Aberystwyth S23 Research Articles

Seedling White Clover Response to Defoliation

Defoliation during the early stages of seedling development can influence growth of white clover (Trifolium repens L.). Our objective was to determine the response of cultivars with diverse leaf sizes to defoliation across a range of seedling growth stages. ‘Regal’ (large‐leaf), ‘Louisiana S‐1’ (medium‐large‐leaf), ‘Grasslands Huia’ (medium‐smallleaf), and ‘Aberystwyth S184’ (small‐leaf) were grown in the greenhouse and were initially clipped to remove all leaf (except cotyledons) and petiole tissue (1.0‐cm stubble) when seedlings attained a unifoliolate leaf or one, two, four, and eight trifoliolate leaves. Seedlings were subsequently clipped in the same manner every 7 or 28 d for the next 28 d. Plant response to defoliation was assessed 7, 14, 21, and 28 d after the last clipping. Seedling shoot dry weight of all cultivars increased linearly in response to initial leaf stage when subsequent clipping occurred every 7 d after the initial defoliation. When subsequent clipping was delayed 28 d, defoliation after the four‐trifoliolate stage did not influence shoot weight of any cultivar except Regal. Despite fewer numbers of leaves after regrowth, seedling leaf area of Regal was always greater than that of the other cultivars. Number of stolon branches of Regal and Louisiana S‐1 increased in response to leaf stage at initial defoliation (0.15 branches stage−1), while that of Grasslands Huia and Aberystwyth S184 was relatively unchanged after the four‐ to six‐trifoliolate stage. Permitting white clover seedlings to attain advanced leaf stages before initial defoliation and increasing the time interval before subsequent defoliation will enhance seedling growth and potential survival.

White Clover Morphology and Physiology in Response to Defoliation Interval

Yield response of white clover (Trifolium repens L.) to defoliation varies with leaf size. Our objective was to determine how specific aspects of plant morphology and physiology are responsible for differences in growth of diverse white clover cultivars in response to defoliation interval. Individual plants of ‘Aberystwyth S184’ (small‐leaf), ‘Grasslands Huia’ (medium‐smali‐leaf), and ‘Osceola’ (large‐leaf) were clipped to remove all fully expanded leaves and petioles 55 d after sowing in the greenhouse and then clipped every 7, 14, or 28 d for the next 28 d. Plant fraction dry matter (DM) accumulation and morphological and physiological characteristics were measured 1, 3, 7, 14, and 28 d after the final clipping. Stolon growth rate was inverse to leaf size classification (Aberystwyth S184, 7.6 cm d−1 Grasslands Huia, 5.8 cm d−1 > Osceola, 3.6 cm d−1). In contrast, maximum stolon weight/length ratio of Osceola increased 31% vs. a 1% increase for Grasslands Hula and Aberystwyth S184 as defoliation interval increased to 28 d, which resulted in greater stolon DM accumulation by Osceola at the 14‐ and 28‐d intervals. Stolon and root carbohydrate concentration of Osceola was greater than and leaf carbohydrate concentration was less than the other cultivars at all defoliation intervals, indicating greater reliance on stored carbohydrates for regrowth by Osceola. Although plant leaf area of Oseeola was greater than that of Grasslands Hula and Aberystwyth S184 at the 28‐d interval only, forage DM accumulation of Osceola was greatest at all intervals due to petiole length. In grazed swards, however, greater petiole length would likely increase accessibility to and removal of leaf tissue, subsequently reducing new leaf and stolon growth.

White clover contribution to continuously stocked sheep pastures in association with contrasting perennial ryegrasses

AbstractWhite clover content and herbage production in grass/clover swards were studied at contrasting altitudes in Wales. The lowland experiment (1) compared the performance of three clover varieties grown with four diploid perennial ryegrass (Lolium perenne) varieties with a range of heading dates. In the upland experiment (2) the productivity and persistence of Aberystwyth S184 (small‐leaved) clover was studied in association with three perennial ryegrasses.In experiment I. clover content and dry matter production with Aurora (very early) ryegrass was superior to that with Frances (early), Talbot (intermediate) and Melle (late). Furthermore, the performance of Kent wild white clover (small‐leaved) was better than that of medium‐leaved Menna and Grasslands Huia. Averaged over two years (1985 and 1986) mean clover content of Kent was 22% compared with 9% and 10% of Menna and Huia.Performance of S184 clover during the five years (1986–90) of experiment 2 was better with Meltra (late tetraploid) than with Aberystwyth S23 (late diploid) and intermediate with Aurora. Clover stolon length and growing point number declined to a low level in 1988 but increased dramatically in 1989 and 1990 after cessation of applying fertilizer N.Results from both sites were related to animal performance data previously published. It is concluded that small‐leaved clover varieties are needed to ensure a high proportion of clover in sheep pastures and also that choice of companion ryegrass can have a significant effect on the performance of the legume component.

