Agronomy and Crop Sciences Commons^™

Regulating Grass And Clover Growth With Mefludide, R J. Haggar, S P. Isaac

IGC Proceedings (1977-2023)

A three-year study on the use of mefluidide, a plant growth regulator, for suppressing seed-head production in a range of grass is reported. The first stage, involving the evaluation of a range of does and timings on up to nine grass species, indicated the potential of mefluidide applied at 150 g ha-1 in early spring to prevent the normal decline in herbage quality associated with flowering and to transfer growth from spring to mid-summer, albeit at a loss of some 30% in total dry-matter production. A supplementary investigation showed that white clover was reasonably tolerant to mefluidide treatment although a …

Photosynthetic Recovery And Regrowth Of Aeschynomene Americana And Hemarthria Altissima Swards After Defoliation, K A. Albrecht, K J. Boote

IGC Proceedings (1977-2023)

An experiment was desined to study regrowth characteristics of aeshynomene (Aeschynomene americana) and hemarthria (Hemarthria altissima) swards after defoliation. Leaf area index (LAI), light interception, and canopy carbon exchange rate (CER) were measured over an eight week period of regrowth in aeschynomene and hemarthria swards cut to 9 or 18 cm. Virtually all leaves were removed by cutting aeschynomene to either height. Regrowth and recovery of photosynthetic activity commenced rapidly in the 18 cm treatment because of leaf and branch growth from remaining axillart buds. Cutting at 9 cm resulted in delayed regrowth and photosynthetic recovery. …

Nonstructural Carbohydrate Storage And Snow Endurance In Winter Annual Forage Crops, Y Tamura

IGC Proceedings (1977-2023)

An experiment was carried out to clarify the relationships of growth characteristics and nonstructural carbohydrate (NSC) storages in relation to snow endurance in winter annual forage crops. Twenty one varieties of oats, barley and rye differing in snow endurance were sown in the fall of 1982 in the experimental field at Hokuriku Natl. Agri. Expt. Stn. Dry matter weights and concentrations and compositions of NSC were measured before snow fall. Dry matter weight of roots was in the same order as snow endurance among the three species while no significant differences were observed in those of tops among them. Roots …

Preliminary Study On The Effect Of Spraying Myricyl Alchohol (1-Hydroxyriacontane, N-Triacontanol) Upon Chinese Wildrye, Wang Yulin, Luo Xinyi, Chai Feng0jiu

IGC Proceedings (1977-2023)

The objective of this experiment was to determine the effect of different concentration, amount and spraying times of the plant growth hormone on Chinese Wildrye production, with the orthogonal comparison. It has been found by the orthogonal analysis that fresh yield per mu mas increased by 11.92%, 12.95%; 17.34%, 7.5%; 11.11%, 13.17%; in the treatment of solution concentration of 0.1 ppm, 0.05ppm; spraying times of 1, 2; solution amount of 10 kg, 20 kg per mu, as compared with that control trial (225.3 kg per mu of fresh yield), respectively. The treatment of concentration of 0.05 ppm, spraying times of …

Nutritio-Physiological Evaluation Of Drought Resistance Of Warm Season Forage Crops, S Ogata, H Saneoka, K Matsumoto

IGC Proceedings (1977-2023)

This study was conducted to evaluate the mechanisms of drought resistence of several warm season forage crops . Plants were grown both in field and greenhouse and subjected to sequences to water stress. During experiment, dry matter yield, leaf water potential('V), stomata[ resistance(rs), apparent photosynthesis (P0), transpiration rate(T), root distribution in stressed soil and nutrient uptake were measured. Ratio of dry matter yield of each plant on non-irrigated field to that of the maximum growth obtained by the most suitable watering were higher as follows: Dallisgrass > Rhodesgrass=Bahiagrass >Sorghum> Corn> African millet> Job's tears. 'V of all plants was decreased by …

Transpiration Intensity Of Alfalfa And Its Effect In Yield, Xu Ling-Ren, Lin Bai-He, Wang Jian-Guang

IGC Proceedings (1977-2023)

We observed that the alfalfa appears diurnal fluctuation of transpiration very clearly by in its flower initial stage. They always appear two transpiration peaks in the morning and afternoon, respectively. In the fruiting stage as well as in flowering stage, the diurnal fluctation of alfalfa was lesser with smaller transpiration retes. Both of the diurnal fluctuations in the two stages are strongly affected by the leaf temperature. In the flower initial stage, from 5:30 to 9:30 a.m., the transpiration rate increases with the increase of leaf temperature. After 9:30, while the transpiration drops down rapidly, till afternoon 16:30 p.m. the …

