COMPARATIVE STUDIES OF PERENNIAL RYEGRASS, TIMOTHY AND MEADOW FESCUE

The voluntary intake by calves of perennial ryegrass, timothy and meadow fescue, when cut with a flail-type forage harvester and fed fresh, was measured. In 1963 a single management was used and rest periods between cuttings were of 10 or 11 days in April and May and 21 days in June to October. In 1964 the effects of managements with long (35–55 days) and short (15–25 days) rest periods were compared. The increases in rest periods within managements were made in June or July. The voluntary intake of the 3 grass species was not significantly different and the live-weight gains made on the species were similar in both years. Digestibility of all species was higher with the short rest periods than with the long ones and this resulted in higher intakes and liveweight gains from the short-rest-period management.     

COMPARATIVE STUDIES OF PERENNIAL RYEGRASS, TIMOTHY AND MEADOW FESCUE

The growth of calves grazing pure swards of perennial ryegrass, timothy and meadow fescue at low grazing pressure was measured. Organic-matter intake was estimated on three occasions during the grazing season. In 1963 rest periods of 7 days in April and May and of 21 days in June-Octoher were used hetween 7-day grazing periods. In 1964 the effect of long (35–55 days) and short (15–25 days) rest periods hetween 3.5-day grazing periods were compared. There were no measurable differences in intake hetween the calves on the three grass species in 1963. In 1964 faecal production was higher with timothy than with the other species and with small differences in digestihility, the intake on this species was higher. The faecal production and intake were higher, hut not significantly so, with the long-rest management in the second year. The liveweight gains of the calves grazing the three species were similar in 1963; in 1964 gains with meadow fescue were lower than with the other species from 13 April to 22 June but this was the only significant difference. The results obtained on slaughtering the calves at the end of each summer are presented.     

COMPETITION BETWEEN PERENNIAL RYEGRASS AND MEADOW FESCUE UNDER FIELD-PLOT CONDITIONS

Perennial ryegrass and meadow fescue were grown alone and in association in field plots, to gain an idea of the nature and importance of the competitive interactions between them, and their relative contributions to the yield of the newly-established sward.
Experiments over 10 weeks and 9 months both showed that the contribution by fescue to the overall dry-matter yield was severely restricted by perennial ryegrass. There were no deaths of fescue plants during the experimental period (which included an overwintered treatment). The depression in yield was rather a result of a marked decrease in size and weight of the individual plants, brought about by competition for light and nutrients from the faster-growing ryegrass.     

COMPARING THE OUTPUT FROM MIXTURES BASED ON PERENNIAL RYEGRASS AND ON MEADOW FESCUE

Herbage and livestock production from swards based on meadow fescue and on perennial ryegrass were measured over three years. The meadow fescue mixture had no practical advantages in terms of either annual output or seasonal distribution of production. This may have been due to inefficient methods of measurement or may have been peculiar to the management imposed, but it is considered that it was due to the depressing effects of timothy and cocksfoot on the meadow feseue.     

SEED PRODUCTION STUDIES ON PERENNIAL RYEGRASS, TIMOTHY AND PRAIRIE GRASS

This paper considers the sequence of seed development by measurement and observation of ehanges in seed moisture content, weight, colour, endosperm consistency, germination capacity and yield in perennial ryegrass Grasslands Ruanui, timothy Grasslands Kahu and a New Zealand strain of prairie grass (Bromus unioloides). Seed moisture content was high (60–70%) after anthesis and declined at different rates, depending on the species and the weather. Maximum seed dry weight (maturity) was reached approximately 30 days after peak anthesis in all species and was influenced by N application and grazing. Colour changes in the seedhead and endosperm solidification proved unsatisfactory as measures of maturity. Endosperm solidification was reached 4, 11 and 12 days before maximum seed dry weight in ryegrass, timothy and prairie grass, respectively. Seeds removed from the plant as little as 7, 10 and 4 days after anthesis in ryegrass, timothy, and prairie grass, respectively, germinated, provided that dormancy was broken; but they did not retain viability after 3 months storage. Maximum viability of ryegrass, timothy and prairie grass seed tested immediately after harvest occurred 30, 38 and 16 days after anthesis, compared with 17, 35 and 12 days, respeetively, when germination testing was delayed for 3 months. In ryegrass, grazing caused a significant increase in seed yield in the second year while N application alone did not significantly increase yield. In timothy, grazing and to a lesser extent N, were both detrimental to seed yield in the second year. Highest yields were obtained in treatments not receiving either grazing or N. In prairie grass, grazing depressed and N application increased yields in both years. In all species similar or increased yield could be obtained by mowing the crop at, or slightly prior to, seed maturity and allowing seed development and ripening to continue on the cut straw for up to 10 days. Using this technique higher seed yields were obtained in ryegrass and timothy than when seed was direct-harvested. In prairie grass similar yields were obtained whether the erop was direct-harvested or threshed following drying in the swath for 10 days. The use of ‘drying curves’ for the prediction of correct cutting time of seed crops is suggested for ryegrass, timothy and prairie grass.     

