The effect of defoliation on inflorescence production, seed yield and hard-seededness in swards of subterranean clover

1978 ◽  
Vol 29 (4) ◽  
pp. 789
Author(s):  
WJ Collins
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
No Reduction ◽  
Initial Level ◽  
Subterranean Clover ◽  
Flower Initiation ◽  
Flowering Period ◽  
Beginning Of Flowering ◽  
Cutting Height ◽  
Seed Yields

Swards of three strains of subterranean clover (Seaton Park, Yarloop, Midland B) were subjected to a range of defoliation treatments. In all strains, cutting at weekly intervals at a height of 1.5–2 cm from 1 month after sowing until the onset of flowering led to a slight delay in flower initiation but the time of flowering was little affected. The rate of inflorescence production, however, was always increased, as was the total number of inflorescences produced by the end of flowering. In particular, seed yields were increased by at least 30% compared with uncut controls. This effect was attributable partly to increased inflorescence numbers and partly to increases in other yield components as a consequence of the burial of a large proportion of burrs. Cutting increased the initial level of hard-seededness in Seaton Park and Yarloop; in addition the rate of breakdown of hard-seededness in all strains was slower in seed from the defoliated swards. When cutting was continued until midway through flowering (with the cutting height progressively raised) the seed yield in Yarloop and especially in Midland B was much lower than that obtained when cutting was stopped at the beginning of flowering; but in Seaton Park there was no reduction. With further cutting-until the end of flowering-seed yields were less than when cutting was stopped midway through flowering. Extending cutting into the flowering period (compared with cutting only until the onset of flowering) resulted in a decline in the initial level of hard-seededness and an increase in the rate of breakdown of hard-seededness in Midland B but had little effect in Yarloop or Seaton Park.

Corrigendum - The effect of defoliation on inflorescence production, seed yield and hard-seededness in swards of subterranean clover

1978 ◽  
Vol 29 (4) ◽  
pp. 789
Author(s):  
WJ Collins
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
No Reduction ◽  
Initial Level ◽  
Subterranean Clover ◽  
Flower Initiation ◽  
Flowering Period ◽  
Beginning Of Flowering ◽  
Cutting Height ◽  
Seed Yields

Swards of three strains of subterranean clover (Seaton Park, Yarloop, Midland B) were subjected to a range of defoliation treatments. In all strains, cutting at weekly intervals at a height of 1.5–2 cm from 1 month after sowing until the onset of flowering led to a slight delay in flower initiation but the time of flowering was little affected. The rate of inflorescence production, however, was always increased, as was the total number of inflorescences produced by the end of flowering. In particular, seed yields were increased by at least 30% compared with uncut controls. This effect was attributable partly to increased inflorescence numbers and partly to increases in other yield components as a consequence of the burial of a large proportion of burrs. Cutting increased the initial level of hard-seededness in Seaton Park and Yarloop; in addition the rate of breakdown of hard-seededness in all strains was slower in seed from the defoliated swards. When cutting was continued until midway through flowering (with the cutting height progressively raised) the seed yield in Yarloop and especially in Midland B was much lower than that obtained when cutting was stopped at the beginning of flowering; but in Seaton Park there was no reduction. With further cutting-until the end of flowering-seed yields were less than when cutting was stopped midway through flowering. Extending cutting into the flowering period (compared with cutting only until the onset of flowering) resulted in a decline in the initial level of hard-seededness and an increase in the rate of breakdown of hard-seededness in Midland B but had little effect in Yarloop or Seaton Park.

The influence of shading on seed yield in subterranean clover

1978 ◽  
Vol 29 (6) ◽  
pp. 1167 ◽  
Author(s):  
WJ Collins ◽  
RC Rossiter ◽  
MA Ramas
Keyword(s):  
Solar Radiation ◽  
Seed Yield ◽  
Unit Area ◽  
Subterranean Clover ◽  
Curvilinear Relationship ◽  
Light Supply ◽  
Beginning Of Flowering ◽  
Seed Yields ◽  
Agro Forestry

Swards of three strains of subterranean clover (Woogenellup, Clare and Seaton Park) were subjected to three shading treatments (30%, 55% and 100% of daylight) from the beginning of flowering onwards. For the 100% daylight (unshaded) treatment the incoming daily solar radiation averaged between 20 and 30 MJ/m2. In the unshaded treatment, seed yields for the three strains ranged from about 120 to almost 200 g/m2. These yields were invariably decreased by shading. Moreover the evidence indicated a curvilinear relationship between seed yield and light supply such that at 50% of daylight there was a reduction of rather more than 50% in seed yield. Shading mainly affected the number of inflorescences produced per unit area, although other components of seed yield were also affected adversely. Even late shading (towards the end of flowering) led to lower seed yield, partly associated with lower inflorescence numbers and partly with lower seed numbers per burr. The results are considered to have significance for clover regeneration in mixed clover/grass pastures and also in the cloveritree associations of agro-forestry.

