derived from official variety trials in Germany and Great Britain. The research yielded the following main results:

–the grain sulphur concentration is an important influencing parameter for the performance of wheat flour during baking process and thus also a major discriminating factor among mutually exclusive quality categories for wheat varieties;

–from a set of mineral element concentrations in the grain (N, P, S, K, Ca, Cl, Si) the loaf volume can be predicted with higher probability than by any other rapid test (e.g. Falling Number or Sedimentation volume). By combination of NIR‐ and X‐RF‐spectroscopy together this elements can be determined with a high accuracy, repeatability and reproducibility in a fairly short time (< 5 minutes).
Changes in ATP Content of Sorghum Seeds Imbibed in Aqueous Extracts of Germination‐Inhibitory Animal‐Waste Composts
Authors: Marambe B. , Ando T.
Published: April 2008

The changes of the ATP content in sorghum seeds imbibed in aqueous extracts of animal‐waste composts were studied to clarify the mode of action of the germination‐inhibitory composts. The seeds were imbibed in water or 1, 4 and 8 % extracts (w/v) of composts for 0, 1,2, 3, 4, 8, 16 and 24 h.

ATP content in the non‐imbibed sorghum seeds was 0.182 n mol seed−1. The ATP content of seeds increased 2.6 fold during the first hour of imbibition. Statistically significant differences in the ATP content were observed between the treatments from 3 h of imbibition. The seeds imbibed in deionized water contained the highest ATP content at all imbibition durations. The ATP content decreased with the increase in concentration of the extracts. Significant linear correlations were observed between the ATP content and the increase of a‐amylase activity at 4 h (r = 0.75**), 16 h (r = 0.70*) and 24 h (r = 0.91**) of imbibition.

The changes in the ATP content in seeds were observed prior to the increase of amylase activity. The reduction of ATP content is the first observable biochemical change in seeds caused by the germination‐inhibitory animal‐waste compost extracts. The ATP content of seeds could be considered as a sensitive indicator to detect the germination‐inhibitory composts.
Modellversuch zur Beschreibung von Konkurrenzvorgängen zwischen Sommerweizen und einer aus Capsella bursa‐pastoris L., Stellaria media L. und Alopecurus myosuroides Huds. bestehenden Mischverunkrautung
Authors: Petry W. , Wirth H. , Kühbauch W.
Published: April 2008

Investigation to Describe the Competition between Spring Wheat and a Weed Population Consisting of Capsella bursa‐pastoris L., Stellaria media L. and Alopecurus myosuroides Huds.

When controlling weeds in cereals using economic threshold as criteria, weed populations must be evaluated for their potential to cause damage at a very early stage. As well as information of actual weed density or weed ground cover, further knowledge about the species specific growth and competition between weed populations is important.

For this purpose the growth and competition between the weeds Capsella bursa‐pastoris L., Stellaria media L., Alopecurus myosuroides Huds. and spring wheat (Triticum aestivum L.) as a model of a typical weed mixture in cereals were studied in a container experiment. The growth with time of individual species was documented using true colour image processing. In that these measurements are non‐invasive, the system lends itself specially to time‐dependent analyses. The increasing amount of ground covered by leaves between two observation times served as a parameter to evaluate the increase in biomass over this time period and could be used as a evaluation of the competitiveness of the weed species studied.

The results can be summarized as follows: 1) Stellaria media L. proved to be the most competitive of the studied species. 2) The competition to spring wheat from each weed species was similar. 3) A multi species weed population had a tendenci to a lower competitiveness to spring wheat, than a weed population of only‐one species.

