摘要:

AbstractThe actual yields from multilocation variety trials are commonly analysed as a two‐way table (rows = varieties, columns = locations) of mean yields. In this paper, relationships between the recently proposed new stability parameter ‘variance of relative yield’ and the two stability parameters of the ‘classical’ joint regression approach in stability analysis, are investigated. The variance of relative yield as a measure of stability exhibits an undesirable dependence on the mean yield of the respective variety. Generalizations and improvements of some recent results and conclusions of Piepho (1994) are

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01131.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe global atmospheric CO2‐concentration is increasing and there has been an increase in Germany of about 30 ppm from 340 ppm to 370 ppm CO2during the last two decades. The hectare yield of many crops has also increased during this time period. The objective of the present study was to estimate whether the past and future change in the atmospheric composition significantly contributes to the increase in hectare yield.Different crop species (beans,Phaseolus vulgaris, cv Pfälzer Juni; spring barley,Hordeum vulgareL., cvs. Alexis and Arena; spring wheat,Triticum aestivumL., cvs. Star and Turbo; maize,Zea maysL., cvs. Bonny and Boss) were grown at ambient (372 ppm) and at slightly elevated CO2‐concentrations (459 ppm and 539 ppm) in open‐top chambers and the effect of the different CCVconcentrations on the growth and yield of the plants was measured. The past and future CO2‐effect was estimated from the slope of a linear CO2‐yield curve (percentage increase in yield per ppm CO2′100% at 370 ppm) fitted to the data and those from previous studies on wheat and maize. The percentage increase in yield per ppm CO2is insignificant for beans, of borderline significance for silage maize (0.06 % per ppm), and 0.35 % per ppm and 0.26 % per ppm for barley and wheat, respectively. The COj‐elevation primarily decreases the tiller dieback of the cereals. Considering the increase in CO2of 30 ppm and in the hectare yield of 25 % (barley) and 28 % (wheat) from 1970 to 1990, the contribution of CO2to the increase in the agricultural production is estimated to be one fourth up to one half of the increase in hectare yield of spring cereals. Given a recent yearly increase of 2 ppm the future CO:‐related increase in hectare yield is estimated to be about 0

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01132.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractMeasurement of total leaf area per plant in crop improvement programmes for a variety of purposes is often very tedious and time consuming. In this paper, we offer a rapid and non‐destructive method of estimating the total leaf area in sunflower at the time of anthesis. We show that multiplying the leaf area of a specific leaf position from the apex by the total number of leaves per plant yields total leaf area with more than 95 % accuracy. The specific leaf position for any given genotype in sunflower can be arrived at by multiplying the total number of leaves per plant by the factor 0.355 and rounding off to the nearest highest integer. This technique can be used for the rapid estimation of leaf area per plant at anthesis for any given genotype of sunflowe

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01133.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractNitrogen (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 aestivumL.) 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−1level. Overwinter changes in soil NO3‐N levels were proportional to the inverse of the fall NC3N levels. Differences between sites were large for many

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01134.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractDuring 1990 and 1991 growth seasons at two locations in Peru four sweet potato cultivars were tested for their response to a short‐term shading. The plants were subjected to artificial shade (42 % light reduction) for 1 month at different growth stages.A high genetic variability was found in the extent to which tuber and total biomass yield of sweet potato was affected by sub‐optimal light conditions. One cultivar was completely tolerant to shade at all growth stages, whereas the others showed a yield decline between 20 % and 55 %. Generally tuber yield was most reduced when shade was imposed at the end of the growth season (fourth and fifth months) and the least at its beginning (first and second months). Yield losses were due to a diminished biomass production and/or an altered assimilate partitioning within the plant. Tuber formation was affected rather than tuber initiat

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01135.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractChanges 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−1caused 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 temperaturesThe intensity of Fndetermined 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 Fnvalues 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

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01136.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractSingle or dual inoculation of wheat seedlings (Triticum aestivumL. cv. Sakha 69) withAzotobacter chroococcum, Azospirillum brasilenseorStreptomyces mutabilisin sterilized soil resulted in significant stimulation of their populations in the rhizosphere, compared with the initial values. Viable counts ofAzospirillumandAzotobacterdecreased in dual inoculations withAzotobacterorStreptomyces,and contrasted with those ofStreptomyces,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 withAzotobacterand all dual inoculations. Soil‐IAA significantly increased by all inoculations. Growth ofA. brasilensesignificantly inhibited by filtrates from 7‐day‐old cultures ofS. mutabilisthan fromA. chroococcum,in vitro. The biosynthesis of antibacterial substance(s) byAzotobactersignificantly decreased by supplementing their cultures with metabolic products fromA. brasilense,but were stimulated by metabolic products fromStreptomycescultures. All metabolic products significantly decreased the growth ofA, chroococcum, A. brasilenseandS. mutabilis,nitrogen‐fixation and biosynthesis of IAA in Achroococcum,whereas biosynthesis of IAA stimulated inS. 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 i

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01137.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAmmonium chloride (AC) and ammonium sulphate (AS) are commonly used nitrogen fertilizers. But the effect of chloride and sulphate ions from these fertilizers on soil enzyme activity has received scant attention. Hence, we conducted a pot culture study to assess the influence of chloride (as AC) and sulphate (as AS) on the activities of urease, amidase, phosphatase and dehydrogenase in soil using rice as the test crop. Chloride and sulphate levels were fixed at 132, 264 and 396 kg ha−1respectively. Controls were also performed. The enzymes were assayed at three stages of the crop growth viz., active tillering, panicle initiation and harvest.The enzyme activities decreased with increasing chloride and sulphate levels; however, the degree of inhibition varied among the enzymes assayed and the nature and amounts of salts added. The inhibition may be due to the specific effects of chloride and sulphate ions on microbial growth and subsequent enzyme synthesis, osmotic desiccation leading to microbial cell lysis, and a salting‐out effect modifying the ionic conformation of the active site of the enzyme prot

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01138.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01139.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Books Reviewed in this Article:Bajaj, Y. P. S. (ed.) Biotechnology in Agriculture and Forestry. Vol. 28. Medical and Aromatic Plants VII.Bajaj, Y. P. S. (ed.) Biotechnology in Agriculture and Forestry. Vol. 29. Plant Protoplasts and Genetic Engineering V.Kübler, E., Weizenanbau.Fritzsche, R. und R. Keilbach. Die Pflanzen‐, Vorrats‐ und Materialschädlinge Mitteleuropas mit Hinweisen auf Gegenmaßnahmen.Basra A. S. (ed.): Mechanisms of Plant Growth and Improved Productivity–Modern Ap

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1995.tb01140.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY