bluuebunny/crossref_metadata_2025 huggingface dataset:
Allelopathic Potential of Parthenium hysterophorus L.
Authors: Singh S. P. , Sangeeta
Published: April 2008

Allelopathic influences of aqueous extracts of congress grass (Parthenium hysterophorus L.) were investigated on germination and seedling vigour of cereals (rice and wheat) and pulses (black gram and chick pea).

The observations on germinations of crop seeds were recorded daily while linear growth of plumules and radicles were measured 2, 4 and 6 days after initiation of study. Aqueous extract of this weed exhibited allelopathic effects on germination and seedling vigour of both cereals and pulses. With increase in concentrations of aqueous extract there was decline in percentage of germination in both cereals and pulses but germination of pulses were more adversely affected than cereals.

It was also observed that aerial portion of plant part was found to be more potent than sub‐aerial portion in reducing germination and length of roots and shoots of both cereals and pulses under test. The aqueous extract of 10 % concentration obtained from aerial/sub‐aerial portion of plant brought about maximum reduction in length of roots and shoots.
Effect of Sulphur and Foliar‐applied Chemicals on Cold Tolerance in Chickpea (Cicer arietinum L.)
Authors: Rao S. S. , Sahu M. P.
Published: April 2008

In a field study it was observed that sulphur fertilization of chickpea at 100 kg S ha−1 imparted cold tolerance under low temperature stress conditions. Further, foliar sprays of DMSO, H2SO4, KCl and H3BO3 proved effective in alleviating cold injury. Glucose spray also showed efficacy in this regard. The effects of sulphur fertilization and foliar applied DMSO and H2SO4 were largely associated with improved sulphur nutrition of plants, while improvement in K content under KCl treatment and B content under H3BO3 treatment was responsible for cold tolerance effects. Improvement in overall soluble carbohydrate and protein status of plants was held responsible for glucose effects possibly associated with osmoregulation.
Einfluß des Stickstoffangebotes auf Substanzbildung, Erntegewicht und Qualität der Zuckerrübe unter besonderer Berücksichtigung von Temperatur und Globalstrahlung in Gefäßversuchen
Authors: Bürcky K.
Published: April 2008

Influence of nitrogen supply on dry matter production, yield and quality of sugar beet with special reference to temperature and irradiance in pot experiments

The influence of nitrogen on yield and quality of sugar beet has been studied in many experiments. In comparison, little is known about the changes in sugar beet metabolism caused by increasing the nitrogen supply. The experiments described in this series of papers deal with the influence of nitrogen supply on mineral metabolism. This first paper describes the influence of nitrogen on dry matter production, yield and quality of beet with special reference to temperature and irradiance. The experiments, conducted in 1988 and 1989 using sand culture in pots, included five nitrogen levels. These treatments were sampled five times during the season and at harvest time. Overall, in 1989 sugar yield (g/pot) was 30 to 50 % greater than in 1988. In 1989 there was only a little more irradiance and duration of sunshine (7 and 11 % respectively) than in 1988, and the larger yield in 1989 was probably caused by a bright period of four weeks in May/June. Where least nitrogen was supplied, deficiency symptoms appeared in early June. When this happened an ammonium‐urea solution was added to the leaves: it increased growth, but not enough to equal the white sugar yield of the treatment where the sand was given the same amount of N at the beginning of the season.
Role of Sulphydryl Compounds in Improving Dry Matter Partitioning and Grain Production of Maize (Zea mays L.)
Authors: Sahu M. P. , Solanki N. S.
Published: April 2008

Three sulphydryl compounds, viz., 2‐mercaptoethanol, 2‐mercaptoethylamine and thiourea, were tested for improving dry matter partitioning and grain production of maize in field culture. The chemicals were applied ca. 0.1 % concentration as foliar spray at grain formation stage. Mercaptoethanol, mercaptoethylamine and thiourea increased grain yield ha−1 by 18.1, 29.2 and 34.1 %, respectively compared with water control Significant improvement in harvest index, a measure of dry matter partitioning for grain production, was also noted with the spray chemicals but stover and biological yields ha−1 remained uninfluenced. Foliar spray of 0.1 % urea did not have any effects on the above parameter and thus the effects of thiourea were largely a function of sulphydryl group. It is suggested that sulphydryl compounds have a considerable potential for increasing grain production of maize and perhaps of similar other cereals.
Influence of Stubble Thickness, Carbohydrate Content and Leaf Senescence on Ratoon Rice
Authors: Balasubramanian R. , Balakrishnan K. , Manoharan S.
Published: April 2008

Experiment conducted with nine rice varieties during Pishanum season of 1989–90 revealed that Co 37 performed better in ratoon crop and recorded 3.2 t/ha grain yield. It was evident that the ratooning ability was influenced by stem thickness of stubble, carbohydrate content and leaf senescence of main crop. The study also suggests that by maintaining higher seed size and productive tiller in ratoon crop, there is ample possibilities to increase grain yield.
Effects of Simulated Hail Damage on the Yield of Forage Maize
Authors: Trappeniers G. , Ledent J. F. , Fayt O. , Nijs A.
Published: April 2008

Hail damage was simulated with defoliation, leaf tearing and damage to ears and stems, applied at five stages and three levels of intensity on forage maize grown in Belgium. Leaf tearing alone had little effect on total dry matter yield. Decrease of yield was the highest when treatments were applied around tasseling‐anthesis. Effects on total dry matter content were small.
Green Area Duration during the Grain Filling Period of an Argentine Wheat Cultivar as Influenced by Sowing Date, Temperature and Sink Strength
Authors: Slafer G. A. , Miralles D. J.
Published: April 2008

The effects of sowing date, air temperature during the grain filling period, sink‐strength, and then‐interactions on the wheat green area (leaves, leaf sheaths and peduncles) duration from anthesis to total senescence were determined under field conditions at Buenos Aires (Argentina). The individual grain weight was determined as an average of either all grains or basal grains of the spikelets 7 and 8 through the treatments.

