bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Presprouting on Yield of Maincrop Potatoes (Solanum tuberosum L.) in Organic Farming
Authors: Karalus W. , Rauber R.
Published: April 2008

From 1991 to 1993 field trials at two sites (Bruchkobel and Gladbacherhof) were carried out to study the coti‐tribtition of presprouting in securing the yield of main‐crop potatoes (cvs. Agria. Granola. Linda and Nicola) in organic farming. In several cases presprouting diminished significantly the number of stems and tubers per plant. While in July (sample harvest) presprouting resulted in significant higher total yields with nearly all cultivars, in September (main harvest) the presprouting effect on total yield differed from year to year and partially from site to site, Presprouting reduced the percentage of undersized tubers, especially in 1992. Significant increases of the percentage of oversized tubers caused by presprouting were found especially with cv. Agria. The presprouted potatoes showed significantly higher marketable yields in 1991 at Bruchkobel (+28%), in 1992 at Bruchkobel (+ 14%) and Gladbacherhof (+ 18%) and in 1993 at Bruchkobel (+ 3%), Considerable yield increases caused by presprouting were observed when the foliage was destroyed early in the growing season by the Colorado beetle (Bruchkobel 1991) or by late blight (both sites 1992). Presprouting proved to be an important method to ensure yields in a farming system using no chemical pesticides.
Canopy Development and Light Absorption of Grain Legume Species in a Short Season Mediterranean‐type Environment
Authors: Mwanamwenge J. , Siddique K. H. M. , Sedgley R. H.
Published: April 2008

The adaptation of a number of grain legume species is being investigated for fine‐textured, neutral to alkaline soils that are unsuitable for narrow‐leafed lupin production. Canopy development and light absorption are important characteristics influencing crop adaptation. In short season, Mediterranean‐type environments, crops with rapid early canopy development minimize evaporation from the bare soil and maximize transpiration and light absorption, leading to rapid dry matter accumulation. In this study, the canopy development and light absorption of faba bean, field pea, narbon bean and chickpea were compared on a fine‐textured, neutral to alkaline soil in a dryland Mediterranean‐type environment at Merredin, Western Australia. The principle factors determining early canopy development of the above grain legumes were investigated.

Among the species studied, high rates of leaf expansion and large leaves resulted in a high percentage of absorbed photosynthetically active radiation (PAR) and rapid ground cover as measured by the sunfleck. Faba bean had high leaf expansion rates (mean of 1.33 cm2 d−1) and a large maximum leaf size (59.4cm2), and hence, absorbed a large percentage of PAR (77% at 74 DAS). In contrast to faba bean, the mean leaf expansion rate of chickpea was only 0.11 cm2 d−1, its maximum leaf size was 6.9 cm2 and it absorbed 43% of the PAR by 74 DAS. The rates of leaf expansion for narbon bean and field pea were similar to that of faba bean, but their leaves were significantly smaller than faba bean and greater than chickpea. Both field pea and narbon bean absorbed 58% of the PAR at 74 DAS.

Rates of leaf appearance did not seem to have a large influence on rate of canopy development due to compensation between the number of branches and leaf size. In general, species with few branches developed their canopy faster than species such as chickpea, which had many branches.
Effects of Population Density and Planting Pattern on the Yield and Yield Components of Leafy Reduced‐Stature Maize in a Short‐Season Area
Authors: Begna S. H. , Hamilton R. I. , Dwyer L. M. , Stewart D. W. , Smith D. L.
Published: April 2008

Maize hybrids that yield well, mature earlier with low grain moisture contents, tolerate higher population densities and take advantage of narrow row spacings better than the currently available hybrids would be more suitable for production in short‐season areas. Leafy reduced‐stature maize hybrids, which have only recently been developed, have traits which address these criteria. The objective of this study was to evaluate the effects of different population densities (65 000 and 130000 plants ha−1) and planting patterns (single rows 76 cm apart and paired rows with 20 cm between rows within a pair of 56 cm between rows of adjacent pairs) on the yield and yield components of two leafy reduced‐stature (LRS1 and LRS2), one non‐leafy reduced‐stature (NLRS), and two conventional corn hybrids (Pioneer 3979, < 2500 CHU; and Pioneer 3902, 2600‐2700 CHU) at two locations. All hybrids had higher kernel numbers per row and single plant grain yields at the lower population densities when in paired rows. However, as plant density increased, these variables decreased more in the conventional hybrids than the LRS and NLRS hybrids, which demonstrates the greater tolerance of the latter to the stresses associated with higher plant densities. Grain yield was higher for the two LRS hybrids and the NLRS hybrid at 130000 plants ha−1 than 65 000 plants ha−1 Grain yield of conventional hybrids was reduced at the higher population density. The LRS hybrids matured before both conventional hybrids and out yielded Pioneer 3979 at the higher plant population density in both row spacings at both sites. Harvest index was not affected by population density and this value was not different among the NLRS and conventional hybrids. However, the harvest index of the LRS hybrids was greater than the others. LRS and NLRS hybrids had lower moisture contents and earlier maturities than conventional hybrids. Rapid growth of the first ear and higher harvest index values might are indications that LRS hybrids are more tolerant of higher population densities than the conventional hybrids.
Cadmium Alters Phosphate Level and Suppresses Activity of Phosphorolytic Enzymes in Germinating Rice Seeds
Authors: Shah K. , Dubey R. S.
Published: April 2008