Improved Efficiency Of Plant Regeneration From Smooth Bromegrass (Bromus Inermis) Suspension Culture, T H. Chen, J Marowitch

IGC Proceedings (1977-2023)

Smooth bromegrass, Bromus inermis Leyss, is the most important forage grass in Canada. Breeding for improvements such as higher yield and faster regrowth has made little progress, mainly due to the polyploidy and cross-pollination which are characteristic of this grass. The application of tissue culture methods to bromegrass improvement holds promise only if an efficient procedure for plant regeneration is found. Various basal culture media and auxins were tested for their effects on callus induction, growth of suspension cultures and plant regeneration. None of the tested auxins gave better in vitro growth than 2,4-D. Eriksson's medium with 2,4-D as the …

Effects Of Mefluidide On Vegetative Growth And Root Production Of Forage Sorhum, A G. Matches, A Martinez, C R. Richardson

IGC Proceedings (1977-2023)

Forage sorghums (Sorghum bicolor) provide high-quality pasture during the summer, but because of their rapid rate of growth quickly become mature and unacceptable for grazing. Maintaining their growth in a more juvenile stage could be expected to improve forage quality and utilization by livestock. Our objectives were to determine the effects of the plant growth regulator meflidide (N-[2,4-dimethy-5-[[(trifluoromethyl) sulfony]amino]phenyl] acetamide) on vegetative growth and root production of a hybrid forage sorghum. In two greenhouse experiments different rates of mefluidide (0, 0.035, 0.07, 0.14 and 0.28 kg/ha) were applied to 'Dekalb ST6+ ' hybrid forage sorghums and plant responses …

Effects Of Flooding On The Metabolism Of Red Clover (Trifolium Pratense) And Bromegrass (Bromus Inermis), Seppo Pulli, Jaana Vaisanen

IGC Proceedings (1977-2023)

Two months old red clover and bromegrass stands were tested for flooding behaviour. Experimental design simulated the environmental conditions of summer, early and late autumn. Stands with normal watering and in anoxia had daylength and temperature conditions of+ 18°C/16 h, + l0°C/12 h and +4°C/8 h during the first, second and third week. Plants were analyzed at the end of each period. In anoxia the peak of ADH-activity of both species was reached at + l0°C/12 h representing the most hermful conditions predominantly for red clover survival. During the hardening period ( +4°C/8 h) the ADH-activity of roots of both …

Mechanisum Of Aluminum Tolerance In Sericea Lespedeza, R E. Joost, C S. Hoveland

IGC Proceedings (1977-2023)

Sericea lespedeza (Lespedeza cuneata) is a warm-season perennial legume tolerant of aluminum (Al) in acid soils. This study was designed to ascertain the mechanism of Al-tolerance in sericea lespedeza. The mechanism of Al-tolerance in sericea was investigated through tissue analysis, rhizosphere pH measurement, and examination of Al distribution using energy dispersive spectrophotometry (EDS) in conjunction with scanning electron microscopy (SEM). Sericea was found to exclude Al from its herbage three times better alfalfa (Medicago sativa), but seedlings reduced pH in their rhizosphere. EDS scans of root tissue embedded in scid soil indicated that Al was accumulated in or …

Patterns Of Tillering And Tiller Bud Development Of Some Temperate Herbage Grasses Under Different Light Intensities, M Ito, Y Tsubota, S Nakayama

IGC Proceedings (1977-2023)

The tiller and tiller bud development in young seedlings of orchardgrass (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.) and reed canarygrass (Phalaris arundinacea L.)were studied anatom­ically. Regular appearance of successive leaves on main shoot and emerged primary tillers were observed in grasses grown under both normal (30,000 lux) and reduced (6,000 lux) light intensities. The leaves expanding simultaneously on different shoots developed analogously. These growth habits in tillering and leaf production were well supported by Katayama's concept on tillering systems in cereals such as rice plant, wheat and barley. The visible synchronization in appearance of …

Effect Of Vernalization And Stem Elongation On Production Physiology Of Lolium Perenne, B Deinum

IGC Proceedings (1977-2023)

