The pathogenicity of Fusarium avenaceum to wheat and legumes and its association with crop rotations

1974 ◽  
Vol 14 (69) ◽  
pp. 572 ◽  
Author(s):  
JF Kollmorgen
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Crop Rotations ◽  
Fusarium Avenaceum ◽  
Wheat Roots ◽  
Barrel Medic ◽  
Wheat Pasture ◽  
Wheat Stubble ◽  
First Time

Studies were made of the pathogenicity of Fusarium avenaceum (Fr.) Sacc. to wheat (Triticum aestivum), subterranean clover (Trifolium subterraneum) and barrel medic (Medicago truncatula var. truncatula), and of the effects of crop rotation on field populations of the fungus. F. avenaceum reduced emergence and dry weight of wheat, subterranean clover, and barrel medic seedlings. Infection reduced the height of both legumes but not the height or yield of wheat. The fungus caused a greater reduction in dry weight and height in barrel medic than in subterranean clover. Barrel medic is recorded as a host of F. avenaceum for the first time. The fungus was isolated from the roots of seedlings and from 0.3 per cent of a commercial seed sample. When this infected seed was sown in wheat stubble in crop rotations of fallow-wheat (stubble burnt), fallow-wheat and fallow-wheat-pasture-pasture its incidence in seed increased to 5.2, 6.0 and 10 per cent, respectively Studies on the effects of rotations on the incidence of F. avenaceum in wheat roots and wheat soil demonstrated a relation between crop sequence and population levels of the fungus. F. avenaceum was more prevalent in fallow-wheat-pasture than fallow-wheat.

The influence of seed size and depth of sowing on pre-emergence and early vegetative growth of subterranean clover (Trifolium subterraneum L.)

1956 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
JN Black
Keyword(s):  
Leaf Area ◽  
Seed Size ◽  
Vegetative Growth ◽  
Dry Matter ◽  
Relative Rate ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Total Leaf Area ◽  
Pot Culture

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.

Defoliation as a factor in the growth of varieties of subterranean clover (Trifolium subterraneum L) when grown in pure and mixed swards

1963 ◽  
Vol 14 (2) ◽  
pp. 206 ◽  
Author(s):  
JN Black
Keyword(s):  
Agricultural Research ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Light Energy ◽  
Weight Changes ◽  
Agricultural Research Institute ◽  
Large Seed ◽  
Waite Agricultural Research Institute ◽  
High Yielding Varieties

This paper describes two experiments analysing the recovery from defoliation of subterranean clover varieties grown in swards in large seed boxes at the Waite Agricultural Research Institute, Adelaide. The first experiment examined the way in which the six common commercial varieties recovered from a single severe defoliation, and showed that under these conditions they can be placed in three groups: Yarloop and Clare are tall, high-yielding varieties with few, large leaves, recovering slowly from defoliation; Tallarook and Dwalganup are prostrate varieties, lower-yielding, with many small leaves, recovering rapidly after defoliation; Bacchus Marsh and Mount Barker are intermediate in all respects. In the second experiment mixed swards of equal numbers of Yarloop and Tallarook plants were grown under three treatments: A, no defoliation; B, defoliated twice at a height which removed the higher Yarloop canopy but left the lower Tallarook plants untouched; C, defoliated twice at a height which removed the canopies of both varieties. Measurement of dry weight on four occasions after each defoliation showed that in the undefoliated treatment, all Tallarook plants died by the end of the experiment. In the defoliated treatments, the removal of the Yarloop canopy resulted in only a temporary improvement in the illuniination in which the Tallarook plants grew, and their dry weight and plant numbers progressively declined. Dry weight changes in the Tallarook component were shown to be dependent on the light energy available to it, which was in turn determined by the light-absorbing capacity of the superior Yarloop canopy. In mixed swards, the ability of Yarloop to re-establish quickly a leaf canopy above that of Tallarook appeared to explain its success when defoliated.