The effect of increasing concentration of Cd on the metabolic status of phosphate and the activity of its metabolizing enzymes acid phosphatase, alkaline phosphatase and inorganic pyrophosphatase were examined in germinating rice (Oryza sativa) seeds. During a 0‐120 h germination period in the two rice cvs., Ratna and Jaya, 500 μM Cd caused a 2‐3‐times increase in phosphate level in embryo axes compared to controls. Cadmium concentration of 500 μM in situ caused about 12‐14% and 20‐30 % decline in acid phosphatase activity in endosperms and embryo axes respectively during 72‐96 h of germination. With 500 μM Cd treatment in situ about 27‐43 % inhibition in alkaline phosphatase activity was noticed in endosperms and 40‐70 % in embryo axes. With 2 mM Cd salt in vitro about 60‐92 % inhibition in the activity of acid phosphatase and 80‐95 % inhibition of alkaline phosphatases was observed in enzyme preparations from embryo axes. However, a Cd level of 50‐100 μM caused stimulation in the activity of inorganic pyrophosphatase. Isoenzymic studies revealed four acid phosphatase isoenzymes in embryo axes with Rf values 0.15, 0.24, 0.36 and 0.49 and three isoenzymes in endosperms with Rf values 0.18, 0.24 and 0.40. The band intensities decreased under Cd treatment. Results indicate possible suppression of the phosphorolytic activities in germinating rice seeds under Cd stress.
Effect of High Lucerne (Medicago sativa L.) Sowing Rates on Establishment Year Yield, Stand Persistence and Forage Quality
Authors: Stout D. G.
Published: April 2008

The effect of very high sowing rates on establishment year dry matter (DM) yield and stand persistence of irrigated lucerne (Medicago sativa L.) was studied. Two cultivars (‘Peace’ and ‘Apollo II’) were sown in 1986 at two row spacings and six sowing rates from 5.6 to 50.4 kg ha−1. Established seedling density (Sd) increased linearly with sowing rate (R):Sd= 24.1R. Establishment year DM yield increased at sowing rates from 5.6 to 16.8 kg ha−1, levelled off as sowing rate increased to 33.6 ka ha−1, and then decreased as sowing rate increased further. Thus, there was a broad optimum sowing rate that gave a maximum sowing year DM yield. Percent plant survival to the third year (1988) decreased with increasing sowing rate so that plant densities became similar for sowing rates greater than 16.8 kg ha−1. Within the range 5.6 to 16.8 kg ha−1, increasing sowing rate increased stand persistence measured as 1988 plant density; however, a corresponding increase in DM yield was not obtained. For all full‐production years, DM yield was independent of sowing rate. Sowing rate did not affect three chemical measures of forage quality.
Behaviour of Sugar‐beet Plants (Beta vulgaris L. ssp. vulgaris var. altissima [Doell]) under Conditions of Changing Water Supply: Abscisic Acid as Indicator
Authors: Wittenmayer L. , Schilling G.
Published: April 2008

Moderate drought stress increases the root‐to‐shoot ratio in sugar‐beet plants. The question arises whether abscisic acid occurs in these plants and whether it plays a role in their adaptation to limited water supply. Thus, after identification by GC/MS, the content of free ABA and its alkaline hydrolysable conjugates was determined by capillary GLC in sugar‐beet plants of pot and field experiments with differentiated water supply. It was shown that leaves had a higher content of free ABA than tap roots. Within the leaf apparatus the young organs contained more ABA than the fully developed leaves. Moderate drought stress increased both free and alkaline hydrolysable ABA contents in leaves of intact plants, whereas the ABA content of tap roots was not demonstrably influenced. In contrast, severe and rapid osmotic stress treatment of detached leaves by dipping the petioles in mannitol solutions increased the free ABA content at the expense of the hydrolysable conjugates. This suggests an ABA release by the latter. Therefore, sugar‐beet plants seem to have two mechanisms for increasing the free ABA content under drought stress conditions: the gradual synthesis of ABA including its conjugates and the release of free ABA from ABA conjugates.
A Note on the Skewness of the Frequency Distribution of Harvest Indices with an Application to Winter Oilseed Rape (Brassica napus L.)
Authors: Hühn M.
Published: April 2008

Based on well‐known statistical approximations for the mean, variance, and for the third moment about zero of the ratio of two random variables, a general expression has been derived for the skewness of the distribution of harvest indices. The skewness of the distribution of harvest indices depends on three parameters: coefficients of variation for the two component traits and their correlation. Conclusions for the sign of this skewness are discussed. Finally, the theoretical results and conclusions have been checked and applied to an experimental data set of winter oilseed rape. The agreement between expected and observed skewness is extraordinary good.
Pearl Millet Phenology and Growth in Relation to Thermal Time under Arid Environment
Authors: Singh R. S. , Joshi N. L. , Singh H. P.
Published: April 2008

Pearl millet (Pennisetum glaucum L.R.Br.) hybrid MH 179 was grown under two moisture regimes viz., optimal moisture and rainfed conditions. The field experiment was continued for three consecutive rainy seasons to quantify the pearl millet development with thermal time. The possible influence of variation in natural sowing date on the relationships between crop development and thermal time have been described. At cardinal temperatures of 10°C (base temperature below which pearl millet development ceases), 33°C (optimal temperature for development) and 45°C (maximum temperature at and above which no development takes place), the crop required 1490–1794°Cd thermal time to reach physiological maturity. The thermal time requirement for different developmental stages was influenced by the sowing time and moisture availability during the growing season of the crop.

