Plant Pathology Commons^™

Hydration-Dehydration As A Presowing Seeding Treatment Physiology And Application, W M. Lush, R H. Groves, P E. Kaye

IGC Proceedings (1977-2023)

Presowing hydration-dehydration treatments, in which seeds are partially hydrated and then dried back to their original weights before sowing, have been claimed to have wide-ranging and beneficial effects on seed germination and plant growth. We have assessed the physiological benefits and problems of hydration-dehydration treatments as they apply to pasture grasses, in particular to annual ryegrass. Pretreatment increased the speed of germination because the embryos of pretreated seeds were in a more advanced develop­mental stage at sowing. Furthermore, the germinability of seeds was increased if hydration-dehydration coincided with ex­posure to dormancy-breaking conditions, but we found no evidence to support other …

Effects Of Treading And The Return Of Excreta On A Perennial Ryegrass - White Clover Sward Defoliated By Continuously Grazing Sheep, M L. Currl, R J. Wilkins

IGC Proceedings (1977-2023)

Grazing sheep may affect the association between grass and clover in a mixed sward by defoliation, treading, and the circula­tion of nitrogen (N) via excreta. Our objective was to examine the effect of treading and excreta on a perennial ryegrass (Lolium perenne)-white clover (Trifolium repens)sward defoliated by sheep at high and low stocking rates. Established swards of perennial ryegrass and white clover were continuously stocked from May to October with yearling wether sheep at 25 and';5() head/ha. Sward production and species composition were measured inside graze-through cages that allowed defoliation without treading and excreta return, and …

The Role Of Temperature Pastures Species In Beef Farming In The Humaid Sub-Tropics Of South America, Y E. Kawabe, E Hayashi

IGC Proceedings (1977-2023)

Attempts were made to identify and solve the problems which a beef farming operation in the humid sub-tropics of South America was facing. A total of 370ha of pasture at C.A.O.S.A. was established using temperate species, Lolium perenne, L. multiflorum, Trifolium repens, T. subterraneum and Medicago sativa, both to establish new and also to improve existing tropical pasture in order to overcome: 1. Cool season feed shortage., 2. Low nutritional value of tropical grasses. A rotational grazing system was introduced and the yield and feed value analysis showed a substantial increase in cool season feed while the …

Maximizing Beef Production From Irrigated Pastures With Light Weight Steers, W W. Heinemann

IGC Proceedings (1977-2023)

An experiment was designed to compare beef production by three successions of light weight steers continuous grazing two kinds of irrigated pastures. Two growth promotant ear implants were superimposed treatments in 1982. Successions of light weight steers were used in an effort to obtain maximum animal gain per ha, comparing rates of gain and gains per ha by trimesters. Average steer gains per ha from orchardgrass (Dactylis glomerata) and from perennial ryegrass (Lolium perenne) over a 4-year period were nearly the same. Average daily gains by steers that grazed perennial ryegrass were greater than by steers that grazed orchardgrass but …

The Role Of Sward Adaptations In Buffering Herbage Production Responses To Management Manipulation, S A. Grant, J King, G T. Barthram

IGC Proceedings (1977-2023)

The aim of this study is to improve understanding of sward responses to grazing manipulation so that objective guidelines for management may be provided. Rates of growth and senescence per tiller, tiller population densities and the photosynthetic efficiency of the sward canopy were measured at intervals on Lolium perenne dominated swards under contrasting management regimes involving steady-state and controlled fluctuations in sward conditions. The results suggest that the combination of changes in tiller populations, sward structure and photosynthetic efficiency and in the balance between growth and senescence per tiller act as a buffer such that net production varies little within …

The Effects Of The Different Cultivars Of Orchardgrass, S143 And Aonami, On Botanical Composition In Perennial Ryegrass/ Orchardgrass/ White Clover Pasture, T Suyama, T Mitamura, S Murasato, Y Takimoto, K Nishimura, H Takeda, E Tsuneishi

IGC Proceedings (1977-2023)

The experiment was conducted to determine the effect of two cul ti vars of orchardgrass, S143 and Aonami, on the botanical composition of pasture under the precursor-follower grazing system. Each cultivar was sown as a main component in the mixture with perennial rye grass and white clover. The herbage mass in the pasture with Sl 43(Sl 43-pasture) was less than that in the pasture with Aon