In order to study the production potential of vernalized, leafy grass, vernalized cultivars of Lolium perenne were grown at different photoperiods and compared with non-vernalized plants. After vernalization stem elongation was greatly accelerated by long days and occurred later in later-heading cultivars. Late cultivars hardly showed any stem elongation in short days, if at all. Total dry-matter production (herbage above 5 cm + stubble + roots) of stemmy and leafy vernalized grass was much higher than that of non-vernalized grass. The stemmy crops allocated much dry matter in herbage and little in stubble, roots and tillers, whereas the leafy …

Branching Geometry And Effective Leaf Area Of Spreading Herbs, The Crabgrass And The Korean Lawn, G S. Kim, N K. Chang

IGC Proceedings (1977-2023)

An attempt was made to study the terminal branching patterns, and maximizing effective spreading stems and leaf surface area of herbs such as crabgrass, Digitaria sanguinalis and Korean lawn, Zoysia japonica. Two dimensional positions of the end-points of the branches could be calculated using branching angle and relative ratio of the branch lenghts. The branching angles and the relative ratio of the branch lenghts were well fitted to analyze effects on the whole canopy structures of herbaceous individuals and communities. The branching pattern and leaf cluster for maximum effective leaf area, and maximum interception and absorption of sunlight were interpreted …

The Regulation Of Winter Growth Of Temperate Pasture Grasses, D R. Kemp

IGC Proceedings (1977-2023)

Temperate pasture grass growth rates are lowest in winter and limit the number of stock that can be carried through the year on many farms. Field studies of the regulation of pasture growth in winter showed that the earlier a grass intiates reproductive development the greater is the mean pasture growth rate through winter. A 5 to 10 fold variation in winter growth rates between a range of genera and ecotypes was simply related to the time of onset of reproductive development. Prospects for improving winter pasture growth by selecting for early flowering outlined.

Italian Ryegrass Response To Allelopathic Effects Of Stubble-Residues From Several Tropical Grasses, Y Takahashi, S Uozumi, S Ono, Y Yoden

IGC Proceedings (1977-2023)

The laboratory experiments with aqueous extracts of 11 tropical grass stubble-residues allowed an examination of the allelopathic effects of the extracts on seed germination and early growth of Italian ryegrass (Lolium multiflorum, cv. Minamiwase, Abbr. as IRG). Germination of IRG was generally found to be reduced with an increase in concentration of the residue extracts. Extracts of African millet (Eleusine coracana), Guinea grass (Panicum maximum, strain GR-171) and setaria (Setaria anceps, cv. Nandi and Kazungula) were very inhibitory to the germination of IRG at a high concentration (4g dried stubble/lOOml) ; whereas …

Relationship Between Germination Tests And Field Emergence Of Perennial Warm-Season Forage Grasses, F H. Hsu, C J. Nelson

IGC Proceedings (1977-2023)

Perennial warm-season forage grasses can be valuable components of forage systems to improve animal performance in summer, but they are difficult to get established. Therefore, two germination tests and two field experiments were conducted to determine relationships between seed germination and field emergence. Chilled and unchilled seed of big bluestem (Andropogon gerardi Vitman), caucasian bluestem ( Bothriochloa caocasica (Prin.) C. E. Hubb.), indiangrass ( Sorghastrum nutans (L.) Nash.), and switchgrass (Panicum virgatum L.) were germinated at different temperatures. Unchilled seed were planted in the field near Columbia, MO., at approximately 2-week intervals from early April to late June in …

Rooting Patterns Of Alfalfa Under Three Irrigation Treatments, D G. Lugg, A S. Abdeul-Jabbar, T W. Sammis

IGC Proceedings (1977-2023)

The research was undertaken to determine the effect of irrigation treatment on rooting patterns of alfalfa (Medicago sativa L.) over a two-year period. The experiment was conducted in.a clay loam soil at Las Cruces, New Mexico. Irrigation water was applied using a line source sprinkler system which provides a gradient of water application, and evapotranspiration (ET) was calculated from irrigation, rainfall and soil moisture data using the water balance method. Measurements were made at three locations on the gradient. Soil was sampled, using a soil tube of 7.8 cm inside diameter, in 15 cm increments to a depth in the …

Cotyledon And Leaf Development Associated With Seedling Vigor Of Six Forage Legumes, S N. Hur, C J. Nelson

IGC Proceedings (1977-2023)

Cotyledon and leaf development of six important forge legumes were compared to study their contribution to the seedling growth. Cotyledons of forage legumes expanded their size rapidly during one week after emergence, then slightly expanded until maximum size was reached and entered senescence. Larger seeds produced greater cotyledon area and speed of cotyledon expansion was closely associated with seedling growth. Earlier onset of leaf production and earlier leaf development were major determining factors for initial seedling growth. Alfalfa and red clover which have larger seeds were good in seedling vigor with larger photosynthetic area. Alsike clover and white clover with …