The leaf tip appearance on the main shoot of pearl millet in relation to thermal time was almost linear under both moisture conditions requiring about 44–50°Cd ± 2.6 °Cd leaf−1, till the appearance of the flag (last) leaf. However, leaf tip appearance on primary tillers was slightly slower and required 53‐58°Cd ± 4.7°Cd for each new leaf. Appearance of first primary tiller was later (at 320°Cd after emergence) under the rainfed condition as compared to the crop under the optimal moisture (at 250°Cd).Thereafter, the tiller appearance in relation to thermal time under both moisture conditions was at a linear rate of about 53‐56°Cd ± 9.5°Cd tiller−1.

Effect of microclimatic variations, canopy temperature, radiation and photoperiod on the phenology‐thermal time relationships have been discussed under both the moisture conditions.
Yield and Resource Use Optimization in Late Transplanted Mint (Mentha arvensis) under Subtropical Conditions
Authors: Ram Muni , Kumar Sushil
Published: April 2008

A field experiment was conducted during 1994 and 1995 at Lucknow (26.5°N, 80.5°E, 120 m above mean sea level) to optimize planting density and fertilizer‐N application for high essential oil yield of late transplanted mint (Mentha arvensis). The treatments studied were 2.5, 2.0 and 1.66 × 105 mint seedlings ha−1 and 0, 80, 160 and 240 kg N ha−1. Under 3 months delayed planting conditions using 2‐month‐old seedlings, the high planting density of 2.5 × 105 plants ha−1combined with 160 kg N ha−1 gave significantly higher herb and essential oil yields compared with those of lower planting densities (2 and 1.66 × 105 plants ha−1) and all other rates of N application. It is demonstrated that a transplanted mini crop, yielding essential oil at a level of 164 kg ha−1, is feasible after the harvest of rabi cereal, oil seed or legume crops in the north Indian plains.
Prediction of Various Effects of Harvest Date in Sugar Beet Growing
Authors: Smit A. B. , Struik P. C. , van Niejenhuis J. H.
Published: April 2008

One crucial decision in sugar beet growing is determining harvest date. This paper focuses on some aspects associated with harvest date which have to be included in a decision support system for sugar beet growing.

Firstly, a module was created for dirt and crown tare, mainly based on lutum (or clay) and soil moisture contents. An independent test of the module showed poor results, because fine tuning of harvest machinery has an overriding effect. Secondly, the variation in weather conditions during autumn in Wageningen over a period of 38 years was analysed. The ranges of future root and sugar production appeared to be so wide that early predictions of the day on which the sugar quota are exceeded will not be very reliable. Thirdly, risks of severe frost or heavy rainfall in autumn were assessed, based on the same 38 year data set. The risk of frost damage to unharvested beets proved to be negligible when the crop was harvested before November 10, as advised by the sugar industry.

The work described in this study makes the model PIEteR (a field specific bio‐economic production model for sugar beet, developed for decision support at field and farm level) more applicable by using its potential to analyse the effects of different years and quota options.
Chlorophyll and Proline as Affected by Moisture Stress in Young and Mature Leaf Tissues of Brassica carinata Hybrids and Their Parents
Authors: Voleti S. R. , Singh V. P. , Uprety D. C.
Published: April 2008

Chlorophyll reduction and proline accumulation under moisture stress at three different growth stages in young and mature leaf tissues of B. carinata hybrids of reciprocal origin and their parents was studied. Greater chlorophyll reduction was observed in mature leaves at flowering stage, whereas proline accumulated significantly in young leaves at pre‐flowering stage. The chlorophyll and proline contents per se in hybrids was higher so as their reduction and accumulation compared to their parents. Maternal influence was apparent for these two characters in Brassicas.
Drought Stress Effects on Seed Yield, Yield Attributes, Growth, Cell Membrane Stability and Gas Exchange of Synthesized Brassica napus L.
Authors: Hashem Abul , Amin Majumdar M. N. , Hamid Abdul , Hossain M. M.
Published: April 2008

Drought stress effects on leaf gas exchange, cell membrane stability, seed yield and yield attributes of synthesized Brassica napus L. cv. Bangla kale and Bangla cabbage were compared. Drought stress treatments were imposed at early vegetative, late vegetative and flowering stages by withholding watering. Bangla cabbage produced greater pods/plant, larger seed size, greater total dry matter/plant, seeds/pot, and 17% greater yield than Bangla kale. The seed yield in plants stressed at early vegetative, late vegetative and flowering stages were 59, 74, 88% lower respectively, than watered plants. Drought stress reduced leaf photosynthesis by 67 to 97%. Bangla cabbage had 68% greater photosynthesis and 56% greater stomatal conductance than Bangla kale under stress at flowering stage. Leaf temperature was 1 to 2°C higher in stressed plants than watered plants. The cell membrane stability (CMS) increased up to 83% at flowering stage under stress compared to 21% under watered conditions. Although Bangla cabbage had high seed yield, yield attributes and photosynthesis under stressed conditions at flowering stage, its CMS values were lower than those of Bangla kale.
The Role of Phenolics and Peroxidase in Resistance to Alternaria triticina in Bread Wheat (Triticum aestivum L.)
Authors: Tyagi M. , Kayastha Arvind M. , Sinha B.
Published: April 2008

