bluuebunny/crossref_metadata_2025 huggingface dataset:
Maize Grain Yield Response to Tillage and Fertilizer Nitrogen Rates on a Tara Silt Loam
Authors: Olness A. , Evans S. D. , Moncrief J. F.
Published: April 2008

Effects of tillage on the appropriate fertilizer N applications needed to achieve maximal grain yield are poorly denned. The study objective was determination of relative corn grain yield response to N application rate for four tillage practices: no‐tillage (NT), ridge tillage (RT), fall chisel plowing (CP) and fall moldboard plowing (MP). Maize (Zea mays L.) grain yield and N accumulation were monitored over a 6 year period with the same tillage treatment and the same fertilizer N rate applied each year to each plot. Two hybrids, differing in relative maturity rating, were planted each year. Fertilizer N rates ranged from 10 to 190 kg ha−1 and consisted of 10 kg ha−1 of liquid starter N applied at planting with varying amounts of fall applied anhydrous ammonia. With only starter fertilizer, grain yields increased with tillage intensity in the order NT ≤ RT ≤ CP ≤ MP. With ≥ 55 kg total applied Nha−1, 6 year average grain yields were unaffected by tillage. Total N removed in grain annually with only starter fertilizer ranged from 25–85 kg ha−1 Maximal amounts of N removed, about 145 kg N ha−1, occurred with 100–145 kg applied N ha−1 for all tillage treatments under the more favorable climatic conditions. Several interactions affecting grain yield appear climatically sensitive with exception of tillage by fertilizer N interactions. Because of variability in climate, planting dates varied by almost 4 weeks. Relative yield loss due to planting delay were Fertilizer N (mean change ≅−124 –−275 kg ha−1 day−1) > Starter N only and MP (mean ≅− 259 kg ha−1 day−1) > other tillages in general. Yield loss due to delayed planting ranged from 0.0–275 kg ha−1 day−1. Grain yield gains due to early spring soil temperatures were 16.0–21.8 kg ha−1 index‐degree−1 with MP tillage and averaged 2.7– 16.7 kg ha−1 index‐degree−1 more than those of other tillage‐hybrid combinations.
Physiological Basis of Salinity Tolerance of Sorghum Seeds During Germination
Authors: Marambe B. , Ando T.
Published: April 2008

Effects of salinity on the isozyme activities of α‐amylase in germinating sorghum seeds were studied under laboratory conditions. Seeds were imbibed in NaCl solutions at concentrations ranging from 0–500 nM (osmotic pressure: 0–2.28 MPa) for 0–24 h and the isozymes activities were estimated after disc‐gel electrophoresis.

Seed germination of sorghum was not affected by NaCl concentrations less than 100 nM (0.46 MPa). Germination was reduced by 50% at 300 nM NaCl (1.31 MPa), and completely inhibited at 500 nM (2.28 MPa). The α‐amylase activity in the treated seeds followed a similar pattern to that of germination.

At least five isozyme patterns of a‐amylase were observed in germinating sorghum seeds. The activities of the respective isozymes were enhanced with increasing duration of imbibition in distilled water. When treated with 100 nM NaCl, the activities of isozymes 2 and 5 decreased, but this was compensated by the increased activity of isozyme 1. The sensitivity of isozymes to the salinity treatments varied where isozyme 1 was the most tolerant. The isozyme activities were completely inhibited by 500 nM NaCl.

The results indicate that sorghum seeds could germinate well in saline environments up to 0.46 MPa. Higher osmotic pressure or saline concentrations could be detrimental to the seed germination of sorghum. The salinity tolerance could be attributable to the compensation of loss of activities of certain isozymes of α‐amylase by the other types.
Time Course of Nitrogen in Soil Solution and Nitrogen Uptake in Maize Plants as affected by Form and Application Time of Fertilizer Nitrogen
Authors: Buerkert B. , Horlacher D. , Marschner H.
Published: April 2008

Field experiments with silage maize were conducted in 1987 and 1988 on a loess‐derived Luvisol in southwest Germany. Four nitrogen fertilizer treatments were compared: application of preplanting NH4 N (plus a nitrification inhibitor, dicyandiamide as Didin) and preplanting NO3‐N, split application of NO3‐N (preplanting and side dressed 45 days after planting) and a control without nitrogen fertilizer in 1987 and with 64 kg N ha−1 as calcium ammonium nitrate in 1988. The total amounts of soil mineral nitrogen (Nmin+ fertilizer N) were 200 kg N ha−1 in 1987 and 240 kg N ha−1 in 1988. Suction cups and tensiometer were installed at five depths and samples were taken in regular intervals.

Nitrate concentrations in the suction solution steeply increased at 15 cm and 45 cm soil depth 3‐4 weeks after fertilizer application (1987 up to 160mgNl−1; 1988 up to 170mgN l−1) and steeply decreased up to 75 cm depth with the onset of intensive N uptake at shooting. Ammonium concentrations in the suction solution were very low (0‐0.16 mg N l−1). Compared to preplanting NCyN application, preplanting NH4‐N and split NO3‐N application decreased nitrate concentrations in the suction solution in spring 1987. In 1988, however, nitrate concentrations in the suction solution of preplanting NH4‐N and split NO3‐N application plots did not fall below 50mgNl−1 at 15 cm depth during the growing season. Nitrate concentrations of split NO3‐N application increased again in autumn 1988 and hence doubled the calculated N losses by leaching during the winter months compared to preplanting N applications. At shooting, plants of the preplanting NH4‐N treatment had lower nitrate concentrations in leaf sheaths compared to plants of preplanting NO3‐N application. Total N uptake of maize between shooting and early grain filling of preplanting NH4‐N and split NO3 ‐N application tended to be higher compared to preplanting NO3‐N application, reflecting the higher N availability in the soil later in the season. However, final dry matter yields and N uptake were not significantly affected by N form or time of N application. Since N losses by nitrate leaching between N application and onset of N uptake by plants were negligible on the experimental site, preplanting NH4‐N application and split NO3‐N application showed no agronomic advantages. High amounts of side dressed NO3‐N may increase nitrate leaching during the winter months, especially in years with delayed rainfall after application.
Variation in Salinity Tolerance in Sunflower (Helianthus annum L.)
Authors: Ashraf M. , Tufail M.
Published: April 2008