The significance of petiole length, leaf area, and light interception in competition between strains of subterrranean clover (Trifolium subterraneum L.) grown in swards

1960 ◽  
Vol 11 (3) ◽  
pp. 277 ◽  
Author(s):  
JN Black
Keyword(s):  
Leaf Area ◽  
Leaf Development ◽  
Plant Competition ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Sampling Period ◽  
Dry Weight ◽  
Petiole Length ◽  
Petiole Elongation ◽  
Light Profiles

Three strains of subterranean clover differing in leaf development were grown in pure swards and in all combinations in mixtures. The strain Yarloop has relatively few large leaves held on long petioles; Tallarook has many small leaves and short petioles; Bacchus Marsh is intermediate in all these respects. The swards were grown in boxes and were sampled on four occasions during the period of vegetative growth. Leaf area in each 2 cm layer of the sward was determined separately, and for both strains in the mixed swards, and measurements of the light intensity reaching each layer were obtained. Root weights were determined for all swards and separately for each component of the mixed swards. Examination of the dry weights showed that the growth of the strain having the lesser petiole elongation was suppressed. In the extreme instance Tallarook was so suppressed when grown with Yarloop that in the final inter-sampling period it grew completely in the dark, and lost about half its dry weight. Bacchus Marsh also suppressed Tallarook, but to a lesser extent, while Bacchus Marsh was itself suppressed in competition with Yarloop. The amount of light energy intercepted by the two components of the mixed swards was calculated from the leaf area and light profiles, and confirmed the importance of the spatial distribution of leaves in plant competition. It was concluded that, in the absence of defoliation, the success of a strain under competition was associated with its potential petiole elongation.

Infection of seed of subterranean clover and allied species by species of Fusarium

1980 ◽  
Vol 31 (2) ◽  
pp. 297 ◽  
Author(s):  
AW Kellock ◽  
LL Stubbs ◽  
DG Parbery
Keyword(s):  
Root Rot ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Scar Tissue ◽  
Seed Infection ◽  
Fusarium Spp ◽  
Blotting Paper ◽  
Optical Brighteners ◽  
First Time ◽  
Healthy Seed

Fusarium avenaceurn (Corda ex Fr.) Sacc. was shown for the first time to be carried in the hilum of subterranean clover (Trifolium Subterraneum L.) seed. Scanning electron microscopy and thin-section techniques showed that the fungus occurred only as dormant mycelium in parenchyma cells of funicle scar tissue. It emerged from these tissues after a 12 h incubation at 24�C and in 48 h penetrated internal parts of the seed through the hilum fissure. After 21 days on moist blotting paper, seedlings grown from infected seed developed lesions on their roots similar to those of root-rot of subterranean clover in the field. Fusarium spp. were also detected in the hilum of seeds of white (T. repens L.) and strawberry (T. fragiferum L.) clover and barrel medic (M. truncatula L.). It was demonstrated experimentally that all parts of the burr, incl~tding the funicle, became infected with F. avenaceuni when subterranean clover plants grown from healthy seed in pasteurized soil buried their burrs in soil inoculated with the fungus. Use of optical brighteners failed to trace seed infection because the compounds, although absorbed by the pathogen in culture, were not translocated.

Subterranean clover mottle virus infection of subterranean clover: widespread occurrence in pastures and effects on productivity

1992 ◽  
Vol 43 (7) ◽  
pp. 1597 ◽  
Author(s):  
JM Wroth ◽  
RAC Jones
Keyword(s):  
Systemic Infection ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Seed Transmission ◽  
Dry Weight ◽  
Widespread Occurrence ◽  
Transmission Rates ◽  
Type Isolate ◽  
Growing Seasons ◽  
South West