Total phenolic content in eight diverse wheat lines showed that PF‐70354 YACO'S’ had the highest (802.90 ± 1.35 μg g−1 fresh weight) and Agra Local possessed the lowest amount (684.72 ± 5.28 μg g−1 fresh weight). However, for further experiments two lines namely, ACC‐8226 and MP‐845, with contrasting disease scores under field trials were assessed. Pre‐infectional levels of total phenolics and peroxidase activity were higher in ACC‐8226 than in MP‐845. Furthermore, the amount of phenolics and peroxidase activity in each case increased after inoculation. The post‐infectional levels of phenolics and peroxidase were again higher in ACC‐8226 than in MP‐845. The peroxidase activity decreased with age in both the varieties, with very little peroxidase activity after 35th day. However, the amount of phenolics started to decrease with the progress of disease and age in MP‐845, whereas in ACC‐8226 an elevated level of it was maintained. Our findings not only support that ACC‐8226 is the resistant and MP‐845 is the susceptible variety but also provide important biochemical parameters for plant breeders to authentically identify potential breeding material and plan effective breeding strategies using these tools.
High‐temperature Effects on Germination and Viability of Weed Seeds in Soil
Authors: Arora A. , Yaduraju N. T.
Published: April 2008

The control of weeds by solar heating of the soil using transparent polyethylene (PE) sheets was studied in the field during the summers of 1994 and 1995. The maximum soil temperature under plastic cover at 5 cm depth averaged 53°C. At 5 cm soil depth, solarization increased temperature by about 9°C. In the non‐solarized soils, such high‐temperature days were fewer. A temperature of 55°C at 5 cm soil depths was recorded both in irrigated and non‐irrigated mulched soils. However, mulched soil recorded 70% of the treatment period compared with 43% in unirrigated and mulched soils. Lower depths of 10 and 15 cm did not attain a temperature 55°C or 60°C on any day during the experimental period.

Solarization treatment with PE sheets significantly increased NO−3—N and NH+4—N in comparison with non‐solarized plots. While uncovered plots showed significant increase in available phosphorus and marginally increased in potassium and electrical conductivity. Organic carbon content and pH did not vary under different treatments.

PE mulching for 30 days significantly reduced the number of weed seeds, specifically Avena fatua L. and Phalaris minor Retz., while Trianthema monogyna Linn, and Asphodelus tenuifolius Cav. were not affected much in comparison with the former. Melilotus indica (L.) All, was not at all affected by the solarization treatment studied. The solarization reduction index (SRI) was calculated for each weed species studied and it was concluded that weeds having a low SRI can be controlled more effectively than weeds with high SRI values. The heating effect from solarization decreased significantly with soil depth. The 30 days’ soil solarization treatment in moist soil was more effective than the 10 and 20 days’ heating treatment in moist and dry soils for weed control.
Effect of Mulch and Irrigation Water Amounts on Soil Evaporation and Transpiration
Authors: Abu‐Awwad A. M.
Published: April 2008

Soil evaporation, transpiration, evapotranspiration, and yield of pepper as affected by mulch and five amounts of irrigation water were studied in greenhouse pot experiments during 1996 (March 26–July 13). Five different amounts of irrigation water were imposed on covered and open soil surface clay loam soil in five replicates. Water losses by evaporation and/or transpiration were measured daily by weighing. Irrigation water was applied once weekly. The amount of irrigation water added to each treatment was determined from the differences in weights.

Covering soil surface reduced the required amount of irrigation water. With deficit (under) irrigation, the reduction in applied irrigation water was about 14%. and increased to 29 % with excess (over) irrigation. Transpiration in covered soil surface treatments were higher than transpiration in open soil surface treatments with limited irrigation water applied, With limited (deficit) irrigation, increasing irrigation water applied decreased the percentage of soil evaporation and the contribution of soil evaporation to crop evapotranspiration. With excess irrigation, increasing water applied increased the percentage of soil evaporation and its contribution to the total evapotranspiration. Soil evaporation reduced pepper yield significantly, and this might be owing to the reduction in the available soil water associated with limited‐to‐complete irrigation.
Differential Response of Two Wheat Genotypes to Nitrogen Supply. II. Mesophyll Cell Characteristics and Photosynthesis of Laminae at Full Expansion
Authors: Sivasankark A. , Lakkineni K. C. , Jain Vanita , Kumar P. A. , Abrol Y. P.
Published: April 2008

Two wheat genotypes, viz. Uniculm ‘Gigas’ (V1) and Kalyansona (V2) were raised to maturity under two levels of nitrogen supply @ 30 (N1) and 120 (N2) kg ha−1, under pot culture conditions. Laminae numbering 1 to 8 on the shoot were examined for area, net photosynthetic rate (Pn) and mesophyll cell characteristics, at full expansion. N1 resulted in greater reduction in the area of upper laminae in V1 than in V2. The flag and penultimate laminae maintained similar Pn rates at both N levels in V1 despite a large reduction in area at N1. However, V2 exhibited about 25% reduction in Pn rates of the flag laminae at N1 as compared with N2. Mesophyll cell number per unit area gradually increased with laminae order in the genotypes. The greater number of mesophyll cells in the upper laminae was essentially due to a reduction in cell size and surface area as a result of low N availability. The large differences in laminae size due to N treatments, particularly in V1, are attributed to mesophyll cell numbers. However, the maintenance of Pn rates in V1, even at low N supply, is a possible outcome of higher activity of the mesophyll cell constituents in this genotype.
Physiological Effects of Winter Rape (Brassica napus var. oleifera) Prehardening to Frost. II. Growth, Energy Partitioning and Water Status during Cold Acclimation
Authors: Rapacz M.
Published: April 2008