The delayed sowing date reduced the period of leaf senescence when it was regarded as calendar time between anthesis to maturity, but it did not affect that period regarded as thermal time. Similarly, the increased temperature has also increased the rate of senescence. On the other hand, the sink strength did not affect the green area duration; since neither the rate nor the period of senescence was altered.

Similarly, both sowing date and mean temperature decreased the individual grain weight, but the sink strength did not affected the weight of the basal grains, which could be interpreted as the effects of the other two factors were independent to the availability of assimilates per grain.

The effect of increased grain filling temperature on reducing grain weight did not operate via reducing the availability of assimilates although it also reduced the total grain area duration. We observed that the increased temperature decreased the individual grain weight of the basal grains at any source sink ratio.
Forage Yield and Sucrose Response of Rhodes and Ruzi Grass to Cutting Height and Cutting Frequency Under Irrigation
Authors: Bebawi F. F. , Gaiballa A. K. , Neugebohrn L.
Published: April 2008

The development of irrigated pastures in the Sudan is still at its infancy. The present study determined the influence of 2 cutting heights (2.5 and 5.0 cm) and 4 cutting frequencies (4‐, 6‐, 8‐, and 10‐week) on forage yield as dry matter and forage sucrose of Rhodes grass (Chloris gayana Kunth. cv. Massaba) and Ruzi grass (Brachiaria ruziziensis Germain et Everard cv. Congo Signal) under irrigated conditions. Forage yield interactions involving species X cutting height X cutting frequency were significant. These yield interactions were attributed to differences in growth period and growth rhythm of the two species. On average, Rhodes exhibited a short growth period (13 months) compared to Ruzi grass (20 months). Forage yield and forage sucrose were, on average, superior in Ruzi compared to Rhodes grass. Forage yield and forage sucrose averaged 5.2 t ha−1 and 7.2 % fw sucrose in Ruzi compared to 2.8 t ha−1 and 6.9 % fw sucrose in Rhodes grass. Forage yield and forage sucrose of both species were negatively correlated with cutting frequency. The highest forage yield may be obtained at an 8‐week cutting frequency in Rhodes (45.6 t ha−1 yr−1) compared to a 10‐week cutting frequency in Ruzi grass (88 t ha−1 yr−1). Results suggest that very high forage yields as dry matter and forage sucrose of Rhodes and Ruzi grass may be possible under irrigated conditions in the Sudan at a cutting frequency of between 8 to 10 weeks.
Dense Cultivation and Fertilization for Higher Yield of Thyme (Thymus vulgaris L.)
Authors: Shalaby A. S. , Razin A. M.
Published: April 2008

Thyme (Thymus vulgaris L.) plants were spaced at 15, 30 or 45 cm distances in a clay‐loamy soil. They received different levels of nitrogen and phosphorus, besides a constant level of potassium. The results showed, that the wider spacing promoted the growth and production of herb and oil per plant, however dense cultivation significantly increased the yields of herb and oil per unit area. In all cases, the applied fertilization treatments significantly increased the productivity per unit area. Dense cultivation accompanied with higher levels of fertilization proved to be very usefull. The essential oil content was not influenced by either the plant spacing or fertilization treatments applied in this study.
Effects of the Application of Amorphous Silica on Transpiration and Photosynthesis of Soybean Plants Under Varied Soil and Relative Air Humidity Conditions
Authors: Küpfer C. , Kahnt G.
Published: April 2008

In epidermal cell walls of soybean leaves treated with amorphous silica accumulation of silica could be detected by means of electron microscopy and electron probe microanalysis. This changed the physical properties of the cell wall and affected the cuticular transpiration and uptake of CO2: When the soil in which the plants were grown was dry (60% of the field capacity) and relative air humidity was below 50 %, the loss of water through the cuticle was smaller than the loss of CO2 uptake. This caused a higher grain yield under the conditions of temporarily restricted low air humidity.
Effect of Water Stress on the Lipid and Fatty Acid Composition of Sweet Pepper (Capsicum annuum L.)
Authors: El Sayed H.
Published: April 2008

Sweet pepper (Capsicum annuum L.) plants were grown under field irrigation and dryland conditions. Stress was imposed 12 d after planting by withholding water for 8 d, and seedlings were harvested for analysis 20 d after planting. In stressed plants, leaf water potential dropped from ‐0.65 to ‐ 1.03 MPa and water saturation deficit increased by 40 %; plant height did not show a significant reduction. The fresh and dry weights of stressed seedlings and their ratio decreased. The total lipid and total phosphorus contents of stressed seedlings decreased by about 43 % and 71 %, respectively, in comparison to the contents of the watered seedlings. The diacylglycerol, free fatty acid and total polar lipid contents decreased significantly with stress, the last mentioned by more than 50 % in phospholipid levels. Glycolipid levels; were unchanged and the amount of triacylglycerol increase by about 30 % over the control.