Effect Of Cytokinin On Lateral Bud Development In Regrowth Of Sorghum Bicolor M., H Nojima, H Oizumi, Y Takasaki

IGC Proceedings (1977-2023)

The effect of cytokinin on regrowth of Sorghum bicolor M. were examined. To determine the effect of applied cytokinin on growth of lateral buds, the lowest 10 cm portion of stems containing 6 visible lateral buds were used. The explants were cultured in the solutions of concentration of 1.0 to 15 .0 ppm cytokinin ( 6-benzyladenoprine riboside). In another, experiment, the endogenous cytokinin levels were analysed during regrowth period, using the plants grown under the shaded and non-shaded condition ( control). The length of lataral bud was the longest at the optimum cytokinin concentration of 5 ppm. The endogenous cytokinin …

Phlein Degradation In Stem Bases Of Temperature Grasses After Defoliation, Shinro Yamamoto, Yosuke Mino

IGC Proceedings (1977-2023)

The mechanism of phlein degradation in the stem bases following defoliation was studied using timothy, orchardgrass, tall fescue and Italian ryegrass. The phleinase(phlein hydrolyzing enzyme) was induced in the stem bases of all these grasses after defoliation, and the variation patterns of the activity varied with the grass species. The activity was inversely related to the phlein concentration, suggesting that the phleinase is involved in the degradation of phlein in all these grasses. The variation pattern of phleinase in orchardgrass was almost the same under different growth conditions, while that was amplified with high temperature, long day condition or N …

Winter Injury Of Alfalfa (Medicago Sativa L.) In Soil Freezing Area Of Japan, T Komatsu, J Maruyama, Y Horikawa, F Tsuchiya

IGC Proceedings (1977-2023)

In spite of the importance of alfalfa for dairy cattle, the cultivation of alfalfa is not yet expanded in eastern Hokkaido, Japan. A combined research project has been carried out, based on (1) observation of winter injury in 130 fields all over the Tokachi district from 1981 to 1983 and (2) observation of the influence of controlled snow depth during the winter 1983-1984 on regrowth of alfalfa. Tokachi was divided into three areas according to the type of winter injury, the depth of snow cover and the depth of soil frost. Both the depth of snow cover and the depth …

Relation Of Non-Structural Carbohydrate Concentration In Autumn To Wintering Ability Of Several Tropical Grasses In Southern Kyushu, K Ito, H Numaguchi, M Inosaka

IGC Proceedings (1977-2023)

In connection with the wintering ability of some tropical grasses, the relation between their growth habits in autumn and accumulation of non-structural carbohydrate (NSC) in stem during winter was examined. Seven species of tropical grasses were grown at the experimental field of Miyazaki University during 1980-1981. They were defoliated every 20th day from early summer until autumn. Tiller number and dry weight per tiller were detemined at each time of defoliation. NSC was estimated from autumn to winter. For the evaluation of regrowth following cool season, photosynthetic capacity of plant population just before the first frost and that on the …

Effect Of Drought On Leaf Senescence And Forage Quality Of Three Temperate Grasses, S Bittman, G M. Simpson, Z Mir

IGC Proceedings (1977-2023)

This study was conducted to compare the effect of a period of drought on leaf senescence, protein yield and P concentration in smooth bromegrass (Bromus inermis Leyss.) (Br), crested wheatgrass (Agropyron cristatum (L.) Gaertn. spp. pectinatum (Bieb.) Tzvel.) (CW g) and Altai wildrye (Leymus angustatus (Trin.) Pilger) (Awr ). Susceptibility to drought in terms of leaf water potential, senescence, and nutritive quality, was greatest in CWg, intermediate in Br, and least in A Wr. Drought induced less sencence in vegetative than in floral tillers in CW g and Br; the ability of A Wr to maintain its quality …

Flowering And Seed Production Of Macroptilum Atropurpureum Cv. Siratro As Influenced By Water Stress, L Kowithayakorn, L R. Humphreys

IGC Proceedings (1977-2023)