Prehardening of winter rape, i.e. its early growth in a reduced day temperature (+12°C) from emergence to the beginning of cold acclimation at chilling temperatures (the 1st stage of cold acclimation), has a beneficial influence on frost resistance. In earlier studies it has been demonstrated that during prehardening, plants formed leaf rosettes and increased the photosynthetic efficiency at chilling temperatures. In the present study investigations were carried out on the effect of prehardening on the growth rate of the plants during the 1st stage of cold acclimation, and the progress of selected physiological processes occurring during this stage and resulting in increased frost resistance. It has been demonstrated that a greater inflow of photoassimilates during the 1st stage of cold acclimation results in greater increments of the dry mass of prehardened plants. These plants show also a distinct inhibition both of the elongation growth and the rate of expanding new leaves. The acquired energy is thus spent to a greater extent on the processes associated with increasing frost resistance, and not on growth. In prehardened seedlings, during the 1st stage of cold acclimation, there have been observed in leaves a higher rate of both water content decrease and drop in the osmotic potential of the cell sap and water potential in the tissues. Also an increased accumulation of soluble sugars and free proline was noticed. However, the beginning of these processes was not observed during the prehardening period. Prehardening stimulated the effectiveness of the 1st stage indirectly through changes leading to the increased amount of available energy and enabling the utilisation of the greater part of acquired energy in the cold acclimation process.
Effect of 1‐Naphthaleneacetic Acid Concentrations and the Number of its Applications on the Yield Components, Yield and Fibre Properties of Egyptian Cotton (Gossypium barbadense L.)
Authors: Sawan Z. M. , Sakr R. A.
Published: April 2008

Field experiments were performed in two successive seasons at the Experimental Station, Faculty of Agriculture, Cairo University, Giza, Egypt, on the Egyptian cotton cultivar Giza 75 (Gossypium barbadense L.). Cotton plants were sprayed with the growth regulator 1‐naphthaleneace acid (NAA) once (at 90 days), or twice (at 90 and 105 days) or thrice (90, 105 and 120 days) after sowing, during the square initiation and boiling stage at the concentrations of 5, 10, 15, 20 or 25 p.p.m. The volume of solution was the same for all treatments. 9601 ha−1. The control plants were sprayed with water only. The effect of the previous treatments on yield components, cotton yield and fibre properties was studied.

The application of NAA increased the number of opened bolls plant−1, boll weight, seed index, seed cotton yield plant−1 and seed cotton and lint yields ha−1. The most significant effects were obtained with the 15 and 20 p.p.m. concentrations. Lint percentage, fibre length parameters and micronaire value were not significantly affected by NAA. Flat bundle strength was significantly affected by NAA but with no definite trend. The application of NAA twice or thrice tended to give the best results on yield components and cotton yield compared with one application. The results of this study suggested that 20 p.p.m. of NAA gave the best figures when applied twice on the Egyptian cotton plants.
Effect of Branch Direction's Arrangement on Soybean Yield and Yield Components
Authors: Asanome N. , Ikeda T.
Published: April 2008

Useful light interception during reproductive stages is very important for soybean (Glycine max (L.) Merr.) dry matter production. The objective of this experiment was to investigate the light utilization in the canopy for yield, and its components in the case of arranging branch direction to row direction with flat type (1/2 phyllotaxy) soybean. The field study was conducted in the field at Niigata University on a loamy sand soil at 25, 16 and 9 plants m−2 in 1994, 1995 and 1996, using cultivar ‘Miyagishirome’ (Maturity Group VII or VIII, phyllotaxy 1/2; branches develop flatly) with treatments so that branches developed at right angles direction (Type R) and in a parallel direction (Type P) to the direction of the row.

Total dry weight (TDW) was greater in Type R than in Type P. A higher leaf area index (LAI) was shown in Type R than in Type P in each plant density among the three years. More light penetrated into the canopy in Type R than in Type P. Higher TDW and LAI were produced by effective light interception at the canopy of Type R.

Yield and its components were greater in higher than lower density and tended to be greater in Type R than in Type P. Increased yield depend on seed, pod and node number m−2. The increase of yield components in Type R was suggested to be due to favorable light condition in the canopy, compared with Type P.
Does Salt Tolerance Vary in a Potential Oil‐Seed Crop Brassica carinata at Different Growth Stages?
Authors: Ashraf M. , Sharif R.
Published: April 2008

The salt tolerance of two salt‐tolerant (C90‐1191 and P5/80) and two salt‐sensitive (C90‐1115 and 77–321) lines of Ethiopian mustard (Brassica carinata) (selected on the basis of their performance in germinating ability and seedling growth in a screening experiment) was assessed at the adult stage under glasshouse conditions to evaluate the consistency of salt tolerance at different growth stages of plant life cycle. No difference in response of all four lines differing in salt tolerance was found to varying concentrations of NaCl in the growth medium, although the latter two lines were slightly better than the former two in shoot dry mass, seed yield or yield components. The relatively good growth of the lines C90‐1115 and 77‐321 at the adult stage can be related to their lower accumulation of Na, Cl and Ca in their leaves. K/Na ratios, Ca/Na ratios, K versus Na selectivity, and Ca versus Na selectivity did not prove to be successful criteria in discriminating the lines differing in degree of salt tolerance. In conclusion, salt tolerance in B. carinata varies with the change in stage of its life cycle. Thus selection based at one particular stage may not produce individuals tolerant at all growth stages.
Effects of Temperature and Photoperiod on Vegetative and Reproductive Growth of Groundnut (Arachis hypogaea L.)*
Authors: Nigam S. N. , Nageswara Rao R. C. , Wynne J. C.
Published: April 2008

Effects of temperature × photoperiod interaction on vegetative and reproductive growth were examined in three selected groundnut genotypes by growing them in controlled‐environment growth chambers with three temperature regimes (22/18, 26/22, and 30/26°C, day/night) under long (12 h, long day), and short (9 h, short day) photoperiods.