In 1989 and 1990, infection with subterranean clover mottle sobemovirus (SCMV) was widespread in subterranean clover ( Trifolium subterraneum L.) pastures in the south-west of Western Australia. The virus was detected in 61% of the pastures sampled and incidences of infection ranged from 1 to 50%. The virus was more common in old pastures than in pastures resown with newer cultivars during the preceeding 5 year period. When 12 isolates of SCMV were inoculated to subterranean clover plants grown in the glasshouse, symptoms varied from mild to severe. SCMV isolates P23 and F4 decreased the herbage dry weight of cw. Daliak and Woogenellup grown in plots as spaced plants by 81-88% while the Type isolate caused losses of 92%. By contrast, losses were 37-49% with cv. Karridale, a cultivar in which systemic infection was either delayed or prevented during winter. Infection decreased seed yield by c. 90% in cvv. Karridale and Woogenellup with all three isolates; seed weight was decreased 21-55%. A small proportion of cv. Woogenellup transplants outgrew the infection in new shoots during late spring to produce abundant healthy foliage. SCMV seed transmission rates in seed collected from infected transplants of cv. Woogenellup were 0.06, 0.07 and 0.43% for the Type, P23 and F4 isolates respectively. It was concluded that SCMV was present in most pastures, but at low incidences, and that it persists in them from year to year. Extended growing seasons and hard grazing are likely to increase its incidence.

Copper nutrition of subterranean clover (Trifolium subterraneum L. cv. Seaton Park). I. Effects of copper supply on growth and development

1981 ◽  
Vol 32 (2) ◽  
pp. 257 ◽  
Author(s):  
DJ Reuter ◽  
AD Robson ◽  
JF Loneragan ◽  
DJ Tranthim-Fryer
Keyword(s):  
Root Growth ◽  
Growth And Development ◽  
Copper Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Growing Season ◽  
Internode Elongation ◽  
Plant Parts ◽  
Lateral Branches

Effects of severe and moderate copper deficiency on the development of leaves and lateral branches, on the distribution of dry weight within the plant, and on seed yield of Seaton Park subterranean clover were assessed as part of three glasshouse experiments. Copper deficiency markedly depressed top and root growth without producing any distinctive symptoms. It retarded phasic development by delaying development of leaves and lateral branches, senescence of plant parts, and flowering: it also depressed the proportion of stem plus petiole in plant tops and decreased internode elongation, pollen fertility and the number of burrs and seeds formed. As a result of its effect in delaying flowering, copper deficiency would depress seed production particularly strongly when low soil water supply shortens the growing season. The need for suitable procedures for diagnosing copper deficiency is emphasized by the lack of specific plant symptoms in this species.

Zinc in subterranean clover (Trifolium subterraneum L. cv. Seaton Park). I. Effects of zinc supply on distribution of zinc and dry weight among plant parts

1982 ◽  
Vol 33 (6) ◽  
pp. 989 ◽  
Author(s):  
DJ Reuter ◽  
JF Loneragan ◽  
AD Robson ◽  
D Plaskett
Keyword(s):  
Zinc Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Physiological Age ◽  
Vegetative Development ◽  
Plant Parts ◽  
Zinc Concentrations ◽  
Complex Relationships ◽  
Lateral Branches

Effects of zinc supply on the distribution of zinc and dry weight among plant parts were examined during the first 55 days of vegetative development of Seaton Park subterranean clover grown in a zinc-deficient soil in a glasshouse. Symptoms of zinc deficiency first appeared in young trifoliate leaves. Zinc deficiency decreased the expansion of blades and petioles, delayed the development of leaves and lateral branches, depressed dry weights of roots and shoots, and increased the proportion of plant dry weight in roots and leaf blades. In each treatment and at each harvest, zinc concentrations varied widely amongst plant parts and with their physiological age. Plant parts also differed widely in the response of their dry matter and zinc concentrations to both zinc treatment and harvest time. It is suggested that these complex relationships explain why plant samples consisting of composite plant parts are not suitable for diagnosis of zinc deficiency. In the present experiment, zinc concentration in whole shoots was unsatisfactory for diagnosing zinc deficiency since concentrations were higher in young, zinc-deficient plants than in older, zinc-adequate plants. In young leaf blades of the same physiological age, zinc concentrations showed reasonably constant relationships with plant growth throughout the entire experiment. However, they varied two- to three-fold in leaves of different ages from the same plants. The results show the importance for diagnosis of zinc deficiency of selecting as a sample a single organ of defined physiological age. The youngest open leaf blade is recommended for diagnosis of zinc deficiency in subterranean clover.

