摘要:

AbstractDifferences in gas exchange parameters i.e. carbon exchange rate (CER), transpiration (Tr), water vapor conductance (g) were investigated, under a controlled environment, in a semi‐dwarf (SD)Triticum aestivumline, its tall (TL) near isoline and the Payne (PA) variety characterized by small leaves. The plants were maintained in: (a) optimal substrate moisture condition (CTR); (b) salinized by watering with a 0.12 m NaCl solution (SLT); (c) water stressed by withholding waterings during a period of six days (STR); (d) stressed and salinized during the same period and with the same saline solution (S + S). CER and Tr were negatively affected by the stresses; SLT and S + S treatments had a higher WUE compared to their respective controls CTR and STR.SD line had a better performance in terms of CER and WUE, particularly when water and salt stresses interacted. Leaf anatomy and assimilation/internal CO2concentration curves contributed to explaining the SD performanc

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00877.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractInvestigations into the effect of location, planting density, N‐fertilization, variety and harvest date on yield and contents of sweet sorghumLooking for high yielding plant species as renewable resources, sweet sorghum (Sorghum bicolor[L.] Moench) seems to be an interesting crop.In field trials at three locations in the south‐west of Germany in 1983 and 1984 should be investigated the effect of N‐fertilization, planting density, variety and harvest date on yield, different morphological characteristics and contents of sweet sorghum.The results indicate that yields of 15‐20 t DM/ha are only feasible when the given temperature sum is higher than 2000 °C (>5°C). The maximum yield of 22.7 t DM/ha resp. 6.5 t/ha “Free Fermentable Sugar” (FFZ) was realized when a sufficient water supply and N‐fertilization had been guaranteed.The different possibilities of utilization of sweet sorghum e.g. as sugar crop, agricultural raw material for combustion or as forage crop urge the plant breeder to intensify the breeding efforts adapting this crop at the climatic condit

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00878.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractResearch is needed to characterize the crop response to soil water deficit through plant parameters. Leaf water potential (LWP), canopy temperature (CT) and transpiration rate (TR) served as indicators of stress and were measured using a pressure chamber, infrared thermometer and porometer, respectively, in irrigated and nonirrigated wheat (Triticum aestivumL.) grown on Haldi loam soil. Nonirrigated wheat had consistently higher CT and, lower LWP and TR during the day. As drought intensified, differences between irrigated and nonirrigated wheat became large and the maximum differences in CT, LWP and TR occurred at 14.00 h where they equalled 3.8 °C, 9 bar and 7.6 μg cm−2:sec−1, respectively, on 109 days after sowing (DAS). In nonirrigated wheat LWP declined at a faster rate until the peak stress period (14.00 h) approached and recovered slowly in the later afternoon and TR increased slowly in the forenoon and declined rapidly in the afternoon as compared with irrigated wheat. Canopy temperature (CT) of nonirrigated plants increased earlier during forenoon and remained higher later in the afternoon than CT of irrigated plants. At a same TR, lower values of LWP and higher values of CT were observed in the afternoon than in the forenoon due to which the phenomenon of hysteresis exhibited. The degree of hysteresis increased with increasing plant water deficit and cro

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00879.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractRooting patterns, biomass production, tillering, and yield formation of four winter wheat cultivars in a low external input systemGrowth conditions of winter wheat in agricultural low external input systems, e.g. ecological agriculture differ from those in conventional agriculture with regard to nutrient flow, impact of diseases, and weed competition. Knowledge of the dynamics of yield formation of winter wheat cultivars is very important for further development of such systems. During two growing seasons root growth, above ground biomass production, tillering, and yield formation were studied with four winter wheat cultivars of different periods of release at two ecologically managed farms in Northern Hessia. The results can be summarized as follows:– In general, plant breeding did not lead to a reduced development of root systems or above ground biomass production in winter wheat (Stöppleret al. 1989 a). Modern wheat varieties develop an extensive root system in greater depth, which means better drought resistance.– Not only root length densities, total root length, characteristics of tillering, and yield formation showed clear genotypic differences between the winter wheat cultivars, but also the development of root systems and above ground biomass production.– Winter wheat cultivars with a high plant density seem to have a retarded root growth after tillering due to intra‐plant‐competition and late root growth during grain filling, whereas cultivars with a high ear weight develop an extensive root system before the grain filling period. At the beginning of this period, a great root length per culm seems to be most important to achieve a high ear weight. The results indicate that those cultivars with poor to medium tillering and high ear weight are very well adapted to the reduced nutrient flow in low external input systems of farming.–In low external input systems, a satisfactory wheat crop need be established befo