Animal Production Of Fattening Young Steers And Beef Cows By Precursor- Follower System On Two Pasture Types, Y Takimoto, K Nishimura, H Takeda, E Tsuneishi, T Suyama, T Mitamura, S Murasato

IGC Proceedings (1977-2023)

Animal productions were compared on two pastures, i.e. PW pasture (perennial ryegrass-white clover dominant pasture) and PO pasture (perennial ryegrass-orchardgrass dominant pasture), through precursor-follower system using feeder steers and beef cows. The experiment was carried out in 1983 and 1984. After close of grazing feeder steers were fattened for 6 or 7 months, then the carcass characteristics were examined. Feeder steers used in the experiment 1983 were born in spring and grazed for 2 seasons. And in the experiment 1984 steers were born in spring and in fall. They grazed for 2 seasons and 1 season, respectivery. By the precursor-follower …

Establishment And Productivity Of Perennial Ryegrass Improved By Control Of Fungi Pathogenic To Seedlings, R E. Falloon

IGC Proceedings (1977-2023)

Results of investigations into effects of fungicide seed treatments on establishment, productivity and seedling disease of perennial ryegrass (Lolium perenne L.) are reviewed. Seedling establishment from seed treated with protectant fungicides was increased compared with that from untreated seed. Seed treatment improved plant and sward productivity during the first year after establishment. Species of Fusarium and Pythium were virulent pathogens of young seedlings. Use of fungicide seed treatments as part of general pasture establishment practice is strongly recommended.

Effect Of Vernalization And Stem Elongation On Production Physiology Of Lolium Perenne, B Deinum

IGC Proceedings (1977-2023)

In order to study the production potential of vernalized, leafy grass, vernalized cultivars of Lolium perenne were grown at different photoperiods and compared with non-vernalized plants. After vernalization stem elongation was greatly accelerated by long days and occurred later in later-heading cultivars. Late cultivars hardly showed any stem elongation in short days, if at all. Total dry-matter production (herbage above 5 cm + stubble + roots) of stemmy and leafy vernalized grass was much higher than that of non-vernalized grass. The stemmy crops allocated much dry matter in herbage and little in stubble, roots and tillers, whereas the leafy …

Selection For Resistance To Snow Mould, H A. Jonsson, C Nilsson

IGC Proceedings (1977-2023)

The snow mould fungi (Fusarium nivale, Typhula incamata and T. ishikariensis) are limiting grass production in cool temperate areas. A programme was initiated to improve the resistance to snow mould in perennial ryegrass (Lolium perenne) and meadow fescue (Festuca pratensis). Hardening and artificial inoculation were performed in controlled environment chambers. A single strain isolate of pink snow mould (Fusarium nivale) was more aggressive in meadow fescue than a mixture of isolates.

he progenies from surviving plants after one test were used for the next cycle of selection. After one cycle of selection in meadow fescue a moderate improvement and after …

Paturage De Ray-Grass Anglais- Trefle Blanc Par Les Vaches Laitieres, A Pflimlin, F Chenais, J F. Annezo, J Kerouanton, D Le Meur

IGC Proceedings (1977-2023)

Dans le contexte des quotas laitiers, les patures de ray-grass anglais - trefle blanc a faible fumure azotee peuvent etre l'une des voies pour maintenir le revenu, dans la mesure ou elles per­mettent des productions laitieres par vache et par hectare pro­ches de celles obtenues sur pature de ray-grass recevant 300 unites d'azote par ha et par an. Le programme de recherche mis en place en Bretagne a partir de 1982 sur ce theme s'appuie sur un reseau d'observations d'une centaine de fermes laitieres et sur des essais en station, dont ceux de Trevarez presentes ci­apres.

Influence Of Temperatures On The Earliness Of Heading And Nutritive Value Of Two Grasses During The First Growth Cycle, J Andrieu, M Berekoutou

IGC Proceedings (1977-2023)

The two objectives of this study were: I) to see if the method of the sums of temperatures allowed for a correct prediction, not only of the earliness of heading but also of the quality of spring growth whatever the surrounding conditions ; 2) to check that the criteria, suggested jn the feed Tables published by INRA in France (INRA 1981; INRA 1988) to predict the quality of spring growth, could be used for the whole of France. This study is drawn from the thesis ofM. Berekoutou (1986).