Forty‐five accessions of sunflower collected from different countries were screened for salinity tolerance after 2 weeks growth in sand culture salinized with 150 meq l−1 of NaCl2+ CaCl2 (1:1 ratio equivalent wt. basis) in half strength Hoagland's nutrient solution. The results for plant biomass of 45 accessions show that there was considerable variation in salinity tolerance.

In a further greenhouse experiment, the salinity tolerance of three tolerant (HO‐1, Predovik, Euroflor) and two sensitive (SMH‐24, 9UO‐985) lines (selected on the basis of their performance in the seedling experiment) was assessed at the adult stage to evaluate the consistency of salinity tolerance at different growth stages. All three salt tolerant accessions produced significantly greater plant biomass, seed yield and seed oil content than the salt sensitive accessions. The tolerant accessions accumulated less Cl− and more K+ in the leaves under saline conditions compared with the salt sensitive accessions. The salt tolerant accessions also maintained relatively high leaf K:Na ratio and K+ versus Na+ selectivity. Although statistically nonsignificant, all three tolerant accessions had greater soluble carbohydrates, soluble proteins, total free amino acids and proline in the leaves than the sensitive accessions. A field trial conducted in a salt‐affected field confirmed the greenhouse results of the selected accessions.

This study shows that salinity tolerance of sunflower does not vary with stage of plant cycle, so selection for increased salt tolerance can be carried out at the initial growth stage. Secondly, it is found that there is great variation of salt tolerance in sunflower. Low uptake of Cl−, high uptake of K+, and maintenance of high K:Na ratios and K+ versus Na+ selectivity in the leaves and possibly the accumulation of organic osmotica such as soluble carbohydrates, soluble proteins, proline and free amino acids seem to be the important components of salt tolerance in sunflower.
Impact of Different Weed Types on Growth and Yield of Mungbean (Vigna radiata L. Wilczek)
Authors: Sangakkara U. R. , Meylemans B. , van Damme P.
Published: April 2008

The influence of different weed types (grass, broadleaved and sedge species) on growth and yield parameters of mungbean (Vigna radiata L. Wilczek) was evaluated under field conditions. The presence of all types of weeks had the most significant effect on growth and yields of mungbean. Broadleaved species alone had a greater adverse effect than grasses, and the influence of sedges was the lowest. The adverse effect of weeds was most prominent on vegetative growth. The influence on yield components reduced with time. However, the adverse impact of weeds on yields was similar to that on vegetative growth. A significant correlation between weed biomass and yield loss was observed. The study indicated the critical competitive period to be in the vegetative phase. Some possible implications for selective weeding are presented.
Evaluation of N Fertilizer Rate and Timing and Wheat Cultivars on Soil Residual Nitrates
Authors: Ayoub Micheline , Mackenzie A. , Smith D. L.
Published: April 2008

Nitrogen (N) fertilizer management for production of bread quality wheat may increase nitrate residues in the soil. To assess soil nitrate levels associated with bread quality wheat (Triticum aestivum L.) production in Eastern Canada, an experiment was conducted for 2 years at each of two sites in Québec. Four cultivars (Columbus, Katepwa, Max and Hege 155‐85), four N levels (0, 60, 120 and 180 kg N ha−1) and two N timings (all at seeding time or 60 % at seeding and 40 % at anthesis) were combined in a factorial arrangement on a Bearbrook clay and a Ste‐Rosalie clay. Residual soil NO3‐N levels were measured in the 0–20 and 20– 60 cm soil layers. The cultivars used have potential as bread wheats. Cultivar effects on soil nitrate levels existed only in the Ste‐Rosalie soil, suggesting that the cultivars used were better adapted to the conditions on the Bearbrook soil. Changes in soil NC3N levels over winter indicated that mineralization had occurred. Calculated balance‐sheet values were larger than measured residual NO3‐N in the autumn of each year, indicating that NO3‐N was lost from the systems, possibly due to denitrification. Potential increases in, and thus potential pollution from, residual soil NO‐N existed only at the 180 kg N ha−1 level. Overwinter changes in soil NO3‐N levels were proportional to the inverse of the fall NC3N levels. Differences between sites were large for many of the variables measured.
Electrolyte Leakage, ATP Content in Leaves and Intensity of Net Photosynthesis in Maize Seedlings at Permanent or Different Daily Exposure to Low Temperatures
Authors: Markowski A. , Skrudlik G.
Published: April 2008

Changes were determined in electrolyte leakage (EL), ATP content in leaves and intensity of net photosynthesis (FJ in maize seedlings as a result of continued exposure to low temperatures for several days or, after a cold night (5 °C, 9 h), alternating application of 5 °C and 20 °C temperatures during the lit phase of the day (h of chilling during day/night: 0/9, 5/9, 10/9, 15/9).

At continuous exposure to low temperatures, permanent reduction of ATP content occurred between days 7 and 10, while EL increased significantly between days 4 to 7 (depending on experimental conditions). Of three leaves differing in age, most injuries were found in the oldest leaf. An increased intensity of irradiation from 150 to 500 μE. m−2.s−1 caused an earlier decrease in the ATP content and a further increase in electrolyte leakage. ATP content showed a 24 h rhythm, it increased at the end of the night and decreased at the end of the day. The rhythm was particularly noticeable in the control plants (20 °C), as well as, however to a lesser extent, in plants exposed to daily fluctuating chilling temperatures. It has also been observed that higher temperatures occurring in day time may diminish electrolyte leakage induced by previous low temperatures

The intensity of Fn determined at 20 °C, 4 h after withdrawal of chilling, decreased with the prolongation of the chilling period during the day.

Thus, it may be assumed that the EL and Fn values as indicators of the plants' sensitivity are in better agreement with the induced chill doses than the ATP content in leaves, which to a greater extent depends on the interaction between chilling and other experimental factors, such as irradiation intensity or the sequence of light and darkness.
Interactions of Azotobacter chroococcum, Azospirillum brasilense and Streptomyces mutabilis, in Relation to their Effect on Wheat Development
Authors: El‐Shanshoury A. R.
Published: April 2008

Single or dual inoculation of wheat seedlings (Triticum aestivum L. cv. Sakha 69) with Azotobacter chroococcum, Azospirillum brasilense or Streptomyces mutabilis in sterilized soil resulted in significant stimulation of their populations in the rhizosphere, compared with the initial values. Viable counts of Azospirillum and Azotobacter decreased in dual inoculations with Azotobacter or Streptomyces, and contrasted with those of Streptomyces, compared with the results of single inoculation. Single and dual inoculations stimulated plant growth, significantly increased the concentrations of indole‐3‐acetic acid (IAA), P, Mg, N and total soluble sugars (TSS) in wheat shoots. Soil content of N increased by single inoculation with Azotobacter and all dual inoculations. Soil‐IAA significantly increased by all inoculations. Growth of A. brasilense significantly inhibited by filtrates from 7‐day‐old cultures of S. mutabilis than from A. chroococcum, in vitro. The biosynthesis of antibacterial substance(s) by Azotobacter significantly decreased by supplementing their cultures with metabolic products from A. brasilense, but were stimulated by metabolic products from Streptomyces cultures. All metabolic products significantly decreased the growth of A, chroococcum, A. brasilense and S. mutabilis, nitrogen‐fixation and biosynthesis of IAA in A chroococcum, whereas biosynthesis of IAA stimulated in S. mutabilis. Most of the measured parameters after exposure to the tested bacteria or their metabolites were significantly correlated. The significance of IAA, nitrogen fixation and antibacterial substances, produced by such agronomically beneficial bacteria in early wheat growth is discussed.
Root and Shoot Development of Phaseolus vulgaris L. (French Beans) as Affected by Soil Moisture and Fertilizer Potassium
Authors: Sangakkara U. R. , Hartwig U. A. , Nösberger J.
Published: April 2008

The development of an extensive root system enables plants to overcome water stress. However, there is little information on the response of food legumes to soil moisture, especially during early growth, which determines crop establishment. Thus, an experiment was conducted under controlled conditions to identify the effect of soil moisture and fertilizer potassium on root and shoot growth of french beans (Phaseolus vulgaris L.) seedlings. The seedlings were grown in a sand medium under a high and low soil moisture regime and with 0.1, 0.8 or 3.0 mM potassium.

Root lengths, dry weights and numbers of root hairs were greater under low soil moisture conditions. Potassium increased root growth irrespective of soil moisture regimes. The impact of potassium on root length was more pronounced under a high soil moisture regime. In contrast, potassium increased root dry weights and root hairs to a greater extent when plants were grown under dry conditions. The lack of adequate soil moisture increased specific leaf weights, and this phenomenon was reduced by the application of potassium. Shoot:root ratios also showed a similar phenomenon. The development of an extensive root system by french bean seedlings under dry conditions to extract a greater quantity of available soil moisture fur establishment and plant growth and the ability of potassium to promote this phenomenon is presented in this study.
Response of Root Branching and Shoot Water Potentials of French Beans (Phaseolus vulgaris L.) to Soil Moisture and Fertilizer Potassium
Authors: Sangakkara U. R. , Hartwig U. A. , Nösberger J.
Published: April 2008

Extensive branching patterns of roots and the maintenance of adequate water within shoots enables plants to overcome water stress. However, information on the relationship between fertilizer potassium, root branching patterns and shoot water potentials of food legumes grown under different soil moisture regimes is scarce. Thus, an experiment was conducted in a phytotron to ascertain the effect of fertilizer potassium on root branching patterns and shoot water potentials of a popular tropical food legumes (Frenchbeans Phaseolus vulgaris L). The plants were grown in a sand medium with 0.1, 0.8 or 3.0 mM of potassium under a suboptimal and optima) soil moisture regime.