A comparison of diploid and tetraploid perennial ryegrass and tetraploid ryegrass/white clover swards under continuous sheep stocking at controlled sward heights. 1. Sward characteristics

AbstractTwo 1·0 ha plots of a late‐heading diploid perennial ryegrass (var. Contender) and a late‐heading tetraploid ryegrass (var. Condesa), and two 1·4 ha plots of the tetraploid with Aberystwyth S184 small‐leaved white clover, were direct sown in May 1987. Over the three years 1988–90 they were continuously stocked by Mule ewes with Suffolk‐cross twin lambs, from early April to the end of August, at a target sward surface height (SSH) of 4–6 cm on one set of plots (constant swards) and, on the other set, al 4–6 cm rising after June to a target 6–8 cm (rising swards). The heights were achieved by variable stocking. Fertilizer N was applied only to the grass plots at the rate of 150‐ 180kgN ha‐1 annually.SSH was mainly within the target 4–6 cm, after higher initial heights at turnout in 1988and 1990. Mean heights of the constant swards (April‐ August) averaged 5·53, 4·43 and 5·04cm in the three years. The rising swards (July‐August) increased in height over the constant swards by an average of 0·88, 0·48 and 0·55 cm, in successive years.Clover content of the herbage mass dry matter in the grass/clover swards increased over each grazing season to average 13·0, 26·5 and 21·2% in the three years, with a high mean stolon density of 130 in m‐2 in August 1990. Ryegrass tiller densities in year 3 were 23% higher in the diploid than in the tetraploid swards, which had 43% more than the 10000 tillers m‐2 of the tetraploid ryegrass/clover swards.It is concluded that the combination of a densely stoloniferous small‐leaved clover with the open growth habit of a tetraploid ryegrass can achieve swards of high clover content under continuous sheep stocking.

Assessment of contrasting perennial ryegrasses, with and without white clover, under continuous sheep stocking in the uplands. 5. Herbage production, quality and intake in years 4–6

AbstractHerbage characteristics were studied over years 4–6 (1988–90) in three perennial ryegrass (Lolium perenne L.) varieties as grass‐only (200 kg N ha‐1) and grass/clover (Trifolium repens L.) swards which received 75kg N ha‐1 in 1988 and 0kg N ha‐1 in 1989 and 1990 when continuously stocked with sheep. Mean total annual herbage production of Aurora, a very early flowering variety, was 11% more than that of late‐flowering Aberystwyth S23 due to 21% higher growth as grass/clover pasture. The grass/clover sward of Meltra, a tetraploid late‐flowering variety, out‐yielded S23/clover by 17%. Herbage production of grass/clover was 86% of that of grass only in 1988 but only 54% of the grass‐only swards averaged for 1989 and 1990. In vitro organic matter digestibility (OMD) of Meltra was 38g kg‐1 OM and 27g kg‐1 OM higher than that of S23 and Aurora respectively. OMD of grass/clover was 15g kg‐1 OM higher than that of grass only during the post‐weaning period. Herbage intake was positively correlated with OMD of herbage.The herbage attributes were related to lamb performance reported previously. Lamb output was positively correlated with intake of digestible organic matter.Differences between the three varieties in herbage characteristics were greater as grass/clover than as grass‐only swards, reflecting their compatibility with white clover. In this respect Meltra was the best and S23 the poorest variety.