Valeur Alimentaire Des Associations Graminees- Trefle Blanc Au Stade Du Paturage, R Giovanni

IGC Proceedings (1977-2023)

Cette etude a eu pour objectif de comparer la composition et la digestibilite du trefle blanc a celles des deux principales gra-. minees fourrageres, le ray-grass anglais (RG) et le dactyle (D), utilisees dans l'Ouest de la France. En effet, ii est apparu interessant de preciser !'influence du trefle blanc (TB) sur la valeur alimentaire de son association avec ces graminees. Cette etude a ete effectuee simultanement sur des fourrages coupes distribues a des moutons en cage de digestibilite et sur des echantillons preleves a chaque cycle du paturage de jeunes bovins.

Influence Des Conditions Edapho-Climatiques Sur La Croissance Printaniere De Ray-Grass Anglais De Differentes Precocites, D Leconte, F Balfourier

IGC Proceedings (1977-2023)

Depuis de nombreuses annees, nous avons observe le mau­vais comportement des varietes tardives implantees sur nos sols froids et humides de fond de vallee. II nous a semble interessant de preciser ces observations en liaison avec notre programme de selection du ray-grass anglais (Lolium perenne).

Recurrent Selection And Hydroponic Cultures For Improving The Efficiency Of Forage Grass Breeding, A.P M. Den Nijs, A.H C.M Schapendonk

IGC Proceedings (1977-2023)

The largest constraint in breeding temperate grasses is the efficiency of selection. This is related to the complex combi­nation of desired characters which ensures persisting pro­ductivity. Selection usually starts with spaced plants, later fol­lowed by progeny tests in sown swards. The applicability of selection among spaced plants for characters to be expressed under heavy competition in the grass sward has often been deb­ated. A solution to this problem is growing spaced plants under competitive conditions provided by a sward of a distinguish­able grass species (Van Dijk and Winkelhorst, 1978). Recurrent selection of slightly inbred populations of perennial ryegrass via this …

Ryegrass Herbage Yield Components And Their Response To Water Deficit Stress, D J. Barker, A.C P. Chu, C J. Korte

IGC Proceedings (1977-2023)

The response of grassland production (herbage mass) to factors limiting its production, can be considered the collective response of a number of components. Understanding the impact of factors limiting individual components will aid understanding of factors limiting total production. Pre-requi­site to such an analysis is quantification of the contribution of each component to herbage mass. Perhaps even more import­ant are the dynamics (rate of change with time) of these components and their response to factors such as water stress.

The objectives of this study were : 1) to assess the importance of seven components to herbage mass using principle component …

Observations Sur La Dissemination D’Epichloe Typhina, L’Agent De La Quenouille Des Graminees Et Reflexions Sur Les Diverses Especes D’Acremonium, G Raynal

IGC Proceedings (1977-2023)

La quenouille des graminees est due a l'Ascomycete Epichloe typhina (Pers. ex Fr.) Tulasne. Des l'epiaison, Jes inflorescences malades sont emprisonnees clans un manchon blanc (stade ase­xue Sphacelia typhina = Acremonium typhinum), qui prend progressivement une couleur orangee, pour donner le symp­t6me typique de quenouille. Le stroma des quenouilles ren­ferme Jes loges peritheciales caracterisant le stade sexue Epichloe et produisant Jes ascospores responsables des conta­minations. De nombreuses graminees sont attaquees, dont le dactyle ( Dactylis glomerata L.), qui peut subir de serieux dom­mages en France clans Jes regions de production de semence. En effet, Jes fleurs ne peuvent pas, …

Effect Of Fungicides On Perennial Ryegrass Seed Production, G H. Horeman

IGC Proceedings (1977-2023)

Significant seed yield increases were obtained (Hampton and Hebblethwaite, 1984) to fungicide application before ear emergence only, but the effects of fungal pathogens on the rye­ grass seed crop could not be assessed. After application of _ propiconazol before anthesis significant seed yield increases were obtained, even in absence of fungal pathogens (Horeman 1987). In this paper results of two experiments are presented. The aim was to investigate whether yield increases after fungicide application is consistent over the years and to find an explanation for these increases.

Weed Seed Contamination: Use Of A Seed Testing Database To Identify Processing Limitations, J S. Rowarth, M P. Rolston, A A. Johnson

IGC Proceedings (1977-2023)

A computerised database maintained by the Official Seed Testing Station of New Zealand provided the opporlunity to survey weed seed contamination in clover and grass seed-lots. Broad-leaf weeds such as Slierardia arvensis, Stellaria ,nedia and Chenopodium album were the major contaminants in Trifolium repens seed-lots. In grass seed-lots the main contaminants were seeds of other grasses such as Bromus hordaeceus, Vulpia spp. and Holcus lanatus. Weed seeds were found to be a major reason for downgrading or rejection from certification of clover and grass seed-lots in New Zealand; this reflects strict quality control measures.