Root lengths and dry weights were enhanced by potassium, especially under a suboptimal soil moisture regime. The branching patterns changed due to potassium, where the numbers of second and third order roots increased under both soil moisture regimes, although the impact was greater in plants grown with low soil moisture. Plant water contents measured in terms of shoot water potential, relative water contents, rurgid weight: dry weight ratio and water uptake capacity were also increased by potassium. A positive relationship was observed between root branching patterns and water potentials with increasing potassium levels especially in plants grown under suboptimal soil moisture conditions. Shoot growth and nodulation was also promoted by potassium. The ability of plants to develop a more extensive branching pattern of roots by inducing a greater number of second and third order roots and changing the root branching habit from a herringbone to a dichotomous type to maintain a greater shoot water potential especially under low soil moisture regimes is presented.
The Effect of Chilling Maize Shoots and Roots on the Electric Potential, Composition of Fatty Acids and the ATPase Activity in the Non‐chilled Organs of Seedlings
Authors: Filek M. , Kościelniak J.
Published: April 2008

The effect of separate chilling (5°C for 2 and 4 days) on the shoots and roots of two maize hybrid seedlings on the electric potential, the composition of fatty acids and the ATPase activity in the microsomes of non‐chilled leaves and roots (20°C) was investigated. It has been found that the low temperatures induced on the non‐chilled organs gave similar changes to organs exposed to a reduced temperature. The changes consisted of a parallel depolarization of leaf and root membranes and similarly a decrease in the ATPase activity as well as changes in the unsaturation of the membranes’ fatty acids. The reduction of the acid content 18:2 was particularly significant, which in the leaf microsomes correlated with a drop in the ATPase activity.

The similarity between the reactions of the chilled and non‐chilled parts of the plant gives evidence of a communication’ between the organs which may facilitate a coordinated reaction of the entire organism to stress. The background for these phenomena could be die action potential of die chilled parts of seedlings which, in the non‐chilled parts, might produce changes in the structure of biomembranes and in the activity of enzymes.
Dynamics of Dry Matter Accumulation in the Developing Grains of Three Wheat Genotypes with Contrasting Grain Weight
Authors: Nagarajan S. , Gambhir P. N. , Gupta N. K. , Pande P. C.
Published: April 2008

The accumulation of dry matter and its major components was studied in developing grains of two bold seeded (Selection‐111 and IWP‐5308) and one small seeded (kalyansona) wheat genotypes grown in pot culture condition. It was observed that in kalyansona, a sharp reduction in grain water content during the critical stage of grain enlargement limits its size resulting in compact filling of grains. In the developing grains of Selection‐111 and IWP‐5308, the high rate of dry matter accumulation was associated with their larger grain sink size. However, their lower grain density compared to kalyansona could be explained on the basis of non‐complementation between synthetic component and grain size (structural component). This non‐complementation may be due to relatively higher thermosensitive synthetic mechanism in the bold seeded genotypes.
Nitrogen Fertilizer Effects on the Duration of the Pre‐anthesis Period and Spikelet Number per Spike in Barley
Authors: KERNICH G. C. , HALLORAN G. M.
Published: April 2008

The effects of increased yield and grain number per unit area in barley in response to nitrogen application are well known. However, the influence of applied nitrogen on the rates and durations of developmental phases in barley are less well understood. Our objective was to investigate the effect of applied nitrogen on the duration of pre‐anthesis development in barley and the number of spikelets per spike in two barley cultivars, Franklin and Schooner, in two studies. We found no effect of nitrogen on the duration of the pre‐anthesis period in Schooner, when applied to pots at a rate of 0 or 55 kg N ha‐1, or when applied in the held at 0, 40 or 160 kg N ha‐1. However, this duration was extended in Franklin in the first study by an application of 55 kg N ha‐1. Both plant biomass and grain yield at maturity were increased between 0 and 55 kg N ha‐1, and 0 and 160 kg N ha‐1. Meld increase was largely associated with an increase in the number of tillers per plant.
Contribution of Plant Breeding to Long‐term Agronomic Trait Changes in Maize Hybrids FAO 100 and 200
Authors: Rozman L. , Kozumplik V. , Vasilj D.
Published: April 2008

The purpose of this study was to assess improvements in performance of maize hybrids during a 20‐year period. Data on FAO 100 and 200 hybrids, released by the former Yugoslav Committee for Releasing Varieties, were utilized. For FAO 100 hybrids group, yield increased 0.0015 Mg ha‐1 year‐1 but was not significant. Breeding resulted in a significant decrease in days to silking. In the FAO 200 group, yield increased on the average 0.046 Mg ha˜ year‐. The genetic gain was not significant. A performance index, based on yield and several other traits, increased significantly during the period for both groups of hybrids, but the increase due to breeding was significant for the FAO 200 hybrids only.
Effects of Timing of Drought Stress on Phenology, Yield and Yield Components of Short‐duration Pigeonpea
Authors: Lopez F. B. , Johansen C. , Chauhan Y. S.
Published: April 2008

