Seed production from three annual species of Trifolium on sandy soils in the wheat belt of Western Australia

1969 ◽  
Vol 9 (36) ◽  
pp. 92 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Soil Moisture ◽  
Seed Production ◽  
Western Australia ◽  
Plant Density ◽  
Subterranean Clover ◽  
Soil Conditions ◽  
Seeding Rate ◽  
Relative Water ◽  
Plant Densities ◽  
Seed Yields

Seed production and persistence of subterranean, cupped, and rose clovers were examined over a period of three years in undefoliated swards, at several plant densities, in the wheat belt of Western Australia. Subterranean clover, although earlier flowering, was outyielded by the other two species in the two driest years. No major differences were found between species in relative water content of leaves during periods of soil moisture deficit. Moreover, species differences in soil moisture exploitation were small. A high proportion of inflorescences failed to set seed in subterranean clover. This reproductive defect, which is associated with restricted inflorescence burial due to dry soil conditions, was thought to be the main reason for the poorer seed yield in this species. Despite low seed yields in the establishment year, plant density after the first year did not seriously limit seed yields, even at the lowest seeding rate, in any of the three species.

The influence of maturity grading on total yield and seed production in strains of Trifolium subterraneun L. grown as single plants and in swards

1959 ◽  
Vol 10 (3) ◽  
pp. 305 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Soil Moisture ◽  
Seed Production ◽  
Plant Density ◽  
Total Yield ◽  
Subterranean Clover ◽  
Reverse Situation ◽  
Production Pattern ◽  
Seed Yields ◽  
The Relationship ◽  
Early Strain

A large number of strains of subterranean clover was grown as single plants and in swards in a series of 1-year experiments. The relationship between the interval from seeding to flowering ("maturity grading") and the production pattern varied according to plant density. In the case of single plants, both total yields and seed yields increased linearly with increasing maturity grading. With swards, on the other hand, total yields showed scarcely any relation to increasing maturity grading – there was a slight decline, in fact – while seed production fell rapidly. Hence the early strain Dwalganup gave the lowest seed yields as single plants, but the highest seed yields in swards, whereas the reverse situation held for the late strains Wenigup and Tallarook. The main factor responsible for the differences in these production patterns was considered to be available soil moisture supply. It was shown that in the few cases where soil moisture was severely limiting in spring for single plants, yields levelled off (and seed yields even declined) at higher maturity gradings. Three points are discussed at some length: the influence of environment on the seed yield of strains grown as single plants, the effect of plant density on the ratio seed weight/total weight, and production in relation to maturity grading in swards.

Effect of plant density and herbicide application on alfalfa seed and weed yields

1991 ◽  
Vol 71 (2) ◽  
pp. 481-489 ◽  
Author(s):  
J. R. Moyer ◽  
R. W. Richards ◽  
G. B. Schaalje
Keyword(s):  
Seed Yield ◽  
Plant Density ◽  
Joint Effect ◽  
Seeding Rate ◽  
Perennial Weed ◽  
Weed Growth ◽  
Alfalfa Seed ◽  
Untreated Check ◽  
Plant Densities ◽  
Seed Yields

Alfalfa was seeded in row spacings of 36, 72 and 108 cm and at broadcast seeding rates of 0.33, 1.0 and 3.0 kg ha−1 on irrigated land at Tilley (1983) and Lethbridge (1984), Alberta to determine the effect of plant density on weed growth and alfalfa seed yield. During the seed-producing years at each location, herbicide treatments were overlaid on seeding treatments in a split-block arrangement to assess the joint effect of herbicides and plant density on alfalfa seed yield. Hexazinone was the main herbicide used for weed control. Alfalfa seed and weeds were harvested for 5 yr following alfalfa establishment. Alfalfa seed yields tended to be maximum with 36-cm row spacings or the 3.0 kg ha−1 broadcast seeding rate, and were similar in row-seeded and broadcast-seeded alfalfa. Dry matter yields of weeds decreased as row spacings decreased or the broadcast seeding rate increased. Hexazinone controlled quackgrass, sow thistle, flixweed and kochia. In the experiment at Tilley with perennial weed infestations, mean alfalfa seed yields from 1984 to 1985 were 20% larger when herbicides were used than in the untreated check. Alfalfa plant densities slightly larger than currently recommended usually produced the largest seed yields and smallest weed infestations. Key words: Medicago sativa, quackgrass, kochia, sow thistle, flixweed, hexazinone

Seed production and persistence of Carnamah and other early strains of Trifolium subterraneum in the wheatbelt of Western Australia

1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Western Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Early Flowering ◽  
The Other ◽  
Factors Affecting ◽  
Seed Yields

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.

The influence of density and nitrogen in seed production stands of S 37 cocksfoot (Dactylis glomerata L.)

