The pattern of reproductive development and the leafiness of spring and early summer regrowths in two contrasting varieties of ryegrass

1972 ◽  
Vol 78 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Ieuan Davies
Keyword(s):  
Perennial Ryegrass ◽  
Reproductive Development ◽  
Early Summer ◽  
Stem Length ◽  
Floral Initiation ◽  
Selection Methods ◽  
Stem Apex ◽  
Early Stages

SUMMARYEarly stages in the development of reproductive tillers of S. 24 and S. 23 perennial ryegrass are described. The pattern of development of the stem apex and of the unemerged leaves present at the time of floral initiation is traced up to the time when internode extension results in the elevation of the stem apices above the level of defoliation. If tillers with stems about 10 cm long, or more, escape damage to the stem apex during defoliation, the regrowth may be expected to deteriorate rapidly in leafiness, since at this stage there are few or no unemerged leaves. Tillers with 3–4 cm stems generally bear 1–2 unemerged leaves, and hence the regrowth is more leafy.For a given stem length apical development was slightly more advanced in S. 24 than in S. 23. Consideration is given to selection methods to be used in breeding for leafy regrowths in springtime.

Investigation of flowering in Banksia baxteri R. Br. and B. hookeriana Meissner for improving pruning practices

1994 ◽  
Vol 34 (8) ◽  
pp. 1209 ◽  
Author(s):  
LJ Rohl ◽  
AM Fuss ◽  
JA Dhaliwal ◽  
MG Webb ◽  
BB Lamont
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Floral Development ◽  
Early Summer ◽  
Stem Length ◽  
First Year ◽  
Floral Initiation ◽  
Scanning Electron

Floral initiation and development in relation to time of flowering were investigated in Banksia baxteri and B. hookeriana with the aid of scanning electron microscopy. Floral initiation occurred in spring in B. baxteri and in early summer in B. hookeriana. Floral development was rapid in B. baxteri (3 months to reach anthesis in summer). In B. hookeriana, development took 5 months, with anthesis occurring in winter. Most B. hookeriana blooms were produced on 2-year-old shoots, while B. baxteri produced about half of its blooms on 2-year-old shoots and almost as many on 3-year-old shoots. In both species, shoots that flowered within 2 years were longer and thicker in their first year than other shoots. A critical minimum stem length was determined for the first year's growth, to be used as a criterion for determining which shoots to remove during pruning. Details are provided for the timing of pruning to achieve maximum bloom production in B. baxteri and B. hookeriana.

scholarly journals Variation in the reproductive development of perennial ryegrass (Lolium perenne L.) cultivars

2014 ◽  
Vol 76 ◽  
pp. 189-192 ◽  
Author(s):  
C.M. Wims ◽  
J.M. Lee ◽  
L. Rossi ◽  
D.F. Chapman
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Temporal Distribution ◽  
Reproductive Development ◽  
Development Stage ◽  
Early Summer ◽  
Lolium Perenne L ◽  
Flowering Behaviour ◽  
The Mean ◽  
Maturity Groups

Abstract Plant breeding has manipulated the flowering behaviour of perennial ryegrass (Lolium perenne L.) by developing later-heading cultivars. However, the impacts of breeding on the intensity and temporal distribution of flowering are not known. This study compared the reproductive development of 23 perennial ryegrass cultivar/endophyte combinations. In the Waikato and Canterbury, two replicate plots were closed from grazing and tillers were collected every two weeks over a 10-week period during late spring and early summer. Plant development stage was determined for each tiller using a quantitative scale, which was then used to calculate the mean stage count of each cultivar. The rate and timing of reproductive development differed among cultivars. Mid-maturing cultivars matured earlier at both sites compared with late- and very late-maturing cultivars. While the intensity of flowering was similar between maturity groups, the temporal distribution of flowering varied: the late- and very late-maturing cultivars had lower proportions of reproductive tillers early in the season. Keywords: Lolium perenne L., reproductive development, flowering behaviour

scholarly journals Modelling factors affecting reproductive development of perennial ryegrass in Waikato dairy pastures

2001 ◽  
pp. 165-170
Author(s):  
C.F. Fiorelli ◽  
S.J.R. Woodward ◽  
M.E. Wastney ◽  
E.R. Thom ◽  
I. Bahmani
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Conversion Rate ◽  
Mechanistic Model ◽  
Reproductive Development ◽  
Early Summer ◽  
Biological Processes ◽  
Factors Affecting ◽  
Analyse Data

A mechanistic model was developed to identify biological processes responsible for differences in reproductive tillering between 'Ellett' and 'Grasslands Ruanui' perennial ryegrass cultivars. In the model, a field perennial ryegrass tiller population was represented with six compartments: vegetative, emerging reproductive, mature reproductive and dead tillers (three compartments). The biological processes driving the transfer of tillers from one compartment to another were: conversion of vegetative tillers to reproductive tillers, maturation of emerging reproductive tillers, senescence of mature reproductive tillers, and death of reproductive tillers due to grazing. The model was used to analyse data from Waikato dairy pastures. This enabled some of the effects of irrigation, nitrogen, cultivar and season (weather) on the biological processes to be identified. During spring and early summer, the proportion of reproductive tillers in 'Ellett' pastures was always higher than in 'Grasslands Ruanui', regardless of treatment and year. The model explained this difference by a higher conversion rate of 'Ellett' vegetative tillers to reproductive tillers, and suggested that conversion rate is the key process determining reproductive development in perennial ryegrass. Opportunities to control reproductive tillering are discussed. Keywords: flowering, Lolium perenne, perennial ryegrass, reproductive development

Regrowth characteristics of an S. 23 perennial ryegrass sward defoliated at early stages of reproductive development

1973 ◽  
Vol 80 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Ieuan Davies
Keyword(s):  
Perennial Ryegrass ◽  
Reproductive Development ◽  
Late Spring ◽  
Growth Stages ◽  
Stem Extension ◽  
Early Stages ◽  
Herbage Quality ◽  
Stem Development ◽  
Cutting Height

SummaryPatterns of stem development in late spring/summer regrowths after initial cuts at three growth stages are described. The stages at which the initial cuts were taken were: (a) before stem apices were raised to defoliation level (5 cm), (b) two weeks later when the apices of about 90% of the stem tillers were raised above this height, and (c) four weeks after (a), when the apices of all stem tillers were raised well above cutting height.Following an initial cut at stage (a) stem development was quickly resumed, the most advanced tillers being devoid of leaf blades. After initial cuts at the later stages there was virtually no stem development until after the fourth week of regrowth.The greater proportion of stem tillers in the earlier regrowth was not reflected in reduced digestibility during the first six weeks from cutting.Reproductive (apical) development was generally weak in tillers in which stems developed in midsummer (after cutting at stages b and c); at least two-thirds of these tillers were indeterminate.The significance of the distinct batch of stem tillers developing in spring is discussed, and the data are also considered in relation to (i) avoiding stemmy regrowths in spring, (ii) stem development and herbage quality, and (iii) summer stem extension and the perennation of the sward.

Time of floral initiation in tobacco as a function of temperature and photoperiod

1975 ◽  
Vol 53 (14) ◽  
pp. 1400-1410 ◽  
Author(s):  
Judith F. Thomas ◽  
C. E. Anderson ◽  
C. David Raper Jr. ◽  
R. J. Downs
Keyword(s):  
Nicotiana Tabacum ◽  
High Temperatures ◽  
Low Temperatures ◽  
Developmental Stages ◽  
Reproductive Development ◽  
Floral Initiation ◽  
Stem Apex ◽  
Long Day ◽  
Time Period ◽  
Nicotiana Tabacum L

Nicotiana tabacum L. cv. Coker 319 has been found to be sensitive to changes both in temperature and photoperiod. Within a given time period fewer leaves are produced at low temperatures than at high temperatures. The classical day-neutral flowering response was not observed for this plant under six photoperiods of varying lengths. The results thus indicate that the plant may be more appropriately classified as being "preferentially ambiphotoperiodic," rather than strict "day-neutral." Preconditioning the seedlings with a long-day photoperiod produced plants that had higher total leaf numbers and flowered earlier than seedlings treated with a short-day photoperiod. The morphology of the vegetative and reproductive stem apex was similar to that reported for other species and cultivars of Nicotiana. Apical meristems were systematically ranked according to their progressive developmental stages encompassing vegetative, transition, and reproductive development.