The effect of photoperiod on the total dry‐matter production (TDM) was significant with the genotypes producing 32–72% greater dry matter under LD than SD. Temperature × genotype interaction effects were significant, with the dry‐matter production being greatest at 26/22°C and least at 30/26°C and 22/18°C in two of the three genotypes.

Leaf area (LA) was greater under LD than SD at all temperature regimes. LA accounted for 76% of the variation in shoot + root dry weight (R2= 0.76, P < 0.01). A lack of relationship between LA and pod weight or pod numbers suggested that the pod development is controlled by factors other than carbon assimilation.

The temperature × photoperiod interaction was significant for root growth, with the root weight being maximal and photoperiod effects being minimal at 22/18°C, while at 26/22°C, root weight declined and photoperiod effects became prominent. Low temperature (22/18°C) affected the reproductive development by reducing the proportion of reproductive nodes in total (vegetative + reproductive) nodes. The conversion of pegs into pods, as indicated by pod to peg ratio (PPR), was lower in LD than in SD conditions. Results suggested that the PPR could be used as an indicator of genotypic sensitivity to photoperiod in groundnut.
Estimation and Partitioning of Nitrogen Fixed by Soybean in Mediterranean Climates
Authors: Koutroubas S. D. , Papakosta D. K. , Gagianas A. A. , Papanikolaou E. P.
Published: April 2008

A field study was conducted to estimate the nitrogen fixation by soybean [Glycine max (L.) Merr.], using the A‐value and the N‐difference methods, and to examine the N partitioning within the plant. The cultivar Clark and its non‐nodulating isoline (as reference crop) were grown in a silty clay (Typic Xerothent) soil, in 1991 and 1992. 15N‐Labelled fertilizer was surface applied in solution, at rates of 20 and 100 kg N ha−1 to the nodulating and non‐nodulating soybean, respectively. Plant samples were taken at full bloom (R2), beginning of seed growth (R5) and physiological maturity (R7). There was little nitrogen fixation at the early growth stages but it increased rapidly during the seed filling period. At R7 nitrogen fixed was estimated by the A‐value method as 155 kg N ha‐1 in 1991 and as 240 kg N ha−1 in 1992. The corresponding estimates by the N‐difference method were significantly smaller. The seeds had a higher, and the vegetative parts smaller, proportion of fixed nitrogen compared to the whole plant. During the seed filling period, the translocation efficiency for fixed nitrogen was greater (93 % in 1991 and 85 % in 1992) compared to the N derived from soil (75 and 56 %, respectively). It was estimated that, after the harvest of pods, the soil was depleted by a net amount of 121 kg N ha−1 in 1991 and 90 kg N ha−1 in 1992.
Erfassung der frischen und trockenen Biomasse und Schätzung der frischen Biomasse von Wintergerste in verschiedenen Regionen Europas mit einem raumgleitergetragenen Radarsensor
Authors: Steingiesser R. , Kühbauch W.
Published: April 2008

The launch of ERS‐1, the first operational radar satellite, in 1993, has led to considerable interest in images acquired at radar wavelengths (1–50 cm) as means of gathering information about agricultural crops and their condition. The main advantage of radar systems with respect to optical satellites is that they can acquire images of the earth's surface irrespective of cloud cover, since clouds are transparent at these wavelengths. This is especially important for agricultural applications, where reliably timed images are needed throughout the growing season in order to follow continously the status of the crops as they develop.

Multi‐frequency polarimetric radar systems represent a convincing evolution of radar systems and their capabilities. The X‐SAR/SIR‐C radar‐instrument, which was flown twice on the space shuttle in April and October 1994, allowed many researchers access to high quality radar images aquired from a space‐borne system for the first time. Thus far, the full potential of radar has not been realized, mostly because existing radar satellites such as ERS‐1 only aquire information at a single‐wavelength and polarization. By restricting the collection of information to a single channel means such images often lack the extra information needed to characterize crops. However, recent studies using multifrequency‐radar have shown that vegetation type, structure and condition can be better characterized when data is aquired at several wavelength and polarizations.