Effect of timing of forage conservation on forage yield and quality, seed yield and seedling regeneration of four subterranean clover (Trifolium subterraneum) cultivars

2008 ◽  
Vol 48 (8) ◽  
pp. 1133 ◽  
Author(s):  
B. S. Dear ◽  
B. F. Hackney ◽  
G. M. Dyce ◽  
C. A. Rodham
Keyword(s):  
Seed Yield ◽  
Seed Set ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Forage Yield ◽  
Seedling Regeneration ◽  
Yield And Quality ◽  
Cutting Height ◽  
Seed Yields ◽  
Forage Yields

Swards of four cultivars of subterranean clover (Trifolium subterraneum L.) were cut at three different times to determine the effect on forage yield and quality, seed set and seedling regeneration in two successive seasons in southern New South Wales. The four cultivars of subterranean clover (Seaton Park LF, Junee, Goulburn and Clare) were cut on 23–25 September (early cut), 8–10 October (mid cut) or 22–23 October (late cut), to simulate an early silage, late silage or hay cut. Additional treatments imposed included either grazing or leaving the regrowth after cutting and raising the cutting height from 3 to 6 cm. Forage yields ranged from 3.5 to 9.3 t dry matter (DM)/ha in the first year and from 2.0 to 5.9 t DM/ha in the second year. Herbage yield was influenced by both cultivar and harvest time with the highest yields achieved with the mid cut. Lower forage yields at the later cut were attributed to losses due to respiration and decay under dense leaf canopies. Changes in forage quality were consistent across both years, with in vivo DM digestibility declining from 76–79% to 69–70% as cutting time was delayed. Crude protein fell from 22–24% to 14–17% over the same period, depending on cultivar. Seed yields in both years were influenced by both cutting time and cultivar with a positive relationship (R2 = 0.45–0.61) between herbage present in late spring after a period of regrowth and subsequent seed yield. The early flowering cultivar Seaton Park LF had the highest seed yield in both years and the more erect cultivar Clare had the lowest. Seed yields declined with later cutting time but increased by an average of 39% when the cutting height was raised from 3 to 6 cm. Seedling regeneration reflected seed yield responses with the largest seedling regeneration occurring in treatments cut early. The study found that forage conservation in early October is likely to yield more and be of higher quality than swards cut later in the season. Seed set is greatly reduced by all cutting strategies to levels unprofitable for seed harvesting but may be adequate for pasture regeneration.

The effect of defoliation on seed yield of two strains of subterranean clover grown in monocultures and in binary mixtures

1983 ◽  
Vol 34 (6) ◽  
pp. 671 ◽  
Author(s):  
WJ Collins ◽  
I Rhodes ◽  
RC Rossiter ◽  
MJ Palmer
Keyword(s):  
Competitive Advantage ◽  
Seed Production ◽  
Seed Yield ◽  
Unusual Case ◽  
Subterranean Clover ◽  
Replacement Series ◽  
Competitive Relations ◽  
Beginning Of Flowering ◽  
Seed Yields ◽  
Competition For Resources

The effect of defoliation on seed production was examined in swards of Seaton Park and Midland B grown in a de Wit replacement series in the field. The three defoliation treatments were: D0, uncut (control); D1, defoliated at weekly intervals until the beginning of flowering; and D3, as for D1 but with cutting continued until the end of flowering. Defoliation up to the commencement of flowering (D1) had no significant effect on seed yield in the monocultures of either strain. However, with severe defoliation (D3) seed yields were reduced in both strains, although more so in Midland B than in Seaton Park. This greater sensitivity of Midland B supports the results of earlier work. The most important finding from this study was that cutting influenced the competitive relations between the two strains. For both the D0 and D1 treatments there was competition for the same resources ('space' of de Wit); in D0 neither strain had a competitive advantage, whereas in D1 Midland B appeared to be the better competitor. By contrast, in the D3 treatment there was the relatively unusual case of competition for resources which were not entirely the same; and here Seaton Park was the better performer. Possible explanations for this response are suggested.