Day-length influence on reproductive development and tillering in ‘Fergus’ barley

1975 ◽  
Vol 53 (23) ◽  
pp. 2770-2775 ◽  
Author(s):  
D. T. Fairey ◽  
L. A. Hunt ◽  
N. C. Stoskopf
Keyword(s):  
Hordeum Vulgare ◽  
Reproductive Development ◽  
Tiller Number ◽  
Day Length ◽  
Floral Initiation ◽  
Internode Elongation ◽  
Spikelet Number ◽  
Hordeum Vulgare L ◽  
Initial Formation ◽  
Double Ridge

Effects of variation in day length on spikelet and tiller development were studied in a two-rowed barley, Hordeum vulgare L. cultivar ‘Fergus.’ Spikelet number and the length of the spikelet-forming phase increased with progressive reductions in day length from 24 to 12 h. However, increases in spikelet number were offset by abortion of spikelet primordia during spikelet differentiation and elongation of the stem internodes. Floral initiation occurred at all day lengths, but intemode elongation and heading were markedly delayed at 12 h. The cessation of spikelet initial formation and the beginning of internode elongation did not occur simultaneously in any day length. The latter began just before or at double ridge formation.Tiller numbers were highest at 12 h and progressively decreased in longer day lengths. Each plant produced four primary tillers at all day lengths, and differences in tiller number were accounted for by secondary and tertiary tiller production.

Increasing home-grown forage consumption and profit in non-irrigated dairy systems. 1. Rationale, systems design and management

2014 ◽  
Vol 54 (3) ◽  
pp. 221 ◽  
Author(s):  
D. F. Chapman ◽  
J. Hill ◽  
J. Tharmaraj ◽  
D. Beca ◽  
S. N. Kenny ◽  
...  
Keyword(s):  
Milk Production ◽  
Perennial Ryegrass ◽  
Systems Design ◽  
Farming Systems ◽  
Early Summer ◽  
Annual Rainfall ◽  
Forage Production ◽  
Winter Cereal ◽  
Dairy Systems ◽  
Milk Solids

The profitability of dairy businesses in southern Australia is closely related to the amount of feed consumed from perennial ryegrass-dominant pasture. Historically, the dairy industry has relied on improvements in pasture productivity and utilisation to support profitable increases in stocking rate and milk production per hectare. However, doubts surround the extent to which the industry can continue to rely on perennial ryegrass technology to provide the necessary productivity improvements required into the future. This paper describes the design and management of a dairy systems experiment at Terang in south-west Victoria (780-mm average annual rainfall) conducted over four lactations (June 2005–March 2009) to compare the production and profitability of two forage base options for non-irrigated dairy farms. These options were represented by two self-contained farmlets each milking 36 mixed-age, autumn-calving Holstein-Friesian cows at peak: (1) well managed perennial ryegrass pasture (‘Ryegrass Max’, or ‘RM’); and (2) perennial ryegrass plus complementary forages (‘CF’) including 15% of farmlet area under double cropping with annual species (winter cereal grown for silage followed by summer brassica for grazing on the same land) and an average of 25% of farmlet area in perennial pasture based on tall fescue for improved late spring–early summer feed supply. The design of these systems was informed by farming systems models (DairyMod, UDDER and Redsky), which were used to estimate the effects of introducing different forage options on farm profitability. The design of the CF system was selected based on modelled profitability increases assuming that all forage components could be managed to optimise forage production and be effectively integrated to optimise milk production per cow. Using the historical ‘average’ pasture growth curve for the Terang district and a mean milk price of $3.71 per kg milk solids, the models estimated that the return on assets of the RM and CF systems would be 9.4 and 15.0%, respectively. The objectives of the experiment described here were to test whether or not such differences in profitability could be achieved in practice, and to determine the risks associated with including complementary forages on a substantial proportion of the effective farm area. Key results of the experiment are presented in subsequent papers.

scholarly journals The feeding value of forage herbs: studies with red deer

2006 ◽  
pp. 199-204
Author(s):  
S.O. Hoskin ◽  
P.R. Wilson ◽  
M. Ondris ◽  
A.H. Bunod
Keyword(s):  
Vitamin B12 ◽  
Perennial Ryegrass ◽  
Red Deer ◽  
Post Partum ◽  
Serum Vitamin ◽  
Early Summer ◽  
Selenium Status ◽  
Liver Copper ◽  
Complementary Role ◽  
Feeding Value

