The effect of defoliation on flowering and seed yield in subterranean clover

1973 ◽  
Vol 24 (2) ◽  
pp. 211 ◽  
Author(s):  
MW Hagon
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Subterranean Clover ◽  
Early Flowering ◽  
Floral Initiation ◽  
Leaf Appearance

The effect of defoliation on flowering and seed production in Woogenellup subterranean clover was studied under sward conditions. Defoliation prior to floral initiation (FI) delayed this event but did not alter the time from sowing to flowering compared with the undefoliated control. However, defoliation between FI and flowering reduced the time from sowing to flowering by 10 days. These findings are discussed in relation to the changes in rates of leaf appearance which resulted from defoliation. Defoliation of the plots either before FI, after FI, or at early flowering did not alter seed yield or any of its components.

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.

Effect of companion perennial grasses and lucerne on seed yield and regeneration of subterranean clover in two wheatbelt environments

2001 ◽  
Vol 52 (10) ◽  
pp. 973 ◽  
Author(s):  
B. S. Dear ◽  
J. M. Virgona ◽  
G. A. Sandral ◽  
A. D. Swan ◽  
B. A. Orchard
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Bank ◽  
Seed Set ◽  
Subterranean Clover ◽  
Seedling Regeneration ◽  
Early Autumn ◽  
Background Population ◽  
Seed Reserves ◽  
Clover Seed

Seed production of subterranean clover (Trifolium subterraneum L.) in mixtures with lovegrass (Eragrostis curvula (Schrader) Nees cv. Consol), cocksfoot (Dactylis glomerata L. cv. Currie), phalaris (Phalaris aquatica L. cv. Sirolan), danthonia (Austrodanthonia richardsonii (Cashm.) H.P. Linder, cv. Taranna), and lucerne (Medicago sativa L. cv. Aquarius) was compared with pure and degraded (invaded by annual volunteers) annual subterranean clover pasture at 2 sites (Junee and Kamarah) in the southern wheatbelt of New South Wales. Seed yields, clover seedlings in winter, and the change in the proportion of 3 subterranean clover cultivars (Dalkeith, Seaton Park, Goulburn) when grown with and without perennials were assessed. The effect of thinning the perennials to 10 plants/m2 on clover seed set was examined at the drier site. Seed production of subterranean clover in the mixtures was depressed by up to 50% compared with the pure and degraded annual swards. Initial clover seed poduction in the mixtures was at least 60 kg/ha even in the drought year at the wetter site (Junee), and >85 kg/ha at Kamarah, the drier site (seedling establishment at Kamarah failed in the drought year). Clover seed reserves in the following 2 years progressively increased to >300 kg/ha in the perennial swards at Junee but were <100 kg/ha by the end of the third year at Kamarah. In comparison, seed reserves in the pure clover and degraded annual swards were >650 kg/ha at Junee and >350 kg/ha at Kamarah. Reducing perennial density to 10 plants/m2 at the drier site increased clover seed yield about 3-fold in the first year compared with unthinned perennial swards. The increased seed yield was due to increased numbers of burrs set and increased seeds per burr and, in all perennial pasture treatments except lucerne, increased seed size. Clover seedling regeneration in 3rd and 4th year after sowing was substantially lower in the perennial-based mixtures than annual plots, with a significant (P < 0.05) positive correlation at both sites between clover seedling regeneration and seed bank size (1996, r2 = 0.46–0.64; 1997, r2 = 0.64–0.85). Following false breaks in early autumn, clover seedling populations were substantially higher in the pure and degraded clover treatments than in most perennial treatments. The proportion of the 3 cultivars present in the seed bank at the end of the pasture phase differed between sites but the sward type only influenced the proportion at the drier site. At the medium rainfall site, the later maturing cultivar Goulburn constituted 27–54% of the seed bank and the early flowering Dalkeith 25–46%, with unsown cultivars being insignificant ( <1%). At the low rainfall site, Dalkeith was the major component (33–52%) of the seed bank but the background population of unsown cultivars constituted 11–48%, the lowest proportion being in swards without a perennial component. The proportion of Goulburn was highest (23%) in the pure sward and lowest (10%) in lucerne and phalaris. It was concluded that subterranean clover could form relatively stable mixtures with perennials in medium rainfall environments, with clover populations increasing with time. In lower rainfall environments, clover seedling populations in perennial swards may be low due to reduced seed set and decreased seedling survival following early autumn rains. In these environments earlier maturing, hard-seeded cultivars are more likely to persist in mixtures and there is more potential for unsown cultivars to constitute a greater proportion of the sward. Decreasing perennial density offers scope for improving clover seed set and survival in these environments.