Siratro (Macroptilium atropurpureum) was grown in soil beds with a controlled water table in the glasshouse, or in the field at Khon Kaen, northeast Thailand. A gradient in leaf water potential (L WP) was evident as water stress developed, the youngest leaves exhibiting lower L WP than older leaves bearing pods. But density was reduced during the drying phase to -10 or -15 bar, but showed a persistent increase for up to 8 weeks following rewatering relative to plants having a constant water table. The ratio of floral to total buds was independent of treatment. Inflorescence density exerted the …

The Effect Of Moisture Stress On Mimosine Content Of Leucaena Leucocephala, R A. Bray, Jan Hoekstra

IGC Proceedings (1977-2023)

To investigate the effect of moisture stress on mimosine contect in Leucaena Leucocephala, seedlings of cv. K8 were grown in pots in a glasshouse. One set was watered to field capacity, and another watered to just above wilting, and harvested after 6, 9, 12, or 14 days stress. Moisture stress increased mimosine content dramatically, both in newly expanded and in older leaves. Mimosine content in stressed leaves remained relatively content with age (in contrast to leaves of control plants), providing another possible example of slower ageing due to moisture stress. Because of the close relationship between leaf age and mimosine …

Soil And Plant Water Relations On A Wooded Grassland In Kenya, M J. Trlica, R D. Child, E K. Maranga

IGC Proceedings (1977-2023)

Field studies of soil and plant water potential as related to transpiration losses of water from grass and shrub species were conducted through a wet and dry season on a wooded grassland in Kenya. Seasonal patterns of leaf conductance and transpiration indicated that deep rooted shrubs utilized more water per unit leaf area than did the dominant grass Digitaria macroblephara. Several shrub species continued to transpire water throughout most of the dry season. Shrub use of deep soil water resources, combined with selective grazing of grasses, may help explain why shrub encroachment into grasslands within Kenya has become a …

Adaptive Co2 Fixation And Nitrate Assimilation In Portulaca Oleracea, N K. Chang, H B. Kim

IGC Proceedings (1977-2023)

The intercellular relationships between leaves and stems for pathways of CO2 and nitrate assimilation were investigated in Portulaca oleracea growing under the natural environmental conditions. The number of stomata was 3,275cm-2 in leaves, while the stomata could not be observed in stems. Stomata! resistance in leaves of the young purslane was high at night and low in daytime. The difference between the highest and the lowest acidity was the greatest at the 2nd node of the intact plant. The order of the node having the highest acidity was changed as the leaves were detached from the top to the bottom. …

Characteristics Of Photosynthesis, Transpiration And Water Use Efficiency Of C3 And C4 Grass Leaves, W Agata, Y Kawamitsu, S Hakoyama, P B. Kaufman

IGC Proceedings (1977-2023)

Characteristics of photosynthesis and transpiration were examined with attached leaves of eight C3 and fourteen C4 grasses under different light conditions. On the basis of these data, water use efficiency, leaf conductance and intercellular CO2 concentration were also calculated. Light saturation point and maximum photosynthetic rate of C4 grasses were higher than those of½ grasses. The light response curve of transpiration was similar in both grasses. However, the values of C3 grasses were higher than those of C4 grasses at a broad range of light intensity. Water use efficiency of both grasses increased rapidly with increasing in light intensity till …

A Measurement Of The Sap-Flow Velocity Using The Heat Pulse Method In Several Forage Crops, K Tateno

IGC Proceedings (1977-2023)

This paper reports a heat pulse method for measuring water flux in the stem and its application to investigation of plant-water relationships in Japanese millet (Echinochloa utilis Ohwi et Yabuno), sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.).

1). The velocity of sap-flow in the stem, evaluated by the heat pulse method, was closely ralated to the water loss due to transpiration measured in weight units. Linear relationships and positive correlations were observed in all species between sap-flow velocity and transpiration rates.

2). Japanese millet had similar pattern in the diurnal courses of the sap-flow …

The Response Of Photosynthesis In Digitaria Eriantha (Steud) Subsp. Eriantha To The Application Of Different Forms And Concentrations Of Nitrogen, M M. Wolfson, C F. Cresswell

IGC Proceedings (1977-2023)

Digitaria eriantha (Steud) subsp. eriantha plants were grown under controlled conditions and treated with different forms and concentrations of nitrogen in order to determine its effect on photosynthetic activity. Single leaf and whole plant net photosythetic rates were meaured and appeared to vary according to the units in which the activity was expressed. Although single leaf photosynthesis was measured on young leaves, near the meristematic tip, the rates had decreased to very low levels by the fourth of month of treatment, irrespective of the mode of expression used. A similar trend was observed when the whole plant net photosythetic rates …