Despite the differences found in the fatty acid composition of various lipid classes and between treatments, the degree of unsaturation did not change significantly either in control or stressed seedlings. Under stress conditions, free sterol levels increased without showing any change in the ratio of ‘more planar’ to ‘less planar’ sterols. The increase in free sterols and the decrease in phospholipid levels under water deficit conditions raised the sterol/phospholipid molar ratio 3‐fold. The different responses of the lipid classes to water deficits and their possible significance are discussed.
Pre‐anthesis Interaction of Cytokinins and ABA in the Transport of 14C‐sucrose to the Ear of Winter Wheat (Triticum aestivum L.)
Authors: Borkovec V. , Procházka S.
Published: April 2008

The effect of the application of abscisic acid (ABA, 10−4 mol 1−1), benzyl adenine (BA, 10−6 mol ‐ 1−1), N6‐m‐hydroxybenzyl‐adenosine (HBA, 10−6 mol ‐ 1−1) and combinations of these cytokinins with ABA on the transport of 14C‐sucrose into the developing kernels of winter wheat, their number and mass, was studied. Growth substances were applied in the period 10 to 5 days before anthesis and their effects were examined 4 and 18 days after anthesis on ears that were detached 10 days before anthesis and then cultivated on a complete nutrient solution. The stimulating effect of HBA on the transport of 14C‐sucrose, number of kernels and their mass was higher than that of BA. ABA partly decreased the stimulating effect of cytokinins and reduced up to several days after anthesis the transport of 14C‐sucrose to the developing kernels, their number and mass. The results revealed that a higher level of cytokinins in the period before anthesis could effectively interact with the inhibiting effect of ABA in that period and influence the accumulation of assimilates in the kernels.
Effect of Post‐Planting Residue Applications and Tillage on Nitrogen Accumulation and Partitioningin Maize (Zea mays L.)
Authors: Olness A.
Published: April 2008

Effects of a tillage‐surface crop residue combination on nitrogen (N) accumulation by maize were examined using a replicated field experiment. Crop residues, < 70 % surface cover, were applied a few days aftei planting conventional‐ and ridge‐tillage treatments. With < 30 % surface cover, total accumulated‐N decreased from about 4 to 2 g plant−1 as the plant population density (PPD) increased from 4 to 7 plants m−2 With < 70 % surface cover, total N accumulated averaged about 3 g plant−1 over the PPD range of 4 to / plants m−1. At a PPD of about 5.5 plants m−2, equal amounts of N were accumulated by plants in al treatments. Nitrogen accumulation was periodically monitored and fitted to a diphasic tanh(k[time]) model About 1.8 to 2.6 g of N and about 0.70 to 1.4 g of N were accumulated before and after anthesis respectively. Maximum N accumulation rates averaged about 92 and 60 mg plant−1 day−1 during vegetativt and reproductive growth‐stages, respectively. Total N accumulation during the vegetative growth‐stag declined exponentially as PPD increased; this may reflect a crop demand‐soil supply relationship.
Untersuchungen zur Optimierung der N‐Aufnahme von Winterweizenbeständen durch ergänzende Düngungmaßnahmen
Authors: Fischbeck G. , Dennert J. , Muller R.
Published: April 2008

Investigations on supplemental N‐fertilizer application for the optimum course of N‐uptake into winter wheat stands

During a period of 5 years 14 N‐fertilization field trials with winter wheat have been carried out in which N‐uptake and biomass production in 6 growth stages were analysed. By comparison with non‐optimal variants of N‐supply a critical range for N‐uptake has been recognized which centered around an optimum value of 86 kg biomass N/ha at growth stage EC32. In connection with intensified N‐uptake during later growth stages, this has allowed full exploitation of the wheat yield potential without substantial decrease of the N‐harvest index.

Field trials on two different soil types (Parabraunerde and humose Auenrendzina), different dates of sowing and long year stands in wheat monoculture as well as applications of N‐fertilizers containing dicyandiamid for delay of nitrification showed differences in efficiency as related to the fertilizer dosages but no systematic deviation from the optimum course of N‐uptake for full exploitation of yield potential.

Provided that excessive fertilizer dosages before EC32 had been avoided, it seems possible to adjust the reuptake of winter wheat stands close to its optimum within an error of not more than 30 kg fertilizer N/ha by growth stage oriented splittings of fertilizer application and adequate account of soil‐N supply and weather conditions during early growth stages.

Full exploitation of the wheat yield potential has been possible in all trials without significant losses in N‐use efficiency if optimal splittings and dosages of supplemental N‐fertilizers were provided.
The Effect of Different Preceding Crops on the Development, Growth and Yield of Winter Barley
Authors: Christen O. , Sieling K.
Published: April 2008

Reliable estimations of the yield response of winter barley to different preceding crops are necessary for the design of crop rotations.