Nine short‐duration pigeonpea genotypes were given adequate soil moisture throughout growth or subjected to water stress during the late vegetative and flowering (stress 1), flowering and early pod development (stress 2), or podfill (stress 3) growth stages under field conditions. The stress 1 treatment had no significant effect on the time to flowering. No stress treatment affected maturity or inter‐plant flowering synchronization. The interval from a newly opened flower to a mature pod was about 30 days for all genotypes, and was unchanged in plants that were recovenng from stress 1 or undergoing stress 2. Seed yield was reduced to the greatest extent by stress 2 (by 37 %) and not significantly affected by stress 3 for all genotypes. No consistent differences were found between determinate and indeterminate genotypes in the ability to maintain seed yield under both stress 1 and stress 2. The harvest index was significantly reduced (22 %) by stress 2 but not by stress 1. However, under each soil moisture treatment, genotypic differences for seed yield were associated largely with differences in total dry matter production (TDM). For all genotypes, the number of pods m‐2 was the only yield component significantly affected by the water stress treatments. The stability of other yield components should be fully exploited to improve the stability of seed yield under drought conditions (drought resistance). Possible characteristics which may improve the drought resistance of short‐duration pigeonpea include the ability to maintain TDM, low flowering synchronization, small pod size with few seeds pod‐1, and large 100‐seed mass.
Influence of Seed Quality on Field Establishment and Forage Yield of White Clover (Trifolium repens L.)
Authors: Pasumarty S. V. , Higuchi S. , Murata T.
Published: April 2008

Two seed lots of white clover (Trifolium repens L.) cultivar ‘Makibashiro’ classified as high and poor quality seed lots, based on the speed of germination (T50), were used to examine the influence of seed quality on field establishment and forage yield. Field emergence rate was estimated approximately three weeks after sowing and found that plots sown with high quality seeds (Lot 1) had 452 seedlings m‐2 compared with 392 seedlings in the plots sown with low quality seed lot (Lot 2), but the difference was not significant. However, plant density in autumn (November, 1993), 3 months after sowing, was significantly (P < 0.05) higher in the plots of the Lot 1 seed than that from the Lot 2 seed. The percentage of clover plants surviving over the winter from Lot 1 plots was 55% compared with 39% from the Lot 2 plots, but the difference was not significant. Total forage yield in Lot 1 plots harvested in July and monthly intervals to October, was significantly increased by 44% (P < 0.05) over that of Lot 2 plots, but this greater forage yield in high seed quality seed lot plots was produced early in the season. The results strongly imply that the primary advantage to be gained from high quality seed is an improved field establishment, which led to increased yield of clover. In Lot 1 plots, the percentage of weed dry matter in all the four harvests remained below 1% of die seasonal dry matter production, whereas in Lot 2 plots die percentage of weed dry matter ranged from 3.3–16.9%.
Influence of Low Light Irradiance on Grain Filling in Rice (Oryza saliva L.) cultivars
Authors: VOLETI S. R. , SINGH V. P.
Published: April 2008

Time course of grain filling pattern in two rice (Oryza sativa L.) cultivars, grown under normal and low light intensities, was studied. The number of spikelets, partially filled grains and high density grains were monitored at a 5 day interval during grain filling period from uniform panicles tagged at anthesis. The low light tolerant cultivar Swarnaprabha had more high density grains and less partially filled grains throughout the grain filling period and at harvest compared to cultivar Ratna under both normal and low light intensities. Further, the opening of spikelets in two flushes in Swarnaprabha seemed to result in a more efficient resource allocation and hence better yield as compared to Ratna, in which the opening of spikelets was in a single flush on day 10.
Effect of Water Stress on Pyruvaté, Pi Dikinase and Phosphoenol Pyruvate Carboxylase Activities in the Leaves of Two Cultivars of Sorghum (Sorghum bicolor L.)
Authors: Contour‐Ansel D. , Ilami G. , Ouarzane A. , Louguet P.
Published: April 2008

The effect of withholding water on the specific activities of pyruvate, orthophosphate dikinase (PPDK EC 2.7.9.1.) and phosphoenol pyruvate carboxylase (PEPC, EC 4.1.1.31) was studied in two cultivars of Sorghum bicolor L. different in their sensitivity to water deficit. The drought sensitive cultivar ICSV 1063 and the more resistant cultivar MIGSOR were subjected to water deficit in controlled conditions. The results showed a decrease in both enzyme specific activities, higher for drought sensitive cultivar ICSV 1063, when leaf water potential (Ψ) was lowered to ‐2.3 MPa. Following rewatering, enzyme specific activities increased in both cultivars, with the increase being more significant in MIGSOR. Relative water content (RWC) decreased significantly for water‐stressed ICSV 1063 cultivar, lower for MIGSOR and returned quickly to that of control plants upon rehydration. Net photosynthesis showed a decrease for water‐stressed plants, higher for ICSV 1063. At minimal Ψ, net photosynthesis was completely inhibited, with the stomata being closed After rehydration, MIGSOR showed a better recovery in photosynthesis but never reached the initial values of day 0. Water stress had a striking effect, both on net photosynthesis by regulation of stomatal aperture and on PPDK and PEPC activities, although the enzymes were still active when photosynthesis ceased. Therefore the level of PPDK and PEPC activities may contribute to the limitation of photosynthetic carbon dioxide fixation.
Competition and Control of Volunteer Jerusalem Artichoke in Various Crops
Authors: SCHITTENHELM S.
Published: April 2008

A major production constraint in Jerusalem artichoke (Helianthus tuberosus L.) is caused by tubers which are not recovered at harvest. Such lost tubers raise a serious weed problem the following season. Winter wheat, oat, spring oilseed rape, sugarbeet, maize and ryegrass were grown in a field which had Jerusalem artichoke as the preceding crop in order to obtain information about their competitive ability and the efficacy of various control measurements against Jerusalem artichoke infestation. The Jerusalem artichoke treatments in these crops were: total control by regular hand weeding (TOC), mechanical/chemical control (MCC), and no control (NOC). Under the NOC treatment, Jerusalem artichoke infestation at harvest was variable among crops, with the number of shoots ranging from 9 to 25 m−2 in oat and maize stands respectively. The number of Jerusalem artichoke shoots in the MCC plots was reduced by 50 to 99 % in oat and maize, respectively. The highest crop yields in each of the six species were realized under the TOC treatment. Insignificant yield reductions were observed in the NOC treatment of wheat, oat, rape and ryegrass. However, under this management yield reductions of 91 and 81 % occurred in sugarbeet and maize respectively. Depending on the preceding crop, 1–9 shoots m−2 of Jerusalem artichoke were still recorded under the MCC plots in the following season. Consequently, for complete elimination of infestation, volunteers must be controlled in the second and probably in the third year following a Jerusalem artichoke crop.
Canopy Temperature Depression Association with Yield of Irrigated Spring Wheat Cultivars in a Hot Climate
Authors: Amani I. , Fischer R. A. , Reynolds M. P.
Published: April 2008

This study examines the utility of measurements of canopy temperature depression (TD) below air temperature as an indirect selection criterion for grain yield in breeding of wheat (Triticum aestivum L.). TD differences can be rapidly assessed using a hand‐held infra‐red thermometer and may reflect differences in stomatal conductance. Replicated small plot experiments were conducted with 23–24 spring wheat cultivars planted at two dates in the winter cropping cycles of 1991–92 and 1992–93 at a hot low latitude location in Mexico.

Across a two fold range in grain yield at each planting, TD was usually highly significantly correlated with grain yield. Averaging the results for each year, the phenotypic correlation TD vs. yield was 0.84** and 0.89** for 1991–92 and 1992–93, respectively. Correlations were strongest when TD was measured between noon and 4 pm, and were unaffected by crop stage of development (pre‐heading, heading, grain fill) or timing relative to irrigation. TD was positively correlated with stomatal conductance. We discuss possible causes of these high correlations, and their implications for wheat breeding.
An Analysis of the Response of Winter Wheat (Triticum aestivum) Components to Cycocel (Chlormequat) Application
Authors: Olumekun V. O.
Published: April 2008

Field‐grown winter wheat (Triticum aestivum cv. Avalon) plants were treated with a formulation of 1.25 % Cycocel (2‐Chloroethyl trimethylammonium chloride) and 0.5% LI‐700 (acidified soya lecithin) at the beginning of stem extension in order to identify the component parts that are most affected and on which an assessment of the effectiveness of Cycocel formulations can be based. Cycocel consistently reduced culm length due to the reduction of the lengths of the first three basal internodes by 43, 37 and 15 % respectively. In absolute terms, the second internode contributed most to stem reduction, a feature retained up till maturity. There was evidence of relative dry matter redistribution from the stem to the leaves, while growth rate was slowed down such that treated plants matured later than the controls. The youngest fully opened leaf at the time of Cycocel application showed a transient reduction in length, area and dry weight, while total leaf area was largely unchanged. From the results, measurement of the lengths of the first two internodes proved to be the most sensitive indicator of effective Cycocel uptake.
Variabilität im β‐Glucangehalt der Haferkaryopse von 132 Kulturhafer‐ und 39 Wildhafergenotypen
Authors: Baur S. K. , Geisler G.
Published: April 2008

Variability of the β‐glucan content in oat caryopsis of 132 cultivated‐oat genotypes and 39 wild‐oat genotypes

In order to establish the genetic variability and the environmental dependency on the β‐glucan contents (% DM) in oat caryopses, several outdoor experiments have been conducted. For a test period of 3 years, 132 oat genotypes from the gene bank of the Federal Research Institute for Agriculture (FAL) in Braunschweig were cultivated in the field. Furthermore, 39 wild‐oat genotypes from the gene bank were grown in Mitscherlich pots in protected areas for a 2‐year test period. The genetic‐variance range of the 132 oat genotypes in terms of β‐glucan content is maximally 2.27 % DM (1993). During the 3‐year test period, the lowest value was 3.23 % DM and the highest 5.67 % DM. For the 39 wild‐oat genotypes, the variance range ofβ‐glucan content was slightly higher (2.95 % DM, 1992). The minimum was 3.13 % DM and the maximum 6.08 % DM (1992). The β‐glucan content (% DM) was significantly influenced by prevailing climatic conditions during the test year. In conclusion, it may be stated that, for oat breeding based on β‐glucan content (% DM) the oat's genetic variability for the cultivated and wild plants investigated is similar, so that there is actually no need to go back to the wild material.
Effects of the Developmental Stage at Harvest on Dry Matter and Chemical Component Partitioning in Berseem
Authors: Iannucci A. , Fonzo N. Di , Martiniello P.
Published: April 2008

The influence of cutting applied at four stages of plant growth on dry matter, crude protein, total available carbohydrates and reducing sugar partitioning was examined in six genotypes of berseem (Trifolium alexandrinum L.). The research was conducted in Foggia (Italy) during 1990 and 1991 in a glasshouse with controlled water application. The plants were grown in a plastic‐lined, PVC cylinder. At each cut, dry matter and chemical components were evaluated in leaf, stem and root fractions; at the end of the biological cycle, seed yield was recorded.