In order to obtain significant differences in growth stages for identical crop types during the first 10‐day long shuttle mission, winter barley fields were chosen along a gradient from southern Italy to southern Germany. These test fields were surveyed coincidentally with shuttle passes over them. One of the main results was that the spread in fresh biomass measured in (g m−2) between winter barley and maize fields as a function of their different growth stages, could be detected with great precision from the backscatter data. The best parameter for the measurement of winter barley and maize biomass was the ratio HH/VV at L‐band. For the extraction of dry biomass in winter barley fields, the cross‐polar polarization HV at C‐band showed the best results.
Plant Development and Stem Yield of Non‐domestic Fibre Hemp (Cannabis sativa L.) Cultivars in Long‐day Growth Conditions in Finland
Authors: Sankari H. S. , Mela T. J. N.
Published: April 2008

Plant development and stem yield of mono‐ and dioecious fibre hemp cultivars (Cannabis sativa L.), introduced to Finland from regions of lower latitude, were studied in field experiments under long‐day growth conditions in 1995–96. Plant density, plant mortality rate, stem elongation and stem yield were determined. Plant densities at seedling stage were less than the targeted viable seeds sown m−2. Seedling densities differed significantly among cultivars, but had no significant effect on plant mortality rate in 1996. Plant mortality during the 1996 growing season averaged 34 plants m−2. Stem elongation was measured at one‐week intervals throughout the growing time. The elongation among cultivars was different and depended on the date of measurement. Rapid elongation began five to six weeks after sowing and elongation was most pronounced in July. Dioecious cultivars were significantly taller than monoecious ones in 1995 but not in 1996 when hemp stands were dense, nitrogen was deficient and an infection of Botrytis vinerea was present. Dioecious cultivars produced higher stem yields than monoecious ones. However, in 1996 the difference in yield was not statistically significant among most of the cultivars, Cultivar Uso 11 was early maturing and produced highest stem yield among monoecious cultivars; it also competed well with the higher yielding dioecious cultivars.
Analyse der räumlichen Korrelation des Unkrautauftretens mit der Verunkrautung des Vorjahres und mit abiotischen Standortfaktoren am Beispiel Efeublättriger Ehrenpreis (Veronica hederifolia L.) und Stickstoffgehalt
Authors: Dammer K.‐H. , Körner S. , Wittmann Ch.
Published: April 2008

Spatial correlation analysis between weed occurrence and those of the previous year and abiotic soil properties by example of ivy‐leaved speedwell (Veronica hederifolia L.) and nitrogen content

The spatial dependence of the occurrence of Veronica hederifolia L. on the previous year and on the nitrogen content of the soil (0–30 cm) is characterized by cross correlograms. These are drawn by use of the correlation coefficient of Pearson's ρ and Kendall's τb. The results from cross correlograms are compared with the correlation coefficients at the same sampling location between the occurrence of the weed for 2 consecutive years running and also between the nitrogen content and the weed occurrence in the same year. With the help of the cross correlograms we found up to which distances the two variables correlate significantly. The correlation coefficient calculated between two variables at the same sampling point are not sufficient to characterize their spatial dependence. Kendall's τb, corrected for ties, as a nonparametric measure of correlation, leads in two cases to more significant dependencies than does Pearson's correlation coefficient.
Optimum Seed Rate and Nitrogen Fertilizer Requirement of Rice Under Semi‐deepwater Ecosystem
Authors: Sharma A. R. , Ghosh A.
Published: April 2008

The effect of varying seed rates (100–1000 seeds m−2) and nitrogen fertilizer (0–60 kg N ha‐1) applied either in a single basal dose or in splits was investigated on a tall elongating, photosensitive rice variety, Nalini, under semi‐deepwater conditions (0–100cm) during 1993 and 1994 at Cuttack, India. Seedling emergence was higher in 1993 (53.9 %) than in 1994 (44.1 %) and it increased proportionately with increasing seed rate, Increase in the number of tillers and panicles m−2 at higher seed rates was associated with a corresponding decrease in panicle weight. Regression analysis indicated a decrease of 0.91–1.28g in panicle weight for an increase of 100 panicles m−2. The grain yield of rice was significantly higher at 400 seeds m−2 in 1993 and at 600 seeds m−2 in 1994 than at low seed rates but further increase in seed rate did not increase the yield. Application of N fertilizer increased the panicle number and thereby grain yield significantly. The effect of basal and split applied N at active or maximum tillering stages as well as between 30 and 60 kg N ha−1 was not significant on the grain yield. The results suggest that a basal dose of 30kg N ha−1 and seeding density of 400–600 seeds m−2, resulting in 40–50 % seedling emergence and 150–200 panicles m−2, each with 2.0–2.5 g weight, may be adequate for optimum productivity of rice under semideepwater conditions.
Seasonal Changes in the Photosynthetic Capacity of Winter Rape Plants under Different Nitrogen Regimes Measured in the Field
Authors: Kappen L. , Hammler A. , Schultz G.
Published: April 2008

Winter rape (cv.‘Falcon’) grown under different nitrogen regimes (N0, N120; 0 and 120 kg.ha−1, respectively) in northern Germany was investigated over the 1996 spring–summer season. Using a CO2, H2O diffusion porometer, diurnal courses or net photosynthesis and respiration were measured in situ and were related to microclimatic conditions and leaf water relations. Photosynthesis was modelled and daily CO2 gain was calculated. In contrast to the N120 plants, plants of the low nitrogen plot (N0) grew less densely and their leaves behaved more like sun leaves. Increased nitrogen supply had little influence on photosynthetic capacity but it increased productivity through higher leaf area index and an extended period of photosynthetic activity. N120 plants also appeared to be better acclimated to hot, summer conditions. Higher nitrogen supply substantially increased seed production with the yield of the N120 plants being 16% of the N0 plants.
Polyamines as Modulators of Soybean Productivity
Authors: Sharma M. L. , Ali Mashiat
Published: April 2008