The grain yield and yield components of winter barley (cv. Tapir) following either rapeseed, oats, wheat or barley were determined in five years of field experiments on a sandy loam (Luvisol) at the Hohenschulen experimental station near Kiel, Germany, F.R. The growth, development and incidence of take‐all (Gaeumannomyces graminis var. tritici) was measured in a total of three years. On average over the five years barley grown after oats yielded 0.8 t per ha (11 %) more than barley following wheat which was mainly due to a higher number of ears per m2. Barley following either oats or rapeseed produced a higher dry weight and a larger number of tillers per m2 compared with barley grown after wheat or barley. This effect was already‐present at the sampling date before winter. Take‐all ratings were constantly higher in barley following a susceptible crop, but only reached a severe level late in the season and therefore could not explain the observed differences in growth, development and subsequently grain yield. Since no other pathogens affected the development other non‐pathogenic causes must be considered as main causes for the described observations and yield differences.
Stoffbildung, CO2‐Gaswechsel, Kohlenhydrat‐ und Stickstoffgehalt von Winterweizen bei erhöhter CO2‐Konzentration und Trocken‐streß
Authors: Müller J.
Published: April 2008

Dry Matter Production, CO2 Exchange, Carbohydrate and Nitrogen Content of Winter Wheat at Elevated CO2 Concentration and Drought Stress

Methods of mathematical modelling and simulation are being used to an increasing degree in estimating the effects of rising atmospheric CO2 concentration and changing climatic conditions on agricultural ecosystems. In this context, detailed knowledge is required about the possible effects on crop growth and physiological processes. To this aim, the influence of an elevated CO2 concentration and of drought stress on dry matter production, CO2 exchange, and on carbohydrate and nitrogen content was studied in two winter wheat varieties from shooting to milk ripeness. Elevated CO2 concentration leads to a compensation of drought stress and at optimal water supply to an increase of vegetative dry matter and of yield to the fourfold value. This effects were caused by enhanced growth of secondary tillers which were reduced in plants cultivated at atmospheric CO2 concentration. Analogous effects in the development of ear organs were influenced additionally by competitive interactions between the developing organs. The content and the mass of ethanol soluble carbohydrates in leaves and stems were increased after the CO2 treatment and exhausted more completely during the grain filling period after drought stress. Plants cultivated from shooting to milk ripeness at elevated CO2 concentration showed a reduced response of net photosynthesis rate to increasing CO2 concentration by comparison with untreated plants. The rate of dark respiration was increased in this plants.
Intercropping and Poultry Manure Effects on Yields of Corn, Watermelon and Soybean Grown in a Calcareous Soil in the Jordan Valley
Authors: Sharaiha R. K. , Hattar B.
Published: April 2008

This study was conducted at the University of Jordan Research Station in the central Jordan Valley during 1988 and 1989 summer growing seasons, to determine the potential and response of summer crops to intercropping system and to poultry manure addition. Corn, soybean and watermelon were grown as sole crops and as intercrops in three paired combinations (corn: watermelon, corn: soybean, watermelon: soybean) with three levels of poultry manure (0, 20, 40 t/ha). The crop yields and land equivalent ratios (LERs) were determined for all treatments. The highest yields for the two cropping systems were obtained in response to the highest poultry manure addition. Corn gave the highest yield when intercropped with soybean, where increases in yield of 45 % and 66 % were obtained over those of corn sole crop at the same level of poultry manure (40 t/ha), in 1988 and 1989 seasons, respectively. Soybean gave the highest yield when grown with corn leading to an increase of 35 % and 34 % over soybean sole crop grown at the same level of poultry manure (40 t/ha) in 1988 and 1989, respectively. Watermelon gave the highest yield when grown with soybean, giving an increase which ranged from 390 to 920 kg ha−1over the yield of sole cropping system under the same level of poultry manure (40 t/ha). The LER values for all intercrop treatments were greater than 1.0 which gave clearly an indication for the superiority of the intercropping over the sole cropping system especially when 40 t ha−1poultry manure was added.
Automatische Erkennung von zehn Unkrautarten mit Hilfe digitaler Bildverarbeitung und Fouriertransformation
Authors: Gerhards R. , Nabout A. , Sökefeld M. , Kühbauch W. , Eldin H. A. Nour
Published: April 2008

Automatic identification of 10 weed species in digital images using Fourier descriptors and shape parameters

Plant species discrimination in mixed plant communities has recently become possible using transforms and shape parameters to classify digital images. In the present study image analysis techniques were used to identify weeds commonly found in winter cereal fields. Those species included Veronica hedenfolia L., Thlaspi arvense Beauv., Alopecurus myosuroides L., Apera spica‐venti L., Poa annua L., Stellaria media L., Capsella bursa‐pastoris L., Lamium purpureum L., Matricaria chamomilla L. and Galium aparine L. Images of several growth stages of these weeds were photographed using a Still Videokamera, binarified, the shape extracted and then Fourier descriptors and shape parameter were calculated for each weed. Classified digital images of each species were stored on the computer. A separate set of photographic images of these 10 weeds were used to test the ability of the classified images for plant identification.