Mass rearing Halotydeus destructor (Tucker) (Acari : Penthaleidae) for use in summer screening of Trifolium subterraneum (L.) for mite resistance

1997 ◽  
Vol 37 (3) ◽  
pp. 343 ◽  
Author(s):  
D. J. Thackray ◽  
T. J. Ridsdill-Smith ◽  
D. J. Gillespie
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Mass Rearing ◽  
Screening Tests ◽  
Common Vetch ◽  
Halotydeus Destructor ◽  
Natural Pasture ◽  
Redlegged Earth Mite ◽  
First Time

Summary. Controlled environment experiments were conducted to establish some of the requirements for successful mass rearing of Halotydeus destructor (redlegged earth mite). Numbers of mites reared on Vicia sativa (common vetch) cv. Blanchefleur grown alone or on a mixture of vetch with Trifolium subterraneum (subterranean clover) cv. Goulburn, were significantly higher than those on subterranean clover or Arctotheca calendula (capeweed) alone. Populations reared on vetch grown in a sandy soil were significantly higher than those reared on vetch grown in a loamy soil, pure sand or pure loam. Covering the soil surface with a natural pasture mulch increased mite numbers compared with leaving the soil bare or placing plant pots inside ventilated cages. Subsequent changes in rearing methodology produced enough mites to enable summer screening of subterranean clover lines for resistance to H. destructorfor the first time. Over 20 000 mites can be produced from vetch at one time for screening tests throughout the year.

Distribution of zinc and copper in subterranean clover (Trifolium subterraneum L.) grown in culture solutions supplied with graduated amounts of zinc

1958 ◽  
Vol 9 (1) ◽  
pp. 73 ◽  
Author(s):  
DS Riceman ◽  
GB Jones
Keyword(s):  
Zinc Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Stages Of Growth

The distribution of dry weight and of zinc and copper at different stages of growth has been examined in Trifolium subterraneum L. var. Bacchus Marsh grown in culture solutions to which graduated amounts of zinc were added. Several characteristics of the growth of the plants were assessed quantitatively. Symptoms of zinc deficiency developed in cultures which were supplied with suboptimal amounts of zinc.

The effect of autotetraploidy in five varieties of subterranean clover (Trifolium subterraneum L.).

1954 ◽  
Vol 5 (3) ◽  
pp. 356 ◽  
Author(s):  
WM Hutton ◽  
JW Peak
Keyword(s):  
Moisture Content ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
The Other ◽  
Seed Setting ◽  
Plant Parts ◽  
Green Matter ◽  
Total Dry Weight

Induced autotetraploidy in the Dwalganup variety of subterranean clover (Trifolium subterraneum L.) resulted in total dry weight increases of 60 and 65.5 per cent. at flowering and maturity respectively. In the other four varieties the tetraploids had decreased yields of dry matter compared with the diploids, although the decreases for leaf weights at flowering were nonsignificant in Mount Barker and Tallarook, as was the total dry weight reduction in Tallarook at maturity. There were no significant differences between the diploids and tetraploids in percentage moisture content. When early development was stimulated by growth in a glass-house, the tetraploids of all varieties showed a significant increase in yield of green matter. The level of increased growth was maintained only in Dwalganup, and decreased in other varieties during flowering. An analysis was made of the way in which the different plant parts mere changed by tetraploidy. Where decreased growth occurred, the leaves and stems were coarser. In all varieties a reduced seed-setting followed autotetraploidy, although in Dwalganup the yield of seed per plant was not affected.

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