An analysis of seed yield in some strains of subterranean clover (Trifolium subterraneum L.) when grown in binary mixtures

1981 ◽  
Vol 32 (3) ◽  
pp. 445 ◽  
Author(s):  
RC Rossiter ◽  
MJ Palmer
Keyword(s):  
Competitive Advantage ◽  
Seed Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Pair Member ◽  
Replacement Series ◽  
Beginning Of Flowering ◽  
Seed Yields

Two experiments using various strains of subterranean clover are described. The first experiment was conducted in the field with mixtures of Dwalganup/Northam A, DwalganupI/Daliak and Yarloop/Seaton Park, and the second in an open-sided glasshouse with Yarloop/Seaton Park. In the field experiment, the plots were grazed continuously from late July until early November when the swards were completely dry; in the glasshouse experiment, the swards were defoliated weekly until shortly after the beginning of flowering. Mixtures were arranged according to the de Wit replacement series. Seed yields for the Dwa1ganup/Northam A mixture showed the classical (de Wit) competition for the same resources, with Northam A the better competitor. On the other hand, for the Dwalganup/Daliak and Yarloop/Seaton Park mixtures there was no clear evidence of a competitive advantage of one strain over the other pair member, at least under our defoliated conditions. Whether or not this absence of 'competition' (as usually understood) is common in clover-strain mixtures is as yet unknown. We emphasize, however, that long-term success of clover strains in mixtures is not invariably associated with competitive advantage.

scholarly journals Heritabilities and phenotypic correlations for seed yield and seed yield components of beans

1969 ◽  
Vol 72 (2) ◽  
pp. 301-308
Author(s):  
Manuel Mateo Solano ◽  
James S. Beaver ◽  
Freddy Saladín García
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Narrow Sense ◽  
Phenotypic Correlations ◽  
Seed Yield Components ◽  
F2 Generation ◽  
Seed Yields ◽  
Advanced Generation ◽  
Weight Number ◽  
100 Seed Weight

Indeterminate bean (Phaseolus vulgaris L.) lines derived from crosses between small-seeded indeterminate and large-seeded determinate genotypes were used to estimate the heritabilities and phenotypic correlations for seed yield and seed yield components. The F2  generation of six bean populations was planted at the Fortuna Substation, Juana Díaz, Puerto Rico, in October 1984. Seed yield per plant, 100 seed weight, number of pods per plant, and number of seed per pod were measured for 50 plants selected at random from each population. A total of 50 F3 plant rows of each population were planted in February 1985 at the Fortuna Substation, and in March 1985 on a small farm in the Constanza valley of the Dominican Republic. Narrow sense heritabilities were estimated by using parent-offspring regressions of the F2 and F3 generation, and phenotypic correlations were estimated by using means of the F3 lines. Mean seed yields per plant of the indeterminate F3 lines were significantly less than the indeterminate parents, whereas the 100-seed weights of the indeterminate F3 were significantly less than the determinate parents. Narrow sense heritabilities for seed yield and seed yield components were intemediate to low. These results indicate that selection for greater seed yield would be more effective by evaluating advanced lines in replicated trials. Spearman rank correlations between locations for seed yield and seed yield components varied among populations. Multilocation testing of advanced generation lines may be the most effective way to identify bean genotypes that perform well in contrasting environments.

Recovery of field-grown canola from sulfur deficiency

1996 ◽  
Vol 36 (1) ◽  
pp. 79 ◽  
Author(s):  
PJ Hocking ◽  
A Pinkerton ◽  
A Good
Keyword(s):  
Seed Yield ◽  
Seed Oil ◽  
No Reduction ◽  
Stem Elongation ◽  
Potassium Sulfate ◽  
Growth Stages ◽  
Flower Buds ◽  
S Deficiency ◽  
Oil Concentration ◽  
Seed Yields

Sulfate-sulfur was applied to sulfur (S)-deficient canola at several growth stages in a field experiment at Cargo near Orange, New South Wales. Applications of 0, 10 or 40 kg S/ha (S0, S10 and S40) as mixtures of potassium sulfate and potassium chloride were made at sowing, the 5-6 leaf rosette stage, flower buds visible, stem elongation and first flowering. The plots received either 80 or 160 kg nitrogen (N)/ha at sowing. Plants from the S0 plots showed symptoms of severe S deficiency during rapid stem elongation, and had a 52% reduction in seed yield and a 21% reduction in seed oil concentration compared with the S40 plants. Application of S10 at sowing, or topdressing S-deficient plants with this rate of S, was inadequate because, although seed oil concentrations were normal (39-42%), seed yields were 25% lower than those from plots that received S40. Topdressing S-deficient plants with S40 at either the 5-6 leaf rosette stage, flower buds visible or stem elongation resulted in the same seed yields and seed oil concentrations as obtained when S40 was applied at sowing. However, there was a 15% reduction in seed yield but no reduction in seed oil concentration when the S40 topdressing was delayed until flowering. Although S10 was inadequate to correct the S deficiency, there was no reduction in either seed yield or seed oil concentration when S10 was topdressed as late as flowering, when compared with this rate of S applied at sowing. Seed meal protein levels were increased by the S40 topdressings. Concentrations of S in seed from the S0 and S10 plants were below the critical value of 0.36% for canola. Seed N:S concentration ratios of S-deficient plants were greater than 10, but 7.5 for plants which received adequate S. Total glucosinolates in seed were increased by the application of S, but the levels were still well below the limit set for the canola standard.

The effects of length of growing season, with and without defoliation, on seed yield and hard-seededness in swards of subterranean clover

1981 ◽  
Vol 32 (5) ◽  
pp. 783 ◽  
Author(s):  
WJ Collins
Keyword(s):  
Seed Yield ◽  
Subterranean Clover ◽  
Growing Season ◽  
Absolute Scale ◽  
Growing Seasons ◽  
Short T2 ◽  
Relative Scale ◽  
Seed Yields

The effects of length of growing season and defoliation on seed yield and hard-seededness were examined in two strains of subterranean clover (Seaton Park, Midland B) grown in swards in the field. All plots were sown at the same time and the length of growing season was varied by altering the time of finish of the season (by withholding water). There were three length of growing season treatments: T1 (short), T2 (intermediate) and T3 (control). The defoliation treatments were D0, uncut (control), and D1, defoliated at weekly intervals until the commencement of flowering. Reducing the length of growing season drastically reduced seed yield. Thus when the growing season was only 3 weeks shorter than the control (i.e. T2 compared with T3), seed yields averaged over strains and defoliations were reduced by at least one half. With a further reduction of 2 weeks in the length of the season (T1) seed yields were only about one-third of those obtained in the control (T3). The reductions in seed yield were due to reductions in both the number of mature burrs produced and to a lesser extent in mean weight per seed. Although defoliation increased seed yield in all growing seasons, the effect when measured on a relative scale was greater in T2 than in either T1 or T3. But on an absolute scale the size of the response was greater in T2 and T3 than in T1. The rate of breakdown of hard-seededness was faster in Seaton Park than in Midland B, but it decreased in both strains with increasing length of growing season.

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.

Effects of phosphorus on seed yields of subterranean clover, serradella and annual medics

1985 ◽  
Vol 25 (3) ◽  
pp. 595 ◽  
Author(s):  
MDA Bolland
Keyword(s):  
Seed Yield ◽  
Subterranean Clover ◽  
Average Weight ◽  
The Third ◽  
Hard Seeds ◽  
Annual Medics ◽  
Alternating Temperature ◽  
Seed Yields ◽  
The Relationship ◽  
Number Of Seeds

In three experiments located near Esperance, Western Australia, the effect of superphosphate phosphorus on seed yields of subterranean clover, serradella and annual medics was measured on newly-cleared soils, using low seeding rates. In two experiments, the relationship between seed yield and the amount of phosphorus applied was linear for subterranean clover and serradella; seed yields increasing by 7-24 kg/ha for each kg/ha of phosphorus applied, depending on species, strain or cultivar, and location. In the third experiment, seed yields of annual medic species also increased markedly with increasing amounts of applied superphosphate phosphorus, this response also depended on species and strain or cultivar, but the responses become less marked with increasing amounts of phosphorus. For the annual medic species, the phosphorus treatments had no effect on average weight of one burr, number of seeds per burr, weight of one seed, or the rate of softening of hard seeds as measured both in a 15/60� alternating temperature oven (one cycle/day) or for samples of burrs collected periodically during summer from the field. For all legumes, the appearance of first flowers was not affected by phosphorus treatment.

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