The average rate of correct identification was 81.9 % ranging from 41.6 % to 100 %.
Dynamisches Entscheidungsmodell zur Lenkung von Unkrautkontrollmaßnahmen in Wintergetreide mit Hilfe digitaler Bildverarbeitung
Authors: Gerhards R. , Kühbauch W.
Published: April 2008

Dynamic decision model for weed control methods in cereals by means of digital image analysis

Field experiments were conducted to study weed‐crop competition in winter wheat, ‐barley and ‐rye. Weed cover and crop cover was determined over time by digital image analysis of slides taken in the field. The relation of percentage weed coverage and crop coverage was most suitable to quantify the competition of weed population on the crop. In addition the model “UNPROG” was established to predict yield losses caused by weed competition and to estimate the profitability of chemical or mechanical weed control. The model was tested on 22 farms in Nordrhein‐Westfalia in autumn 1991 and spring 1992. In 65 out of 72 field plots (92 %) of winter cereals “UNPROG” gave correct prediction with respect to necessity of weed control.
Photosynthesis as Influenced by Assimilate Level in Sunflower (Helianthus annuus L.)
Authors: Mitra Surma , Srivastava G. C.
Published: April 2008

The regulation of photosynthesis by its assimilates was investigated in sunflower by altering the assimilate level in leaves by girdling, detopping, shading and defoliation. The level of assimilates like sucrose accumulated in leaves did not inhibit photosynthesis or Rubisco activity. Starch levels also did not have an influence on the photosynthetic rate.
Stickstoff‐Eintrag und ‐Verbleib im Boden unter offenen und abgedeckten Mistmieten
Authors: Dewes T. , Ahrens E. , Koch Ch.
Published: April 2008

Nitrogen penetration and persistence in soil under uncovered and covered farmyard manure heaps

After deposition of cattle manure for 308 days neither the total nitrogen nor the nitrate but onlv the ammonia content in the soil (0–70 cm) was significantly increased. During a 258 days period from autumn to spring the observed microbial oxidation of penetrated ammonia to nitrate was tardy and by no means quantitative. So leaching of nitrate was hardly to be detected during the whole period. In the soil layer 40–70 cm a maximum of 1.6 g NO3−‐N/m2was measured, which was in an equivalent range with the amounts detected by large scale investigations in agricultural soils at the same season. Therefore the manure heaps in question did not lead to an uncommon increase of nitrate in soil. The protection of the heaps against precipitation simply brought about small and only a few times significant reductions in soil Nmincontent.
Responses of Some Local/Exotic Accessions of Lentil (Lens culinaris Medic.) to Salt Stress
Authors: Ashraf M. , Waheed A.
Published: April 2008

Assessment of salt tolerance at all growth stages is crucial to determine the overall tolerance of a crop. Salt tolerance of five tolerantILL 5845, ILL 6451, ILL 6788, ILL 6793 andILL 6796, three moderately tolerant ILL 6431. ILL 6770 andILL 6784, and three sensitiveILL 6210, ILL 6439 andILL 6778 accessions selected at the germination and seedling stages was assessed at the adult stage using sand culture sahnized with 0, 30, or 60 mol m−3 NaCl. A positive correlation was observed between degrees of salt tolerance at different growth stages in three tolerant accessionsILL 6451, ILL 6788 andILL 6793 which produced significantly higher seed yield than the other accessions. This was also affirmed in three sensitive and two moderately tolerant accessions (ILL 6770 andILL 6784) whose salt sensitivity was conferred consistently at all growth stages. In contrastILL 5845, andILL 6796 which were highly salt tolerant andILL 6431 which was moderately tolerant at the early growth stages had relatively low seed yield, hence showing a negative correlation between tolerances at different growth stages.

High yielding accessionsILL 6451, ILL 6788 andILL 6793 in general, accumulated higher Na+ and higher or moderate Cl− in their shoots compared with the other accessions, thus showing a typical halophytic mechanism of salt inclusion. K/Na ratios of all the tolerant, moderately tolerant and sensitive accessions exceptILL 6784 andILL 6778 were less than 1, a suggested minimum level for normal functioning of many metabolic processes in plants.

The present study shows that salt tolerance observed previously at the early growth stages is conferred at the adult stage in most of the accessions of lentil examined here; but for others in which no positive correlation was observed between different growth stages suggests that a combination of certain characters can be used as selection criterion for improving salinity tolerance in lentil through exploitation of inter‐ and intra‐cultivar/line variation.
Environmental Adaptation and Stability Relationships between Grain Yield and some Agronomic Traits in Winter Oat
Authors: ÖZgen M.
Published: April 2008

This study was conducted to determine the stability of grain yield, harvest index, plant height, and panicle length and to determine the association of grain yield with these traits in winter white oat (Avena sativa L.) genotypes. The genotypes were grown in replicated tests in Ankara in 1985–1991. Each experiment year was regarded as an environment, and entry mean of each year was used as the environmental index. Stability parameters were estimated from the regression analysis as linear regression coefficient (b), deviations from regression (S2d) and coefficient of determination (r2).

Genotypes differed significantly for all traits and significant genotypes X environment interactions occurred for these traits. On the basis of estimates of stability parameters, A‐24 genotype was stable for grain yield. Correlation coefficients between traits were inconsistent in good and poor environments except between grain yield and panicle length. The study suggested that these traits are differently affected by environmental changes and selection for panicle length might be effective as selection for grain yield in improving oats with high grain yield for diverse environments.
Die Ertragsbildung und Ertragsstruktur eines konventionellen und eines epigonalen Genotyps der Weißen Lupine (Lupinus albus)
Authors: Stützel H. , Aufhammer W. , Rautenkranz A. , Wagner B. , Falfus J. , Nalborczyk E.
Published: April 2008

Yield formation and yield components of a conventional and an epigonal genotype of white lupin (Lupinus albus)