The importance of this and other similar studies for the improvement for the prediction of economic weed thresholds to estimate weed populations in early stages will be indicated.
The Effect of Nitrogen and Phosphorus Fertilization on the Nitrogen Absorption by Sunflowers
Authors: Loubser H. L. , Human J.J.
Published: April 2008

I. Abstract

Little is known about the effect of fertilization on the N uptake of sunflowers. A 42 factorial trial with 0, 60, 120 and 180 kg N ha−1 and 0, 15, 30 and 45 kg P ha−1 was conducted over three years. The N content and concentration of leaves, stems and capitula were determined at three growth stages. High N levels increased the N content and concentration of all plant parts at all growth stages sharply. High P levels increased the N content of all plant components through better growth. P has an inconsistent effect on N concentration but tended to decrease it. After flowering the crop assimilated 20 to 25 % of the total N. This implies that N applied can still be applied and utilized by the crop at a late stage. This should be substantiated by further research.
Soil Temperature Model for CERES and Similar Crop Models
Authors: Hoffmann F. , Beinhauer R. , Dadoun F.
Published: April 2008

Frequently the soil heat transfer is considered as a one‐dimensional (vertical) process which may be described by the differential equation (DE) of soil heat flow. Regarding the upper boundary, equations for bare and cropped fields are developed by means of data of Kiel and Michigan. For the lower boundary a theoretical and an empirical equation are given. The soil heat conductivity was estimated by the formulas of McInnes (1981). Equations are proposed for estimating the clay and quartz contents which are needed in these formulas. The convective term in the differential equation (DE) may be omitted without significant loss of precision. For the SALUS model in which the two upper layers are 2 resp. 5 cm thick a simple approximative solution for these two layers is given. The temperatures of the deeper layers are calculated by the DE for which in this case only two time steps per day are necessary. This yields short computing times.
Agronomic Potential of Three Vetches (Vicia spp.) Under Rainfed Conditions
Authors: Abd El Moneim A. M.
Published: April 2008

The major limiting factor to livestock production in West Asia and North Africa is the inadequate feed supply. The introduction of leguminous forage species into fallow lands represents a means of increasing feed supplies for the rapidly growing livestock population.

Twenty five lines each of common vetch (Vicia sativa L.) wooly‐pod vetch (Vicia villosa ssp. dasycarpa Ten.), and bitter vetch (Vicia ervilia L.) were tested over three seasons with contrasting rainfalls and winter temperatures. For each species, seedling vigour, winter growth, cold effect, spring growth, leafiness, herbage yield at 100 % flowering, grain yield, harvest index and aspects of herbage quality were recorded. There were considerable variation among entries with the same species, entries of V. ervilia were the earlier in flowering and maturity, and V. villosa ssp. dasycarpa almost the latest by 45 days. V. sativa, was the most affected by frost whilst both V. villosa ssp. dasycarpa and V. ervilia proved to be cold tolerant.

Although V. villosa ssp. dasycarpa produced high herbage yield in springs its grain yield is low resulting in a low harvest index. Both V. ervilia and V. sativa produced high grain yield with high harvest index. Seed yield was negatively correlated (P < 0.01) with days to flowering and maturity indicating the need of earlier types.

Quality of the herbage in term of digestibility was far lower (46 % IVDMD) in V. villosa ssp. dasycarpa than the other two species (69 % and 72 %).

The possible niches and utilization of each species as animal feed in the prevailing farming systems are discussed.
Der Einfluß der Wachstumsrate auf die Effizienz des produktiven Wasserverbrauches durch die Kulturpflanze unter Berücksichtigung von C3‐ und C4‐Arten
Authors: Neuhauser W. , Storchschnabel G.
Published: April 2008

The influence of the growth rate on the water use efficiency by different cultivated plants in consideration of C3‐ and C4‐species

The influence of the growth rate (dry matter production per unit of time) on the water use efficiency by different cultivated plants (maize, sunflower, durum wheat, sorghum, amaranthus) was examined using hydroponic culture. The water use efficiency was expressed by the relative water requirement (1 transpirated water per kg produced dry matter), at which the evaporation was absolutely eliminated. The results showed a definite conformity with the hypothesis, which was taken as the basis for these studies:

– The relative water requirement was not constant on the basis of the changing growth rate during the course of growth and development of the plants. With increasing growth rate decreased the relative water requirement. The effect of the increasing growth rate on the decrease of the relative water requirement was greater all the more, the more the growth rate increased.

– Plants of one and the same species and variety but with different growth rates had different relative water requirements. Those ones with a higher growth rate showed a lower relative water requirement.