1963 ◽  
Vol 61 (3) ◽  
pp. 361-373 ◽  
Author(s):  
D. A. Lambert
Keyword(s):  
Seed Production ◽  
Plant Density ◽  
Unit Area ◽  
The Third ◽  
Plant Densities ◽  
Dactylis Glomerata L ◽  
High Level ◽  
Seed Yields ◽  
Area Percentage ◽  
Lower Plant

1. Seed production stands of S 37 cocksfoot were obtained with varying plant densities by utilizing two drill widths, removing sections of drill, or over-sowing drilled material. All density treatments were operative at two levels of N, 87 or 174 lb. N per acre per annum.2. Tillers in selected quadrats were labelled at monthly intervals during autumn and/or winter for 3 years. Performances of tiller populations were assessed from these quadrats.3. Seed yields were increased in many cases by reducing plant density from a continuous drill pattern. Increased plant density reduced yields. With plant communities on a 1 ft. square arrangement at the high level of nitrogen, an increase of 33%, or 243 lb. seed, per year over a 3-year period was obtained compared with continuous rows at any level of N. The yield of gapped stands increased over the 3-year period, whilst the yields of continuous rows dropped in the final year.4. Nitrogen significantly increased the yield of cocksfoot, except in the third year, by increasing the weight of seed per ear.5. Tiller numbers per quadrat increased in most treatments over the course of the experiment, both within years and from year to year; seasonal peaks of tillering were apparent. The effect of N on tiller numbers differed each year, presumably due to the state of the populations when the N was applied.6. Higher tiller numbers per plant were obtained with lower plant numbers per unit area. Percentage fertility of tillers was generally higher with lower plant densities, and lower tiller numbers per plant, other factors being equal. The only significant effect of N on fertility was to decrease it in the third year.

scholarly journals Relationship Between Plant Density and Fruit and Seed Production in Muskmelon

2002 ◽  
Vol 127 (5) ◽  
pp. 855-859 ◽  
Author(s):  
Haim Nerson
Keyword(s):  
Seed Production ◽  
Seed Size ◽  
Seed Yield ◽  
Field Experiments ◽  
Seed Quality ◽  
Plant Density ◽  
Small Fruit ◽  
Plant Densities ◽  
Seed Yields ◽  
High Seed Yield

Field experiments were conducted in 1996 and 1997 to examine the effects of plant density on yield and quality of fruit and seeds of muskmelons (Cucumis melo L.). Two open-pollinated cultivars, Noy Yizre'el (Ha'Ogen type) and TopMark (western U.S. shipper type), were grown at plant densities ranging from 0.5 to 16.0 plants/m2 under commercial conditions. The highest marketable fruit yields were achieved with plant densities of 2 to 4 plants/m2. In contrast, the highest seed yields were obtained at 8 to 12 plants/m2. Seed yield index [seed yield (g)/fruit yield (kg)] was used as a parameter to define seed production efficiency. High seed yield was closely related to high value of the seed yield index. High seed yield indexes resulted from high plant densities (up to 12 plants/m2), at which the crops produced many, but relatively small fruit. In all cases, the seed yield per fruit (seed number and seed size) increased with increasing fruit weight. However, the sum of the seed yield of two small fruit was always greater than the seed yield of one, double-sized fruit. There was a clear exception with extremely small fruit (<500 g), which produced both low seed yields and poor seed quality. A positive relationship was found between fruit size and seed size in both cultivars. Nevertheless, relatively small seeds (25 to 30 mg) extracted from relatively small fruit (500 to 1000 g) showed the best performance in terms of germination and emergence percentages and rates, and in the vegetative development vigor of the seedlings.

scholarly journals SEED PRODUCTION OF SULLA - A PLANT FOR SOIL CONSERVATION

1984 ◽  
pp. 239-242
Author(s):  
G.B. Douglas
Keyword(s):  
Seed Production ◽  
Soil Conservation ◽  
Sandy Loam ◽  
Ground Cover ◽  
Soil Conditions ◽  
Higher Plant ◽  
Wide Range ◽  
Hedysarum Coronarium ◽  
Plant Densities ◽  
Seed Yields

Sulla (Hedysarum coronarium L.) is suitable for soil conservation work because it fixes nitrogen, grows satisfactorily over a wide range of soil conditions and tolerates drought and coastal conditions. A nursery trial conducted on a Manawatu fine sandy loam examined the effect of sowing rates (20, 40 and 60 kg/ha) and dehulling seed on establishment and forage and seed production. While increasing seed rate and dehulling seed resulted in more rapid establishment (higher plant densities, ground cover and canopy height) they did not affect forage or seed yields at harvest six months later. Keywords: sulla, soil conservation, hulling.

scholarly journals A Comprehensive Study of Orchid Seed Production Relative to Pollination Traits, Plant Density and Climate in an Urban Reserve in Western Australia