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00880.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPot experiments were conducted on mung bean by spraying 500, 1000 and 1500 ppm CCC, 14 days after the emergence of seedlings. Results showed that:CCC application at 1000 and 1500 ppm led to stem shortening.Dry weight of shoot system, leaf area, leaf thickness and total chlorophyll content were significantly increased by 1000 ppm CCC.CCC at 1000 ppm increased amylase and invertase activity in the leaf tissue.CCC at 1000 ppm increased the pod number/plant, seed number/pod, leading to increased seed yield/plant.CCC had no effect on the 1000 seed weight.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00881.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractIn the very large areas of arid highlands in West Asia, of which land over 1000 m in Balochistan is typical, as a result of rapidly increasing numbers of small ruminants and subsequent overgrazing of natural rangelands, severe shortages in animal feed are being experienced. To address this problem the And Zone Research Institute (AZRI) have been evaluating annual forage legume germplasm for adaptability to the harsh climatic conditions of highland Balochistan. Due to the marginality of the environment for sustained crop production an unconventional germplasm evaluation strategy has been adopted which emphasizes the introduction of landraces, particularly of the genusVicia.The substantial risk of crop failure from either cold or drought, in any year, makes continuity of seed supply of selected lines a major problem. Support from ICARDA in Syria for re‐supply of seed is a major advantage to the AZRI program.In the last three years some tangible progress has been made in selection.V. villosassp.dasycarpaAce. 683 has with autumn sowing shown sufficient cold tolerance and is highly productive in wet years.V. erviliaAce. 2542 has shown some potential for drought tolerance which could be exploited for spring sowin

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00882.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA field experiment was conducted to evaluate the performance of pasture legumes (Desmanthus virgatus, Sesbania aegyptica, Macroptelmm autropurpureum, Desmodium tortuosum, Stylosanthes hamataused as in intercropped element) in terms of nitrogen economy, seed production efficiency and seed vigour potential ofPanicum maximum– a grass based management maintained for 1986–88 at Research Farm, Indian Grassland and Fodder Research Institute, Jhansi under rainfed condition. Nitrogen economy under these intercropped pasture legumes was estimated on equating its value against nitrogen treatment i.e. 0, 10, 20, 30 and 40 kg N/ha. Among five intercropped legumes,Stylosanthes hamataandMacroptelium autropurpureumintercropping doubled the seed yield;S. aegypticaandM. autropurpureumbrought out 46–55 per cent increase in biomass production over control value of 41.7 kg seed and 223.4 q biomass/ha respectively. These treatment showed 20–40 kg N/ha nitrogen equivalent value. Further more increased seed yield ofPanicum maximumunder intercropping was attributed to its better ear production, spike length and potential sink strength. Germination potential of harvestedPanicumseeds under different treatments did not show variation among themselves. Potential seed production performance ofPanicum maximumin the first year as compared to subsequent years might be due to its general transcript of plants and have some interaction with r

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00883.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThis study was undertaken to measure the effect of water stress on yield and yield components in guar(Cyamopsis tetragonoloba[L.] Taub.) grown under water‐stressed and water‐optimal field conditions. Fifteen guar germplasms were grown in irrigated and dryland tests at Lubbock, TX on an Amarillo loam (fine‐loamy, mixed thermic Aridic Paleustoll). Plants in each germplasm were hand harvested at maturity and data recorded for number of racemes/plant, pods/plant, seeds/pod, weight/100 seeds and g/seed/plant. We found differences among germplasms for yield components under both dryland and irrigated conditions. Germ‐plasms responded statistically the same in both moisture levels. Among three pre‐selected cultivars, water use efficiency did not differ statistically. Our analyses indicated that the component of yield most affected by water stress was number of pods/plant. Seed weight, seeds/pod, and racemes/plant each had progressively smaller effects on s

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00884.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractWe introduce a method to measure leaf area from plant leaves using a personal computer, and a handy scanner with corresponding software. Measurement of standard areas revealed a very high correlation (r = 0.999) between the number of measured pixel (1540 pixel/cm2) and the tested areas. Comparisons of scanner derived measurements with those from a standard area meter instrument revealed a high correlation (r = 0.998). Our method is a cheap and efficient alternative to the conventional area meters and can also replace more laborious ‘home‐made’ methods of measuring plant leaf

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00885.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Books Reviewed in this Article:Kranz, R.: Wie finde ich Literatur zu den Landbauwissenschaften(How to find literature on agriculture).Gliessman, S. R. (ed.): Agroecology, Researching the Ecological Basis for Sustainable AgricultureHugger, H.: Sonnenblumen. Züchtung – Anbau, Verarbeit

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00886.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY