摘要:

AbstractDry Matter Production of Spelt (Triticum speltaL.) and Wheat (Triticum aestivumL.) under Different Environmental Conditions in the FieldThe primary aim of our work was to obtain information regarding the germination characteristics of spelt under different environmental conditions in field experiments, and to trace possible differences between spelt and wheat, with regard to crop production. For the present study two spelt varieties (Ostro/Rouquin)and two wheat varieties (Arina/Probus)were used. In addition the spelt cultivarsAltgold, OberkulmerandHerculewere included in some of the experiments. To obtain information on the influence of the glumes, spelt was planted in the hulled (SP +) and dehulled (SP‐) form.Field emergence of spelt SP‐ was up to 40 % lower than that of SP+, Under water logged soil, the percentage of germination was higher for spelt SP+ than for wheat.Spelt produced more tillers per plant than wheat. However, tiller reduction was also higher for spelt so finally both species had similar numbers of ears per plant. Plants with a high tiller production might be more flexible in response to unfavourable growing conditions.Grain yield of spelt and wheat was developed in different ways. Spelt produced fewer but larger kernels per ear, whereas wheat produced more but smaller kernels. In 1986 grain yield was up to 20 % higher in wheat than in spelt. In 1987, an unfavourable year for cereal crop production in marginal areas, grain yield was higher for spelt than for wheat. For the farmer, the “husked” form of spelt is economically important. This was equal or higher than the grain yield of wheat in both years.The high germination rate under unfavourable conditions, in combination with a high tillering capacity and the production of large kernels appear to be the major reason for the stable yielding ability o

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00800.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSeventeen determinate soybean (Glycine maxL.) cultivars from maturity groups V through VIII were screened for drought tolerance during germination and seedling stages. Germinating seeds and hydroponically‐grown seedlings were subjected to osmotic stresses of ‐0.3 and ‐0.5 MPa using polyethylene glycol M.W. 8000. Genotypic variability was found among the cultivars for all the parameters analyzed in both germination and seedling tests. Germination stress index was lower for seeds exposed to ‐0.5 MPa than for ‐0.3 MPa osmotic stress. Lower osmotic potential in the treatment medium was also correlated with lower leaf water potential in seedlings subjected to it. A significant relationship was found between fresh weight and height stress indices. The cultivars that grew taller under drought stress conditions had greater dry matter accumulation and higher germination stress indices indicating the reliability of height to predict cultivar performance under such conditions. The cultivarsLee‐74andWrighthad higher dry matter accumulation, greater height, and better germination under stress conditions than the other cultivars tested. Conversely, the cultivarsRa 401andBayperformed poorly in the drought tests at both levels. In the seedling tests, there was no strong relationship between the leaf water potential and the overall performance of the plant suggesting no clear osmoregulatory mechanism. Based on results from germination and seedling tests, the cultivarsLee‐74, Wright, andRa 401were selected for further studies in greenhouse and

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00801.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe breakage resistance of the seedcoat ofEuphorbia lathyriswas measured in terms of compressive force and deformation. Using an Instron Universal Testing Machine, seeds of genetically divergent descent were tested at a moisture content comparable to that at harvesting time in the field.In comparison to other crop species breakage resistance of caper spurge is characterized by low values of force and medium ones for deformation. In connection with a likewise weakly expressed degree of elasticity the large portion of damaged seeds observed during mechanical harvesting becomes understandable. Regarding the descent of seed samples the eventual implication of an unsufficient variation of the character in question is becoming evident.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00802.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA versatile method was developed for the application of 1000 ppm CO2during the whole growth period of plants. Temperature controlled water cooling and ventilation of the greenhouse resulted in a monthly CO2enrichment time of 60 to 90 % of the total light period.Digitalis lanata, grown in greenhouses with CO2enrichment during the whole growth phase from April to November, produced twice as much biomass as field cultivated plants.The relative yield of the glycoside digoxin per gramDigitalisdrug dry weight was 0.4% in field grown and 0.7% in greenhouse cultivated plants. The production of digoxin per hectare in the greenhouse at 1000 ppm CO2was almost 3.5‐fold that by field cultivation. Drug yield and secondary metabolite production inD. lanatawere remarkably influenced by increased temperature and elevated CO2partial pressure in the greenhous

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00803.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA field study was conducted on the winter wheat cultivarsArmindaandOkapi, using two seed rates (80 and 160 kg/ha) and three N applications (40, 80 and 120 kg/ha).The cultivars did not differ in total dry matter production but did differ in grain yield. The difference in grain yield was mainly attributable to a higher harvest index (HI).Increased plant density reduced HI; it resulted in more shoots per m2, but in a lower grain yield. The reduction in grain yield was caused by fewer kernels per ear and a lower 1000‐grain weight in both cultivars.A higher rate of N increased total dry matter production and grain yield, except inOkapiat the high plant density. The number of kernels per ear increased, but 1000‐grain weight fell.The higher the N applications, the higher the N‐content of the roots was.Total N yield was greater inArmindathan inOkapi.The cultivars differed in the amount of nitrogen they took up after anthesis.The content of water‐soluble carbohydrates (WSC) differed between the cultivars, N treatments and growth stages. Carbohydrate formed before anthesis accounted for 23 % ofArminda'sgrain yield and for 10 % ofOkapi'sgrain yield.The content of cell‐wall constituents (CWC) depended on cultivar, growth stage and the rate of the N dressing. Differences in CWC were more pronounced inArmindathan inOkapi.During leaf, stem and ear development there was a strong increase in content and amount of CWC. Concomitantly, WSC decreased. This implies that a large consumption of WSC is necessary for the formation of CWC. The competition for the WSC, necessary for CWC and shoot and ear development influences kernel initiation. Per unit of dry matterOkapicontained more CWC thanArminda.This was not in agreement with differences in straw s