Plants showed similar dry matter partitioning between leaves and stems at the eighth internode stage. The crude protein concentration was highest in leaf fractions, reaching the maximum value (31%) at an early stage of growth (fourth internode stage). The maximum value of total available carbohydrates was obtained in the stems at the early flowering stage (11 %), whereas reducing sugars almost always showed higher concentrations in the leaves (4 %). As for forage and seed yields, the developmental stage at cutting had a great influence on dry matter and chemical component partitioning among the different organs. Genotypic differences were observed for dry matter partitioning in leaves and stems in all developmental stages, but diversity in chemical component content was more evident in the roots.
Nitrogen Level and Seeding Rate Effects on the Performance of Hulled Wheats (Triticum monococcum L., T. dicoccum Schubler and T. spelta L.) Evaluated in Contrasting Agronomic Environments
Authors: Castagna R. , Minoia C. , Porfiri O. , Rocchetti G.
Published: April 2008

Effects of the nitrogen level and of the seeding rate on the performance of Triticum monococcum L., T. dicoccum Schübler and T. spelta L. (hulled wheats, together referred as ‘farro’) in comparison with bread wheat (variety Eridano) were evaluated. Field trials were conducted in five contrasting environments located in the north and central areas of Italy. Eridano mean grain yield was 3.86 t ha−1, resulting the highest in all the field trials. T. spelta, T. dicoccum and T. monococcum net grain yield was 2.71 t ha−1, 2.371 ha−1 and 1.06 t ha−1, respectively. Significant differences in all the evaluated parameters were observed among the species as well as among the environments. Biomass yield, grain protein and SDS sedimentation values of the hulled wheats were significantly influenced by nitrogen, which had no effect on grain yield. The results show the necessity to breed hulled wheat varieties adapted to the Italian environments and competitive with the bread wheat productivity in the marginal areas.
Salinity Effects on the Growth and Ion Contents of Some Chickpea (Cicer arietinum L.) and Lentil (Lens culinaris Medic.) Varieties
Authors: Mamo T. , Richter C. , Heiligtag B.
Published: April 2008

The effect of salinity on seed germination, plant yield parameters, and plant Na, Cl and K concentrations of chickpea and lentil varieties was studied. Results showed that in both crops percentage emergence was significantly reduced by increasing NaCl levels (0–8dSm−1). From the plant growth studies it was found that differences existed among chickpea and lentil varieties in their response to NaCl application. In chickpea, the variety Mariye showed the comparatively lowest germination percentage and the lowest seedling shoot dry weight in response to salinity and was also among the two varieties which had the lowest relative plant height, shoot and root dry weight and grain yield at maturity. Similarly, variety DZ‐10‐16‐2, which was the second best in germination percentage and the highest in terms of seedling shoot dry weight, also had the highest relative plant height, shoot and root dry weights, and grain yield at maturity. In lentil, however, such relationships were less pronounced.

Chloride concentration (mg g−1) in the plant parts at salt levels other than the control was about 2–5 times that of Na. K concentration in the plants was significantly reduced by increasing NaCl levels. Chickpea was generally more sensitive to NaCl salinity than lentil. While no seeds were produced at salinity levels beyond 2dSm−1 in chickpea (no seeds were produced at this salt level in the most sensitive variety, Mariye), most lentil varieties could produce some seeds up to the highest level of NaCl application.

Overall, varieties R‐186 (lentil) and Mariye (chickpea) were the most sensitive of all varieties. On the other hand, lentil variety NEL‐2704 and chickpea variety DZ‐10‐16‐2 gave comparatively higher mean relative shoot and root dry weights, and grain yield, thus showing some degree of superiority over the others. The observed variations among the varieties may be useful indications for screening varieties of both crops for salt tolerance.
Interaction of Phosphate and Salinity on the Growth and Yield of Rice (Oryza sativa L.)
Authors: Aslam M. , Flowers T. J. , Qureshi R. H. , Yeo A. R.
Published: April 2008

The role of phosphorus application on growth and yield of rice under saline conditions was studied in a set of two experiments, one in nutrient and the other in soil culture. In experiment 1, the effect of inorganic phosphate (Pi) on the growth and ionic relations of four rice cultivars, varying in salt tolerance and phosphorus use efficiency, grown in nutrient solution with and without 50 mol m−3 NaCl was measured in a 2 week trial. The growth of all rice cultivars was affected to different degrees due to external P, in the presence of salt. External P, concentration up to 100 μM in the presence of NaCl caused stimulation of all growth parameters (shoot, root, tillering capacity), above this concentration P, had an inhibitory effect. Salt‐induced P toxicity was exhibited at a much lower P, concentration (10 μM) by the salt sensitive cultivar. Increasing the supply of phosphorus (from 1 to 100 μM Pi) to the saline medium tended to decrease the concentrations of Na1 and CI in all cultivars except IR 1561. Shoot concentrations of these saline ions were much lower in the salt tolerant and moderately salt tolerant rice cultivars. Shoot P and Zn concentrations showed an increasing trend in the presence of external P, and salt in the rooting nr ‐idium but most strikingly P: Zn ratio was lower in salt tolerant and moderately salt tolerant cultivars. Significantly higher concentrations of Na+, P and CI, and lower concentrations of Zn, were determined in the shoots of salt sensitive cultivars when exposed to salt stress in the presence of Pi Results were confirmed in naturally salt‐affected soils of two different types (saline‐sodic and saline) where paddy yield of NIAB 6 (salt tolerant) and IR 1561 (salt sensitive) showed improvement through moderate phosphorus supply (18 kg P ha−1).
Evaluation of Wheat (Triticum aestivum) and Legume Intercropping Under 1:1 and 2:1 Row‐replacement Series System
Authors: Banik P.
Published: April 2008