An influence of the growth rate on the different relative water requirement of C3‐ and C4‐species also was observed. Under better growth conditions for C3‐plants than for C4‐plants, the growth rate of C4‐plants was slowed down, so the relative water requirement was higher than by C3‐species.

Concluding from this research, there is the possibility to employ the growth rate of plants for a measure to use water more efficient in plant cultivation.
Effect of Intercropping Cereal, Pulse and Oilseed Crops in Redgram on Yield, Competition and Advantage
Authors: Sarkar R. K. , Shit D.
Published: April 2008

Results of a field experiment conducted in rainy season (June to December) of 1988 and 1989 at Deochanda Experiment Station, Bihar, India, indicated that intercropping cereals, pulses and oilseeds with normal planted base crop of redgram (Cajanus cajan [L.] Mill sp.) increased land use efficiency and gave higher total yields compared to pure cropping of redgram under rainfed conditions on upland oxisols of Bihar plateau. Cereals like maize, rice and fingermillet were more aggressive in intercropping system and they tended to have depressing effect on redgram. Intercropping of short duration pulses like blackgram and greengram and legume‐oilseed crops like peanut and soybean with redgram showed balanced competitive abilities and proved more efficient in the system. Intercropping system of redgram‐peanut proved to be the most efficient and productive.
Simulation Analysis of Variation among Seasons in Winter Wheat Yields in Northern Italy
Authors: SINCLAIR T. R. , Mosca G. , Bona S.
Published: April 2008

Winter wheat growth and yield was observed in two sets of field experiments performed at the Experimental Farm of Padova University in Legnaro, over seven years beginning in 1981. A spring wheat model in which leaf area development was calculated as a function of temperature and biomass accumulation was utilized. The final number of leaves in each season was calculated based on a previous winter wheat model and the biomass accumulation was decreased when average daily temperature was below 10 °C. In addition to the two modifications described above, the soil/crop nitrogen submodels were modified so that denitrification was a function of temperature and plant nitrogen uptake rate was sensitive to variations in daily temperature. Nitrogen leached below 60 cm was assumed to be no longer available to the winter wheat crop. The winter wheat model with the soil/crop nitrogen budged resulted in good agreement between the simulated and observed yields (less than 14 % difference existed in 12 of 14 environments). A strong negative correlation (r = ‐0.74) existed between the simulated yields and the simulated amount of nitrogen leached out of the root zone. Under the conditions of nothern Italy, retention of root zone nitrogen appears to be particularly important in achieving high winter wheat yields.
Soil Moisture Conservation for Wheat Production in the Central Highlands of Jordan
Authors: Al‐Turshan M. A. , Battikhi A. M.
Published: April 2008

A study was carried out at Mushaqqar Agricultural Experiment Station located in the Central Highlands of East Jordan. The objectives were to study and compare three crop rotations: Duck foot fallow–wheat; chemical fallow–wheat; and wheat–wheat, on soil moisture conservation and storage and on wheat yield.

Results indicated that, the storage efficiency for the duck foot fallow treatment was higher than that of chemical fallow (13.4 and 8.7% respectively). Also it was found that two duck foot or chemical fallow applications, for weed control, were needed before June.

Wheat yield was the highest after the duck foot fallow, followed by chemical fallow. Wheat yield had decreased from 3.34 Mg/ha to 1.08 Mg/ha, for continuous wheat.
Microbiological and Physicochemical Properties of Carbamate Insecticides Treated Soil
Authors: El‐Sayed M. A. , El‐Shanshoury A. R. , Swelim M. A. , Abd El‐Salam S. S.
Published: April 2008

Treatment of clay loam soil with carbaryl (sevin), thiodicarb (larvin) and methomyl (lannate) at field and 10 folds the recommended doses showed a variable effect on population of total bacteria, azotobacters and nitrifying bacteria, in addition to the soil content of total soluble salts; the effect differed according to the herbicide and the dose level. The bacterial population was significantly increased in the first five days of treatment, then a decrease was recorded. The increase in the microbial population and total soluble salts were proportion to the levels of the insecticides. Moreover, supplementation of glucose to the soil caused substantial increase over that in the insecticide and/or glucose free soils.