SEED PRODUCTION STUDIES ON PERENNIAL RYEGRASS, TIMOTHY AND PRAIRIE GRASS

A study over two years involving tiller identifica tion according to month of origin enabled the contribution of individual tillers of perennial rye grass Grasslands Ruanui, timothy Grasslands Kathu and a local New Zealand strain of prairie grass (Bromus unioloides) to be determined at seed harvest. In addition, the distribution of seed-heads in different arbitrary emergence groups was detemined so as to allow analysis of individual seedhead components within each group. In all species, tillers formed during the first 4 months following an autumn sowing in the first year, and also in the immediate post-harvest period and through the autumn in the second year, made a major contribution to seedhead numbers and seed yield at harvest. These tillers had a lower vegetative mortality rate than those formed in the spring. Primary tillers formed after sowing were highly persistent and became almost exclusively repro ductive. Many vegetative tillers died before har vest, behaving as annual tillers. Spring-formed tillers made a major contribution to the vegetative growth of the plant over the summer and early autumn. These tillers generally died before the following winter. Tillers formed in winter and early spring by ryegrass and prairie grass showed a high mortality, particularly in the second year. In timothy, mortality was highest amongst tillers formed in late spring. The reduced contribution of spring-formed tillers to the seed head population occurred as a result of fewer heads numerically compared with older tillers. In all species, most seedhead components varied according to time of ear emergence. Early emerged heads were generally longer, bore more spikelets and more florets per head and had a greater culm length than late-emerged heads. The major trend in all species was a general depression in head length, spikelet and floret number and culm length with grazing. These effects were in most cases partly or completely overcome by N application. The major effect of applied N was to increase floret number per head.     

EFFECTS OF WHITE CLOVER ON THE BOTANICAL COMPOSITION OF SWARDS OF RYEGRASS, TIMOTHY AND MEADOW FESCUE AND MIXTURES OF THESE THREE

Results are presented to show the effect of white clover (Trifolium repens) and of applied N on the hotanical composition of swards sown with perennial ryegrass (Lolium perernne), timothy (Phleum pratense), meadow fescue (Festuca pratensis) and mixtures of two and three of these species. White clover had a more favourahle effect on the growth of perennial ryegrass than on either timothy or meadow fescue both in terms of yield and in terms of tiller numbers. Tiller numbers of rough-stalked meadow grass (Poa trivialis) were increased and tiller numbers of Agrostis species were reduced by application of N and by inclusion of clover. Possible reasons for these effects are considered.     

THE INFLUENCE OF SEASONAL CHANGES IN LIGHT ENERGY ON LEAF AND TILLER DEVELOPMENT IN RYEGRASS, TIMOTHY AND MEADOW FESCUE

The importance of leaf area as a determinant of yield in herbage crops is now widely realized. Selection for a rapid increase in leaf area might therefore be a useful approach to the problem of breeding for yield.
The present paper describes the seasonal changes in two important components of leaf area, rate of leaf and tiller production, in contrasting varieties of ryegrass, timothy and meadow fescue. The regular seasonal variation in these components in the glasshouse is shown to be determined primarily by available light energy, the species and varieties differing in their response to changes in light energy. The possibilities of selection for these components of leaf area are discussed, but it is pointed out that individual leaf size must also be considered.     

THE DIGESTIBILITY AND VOLUNTARY INTAKE OF S22 AND H.1 RYEGRASS, S170 TALL FESCUE, S48 TIMOTHY, S215 MEADOW FESCUE AND GERMINAL COCKSFOOT

Pure swards of S22 Italian ryegrass, H.1 hybrid ryegrass, S170 tall fescue, S48 timothy, S215 meadow fescue and Germinal cocksfoot were each harvested at several stages of maturity during first growth in the spring, and in the subsequent regrowths. Each batch of herbage was fed to sheep in a digestion trial under conditions of voluntary intake. Results from the first growth herbages showed the expected fall in digestibility with increasing maturity. However, the digestibility of S22, H.1, S170 and S48 began to fall well before ear emergence, whereas the digestibility of Germinal fell only slowly up to the time of ear emergence, as had been found previously with S24 and S23 ryegrass and S37 cocksfoot. The rate of fall of digestibility in H.1 and S48 (0.4 units/day) also appeared to be lower than with the perennial ryegrasses and cocksfoot (0.5 units/day). The monthly regrowths within each herbage were of similar digestibility, but the mean digestibility of regrowths differed between herbages, being highest for S215 and lowest for Germinal and S170. The grasses with highest digestibility in the early Spring, in particular S22 ryegrass, were not, however, always the most digestible in the subsequent regrowths. The numbers of sheep fed on each herbage were insufficient to show whether there were significant differences in voluntary intake between different herbage species of the same digestibility. It is suggested that an intake/digestibility relationship, based on data from more animals, should be developed for each herbage species. Only if different relationships are found can it be concluded that factors other than level of digestibility have an effect on intake.     

THE DIGESTIBILITY OF THE LEAVES AND STEMS OF PERENNIAL RYEGRASS, COCKSFOOT, TIMOTHY, TALL FESCUE, LUCERNE AND SAINFOIN, AS MEASURED BY AN IN VITRO PROCEDURE

Determinations of the in vitro digestibilities of leaf-blade, leaf-sheath and stem fractions of the grasses cocksfoot, perennial ryegrass, timothy and tall fescue and of the leaves and stems of lucerne and sainfoin have shown that all parts of the plant have a high digestibility at early stages of growth. With increasing maturity, however, the digestibility of the stem falls off at a much faster rate than that of the leaf; in grasses, leaf-sheath digestibility declines at an intermediate rate. The decline of digestibility is associated with a reduction in the content of water-soluble and protein constituents in the plant, and with a reduction in the digestibility of fibre. This may provide a biochemical basis for the selection of forage plants of high digestibility in plant-breeding studies.     

PRODUCTIVITY OF ITALIAN AND PERENNIAL RYEGRASS MIXTURES

Italian ryegrass cv. Leda and perennial ryegrass cv. Presto were sown alone and in five mixtures containing different proportions of viable seed and compared with hybrid ryegrass cv. Manawa and Italian ryegrass cv. S22. Yields and herbage composition were measured five times in 1962 and 1963, with particular reference to the contribution from perennial ryegrass in the first year and the effects of Italian ryegrass on second-year production. Italian ryegrass dominated first-year production wbile perennial ryegrass dominated second-year production. Manawa was the top yielder in the first year, but both Manawa and S22 bebaved as Italian ryegrasses and were badly frosted and weedy in the second year. The mixtures were generally intermediate in yield between the components and tended towards the yield of the more vigorous component. Since the more vigorous component changed from cut to cut or from season to season, the sums of harvests sbowed some advantage for certain mixtures. Certain pairs of herbage varieties can be sown togetber witb yield advantage. Furtber physiological investigations are warranted and the breeder has a part to play in a search for complementary varieties.     

SPRING GROWTH OF PERENNIAL RYEGRASS AND COCKSFOOT

Preliminary results are given of experiments in progress to investigate the onset of spring growth and to compare spring growth rates in early- and late-types of perennial ryegrass and cocksfoot.     

HEADING DATES OF S24 PERENNIAL RYEGRASS AND SPRING TEMPERATURES

For spaced plants of Lolium perenne cv. S24 at the Welsh Plant Breeding Station, Aberystwyth, and at the National Institute of Agricultural Botany, Cambridge, linear relationships were obtained between the recorded heading dates and (a) mean March earth temperatures at 30 cm depth and (b) mean March plus mean April earth temperatures at 30 cm depth. The residual standard deviations were ±2.97 days and ±2.65 days, respectively, A mean March earth temperature of 8°C predicted heading on 5 May, 6° C predicted heading on 12 May, and 4°C predicted heading on 20 May. For sites with an average April temperature significantly below 8.7°C a correction of +2 days per degree mean temperature difference in April had to be applied to these dates. These equations could be used to predict dates for 50% ear emergence in swards with a 50% confidence limit of ±22 days for sites in Central and Southern England and Wales. In certain years, cold, wet weather in May appeared to delay heading considerably at two Scottish sites.     

THE CONSUMPTION OF PERENNIAL RYEGRASS AND RED CLOVER BY GRAZING LAMBS

Groups of six-month old lambs, which were either experienced or inexperienced grazers, strip-grazed swards of S24 perennial ryegrass or Hungaropoly tetraploid red clover, at daily herbage allowances of 20 or 40 g OM/kg LW, in late August and September. The swards were similar in N content, but the weight of standing crop, and its digestibility, were higher on grass than on clover. Estimates of herbage intake were made in two successive periods of 19 days. Intake (g OM/kg LW) was lower at low than at high allowance (by 22% and 28% in periods I and II). and experienced grazers ate more than inexperienced animals (by 27% and 22%). Intakes on clover were 28% higher than on grass in Period I, but in Period II the difference was not significant.     

A QUANTITATIVE ANALYSIS OF GERMINATION AND EARLY SEEDLING GROWTH IN PERENNIAL RYEGRASS

Seedlings of perennial ryegrass were grown in soil and growth was studied up to 21 days from sowing. The shoot grew exponentially during this period. The weight of the whole plant fell to about 65% of the original weight of the caryopsis at about 9 days from sowing and did not regain this original value until about 16 days after sowing. Endosperm reserves were virtually exhausted within 14 days.
The interval between the 7th and 14th day appears to be critical in the establishment of the seedling, when conditions adverse to the development of a rapid rate of photosynthesis by the shoot could severely reduce seedling growth and the chances of survival.     

DEFOLIATION AND MANURING OF PERENNIAL RYEGRASS (S24) FOR SEED PRODUCTION

Autumn defoliation of the early perennial ryegrass, S24, expedited or delayed heading and increased or decreased the number of heads and seed yield, according to the age of the stand, winter conditions and previous management.
Nitrogen applied as late as anthesls significantly increased the seed yield of the first harvest crop, but the after-effect on the next seed crop was not better than from an application made immediately after the first harvest. One application in spring was more effective than two in the previous summer and autumn.
Autumn defoliation influenced seed yield more strongly than the gross weight of the unthreshed crops.     

EFFECTS OF METHOD OF ESTABLISHMENT ON TALL FESCUE AND ITALIAN RYEGRASS MIXTURES IN THE FOLLOWING YEAR

Tall fescue and Italian ryegrass mixtures react differently to management in the year of sowing. The decrease in yield of tall fescue and the increase in growth of red clover, caused by the use of a cover crop, was still evident in the following year. In both the spring grazing and total yield of the first harvest year, the Italian ryegrass/ white clover mixture was better than the tall fescue/white clover mixture when a cover crop was used. The reverse trend was recorded when the grass plus clover was sown without the cereal. In general, the addition of red clover to the tall fescue/ white clover, or Italian ryegrass/white clover mixture, increased the yield, but the magnitude of the increase was modified by management during establishment. The increase in total herbage yield and the reduction of white clover growth due to nitrogen application were both related to management in the year of sowing. Consideration should thus be given to method of establishment in the assessment of herbage seeds mixtures.     

THE BEHAVIOUR OF COCKSFOOT AND PERENNIAL RYEGRASS FAMILIES FROM WESTERN FRANCE GROWN AT ABERYSTWYTH

Families of Dactytis g/omerata and Lolium perenne derived from ripe inflorescences collected in western France over a range of nearly 7° of latitude were grown at Aberystwyth, 52° N lat. Their growth was examined to determine whether latitude and the habitat of the collected families affected the dates of ear emergence, phml form, and height of the flowering shoots when the grasses were grown at Aberystwyth, Ear emergence was found to be delayed as the latitude of the seed source increased, irrespective of the year of sowing, or, in the case of cocksfoot, irrespective of whether the plants were in their first or second harvest year.
Plant growth-form and panicle height were recorded only for the cocksfoots, and the results indicate that they were influenced by habitat and that they reflected the intensity of biotic control that had operated.
The families derived from meadows or road verges tended to contain a higher percentage of erect tall types. When, however, the seeds came from grazed orchards or pastures, there were few or no erect plants, but many with a more or less prostrate habit and shorter panicles.     

ANALYSES OF YIELD FROM A COMPETITION TRIAL WITH PERENNIAL RYEGRASS

Four varieties of perennial ryegrass, (S24, S321, S23 and Endura), were grown in monoculture and in all possible binary mixtures. Three spatial arrangements of varieties within mixtures were used. Total DM yields were recorded from nine harvests during 1969 for mooocultures and mixtures and for the mixture components. The arrangement of varieties within mixtures had no effect on the total DM yield of the mixtures. Monocultures and mixtures did not differ significantly in yield at any harvest or in annual total, bnt there were differences between monocultures at some harvests. No differences between mixtures were detected. The experiment took the form of a competition diallel in which monocultures corresponded to the parents in a genetic diallel and mixtures to the crosses between these parents. There was a significant interaction hetween the rows (i.e. main variety effects) and the columns (i.e. associated variety effects) of the diallel table only at the first harvest. The change in the competitive ability of the four varieties throughout the season was examined. The relative ranking order of varieties for competitive ability altered as the season progressed.