Model Herbage Seed Farm Establishment In South-West China, Guizhou Province, M P. Rolston, G W. Lill, R W. Brougham, Xie Jishi

IGC Proceedings (1977-2023)

A model herbage seed farm was established during 1983-1988 in Guizhou to provide a base for research, training and the product.ion of quality seed for smallholder pasture development. The site is at 26°N in a monsoonal subtropical zone at 1000 m asl. Mean monthly temperatures range from 4°C in winter to 25°C in summer. Seed yield potential of cultivars of perennial ryegrass (Lolium perenne), cocksfoot (Dactylis glomerata), white clover (Trifolium repens) and red clover (Trifolium pratense) was evaluated. Major nutrient limitations were identified, including responses to K and P. Management strategies to …

Pasture Grasses For Semi-Arid Environments In New Zealand, R F. Woodman

IGC Proceedings (1977-2023)

The production of 8 dryland forage gross species and compatibility with lucerne were evaluated over a period of 2 years in the Hakataramea Valley, South Canterbury, New Zealand. Black Mountain rye (Seca le 1110111am1111) is highly promising as a palatable, drought, frost- and pest-tolerant species that provides large amounts of green feed, par ticularly in early spring and autumn. Cocksfoot (Dactylis glomerala), tall oat grass (A rrhenalherum e/atius), smooth brome (Bro111 11s inennis) and phalaris (Phalaris aq11atica) also show potential as productive drought-tolerant grasses, compatible with lucerne (Medicago saliva cv .), and exhibiting good cool•season growth. Wheatgrass (Electrlgia i111ermedia) appears …

Annual Bluegrass And Rat's Tail Fescue Control In Perennial Ryegrass, M E. Mellbye, William C. Young Iii, George W. Mueller-Warrant

IGC Proceedings (1977-2023)

Annual bh1egrass (Poa annua L.) and rat's-tail fescue (Vulpia myruros (L.) C.C. Omel.) are common weed contaminants in seed from perennial ryegrass fields Lolium perenne L. grown in Oregon. A trial was conducted to evaluate post-harvest residue removal methods and herbicides to reduce the level of these impurities. The best weed control was obtained from herbicides following crew-cut management, a comparatively thorough non-thermal nppronch to residue removal. Control was good with sequential herbicide treatments, especially when an effective pre-emergence herbicide such as pendimethalin was used, although no treatment completely eliminated annual bluegrass and rat's-tail fescue from threshed seed samples …

A Development Scale For Perennial Ryegrass, Miriam L. Martin, Roger J. Field

IGC Proceedings (1977-2023)

Vernalised plants of perennial ryeg ra ss (Lolium prenne L. cv. Orasslonds Nui) were grown under controlled conditions and apical development followed by regular excision of apices, which were examined by light and scanning electron microscopy. A 12-point scale describing apical development from the vegetative stage to ear emergence has been produced that is presented in 2 forms: a developmental sequence describing organogenesis events at specific stages, and a commentary on easily recognised features of each stage. The developmental scale provides a detailed analysis that is of value as a botanical description and as a practical aid to those involved …

Mixed Herb Ley No Advantage Over Ryegrass-White Clover Pasture For Early Lamb Growth, I Popay, W Stiefel

IGC Proceedings (1977-2023)

The performance of lambs at 2 stocking rates, on either ryegrass­white clover (Lolium perenne- Trifolium repens) pasture or on a mixed herb ley, were compared under a system which precluded use of pesticides (including drenches) and highly soluble fertilisers. The mixed herb ley included 8 grasses, 5 legumes and 3 herbs: chicory (Cichorium lntybus), sheep's burnet (Sangulsorba minor ssp. muricata) and narrow-leaved plantain (Plantago lanceolata). In the first grazing cycle, there were no significant differences in lamb growth rates, nor in faecal egg counts, between the two pasture types, although in the …

Invertebrate Pests Of Endophyte-Infected And Endophyte Free Perennial Ryegrass Swards In Northern New Zealand, R A. Prestidge, R N. Watson, E R. Thom

IGC Proceedings (1977-2023)