This paper summarises three studies that: 1) compared the feeding value of perennial ryegrass-based pasture with chicory and plantain during 8 weeks grazing by weaner red deer in spring 2003 and 13 weeks grazing plantain by weaner deer during autumn 2004; 2), compared the liver copper, liver and serum vitamin B12 and blood selenium status of weaner red deer grazing ryegrass-based pasture, chicory or plantain for 8 weeks during spring 2003; and 3) determined the effect of grazing perennial ryegrass-based pasture alone, or with intermittent grazing of plantain from 1 month pre-partum to 1 month post-partum on liver copper and vitamin B12 status of calves during December 2004 and January 2005. Feeding value (as determined by liveweight gain) of chicory was 40-48% higher than other forages in spring. Feeding value of plantain was 14% higher than pasture in autumn, but similar to pasture in spring. Grazing chicory significantly enhanced the liver copper concentration of weaner deer in spring compared with both ryegrass and plantain. Grazing plantain significantly enhanced the copper status of weaners in autumn, but not of weaners or calves in spring and early summer, enhanced the vitamin B12 status of weaners in autumn and spring and calves in early summer and increased the selenium status of weaners during both spring and autumn. This study has highlighted the complementary role of forage herbs in improving growth and maintaining trace element status of farmed deer. Keywords: chicory, plantain, copper, vitamin B12, selenium, weaner deer

The influence of grazing frequency and intensity on the vigour of Lolium perenne L. under subtropical conditions

1996 ◽  
Vol 47 (6) ◽  
pp. 975 ◽  
Author(s):  
FR McKenzie
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Grazing Intensity ◽  
Early Summer ◽  
Grazing Management ◽  
Lolium Perenne L ◽  
Continuous Grazing ◽  
Second Year

Lolium perenne L. (perennial ryegrass) exhibits poor persistence in subtropical environments. Grazing management may enhance the vigour and hence persistence of this species. Perennial ryegrass was subjected to various grazing treatments, and its vigour, indexed by etiolated growth, was evaluated over 2 years. Pasture and individual tiller vigour were monitored under 5 combinations of grazing frequency and intensity, applied rotationally, and 1 treatment of continuous grazing. The vigour of infrequently grazed plots was greater than that of frequently or continuously grazed plots; however, grazing intensity did not influence vigour. Seasonally, vigour declined during mid (December and .January) to late (February and March) summer of the establishment year and from early summer (October) to autumn (May) during the second year. Poor vigour in frequently grazed plots was associated with low growth reserves rather than a lack of active tiller growth points. Towards the end of the second year, however, a lack of active tiller growth points also limited vigour in frequently grazed plots. Tillers from infrequently grazed plots (regardless of grazing intensity) had greater vigour than tillers from the frequently grazed plots. To enhance the vigour of perennial ryegrass in subtropical environments, the frequency of grazing should be reduced, particularly in summer.

Digestion and rumen metabolism of red clover and perennial ryegrass/white clover forages by red deer

1994 ◽  
Vol 122 (1) ◽  
pp. 115-120 ◽  
Author(s):  
D. O. Freudenberger ◽  
C. J. Burns ◽  
K. Toyokawa ◽  
T. N. Barry
Keyword(s):  
Perennial Ryegrass ◽  
Degradation Rate ◽  
Volatile Fatty Acids ◽  
Red Deer ◽  
Nitrogen Retention ◽  
Red Clover ◽  
Early Summer ◽  
Pool Size ◽  
Total N ◽  
Protein Cell

SUMMARYRed clover (RC) and perennial ryegrass (PRG)-based forages were cut fresh during late spring/early summer and fed at similar levels of dry matter (DM) intake to rumen fistulated castrated red deer kept indoors in metabolism pens. RC contained higher concentrations of total N and non-protein cell contents than PRG and lower concentrations of fibre. Rumen pool size and fractional outflow rates of liquid (13·3 ν. 15·1%/h) and of paniculate matter (2·5 ν. 3·9%/h) were lower for deer fed RC than PRG. Apparent digestibility of energy and fibre, rumen fibre fractional degradation rate and rumen fractional disappearance rate of non-protein cell contents were all higher for RC than for PRG deer. Nitrogen retention was similar for deer fed both forages. However, the concentration, pool size and outflow of ammonia from the rumen, together with urinary N excretion, were all much greater for deer fed RC than those fed PRG. The acetate: propionate ratio in rumen volatile fatty acids (VFA) was lower for the RC than the PRG group. It was concluded that the greater fibre digestion in deer fed RC was due to a faster rumen fractional degradation rate and a longer particulate mean retention time in the rumen, and that the very rapid outflow of water from the rumen relative to particulate matter in deer fed RC (5·5:1 ν. 3·8:1) may explain why deer are not susceptible to rumen frothy bloat when grazing RC. One reason for the greater voluntary feed intake (VFI) of deer grazing RC than those grazing PRG may be due to its greater concentration of protein and non-protein cell contents and their more rapid degradation and removal from the rumen.

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