A field experiment was conducted during the winter season of 1992–93 and 1993–94 at Agricultural Experimental Farm, Giridih, Bihar to evaluate the intercropping systems of legumes, gram (Cicer arietinum L.), pea (Pisum sativum) and lentil (Lens culinaris) with wheat (Triticum aestivum) in 1:1 and 2:1 ‘row replacement series’. Intercropping systems were assessed on the basis of new indices termed as actual yield loss (AYL) and intercropping advantage (IA). This paper highlights the comparative effectiveness of evaluating the intercropping systems through the existing intercropping indices like LER, RCC, aggressivity. The indices AYL and IA seem to be more appropriate particularly when per plant yield is considered. Intercropping reduced the yield of component crops compared with respective pure stands. Wheat + pea in 1:1 row replacement series gave the highest wheat yield equivalent value (3.02 t ha−1) followed by wheat + lentil (2.91 tha−1). When the actual sown proportion was considered wheat + lentil (1:1) resulted in maximum AYL (+0.610) and IA (+0.279) values. This treatment also gave the maximum monetary advantage (Rs 5985.45 ha−1).
Prospects of Agronomic Improvement in Spring Barley Based on a Comparison of Old and New Germplasm
Authors: Schittenhelm S. , Okeno J. A. , Friedt W.
Published: April 2008

The aim of this study was to determine the direction and magnitude of change in morphological and agronomical characters of spring barley (Hordeum vulgare L.) in Germany over a period of 80 years and to assess the value of various strategies for further crop improvement. Old and new two‐rowed cultivars, eight in each case, were tested together with their F2 intra‐group diallel crosses in a field trial at Braunschweig‐Völkenrode in 1994. New parents and their crosses showed a higher dry matter grain and total biomass yield, a lower plant height, and a higher harvest index as compared to the respective old germplasm. The annual genetic gain in grain yield was estimated at 0.15%. The superior grain yield of the new germplasm was attributable to the higher number of ears per plant and the larger kernel weight. The F2 mid‐parent heterosis in grain yield was 7.6 and 7.2 % for the old and new crosses, respectively. The differences between the two types of crosses were nonsignificant except for the higher heterosis for plant height in the new crosses. General combining ability effects were significant for all characters in both types of crosses, whereas specific combining ability effects were significant in a few cases only. In the new crosses, a significant positive correlation was found between grain yield and straw yield (r = 0.52), whereas no such association was observed between grain yield and harvest index. For further gain in grain yield, improvement of the straw yield is more promising than increasing harvest index.
Responses to Aluminium Toxicity Effects of Two Populations of Piptatherum miliaceum (L.) Cosson
Authors: Zavas T. , Symeonidis L. , Karataglis S.
Published: April 2008

The effects of different aluminium (Al) concentrations (0 (control), 5 and 25 ppm) and pH levels (4.5 and 10.0) on two Piptatherum miliaceum populations, one from a bauxite area (population 1) and the other from pasture soil (population 2) were studied. Root length of both populations was severely inhibited at 25 ppm Al concentration and pH 4.5. Positive correlations between the Al content of roots of the two populations and increasing Al concentrations and pH levels in the nutrient solution were observed. Increase of Al concentrations in nutrient solution resulted in the decrease of calcium (Ca) content of the roots of the two populations in both pH values, while potassium (K) concentrations in the roots slightly differed from those of the control. Leaf chlorophyll content increased with increasing Al concentrations and pH values of nutrient solution in population 1 but decreased in population 2.

Based on relative values at different treatments of root length (R.L.), Ca and K content of roots and leaf chlorophyll content, it is concluded that population 1 is more tolerant to Al than population 2.

The chlorophyll content, under Al influence, may serve to distinguish Al‐tolerant and non‐tolerant ecotypes.
Effect of Phenological Stages on Plant Dry Matter Partitioning and Seed Production in Berseem (Trifolium alexandrinum L.)
Authors: Martiniello P. , de Santis G. , Iannucci A.
Published: April 2008

Berseem clover (Trifolium alexandrinum L.) is an annual forage crop widely grown in Mediterranean environments. Dry matter partitioning in the leaf, stem and root and seed production of three populations of Egyptian as well as Italian origin were evaluated under four cutting regimes. The cutting treatments were applied to the plants at different stages of plant development: at the fourth (A) and eighth nodes elongation (B), at early flowering (C) and physiological maturity of seeds (D), After herbage, harvest plants were utilized for seed yield and evaluation of its seed yield components. Higher dry matter and seed yield was obtained in treatments D and B, respectively. In the other treatments, dry matter content was lower than in treatment D and related to the phenological development of the plant. Dry matter content in the root was higher when the cut was applied at early flowering. Cutting regimes influenced plant mortality, with the number of dead plants increasing from the cut applied in early (A) to that in the final treatment (D). Cuts applied at early stage of development depleted root reserves causing plant death. This peculiarity could be a tool for selecting populations with higher persistence and with a more tolerant physiological response to stress imposed by cuts. The populations of Egyptian origin, in comparison with the Italian ones, were more productive in dry matter in the early stage of growth and in all treatments were higher in seed weight.
Critical Plant Densities for Resowing of Sugar Beet
Authors: Smit A. B. , Struik P. C , van Niejenhuis J. H. , Renkema J. A.
Published: April 2008

In cases of poor crop establishment of sugar beet, the grower may consider resowing. In these considerations, the differences between the actual and the optimal plant densities and their effects on yield and quality must play an important role, A module to describe these effects is presented. The later in the growing season the decision has to be taken, the lower the plant densities for which resowing is profitable.