Differences in yield formation and yield structure of two contrasting Lupinus albus growth types, the conventional, freely branching cultivar Kalina and the epigonal. little branching cultivar Ep I were analyzed. Both cultivars were grown in field experiments at Hohenheim in 1987 and 1988 with a combined variation of population density (30–120 plants/m2) and plant distribution. In addition, assimilate distribution within the plant was studied using a 14C‐labelling experiment. – The contributions of branches to light interception of the crops during the generative phase were > 90 % in Kalina as compared to about 30 % in Ep 1. Relative 14C uptake of branches was in a similar range, but great proportions of the 14C taken up by branches was translocated to main stems. No genotype x plant density interactions with respect to grain yield were recorded, indicating that yield formation at main stems and branches was affected by cropping conditions similarly in both genotypes. This applies to the conditions of the experiments, where stress effects were absent. Under these conditions, the conventional genotype showed agronomic, but no physiological disadvantages.
Population and Planting Pattern Effects on Intercropped Maize and Cowpea
Authors: Ezumah H. C. , Ikeorgu J. E. G.
Published: April 2008

Field studies on the nature of competition and the effects of various planting patterns on maize/cowpea intercrop yields were conducted in Southwestern Nigeria. Relative Crowding Coefficient values indicated that maize dominated cowpea. The magnitude of competition between maize and cowpea is related to season and nitrogen fertilizer. Based on grain yields, maize and cowpea compete for N only when it was applied but tended to derive it from different sources in the absence of applied N.

Spatial arrangements designed to increase light reaching intercropped cowpea included alternate and double rows of cowpeas between maize rows. These did not, however, increase grain yields of cowpeas over those intercropped with maize in the same row.
Water Stress and Potassium Fertilization in Field Grown Maize (Zea mays L.): Effects on Leaf Water Relations and Leaf Rolling
Authors: Premachandra G. S. , Saneoka H. , Fujita K. , Ogata S.
Published: April 2008

Three cultivars of maize (Zea mays L.) were grown in the experimental field at Hiroshima University, Japan under two levels of K fertilization with a non‐irrigated water stress treatment and an irrigated control during June to August 1990. Leaf water potential, osmotic potential and stomatal conductance were measured 21 d after withholding water. Diurnal changes in degree of leaf rolling were measured on the 22nd day after withholding water. Leaf water potential and osmotic potential at full turgor were lower in the non‐irrigated plants than irrigated and they were lower in the high K plants than the low K plants. Lowering of osmotic potential (osmotic adjustment) helped to maintain turgor under low water potential conditions. Turgor potential was increased by the higher K fertilization. Higher turgor potential may contribute to the higher stomatal conductance observed in non‐irrigated high K plants. The degree of leaf rolling increased towards noon, and it was lower in high K plants than in low K plants. High K plants recovered from leaf rolling faster than the low K plants during the afternoon. High K. plants could maintain higher turgor potential throughout the day than the low K plants. Degree of leaf rolling was the lowest in the cultivar K‐8388 which maintained the highest turgor potential via osmotic adjustment and it recovered from leaf rolling faster than the other two cultivars. Higher levels of K fertilization may be beneficial for maize plants to tolerate to water stress conditions.
Dynamics of the Cumulation of Iron, Copper and Sodium During Development to Maturity of Soybean Seed
Authors: Slipčević V. , Vedrina‐Dragojević I. , Balint L.
Published: April 2008

The dynamics of the cumulation of iron, copper and sodium with four genotypes of soybean cultivated in the same topographical and agrotechnical conditions during three years was followed. Sampling was done in weekly intervals until complete maturity of seed. It was found out that the most intense cumulation took place during the seed development stages III and IV at the time of mostly expressed metabolic activity of the seed. The absolute values of the contents were increasing along with seed maturing and maximums were reached by the end of the stage IV or rather by the beginning of the seed development stage V. Although the dynamics of cumulation regardless of the year of investigation was equal with all the genotypes the analysis of the impact of climatic factors showed that higher precipitation at the period of seed development along with moderate air temperature affected mineral cumulation. Similarly, the highest contents of iron, copper and sodium observed with the genotypes Srecka and Maksimirka point out that the cumulation of the investigated minerals in soybean seed is affected by genetic particularity.
The Effect of Plastic Mulch and Greenhouse‐Raised Seedlings on Yield of Maize
Authors: van der Werf H. M. G.
Published: April 2008

The yield of maize (Zea mays L.) can be increased appreciably if canopy closure is brought forward. In France and Germany, the use of plastic mulch has boosted dry matter yields of silage maize by approximately 4 t/ha. In Germany, the grain yield of maize plants grown from greenhouse‐raised seedlings was 2.4 t/ha more than that of plants grown conventionally. The present study aimed to review and quantify the effect of the use of plastic mulch and greenhouse‐raised seedlings on yield of maize. In field trials the effect of a photo‐degradable transparent plastic mulch on the yield of two hybrids: Clipper (early‐maturing) and Dea (late‐maturing) was tested. In two of these trials the effect of using seedlings raised in the greenhouse up to the five‐leaf stage was also tested. Crops with plastic mulch required 10 % fewer growing degree days from planting to silking than the unmulched crops, and this number was more constant between years and sites. On average, plastic mulch increased whole plant dry matter content from 29 % to 33 %, and the dry matter of the ear from 45 % to 52 %. In Dea, dry matter yields of the whole plant and of the ear rose by 2.6 and 2.1 t/ha respectively. In Clipper the yield increases were half as large. The regression of whole plant dry matter yield on the sum of global radiation from silking to harvest was similar for mulched and unmulched crops. This suggests that the yield increases obtained with the plastic mulch were largely attributable to advancement of canopy establishment. The whole‐plant dry matter yield of plants initially raised in the greenhouse was similar to that of maize sown in situ, but the ear dry matter yield was 2.4 t/ha higher.
Plant Growth Regulator Effects on Protein Content and Yield of Spring Barley and Wheat
Authors: Ma B. L. , Leibovitch S. , Smith D. L.
Published: April 2008