Plots of endophyte-infected and endophyte-free perennial ryegrass (Lollum perenne) cv. Ellett and white clover (Trifolium repens) cv, Grasslands Pitau were established in autumn 1990 by direct drilling into pastures previously sprayed with glyphosate herbicide. Plots were rotationally grazed by dairy cows. Insect pests were sampled by soil coring and extraction, and plant pathogenic nematodes by root staining and examination. Ryegrass tiller density and the proportion of ryegrass in the swards were-significantly less in November, March and May on plots sown with endophyte-free ryegrass c_ompared with endophyte-infected ryegrass. Conversely, the propo!'tion __ of white clover was greater on endophyte-free …

Economics Of Milk Production From Perennial Ryegrass Cultivars With Different Seasonal Growth Patterns, I M. Brookes, A F. Mcrae, D I. Gray, N Cameron

IGC Proceedings (1977-2023)

Cutting trials at 4 sites throughout New Zealand over 2 years with perennial ryegrass (Lolium perenne L) cultivars showed that Bmbassy (B) produeed similar annual dry matter (DM) yields to Supernui (S) and Yatsyn (Y). However, B grew 10% more DM in January-August, but 5% less DM in September-December. The economic value of these diffecent patterns of growth for milk production was assessed using a computer model. The model constrained pasture covers within specified limits by removing excess feed for conservation and adding additional feed as supplements during periods of deficit. Stocking rates needed to maintain the system in equilibrium …

Physiological Characteristics Of Nitrate Uptake By Different Catch Crop Species, P Laine, A Ourry, J Boucaud, J Salette

IGC Proceedings (1977-2023)

The pollution of aquifers by nitrate is aggravated by farming practices that leave the ground bare during winter. Establishment of catch crops during this time could be suitable farming strategy to decrease nitrate loss from the soil. Only a few studies are available on the physiology of nitrate uptake by these species. Experiments were conducted on Lolium perenne, Secale cereale, Trifolium incarnatum, Trifolirim alexendrnum, Phacelia tanacetifolia, Brassica rapa, Brassica napus, Sinapsis alba and Raphanus sativus grown in hydroponic conditions, in order to investigate the physiological basis of the NO3- uptake system when plants are grown with optimum ocniditons of light, …

Herbage And Animal Production From Tall Fescue- And Ryegrass-Based Pastures In A Summer-Dry Environment, D E. Hume, R.J M. Hay, T B. Lyons

IGC Proceedings (1977-2023)

Herbage production and animal performance were measured over 3 years In Hawkes Bay, a summer-dry region of New Z'.ealand. Tall rescue (Festuca arundinacea) (3 cultivars, all endophyte free) was compared with high endophyte perennial ryegrass (Lolium perenne). All pastures were sown with white clover (Trifolium repens). Herbage production and composition were determined for all seasons while cattle were monitored for live-weight gains from spring through to autumn. Tall fescue pastures produced 27% more total dry matter/ year than the ryegrass pasture, primarily in autumn. In summer­autumn, ryegrass pastures had up to 76% dead matter …

Purification And Characterization Of A Proteinase Inhibitor From Lolium Perenne L., Mohammed Tasneem, C A. Cornford, M T. Mcmanus, D W.R White

IGC Proceedings (1977-2023)

A proteinase inhibitor from dry seeds of Lolium perenne L. cv. Grasslands Ruanui has been partially purified and characterised. Standard protein separalion techniques have been used to enrich the presence of lhe inhibitor in seed extracts by 37-fold. Using synthetic substrates the inhibitor can retard the activity of bovine chymotrypsin, but not bovine trypsin. Gel filtration column chromatography indicates that the native protein has a molecular weight of c. 20 KDa.

Response Of Natural Turves Of Pasture To Elevated Carbon Dioxide In A Controlled Environment, P.C D. Newton, H Clark, C C. Bell, E M. Glasgow

IGC Proceedings (1977-2023)

Large natural turves from a ryegrass-white clover (Lolium pernne, trifolium repens) pasture were exposed to increasing day/nighl temperatures at 350 and 700 µVI CO2 over a 7•month period. Growth rate al the highest temperature (22/16°C day/night) was IS% higher at the elevated CO2 level; at lower temperatures the response to CO2 was reduced or even negative (-6% at 10/4°C). The growth rate of ryegrass was much lower at elevated CO2 while that of white clover and other grasses was increased. These results are compared with previous studies using synthetic communities, and the limited response to CO2 is noted …