Seed production in Brachiaria decumbens and Paspalum plicatulum as influenced by system of residue disposal

1987 ◽  
Vol 38 (5) ◽  
pp. 869
Author(s):  
WW Stnr ◽  
LR Humphreys
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Nitrogen Supply ◽  
Floral Initiation ◽  
Spikelet Number ◽  
Brachiaria Decumbens ◽  
Short Day ◽  
Cotton South ◽  
Defoliation Treatment

Long-established swards of Brachiaria decumbens cv. Basilisk and of Paspalum plicatulum cv. Rodds Bay at Mt Cotton, south-east Queensland, were cut, field dried and burnt, or cut and the residues removed in late November or early January. Burning initially reduced tillering, especially when the interval between cutting and burning was 7 days, but this difference disappeared in P. plicatulum when there was a long interval to floral initiation. A juvenility requirement was evident in the short day P. plicatulum swards, where late burning or cutting delayed floral initiation 11 days relative to early defoliation. Strong compensatory and hierarchical effects on the components of seed yield occurred, and seed yield was similar in cut or burnt treatments, except for 23% decrease in late cut P. plicatulum. Late defoliated B. decumbens yielded 31% more seed than early defoliated swards, due mainly to reduced spikelet number per raceme (branch). Burning slightly increased synchrony of inflorescence exsertion in P. plicatulum and reduced crop lodging, although in a subordinate experiment with P. plicatulum lodging was positively related to level of nitrogen supply rather than to defoliation treatment.

The effect of withholding water during flowering on seed production in Trifolium subterraneum L

1977 ◽  
Vol 28 (2) ◽  
pp. 301 ◽  
Author(s):  
P Andrews ◽  
WJ Collins ◽  
WR Stern
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Weight ◽  
Marked Reduction ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Strain Response ◽  
Long Duration ◽  
Prolonged Stress ◽  
Practical Implications

An experiment was conducted in a glasshouse to study the effects of withholding water during flowering on seed production in subterranean clover. Two strains, Northam A (long duration of flowering) and Geraldton (shorter duration) were grown as swards in boxes, defoliated weekly until flowering, and subjected to the following watering regimes: T1, a control; T2, water withheld over the whole of the flowering period; T3 and T4, water withheld for short periods only, during flowering. Regular determinations were made of soil water, leaf water potential and inflorescence number. Seed yield and some of its components were measured in all treatments. The prolonged stress (T2) reduced seed yield by about 80% in both strains. Rates of inflorescence production, duration of flowering and individual seed weight were also reduced. The shorter stress treatments (T3, T4) had no effect on seed yield in the longer-flowering cultivar Northam A, but in cv. Geraldton, T4 caused a marked reduction in seed yield. The practical implications of this differential strain response are discussed.

The influence of nitrogen nutrition of Desmodium uncinatum on seed production

1973 ◽  
Vol 24 (5) ◽  
pp. 667 ◽  
Author(s):  
TA Gibson ◽  
LR Humphreys
Keyword(s):  
Ammonium Nitrate ◽  
Seed Production ◽  
Seed Yield ◽  
Nitrogen Nutrition ◽  
Floral Initiation ◽  
Plant Nitrogen ◽  
Development Stages ◽  
Whole Plant ◽  
Initiation Stage ◽  
Nitrogen Demand

Desmodium uncinaium cv. Silverleaf was grown in simulated swards well supplied with water and basal nutrients. Nodulated control swards yielded 179 g m-2; whole plant nitrogen accretion was 25 g m-2. The rate of nitrogen uptake decreased during seed maturation and redistribution of nitrogen from leaf, stem, and raceme was inadequate to meet the nitrogen demand of maturing seeds. Ammonium nitrate applied at 16.9 kg nitrogen ha-1 wk-1 from the immediate pre-floral initiation stage or at later development stages increased seed yield by 21 to 31 % according to timing. Applied nitrogen increased the number of racemes differentiated per runner and the size of seeds, and decreased the number of seeds formed per floral node. Components of seed yield such as raceme number per runner, floral nodes per raceme, seeds per node, and seed weight were influenced by position on the plant. The greater part of the ammonium nitrate response was due to increased seed production from the secondary racemes on the larger primary runners.

scholarly journals The effect of continuous grazing on the seed production of Subterranean clover (Trifolium subterraneum).

2003 ◽  
Vol 11 ◽  
pp. 155-160
Author(s):  
M.L. Smetham ◽  
B.S. Dear
Keyword(s):  
Leaf Area ◽  
Seed Production ◽  
Seed Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Area Ratio ◽  
Area Index ◽  
Plant Weight ◽  
Continuous Grazing ◽  
Intensive Sampling

Three pure swards of subterranean clover were either (a) left ungrazed with a leaf area index (LAI) of 4.6, or (b) continuously grazed leniently to leave 1 600 kg DM/ha herbage mass equivalent to an LAI of 1.0, or (c) hard grazed to leave 1 400 kg DM/ha herbage mass equivalent to an LAI of 0.6 throughout the flowering period. These swards yielded 1 250, 320 and 70 kg/ha of seed, respectively. One intensive sampling during the middle of flowering showed that seed yield was positively correlated with plant weight, leaf area per plant, and area per leaf, specific leaf area and leaf area ratio. Grazing reduced numbers of both inflorescences and burrs and hence seed yield. Whilst reduced leaf area and plant weight may have also been partly responsible, under hard grazing, only 58% of potential reproductive sites were occupied which suggests that grazing animals also reduced seed yield by consuming these. It is recommended that continuous grazing during flowering and seed maturation should be controlled to leave at least 1 600 kg DM/ha of residual herbage mass, equivalent to an LAI of 1.0, if adequate seed is to be produced to be ensure the establishment of a high producing sward in the following growing season. Key words: flowering, grazing, herbage mass, leaf area, seed production, Trifolium subterraneum

The influence of defoliation on the components of seed yield in swards of subterranean clover (Trifolium subterranean L.)