Plant growth regulators (PGR) have potential to increase grain yield and may also alter grain protein levels of cereal crops. A 3‐yr field experiment with spring barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) cultivars was conducted to determine whether ethephon treatment increased protein concentration, protein yield, and grain yield. A greenhouse experiment was also conducted to evaluate the response of barley grain protein concentration to gradual addition of ethephon (2.2 × 10‐3 mM) or chlormequat (5.8 × 10‐3 mM) solution after an thesis. Under field conditions, ethephon treatment increased barley and wheat grain protein concentrations by as much as 16 % but decreased grain yield so that protein yield increases were small or did not occur. For Laurier barley, total gram N content was increased by up to 20 % in one year of this study. However, over the 3 years, an inverse relation existed between grain protein and yield. Greenhouse data showed that i) the gradient in grain size and protein concentration among spikelets of a spike, which is established before anthesis, was not affected by either chlormequat or ethephon; and ii) chlormequat increased grain protein by 7 to 11 % whereas ethephon increased protein concentration by up to 13 % in one of the two experiments. Our data indicate that PGR can alter protein accumulation in the grain, and thus, the quality of bread wheat and feed barley crops can be increased m regions with a short crop‐growing season. However, a portion of the increase in gram protein concentration is due to decreased starch deposition, which is associated with yield reductions. The greenhouse data confirmed that a portion of the increase in grain protein concentration due to PGR application is caused by increased protein accumulation in the barley grain.
Effect of Different Methods and Timings of Stand Establishment on Performance of Rainfed Lowland Rice Under 0–50 cm Water Depth
Authors: Sharma A. R.
Published: April 2008

About one‐third of the total rice is grown under rainfed lowland conditions, mostly m south and south‐east Asia. Crop productivity in this ecosystem can be improved by adopting suitable management practices as drainage of excess water is not feasible in the catchment and coastal areas. Field experiments were conducted using a long‐duration (165 days), photosensitive, semi‐tall (150 cm) rice cultivar Utkalprabha established through direct sowing or transplanting on different dates under 0–50 cm water depth at Cuttack, India, during 1989–91. Direct sowing was done in lines in dry soil from 10 May onward using 400 seeds/m2 and continued at 10 day intervals until June. Transplanting was done after accumulation of water in the field from July until 15 August with seedlings raised in nursery seed‐beds with or without fertilizer application (100 kg N and 8.7 kg P and 16.7 kg K/ha) and tillers removed from the direct‐sown crop. Seedling emergence varied significantly from 127–212/m, irrespective of sowing date and was dependent on rains received after sowing. However, the early sown crops in spite of poor germination, performed well due to better establishment and tiller production before water rose to higher depths in the field. There was a decreasing trend in grain yield, particularly when the sowing was delayed beyond end of May. The loss in yield with delayed sowing in June was due to poor crop stand which could not be compensated for by applying 50 % more seed (600/m2) and N fertilizer (60 kg N/ha). Removal of some of the tillers (100–130/m2) from crops sown on 30 May with 600 seeds/m2 for planting on an equivalent plot area did not cause any adverse effect on the performance of mother crop. The anticipated shortfall in yield due to lower panicles/m2 with clonal tiller separation was compensated for by the resulting increase in panicle weight.

The performance of transplanted crops depended greatly on the water depth at or soon after planting. In 1990, planting on 15 July in 30 cm water depth helped in relatively better establishment and grain yield at par with sowing on 10 May. However, in 1991, when there was a sudden and rapid increase in water level to higher depths (50 cm) immediately after planting, the early planted crops produced only a negligible yield (0–1.2 t/ha). Highest yield was obtained from the crop planted with clonal tillers followed by that raised with fertilized and unfertilized nursery seedlings. Clonal tillers were taller (90 cm) and had more dry weight (1.78 g) compared with nursery seedlings (50–80 cm and 0.25–0.91 g). Therefore, the clonally propagated crop established well and acclimatized faster in the similar flooded environment, resulting in significantly higher grain yield particularly under late planted conditions. The results suggested early sowing by the end of May and transplanting with clonal tillers uprooted from the direct‐sown crops for higher productivity of rice under uncontrolled excess water conditions.
Soil Type Influences Relative Yield of Barley and Wheat in a Mediterranean‐type Environment
Authors: Simpson P. G. , Siddique K. H. M.
Published: April 2008

In the eastern wheatbelt of Western Australia the yield of barley relative to wheat is influenced by soil type. Field trials studied detailed aspects of growth, development, yield and water use of a range of barley and wheat cultivars on 2 soil types at 2 locations to identify those factors that lead to the differential relative yields.