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00804.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractWe examined the relationship between grain yield (GY) and grain protein concentration (GPC) in durum wheat (Trticum turgidumL. var.durum) as affected by N application rate, seeding rate, and irrigation levels. Field experiments were conducted for four years with five N rates, five seeding rates, and four Irrigation regimes: A. Only a preplant irrigation; B. A + one irrigation at tillering; C. B + one irrigation at booting stage; and D. C + one irrigation at early soft dough stage. These treatments produced a large variation in GY and GPC which provided the basis for examining the GY‐GPC relationship by all possible correlation analyses and by analysis of variance after partitioning the bivariate responses (GY and GPC) into pairs of univariate responses. The contribution of N, seeding rate, and irrigation on parallel (simultaneous changes in the same direction) and opposite changes in GY and GPC was determined. The effects of N and seeding rate on parallel increase in GY and GPC were significant. For a given level of irrigation, increasing N application resulted in significant parallel increase in GY and GPC to the highest level of N. At low N levels, increase in irrigation level from A to B increased GY and decreased GPC; however, it was not true at higher N levels. For a given N level, GY plateaued at irrigation C, whereas GPC increased up to irrigation D. The overall effects of irrigation treatments on parallel changes (positive correlation) in GY and GPC significantly outweighed their effects on opposite changes (negative correlation) in GY and GPC. Increasing levels of N and irrigation improved the correlation between GY and GPC and the yield‐protein index. This study suggests that with proper management practice it is possible to increase both GY and GPC simultaneously and obtain high protein yield h

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00805.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of plant water stress on net photosynthesis and leaf growth were investigated in order to determine to what extent leaf water potential during vegetative growth and silking affects maize development.Two commercial maize hybrids grown in pots in a glasshouse were subjected to leaf water potentials of ‐1300 and ‐1700 kPa during the eighth leaf stage and during silking to ‐1700 and ‐2300 kPa to previously unstressed, moderately and severely stressed plants. The effect of stress on inhibiting CO2uptake rates and leaf areas, as well as the recovery after alleviating stress, were compared to that of unstressed plants.No substantial differences in CO2uptake rates were found between medium and long seasoned cultivars. The CO2uptake rates per unit leaf area decreased to negative values under both moderate and severe stress conditions during both growth stages. During silking, the recovery of CO2uptake rate was much lower than during the eight leaf stage. Leaf area decreased proportionally with increased stress but did not recover after alleviating stress on plants stressed during both the eighth leaf and silking

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00806.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractNitrogen fixation was estimated by the difference method for two cultivars of berseem clover (Trifohum alexandrinumL.), using annual ryegrass (Lolium multiflorumLam.) as the control in field trials from 1983 to 1988. Five or six cuttings were obtained each year under supplemental irrigation, and dry matter production and uptake of nitrogen into harvested forage were measured.Estimates of nitrogen fixation by berseem clover ranged from 272 to 400 kg N/ha depending on year and cultivar, while plant N derived from soil (based on N uptake by the ryegrass) ranged from 50 to 235 kg N/ha. Graphs of nitrogen fixed versus available soil nitrogen had a reverse linear‐plateau shape with a plateau at lower soil nitrogen levels that broke sharply in a linear decline as available soil N surpassed a minimum threshold. Such a two‐phase response suggests that nitrogen fixation by the clover was limited by soil N supply above this threshold and by other limiting factors at low soil N levels, perhaps genetic traits controlling carbon assimilation or environmental limitations other than nitrogen. Seasonal nitrogen process patterns showed abundant nitrogen fixation by the clover after it had depleted most of the soil nitrogen sup

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00807.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractEstimation of herbage mass is essential in pasture research and in making practical grazing management decisions. Sward height and a capacitance probe were evaluated as non‐destructive measures of herbage mass at seven dates from April 16 to July 30 on continuously grazed predominantly Kentucky bluegrass (Poa pratensisL.) pasture. Paddocks were 1 ha in size and were stocked at 3, 4 or 5 steers ha−1(average initial weight 312 kg). Four to six, sampling points were located randomly in each paddock at each date. Sward height was measured with a ruler, the vegetation in a 0.2 nr area visually designated “high” or “low” according to legume percentage, ten readings using a single capacitance probe were made and the herbage clipped. Paired data with clipped dry weight as dependent variable and height and/or the average corrected probe reading as covariates were analyzed statistically. The relationship between clipped dry weight and nondestructive measures of herbage mass was found to be linear. There was a small effect of sampling date in Spring on the relationship between destructive and non‐destructive measures of herbage mass, but each of the measures, including herbage mass predicted from probe and height measurements, resulted in the same inferences being made about differences between treatments. Neither stocking rate nor small differences in percentage legume affected the relationship. Thus, sward height and capacitance probe show promise as nondestructive measures of pasture

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00808.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of seed size on germination and seedling growth was assessed using cultivars of greengram and blackgram. Significant positive correlation was noticed between seed size and germination, seedling height, root length, primary leaf size and seedling weight. The possible advantages of choosing cultivars with heavier seeds for attaining better crop stand especially under rainfed situation are discussed.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00809.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY