Pre-maturation cold acquisition in Trifolium subterraneum

1974 ◽  
Vol 25 (6) ◽  
pp. 875 ◽  
Author(s):  
WJ Collins ◽  
DF Smith
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Seed Maturation ◽  
Flower Initiation ◽  
Appearance Time ◽  
Rate Of Development ◽  
Wide Range ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
Different Levels

The influence of different levels of temperature during seed maturation on the subsequent rate of development in plants grown from that seed was studied in a range of subterranean clover cultivars. In one study the cultivars Carnamah, Yarloop, Woogenellup and Mt. Barker were grown at 7, 11, 14 and 17°C, and the seed produced grown on at 17°. Observations were made on the rate of leaf appearance, time of flower initiation, and time and node of first flowering. The rate of development was closely related to the temperature under which the seed was produced—the lower the temperature the faster was the rate of development. This effect was greatest with the later-flowering cultivars. In a second experiment, seed of a number of cultivars harvested commercially from a wide range of sites in southern Australia was grown on at 17°C and the rate of development observed. Time of flowering varied markedly between samples of only three cultivars. Accordingly seed of these samples were grown on for a further generation in a controlled environment. Within two of the cultivars, Mt. Barker and Bacchus Marsh, the differences in flowering observed in the previous generation persisted, which suggests that such differences were not based on environmental factors. In the cultivar Woogenellup the differences in flowering disappeared, which suggests that the original differences arose through different environmental conditions occurring during seed maturation. Cold acquisition in the maturing embryo does not seem to be a matter of practical consequence at present in subterranean clover, but may become so with changes in the location of seed production.

The effect of leaf removal on flowering time in subterranean clover

1970 ◽  
Vol 21 (6) ◽  
pp. 893 ◽  
Author(s):  
WJ Collins ◽  
Y Aitken
Keyword(s):  
Flowering Time ◽  
Subterranean Clover ◽  
Early Growth ◽  
Grazing Management ◽  
Flower Initiation ◽  
Leaf Removal ◽  
Main Shoot ◽  
Delayed Flowering ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

The removal of fully expanded leaves delayed flowering by up to 30 days in subterranean clover cv. Mt. Barker sown in winter at Melbourne (38�S.). This effect on flowering was attributable partly to a delay in flower initiation and partly to a slower rate of leaf appearance after flower initiation. Thus leaf removal may be added to the factors already known to influence flower initiation in subterranean clover. When plants were grown under a 24 hr photoperiod. leaf removal had no effect on flower initiation; the slight delay that leaf removal caused in flowering was therefore due entirely to its effect in reducing the rate of leaf appearance. In other experiments leaf removal delayed the time of flower initiation but had no effect on the rate of leaf appearance. The effect of leaf removal on the time of flowering on the main shoot in lateral-dominant plants (as occur in the field) was qualitatively the same as in plants from which the laterals had been removed. Grazing management of subterranean clover which results in severe defoliation during early growth may delay flowering to such an extent that seed production is reduced substantially, and persistence thereby prejudiced.

scholarly journals Leaf development and dry matter production of subterranean clover cultivars in relation to autumn sward management

2003 ◽  
Vol 11 ◽  
pp. 193-200
Author(s):  
D.J. Moot ◽  
A.D. Black ◽  
W.R. Scott ◽  
J. Richardon
Keyword(s):  
White Clover ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Physical Damage ◽  
Trifoliate Leaf ◽  
Temperature Regimes ◽  
Matter Production ◽  
Wide Range ◽  
Leaf Appearance ◽  
Lincoln University

Seeds of five cultivars of subterranean clover, together with one of white clover, were sown in a wide range of temperature regimes under both controlled environment and field conditions. Results were consistent across temperature regimes and showed that the first trifoliate leaf emerged after 230 °Cd for all subterranean clover cultivars and 309 °Cd for the white clover cultivar. For subterranean clover, exponential leaf appearance commenced after 434 °Cd at the six total leaf stage. At this time, subterranean clover can be defoliated without causing permanent physical damage to seedlings. The field study at Lincoln University showed that subterranean clover that germinated in March produced 44 kg DM/ha/day for 158 days to yield approximately 7 000 kg DM/ha by mid-September. Subterranean clover that germinated in May produced 15 kg DM/ha/day for 120 days to yield only 1 800 kg DM/ha by mid September. These results are discussed in relation to the time of autumn grazing management for subterranean clover, including extrapolation to other climatic areas of New Zealand. Key words: herbage yield, phyllochron, seedling establishment, thermal time, Trifolium subterraneum, T. repens, white clover

Vernalization as a factor influencing the rate of development in subterranean clover (Trifolium subterraneum L.)

1975 ◽  
Vol 26 (6) ◽  
pp. 959 ◽  
Author(s):  
WJ Collins ◽  
DF Smith
Keyword(s):  
Environmental Conditions ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Flower Initiation ◽  
Rate Of Development ◽  
Practical Consequence ◽  
Normal Field ◽  
Delayed Flowering

An investigation of the influence of vernalization on the rate of development in three cultivars of subterranean clover was conducted under controlled environmental conditions. Effects were evaluated in terms of the time from imbibition to flower initiation or flowering, i.e. including the time during which vernalization was imposed. In these terms, vernalization actually delayed flowering in the Yarloop and Mt. Barker cultivars, hastening it only in Tallarook. Some practical considerations are discussed. The effects of periods of higher temperatures after vernalization on the rate of development were also studied. No evidence was found for the occurrence of devernalization. If devernalization docs occur in subterranean clover, it is unlikely to be of practical consequence in normal field situations.

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.

Flower initiation in pasture legumes. I. Factors affecting flower initiation in Trifolium subterraneum L.

1955 ◽  
Vol 6 (2) ◽  
pp. 211 ◽  
Author(s):  
Y Aitken
Keyword(s):  
Low Temperature ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Cold Period ◽  
Effect Of Temperature ◽  
Flower Initiation ◽  
Temperature Level ◽  
Factors Affecting ◽  
Pasture Legumes ◽  
Precise Knowledge

The value of the annual legume Trifolium subterraneum L. (subterranean clover) in Australian agriculture warrants more precise knowledge of factors affecting flowering and prolific seeding. The effect of temperature and photoperiod on flower initiation in early and later flowering varieties has been investigated in an effort to determine the geographical limits of the use of subterranean clover in Australia. At any time of sowing, the length of the growing season of a variety depends greatly on the variety's response to the temperature level and to the photoperiod of the first few weeks after germination. In all varieties of subterranean clover so far examined flower initiation is accelerated by a period of low temperature. In the later varieties, flower initiation is prevented by an insufficient period of low temperature. The length of the necessary cold period is shortened under longer photoperiod. Early varieties are early flowering because they do not require so long a cold period or so low a temperature as late varieties.

Some characteristics of "Carnamah", a very early-flowering strain of Trifolium subterraneum L., when grown as single plants

1961 ◽  
Vol 12 (1) ◽  
pp. 27 ◽  
Author(s):  
RC Rossiter ◽  
AJ Millington
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Early Flowering ◽  
Winter Period ◽  
Flower Initiation ◽  
Total Production ◽  
Initiation Rate ◽  
The Difference ◽  
Early Flower ◽  
Early Strain

A very early-flowering strain of subterranean clover was discovered in 1957 at Carnamah, W.A. From extensive studies at several field centres, it was demonstrated that the new strain – now called Carnamah – commenced flowering from 30 to 10 days before Dwalganup (the standard commercial "early" strain) when sown in the autumn-early winter period. With very early planting – late March – the difference in flowering time was even greater (about 45–50 days). The very early-flowering nature of the Carnamah strain is associated with early flower initiation. Rate of flower development (from flower initiation to flower appearance) in relation to temperature was similar for Carnamah and Dwalganup. Under spaced-plant conditions the total production of Carnamah was much less than that of Dwalganup, a finding which conforms to the results of previous single-plant studies. The new strain was not readily distinguished from Dwalganup, but several minor differences in morphology are mentioned. The chromosome number was normal for the species (2n = 16). The relevance of these data to sward conditions is discussed briefly, and it is suggested that the Carnamah strain may be more effective than Dwalganup in extending the "clover belt" inland in southern Australia.

Seed yield and nutritive value of dry, mature subterranean clover (Trifolium subterraneum L.)

2001 ◽  
Vol 41 (2) ◽  
pp. 169 ◽  
Author(s):  
Y. J. Ru ◽  
J. A. Fortune
Keyword(s):  
Seed Yield ◽  
Dry Matter ◽  
Mineral Content ◽  
Nutritive Value ◽  
Subterranean Clover ◽  
Zinc Content ◽  
Trifolium Subterraneum ◽  
Crude Fibre ◽  
Dry Matter Digestibility ◽  
Wide Range

The nutritive value of 26 cultivars of dry, mature subterranean clover was evaluated at Shenton Park, Perth, Western Australia. The cultivars were divided into 3 maturity groups according to flowering time and each cultivar was sown in blocks comprising 4 replicates. The plots were grazed by sheep at 2-week intervals during the growing season. Dry mature plant material and soil were sampled in summer to examine the effect of grazing and cultivar on seed yield and nutritive value of feed residues. Cultivars heavily grazed in spring had a low herbage mass. There was no difference in seed yield and seed weight between heavily and lightly grazed cultivars. Dry matter digestibility and mineral content of dry residues was inconsistent for the 2 grazing treatments. The dry matter digestibility of dry, mature subterranean clover ranged from 40 to 56%, with a wide range of crude fibre, nitrogen and mineral content for the 26 cultivars. While most minerals in the dry residues were above the requirement for sheep, 7 cultivars had a zinc content less than the maintenance requirement for sheep. There was an imbalance for all cultivars in calcium: phosphorus with a range of 4–10: 1. Concurrent estimates on the yield and composition of seed indicated that seed can be resource of minerals for grazing animals in summer. Most cultivars had a seed yield over 100 g/m2 with that of 9 cultivars being over 130 g/m2. Seed was rich in nitrogen, sodium, phosphorus, potassium, magnesium, zinc and copper, and poor in sodium, calcium and manganese. However, there were no cultivars with an appropriate ratio of calcium and phosphorus. The imbalance in nitrogen and sulfur was a result of high nitrogen content with the ratio ranging from 19: 1 to 29: 1.

Flower initiation in Trifolium subterraneum L. II. Limitations by vernalization, low temperatures, and photoperiod, in the field at Canberra

1959 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
FHW Morley ◽  
LT Evans
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Day Length ◽  
Flower Initiation ◽  
Inhibitory Effects ◽  
Low Field ◽  
The Times ◽  
Short Days

At various times throughout the winter, autumn-sown plants of five strains of subterranean clover were removed from the field to a series of day length and temperature treatments. The times to inflorescence initiation in all treatments were determined by dissection. As vernalization proceeded the requirement of all strains for long days was progressively reduced until, by midwinter, several strains had become virtually independent of day length. Similarly, with the progress of vernalization the inhibitory effects of high temperatures during short days became progressively less marked. Whereas exposure to long days at high temperatures greatly accelerated inflorescence initiation in all strains, long days at low field temperatures had little effect. Evidence is presented which suggests that the limiting effect of very low temperatures on initiation is due not only to retardation of the rate of inflorescence primordium formation (realization), but also to limitation of an inductive process other than vernalization and dark period inhibition. The flowering behaviour of the various strains is discussed in terms of their responses to the partial processes leading to inflorescence initiation, and the interrelationships of these processes are considered.

Appearance and growth of individual leaves in the canopies of several potato cultivars

1995 ◽  
Vol 125 (3) ◽  
pp. 379-394 ◽  
Author(s):  
D. M. Firman ◽  
P. J. O'Brien ◽  
E. J. Allen
Keyword(s):  
Air Temperature ◽  
Field Experiments ◽  
Strong Dependence ◽  
N Fertilizer ◽  
Potato Cultivars ◽  
Main Stem ◽  
Planting Dates ◽  
Wide Range ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

SUMMARYLeaf appearance of contrasting potato cultivars was examined in field experiments at Cambridge, UK, between 1985 and 1990. Three experiments examined the effects of N fertilizer on the appearance and growth of leaves. Four experiments examined leaf appearance over a wide range of planting dates and in two of these experiments different physiological ages of seed were compared.Linear regression of rate of appearance of main-stem leaves on air temperature indicated a strong dependence of rate of leaf appearance on temperature in the cultivar Maris Piper with a phyllochron of c. 31 K d/leaf but in Estima variation in rate of leaf appearance was only partly explained by differences in air temperature. The phyllochron of main-stem leaves in Estima and Home Guard was shorter for old seed than young seed but there was little effect of seed age in four other cultivars. The phyllochron of main-stem leaves was longer without N fertilizer than with N but the difference in the phyllochron between rates of applied N was small. Leaf appearance on sympodial branches was slower and more variable than on the main-stem. Growth of branches differed between cultivars, particularly with no N fertilizer. In the determinate cultivars Estima and Diana there was restricted growth of branches but in the indeterminate cultivar Cara, significant leaf area was contributed by branches. The duration of leaf appearance and longevity of individual leaves is discussed in relation to N, temperature and cultivar.

Flower initiation in relation to maturity in crop plants. I. Flower initiation in relation to maturity in some Australian oats (Avena spp.)

1961 ◽  
Vol 12 (3) ◽  
pp. 371 ◽  
Author(s):  
Y Aitken
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Subterranean Clover ◽  
Late Summer ◽  
Crop Plants ◽  
Leaf Number ◽  
Flower Initiation ◽  
Early Group ◽  
Wide Range ◽  
Cold Requirement

The description of oat varieties as early, mid, and late depends mainly on differences in their time of flower initiation. Flower initiation has been studied in varieties grown in southern Australia and ranging in maturity from first early to late. The time to flower initiation was found to depend greatly on the variety�s response to photoperiod and temperature. In all groups but the first early one, initiation was hastened by lengthening photoperiod and reducing temperature. The later the variety, the greater was the effect. Early varieties are those in which initiation occurs at a low leaf number over a wide range of photoperiods and temperatures. Late varieties result from initiation at a high leaf number, the delay compared with early varieties being due to sensitivity to high temperatures and to short photoperiods. These are the conditions prevailing after late summer and autumn sowings. Late varieties mature early in the field when grown either at low temperatures (below 50�F), or at slightly higher temperatures (below 60�F) and intermediate photoperiod. This is similar to the reaction of variety Clare in the second early group of' subterranean clover. Very late varieties of oats, similar to winter wheats which have a pronounced cold requirement for initiation, are not yet present in Australia.

Sign in / Sign up

Export Citation Format

Share Document