1961 ◽  
Vol 12 (5) ◽  
pp. 821 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Unit Area ◽  
Control Level ◽  
Subterranean Clover ◽  
Supplementary Data ◽  
Promotive Effect ◽  
Grazed Swards ◽  
Practical Implications ◽  
Number Of Seeds

Six defoliation treatments were imposed on two strains of subterranean clover (Dwalganup and Yarloop) grown in dense swards. Seed yield (weight per unit area) was increased by 27% over controls by July, or July plus early September, defoliations. With progressively later defoliation, yields fell to the control level, then to 15% below it. The number of seeds per unit area showed an increase of almost 40% with early defoliation, whereas with later defoliation the numbers fell to the control level. The increase was due primarily to larger numbers of inflorescences per unit area and a greater proportion of buried burrs. Supplementary data from grazed swards confirmed the promotive effect of early defoliation on seed production. The promotive and detrimental effects of defoliation are discussed, and brief consideration is given to practical implications.

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.

The effect of defoliation on flower production in subterranean clover (T. subterraneum L.)

1972 ◽  
Vol 23 (3) ◽  
pp. 427 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Subterranean Clover ◽  
Growing Season ◽  
Early Flowering ◽  
Flower Initiation ◽  
Flower Production ◽  
Mature Leaves ◽  
Opposing Effects ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

Three experiments were done in an open-sided glasshouse during the normal winter growing season. In experiment 1, swards of the Dwalganup strain which were severely defoliated, either after flower initiation or at early flowering, had 17% more flowers per unit ground area than uncut controls. Swards which were defoliated at both stages had 28% more flowers than the controls. In experiment 2, with single plants of the Dwalganup strain, comparable defoliations greatly decreased flower numbers per plant. The opposing effects of defoliation on flower numbers of single plants and of swards are believed to reflect opposing effects of defoliation on the rate of leaf appearance and on branching. In experiment 3, with single plants of the Dwalganup and Yarloop strains, either the young or the mature leaves were repeatedly removed before flower initiation. This delayed the date of commencement of flowering by 15–19 days; but the node of first flowering was not affected by defoliation.

scholarly journals Paclobutrazol Improves Sesame Yield by Increasing Dry Matter Accumulation and Reducing Seed Shattering Under Rainfed Conditions

2021 ◽  
Author(s):  
Muhammad Zeeshan Mehmood ◽  
Ghulam Qadir ◽  
Obaid Afzal ◽  
Atta Mohi Ud Din ◽  
Muhammad Ali Raza ◽  
...  
Keyword(s):  
Leaf Area ◽  
Seed Production ◽  
Seed Yield ◽  
Dry Matter ◽  
Biomass Accumulation ◽  
Total Biomass ◽  
Dry Matter Accumulation ◽  
Seed Shattering ◽  
Rainfed Conditions ◽  
Leaf Greenness

AbstractSeveral biotic and abiotic stresses significantly decrease the biomass accumulation and seed yield of sesame crops under rainfed areas. However, plant growth regulators (such as Paclobutrazol) can improve the total dry matter and seed production of the sesame crop. The effects of the paclobutrazol application on dry matter accumulation and seed yield had not been studied before in sesame under rainfed conditions. Therefore, a two-year field study during 2018 and 2019 was conducted with key objectives to assess the impacts of paclobutrazol on leaf greenness, leaf area, total dry matter production and partitioning, seed shattering, and seed yield of sesame. Two sesame cultivars (TS-5 and TS-3) were treated with four paclobutrazol concentrations (P0 = Control, P1 = 100 mg L−1, P2 = 200 mg L−1, P3 = 300 mg L−1). The experiment was executed in RCBD-factorial design with three replications. Compared with P0, treatment P3 improved the leaf greenness of sesame by 17%, 38%, and 60% at 45, 85, and 125 days after sowing, respectively. However, P3 treatment decreased the leaf area of sesame by 14% and 20% at 45 and 85 days after sowing than P0, respectively. Compared with P0, treatment P3 increased the leaf area by 46% at 125 days after sowing. On average, treatment P3 also improved the total biomass production by 21% and partitioning in roots, stems, leaves, capsules, and seeds by 23%, 19%, 23%, 22%, and 40%, respectively, in the whole growing seasons as compared to P0. Moreover, under P3 treatment, sesame attained the highest seed yield and lowest seed shattering by 27% and 30%, respectively, compared to P0. This study indicated that by applying the paclobutrazol concentration at the rate of 300 mg L−1 in sesame, the leaf greenness, leaf areas, biomass accumulation, partitioning, seed yield, and shatter resistance could be improved. Thus, the optimum paclobutrazol level could enhance the dry matter accumulation and seed production capacity of sesame by decreasing shattering losses under rainfed conditions.

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