Polyamines have been shown to be involved in several aspects of plant growth and development. In soybean, increase in number of pods per plant, 100 seed weight, seed, biological and oil yield was highest with spray of spermine and lowest (but significantly higher than control) with putrescine. The soybean seed and oil yield increased by about 12.46 and 20.94% respectively with application of 10−3m spermine at 50% flowering stage. Another spray of polyamines at pod initiation stage had little effect on different parameters.
The Effect of Planting Date and Plant Density on Potassium and Magnesium Uptake and Harvest by Brussels Sprouts
Authors: Everaarts A. P. , van Beusichem M. L.
Published: April 2008

The effects of planting date and plant density on potassium (K) and magnesium (Mg) uptake and harvest by Brussels sprouts (Brassica oleracea var. gemmifera) were studied in field experiments. Crop potassium concentration generally decreased towards harvest, but the pattern in potassium concentration during crop growth differed between planting dates. Plant density in the range of 2.7–4.4 plants m−2 had no effect on crop potassium concentration. The amount of potassium in the crop at harvest decreased with a delay in planting, but was not influenced by plant density. Mainly depending on the planting date, around 100–200 kg potassium ha−1, or approximately 40–50 % of the potassium in the crop at harvest, is removed from the field with the product. Averaged over treatments and years, potassium concentration in the (fresh) product was 5.2 kg ton−1. The amount of magnesium in the crop at harvest decreased with a delay in planting. Depending on the planting date, uptake at harvest was 10–17 kg magnesium ha−1. Plant density had no effect on this amount. On average per ton (fresh) product, 0.20 kg of magnesium was removed from the field.
Effects of Weed Removal in Clusterbean (Cyamopsis tetragonoloba) under Different Rainfall Situations in an Arid Region
Authors: Yadav R. S.
Published: April 2008

In dry land agriculture, intensity and type of weed pressure depend upon the rainfall pattern during the crop season. A two year field study was conducted to determine the effect of time of weed removal in clusterbean (Cyamopsis tetragonoloba (L.) Taub.). Treatments consisting of weed removal at 10, 20, 30,40 and 50 days after sowing were compared with clean weeded and unweeded controls. The xerophytic weeds Gisekia pharnacioides (L.) M., Mollugo cerviana (L.) Ser. and Tribulus terrestris L. dominated in the low and erratic 1993 rainfall season while grassy weeds such as Eragrostis pilosa (Beauv) were predominant in the 1994 season with well‐distributed rainfall. The number of weeds was maximum at 30 days after sowing (DAS) in 1993 and at 40 DAS in 1994. The dry weight of weeds increased up to 50 DAS in 1993 and up to harvest in 1994. Removing weeds at 20 or 30 DAS increased the number of pods per plant, water use efficiency and seed yield of clusterbean. Water consumption was higher in unweeded plots. Water use efficiency decreased with the increase in time of weed removal beyond 20 days after crop sowing.
Cell Enlargement as an Important Factor in Controlling Grain Weight in Wheat
Authors: Chanda Sumitra V. , Singh Yash Dev
Published: April 2008

Grain dry weight, water content and changes in wall‐bound α‐galactosidase and β‐glucosidase activities were estimated in three grains (differing in their position on the spike and final dry weight) of wheat (Triticum aestivum L.) cultivar Lok‐1 during the entire period of grain development. Considerable differences in the grain weight within a wheat spike are reported, but the physiological and biochemical bases of these differences are poorly understood. The experiments described here indicate that the maximum grain weight is dependent upon the rate of grain filling. A highly significant correlation (P < 0.001) between maximum grain weight and maximum water content per grain, and a close correspondence between the rate of grain filling and wall‐located α‐galactosidase activity, suggests that the process of cell enlargement may be important in determining the rate of grain filling, and thus, for maximum grain weight in wheat.
Cadmium Suppresses Phosphate Level and Inhibits the Activity of Phosphatases in Growing Rice Seedlings
Authors: Shah K. , Dubey R. S.
Published: April 2008

The effect of increasing concentration of Cd in situ on the metabolic status of total phosphate and the activity of its metabolizing enzymes acid phosphatase, alkaline phosphatase and inorganic pyrophosphatases were examined in growing rice (Oryza sativa L.) seedlings. Some 500 μm Cd in the medium caused 68–77% decline in phosphate content in shoots and 56–66% decline in roots in 20‐day‐old seedlings of the two rice cultivars Ratna and Jaya. In situ Cd levels of 100 μm and 500 μm led to a significant decline in the activities of the three phosphorolytic enzymes studied. Inhibition in the acid phosphatase activity was greater in roots than in shoots. With 500 μm Cd 62–88% inhibition in acid phosphatase activity was observed in roots. A similar Cd level caused 28–31% inhibition in shoots in 20‐day‐old seedlings, whereas inorganic pyrophosphatase activity was inhibited by 27–53% in roots and nearly 50% in shoots. Under in vitro conditions more than 200 μm Cd(NO3)2 in the reaction medium significantly inhibited the activities of the phosphorolytic enzymes. Alkaline phosphatase appeared to be more tolerant than acid phosphatase at lower (20–100 μm) concentrations whereas the activity of inorganic pyrophosphatase was completely lost with 2 mM Cd. Isoenzymic studies revealed three acid phosphatase isoenzymes with RF values of 0.18, 0.24 and 0.40 in both roots and shoots. The band intensities decreased under Cd treatments. The results indicate suppression of the activities of phosphatases due to Cd in growing seedlings.