Barley had greater grain yields than wheat on both fine and coarse textured soils. On both soil types barley had a greater number of mainstem leaves which appeared faster than those of wheat and this was associated with greater tillering (6.5 v. 3.5 shoots/plant), higher GAI and greater dry matter production (845 v. 804 g/ m). The difference in yield between the two species was greater on the fine textured soil (15 v. 7 %). Barley also had greater harvest index than wheat (6—15%), and this combined with greater dry matter production on the fine textured soil led to a larger yield advantage over wheat than occurred on the coarse textured soil. Water use efficiency was greater for barley than for wheat on both soils.

The greater yield advantage of barley over wheat on the fine textured soil was the result of greater biomass production by barley and greater harvest index. Differences in pattern of water use, and water use efficiency of grain production were associated with greater barley yields but are not themselves considered to be the cause of relative yield differences across soil types. The possible implications of factors such as intrinsic nutrient supply on the 2 soil types in relation to observed yield differences are discussed.
Irrigated Sweet Corn Crop Production Functions and Efficient Water Use1
Authors: Abu‐Awwad A. M.
Published: April 2008

The yield of sweet corn (Zea mays L.) and seasonal evapotranspiration as affected by different amounts of irrigation water was studied in a field plot experiment during 1991 and 1992 in the Jordan Valley. Four different amounts of irrigation water were imposed with trickle irrigation on a clay soil.

The different sweet corn components differed in their response to seasonal evapotranspiration. Sweet corn yields of total fresh and total oven dry matter at W3 (W3 = Eo) and W4 (W4 =1.5 EJ were significantly higher than yields at lesser water amounts (W1 = 0.25 Eo and W2 = 0.5 EJ, while good husked fresh ear yield at W4 was significantly higher than yield at W1, W2, and W3. Seasonal evapotranspiration increased in a decreasing rate as total water applied increased. Increasing total water applied more than 400 mm resulted in a negligible increase in sweet corn seasonal evapotranspiration. Crop productivity and water use index (defined as the change in crop yield per unit change in seasonal evapotranspiration) were the highest, when optimal water levels were used.
Effect of High Temperature Stress on 14CO2 Assimilation and Partitioning in Indian Mustard
Authors: Subrahmanyam Desiraju , Rathore V. S.
Published: April 2008

Effect of heat stress on 14CO2 assimilation and translocation by different parts was investigated in Indian mustard (Brassica juncea (L.) Czern.]. Heat stress reduced 14CO2 assimilation by leaves, stem and pods. Export of radioactive carbon from upper and lower leaves, upper and lower stem and stem of terminal raceme was inhibited in response to heat stress. Import of 14C‐photosynthates into pods was also inhibited by heat stress indicating reduction in sink strength of the developing pods.
Symbiotic Nitrogen Fixation of White Clover in a Mixed Sward is not Limited by Height of Repeated Cutting
Authors: Seresinhe T. , Hartwig U. A. , Kessler W. , Nosberger J.
Published: April 2008

The aim of this study was to investigate whether symbiotic nitrogen fixation in white clover nodules limits nitrogen supply and hence clover growth by repeated defoliation at two cutting heights. Other possible factors governing symbiotic nitrogen fixation in the field were also elucidated. Using 15N, a 2‐year field experiment including white clover (Trifolium repens L. cv. Ladino) and perennial ryegrass (Loliumperenne L. cv. Bastion) in monocultures and in mixtures was conducted in Eschikon, Switzerland. The effect of two cutting heights (4 cm and 10 cm above ground level) on the performance of symbiotic nitrogen fixation of white clover in the different sward‐types was investigated. After each harvest, the plots were fertilized with 3 g N m‐2(equivalent to 30 kg N ha‐1 cut‐1 or 210 kg N ha‐1 year‐1). In both years, white clover grown in a mixture with grass received a significantly higher percentage of nitrogen from symbiotic fixation compared with clover grown in monoculture. This phenomenon is attributed to the strong competitiveness of ryegrass in soil nitrogen uptake. Consequently, white clover in the clover‐ryegrass mixture was more dependent on symbiotic nitrogen fixation than that grown in monoculture. The cutting height did not preferentially influence symbiotic nitrogen fixation, as opposed to the uptake of mineral nitrogen from the soil. From this finding it is suggested that symbiotic nitrogen fixation did not limit the supply of nitrogen to clover and hence its growth. It is proposed that symbiotic nitrogen fixation in white clover is regulated by the demand for nitrogen rather than by the availability of carbohydrate reserves in the stolons. Symbiotic nitrogen fixation should thus be looked upon as an integrated plant growth factor and not as an isolated phenomenon.
Yield and Seed Quality of Mungbean as Affected by Irrigation in a Dry Season
Authors: Sangakkara U. R.
Published: April 2008

A field study was conducted with the objective of determining the effects of soil moisture on seed yield and quality of mungbean (Vigna radiata L. Wilczek) when grown under rainfed and irrigated conditions in a dry season. Seed quality was determined in terms of germination and production of normal seedlings after controlled deterioration. The presence of adequate soil moisture increased growth and yields of mungbean significantly. The seeds from irrigated plots had a greater weight, owing to heavier cotyledons. Although germination of seeds from the irrigated plots was higher before and after controlled deterioration for 72 h, the number of abnormal seedlings was also greater. Controlled deterioration reduced germination of both categories of seed in the same manner. These factors indicate the low potential of using seeds produced under irrigation in dry seasons as planting material, especially after storage.