Diversity ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 123 ◽  
Author(s):  
Mark C. Brundrett
Keyword(s):  
Seed Production ◽  
Western Australia ◽  
Fruit Set ◽  
Plant Density ◽  
Resource Competition ◽  
Higher Plant ◽  
Trade Offs ◽  
Terrestrial Orchids ◽  
Plant Densities ◽  
Disturbance Tolerance

The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0–95% of flowers, floral displays from 90–3300 mm2 and capsules from 15–1300 mm3 per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59—95%), followed by sexually deceptive autumn or winter-flowering (18–39%), visual deception (0–48%) and sexually deceptive spring-flowering (13–16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4× greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.

scholarly journals Recent grass seed production studies in Canterbury

1980 ◽  
Vol 1 ◽  
pp. 12-14
Author(s):  
K.R. Brown
Keyword(s):  
Seed Production ◽  
Plant Density ◽  
Stem Elongation ◽  
Seeding Rate ◽  
Grass Seed ◽  
Time Of Application ◽  
Negative Effect ◽  
High Yields ◽  
Seed Crops ◽  
Seed Yields

Seed production trials in Canterbury have shown (1) strong negative relationships between plant density and seed yields per plant, and (2) plant density ranges above which high plant numbers failed to compensate for low yields per plant and below which high yields per plant failed to compensate for low plant numbers. The net result was that seed yields per unit area tended to plateau at this density range, with no further gains being made by increasing plant numbers. It is concluded that the function of seeding rate is to provide sufficient viable seeds to attain this density. Optimum density ranges for 'Grasslands Tama' Westerwolds ryegrass and 'Grasslands Nui' perennial ryegrass were 300 to 400 plants/m, and for 'Grasslands Matua' prairie grass 100 to I30 plants/m. The value of superphosphate and potassic fertilizers for seed production was doubtful, but nitrogen increased seed yields regardless of time of application. Work in Canterbury concentrated on the time of N application and showed that nitrogen for seed production was most efficient when applied just after stem elongation had commenced. Grazing grass-seed crops reduced seed yields because of an indirect negative effect on seedhead size and individual seed weights, both of which proved to be more important than seedhead numbers in determining seed yields. Keywords: Seed production, grasses, plant density, nitrogen, stem elongation, grazing, seedhead size, seed weight.

IRRIGATION MANAGEMENT OF ALFALFA FOR SEED

1977 ◽  
Vol 57 (3) ◽  
pp. 891-896 ◽  
Author(s):  
K. K. KROGMAN ◽  
E. H. HOBBS
Keyword(s):  
Soil Moisture ◽  
Medicago Sativa ◽  
Seed Production ◽  
Irrigation Management ◽  
Growing Season ◽  
Moisture Stress ◽  
Field Plot ◽  
Southern Alberta ◽  
Medicago Sativa L ◽  
Seed Yields

In field plot experiments conducted in southern Alberta over a 6-yr period, highest seed yields of alfalfa (Medicago sativa L. cv. Beaver) were obtained with one or two irrigations in the first half of the growing season. In outdoor lysimeters protected from rain, moisture stress for more than 8 days before seed ripening severely reduced seed production. Under field conditions, stored soil moisture from irrigation during the vegetative stage of growth plus occasional rain in July and August permitted irrigation of alfalfa for seed to be stopped at the bud to early bloom stage (June to early July).

Seed-setting in subterranean clover (Trifolium subterranean L.). III. The effect of plant density

1961 ◽  
Vol 12 (1) ◽  
pp. 10 ◽  
Author(s):  
JJ Yates
Keyword(s):  
Seed Production ◽  
Seed Weight ◽  
Plant Density ◽  
Plant Cover ◽  
General Pattern ◽  
Strain Differences ◽  
Subterranean Clover ◽  
Seed Setting ◽  
Below Ground ◽  
Australian Wheat

Various aspects of seed production in a number of strains of subterranean clover sown at fire seeding rates at two sites in the Western Australian wheat-belt were investigated. Dry matter yields and percentage leaf in the foliage were also recorded. Percentage leaf increased with plant density in the earlier-maturing, stemmy strains, so that differences amongst strains diminished as density increased. The differences amongst strains in number of inflorescences when grown as single plants were largely eliminated under dense sward conditions, so that the two main factors in seed production were number of seeds per inflorescence and mean seed weight. The proportion of burrs above and below ground varied widely amongst strains, and was influenced by plant density in some strains. It is postulated that the extent of burr burial depends on the interaction between strain, environment, and condition of the surface soil. Burr burial improved the efficiency of seed-setting, particularly in the more severe environment. Strain differences in seeds per inflorescence below ground were relatively small, but within each strain, values were higher in the more favorable environment. The efficiency of seed-setting above ground differed considerably amongst strains and between the two environments, and tended to increase with plant density particularly in the earlier-maturing strains. Correlations were established between seeds per inflorescence above ground and the amount of plant cover in these strains. An artificial covering of wood-wool also improved seed-setting above ground. Mean seed weight followed the same general pattern as seeds per inflorescence.

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