Assessment of contrasting perennial ryegrasses, with and without clover, under continuous sheep stocking in the uplands. 4. Animal performance in years 4–6

AbstractRelative sheep production from Aurora (very early flowering), Mellra (late‐flowering tetraploid) and Aberystwyth S23 (late flowering) perennial ryegrass (Lolium perenne L.) varieties was compared during harvest years 4‐6 (1988‐90) as grass only (200 kg N ha−1) and grass/clover (75 kg N ha −1 in 1988, 0 kg N ha−1 in 1989 and 1990) at Bronydd Mawr Research Centre (310‐363 m) in mid‐Wales. The pastures were continuously stocked with Beulah Speckled Face ewes and their Suffolk cross lambs from spring to mid‐July. From late July to early November only the weaned lambs grazed the swards.Mean (1988‐90) total annual lamb production per hectare from Aurora and Meltra was 70% and 16% more than that from S23. However, the difference between both varieties and S23 was much greater as grass/clover (Aberystwyth S184 small‐leaved type) than as grass‐only swards. Differences between the grasses in individual lamb growth rates were most pronounced during the post‐weaning period, when that on Meltra was 38% and 23% more than on Aurora and S23 respectively.Mean annual lamb output from grass/clover swards was only 70% of that from grass‐only swards during the 2 years when the former swards received no fertilizer N. Averaged over the 3 years (1988‐90) individual lamb liveweight gain post weaning was 38% higher on grass/clover than on grass‐only swards.The results are discussed in relation to those for the first 3 harvest years (1985‐87). It is concluded that, although Aurora was less persistent than both late‐flowering varieties, its superiority in providing an average of 29% more lamb output than S23 during the critical spring period (up to early June) would be of considerable practical significance in upland sheep systems, as would be the overall superiority of the tetraploid Meltra over S23.

Effect of leaf age and nitrogen fertilisation on sporulation of crown rust (Puccinia coronata var. lolii) on perennial ryegrass (Lolium perenne L.)

SummaryIndividual leaves of perennial ryegrass cv. Aberystwyth S23 of two leaf ages and at two levels of nitrogen fertilisation were point inoculated with Puccinia coronata f.sp. coronata in a growth chamber. In general, there was no significant difference in the lifespan of inoculated versus control leaves. However, the higher rate of nitrogen extended leaf lifespan more markedly in rusted than in control leaves.Uredospore production varied according to leaf age: colonies on juvenile leaves produced three times as many spores as those on mature leaves.

Effects of fishmeal supplementation of baled grass and clover silages fed ad libitum to lambs

Sustainable clover dominant swards have been developed for upland UK sheep grazing conditions by sowing a mixture of tetraploid perennial ryegrass cv Condesa and small leaved clover cv Aberystwyth S184. These pastures have produced equal output to Condesa only swards given 150-160 kg N/ha/year. Lamb liveweight gain from April to August was increased by 50 g/day on the grass/clover vs grass swards. A comparison of the suitability of these grass/clover and N-fertilised grass only swards for silage was undertaken in order to assess silage yield potential and silage feeding value. The enhanced animal performance of lambs on clover has been partly attributed to the higher levels of dietary amino acid clover has been observed to provide. In order to quantify this effect sufficient supplementary fishmeal (60 g/day) to fully meet tissue N needs was fed to lambs on the grass/clover and grass silages and responses in lamb performance compared.

Assessment of contrasting perennial ryegrasses, with and without white clover, under continuous sheep stocking in the uplands. 3. Herbage production, quality and intake

AbstractHerbage characteristics were monitored over 3 years (1985–1987) in three perennial ryegrass (Lolium perenne L.) varieties as grass/only (200 kg N ha−1) and grass/clover (Trifolium repens L.) (75 kg N ha−1) swards when continuously stocked with sheep. Although mean total annual herbage production was similar from the grass varieties, growth of Aurora, a very early‐flowering variety, was higher than that of Aberystwyth S23 and Meltra (tetraploid) late‐flowering types in spring. Herbage production from grass‐only swards was 15% higher than from grass/clover swards. In vitro organic matter digestibility (OMD) of Aurora and Meltra was 34 g kg −1 and 26 g kg −1 higher (P < 0·01) than that of S23. Averaged over varieties, the OMD of grass/clover was 25 g kg −1 higher (P < 0·05) than grass‐only during the post‐weaning period. Individual lamb digestible organic matter intake (DOMI) was 22% higher (P < 0·05) on grass/clover than on grass‐only during this period. Water‐soluble carbohydrates content of Aurora was 42% higher (P < 0·001) than that of both Meltra and S23.Herbage characteristics were related to lamb performance reported previously. Lamb production was positively correlated with DOMI. However, the magnitude of differences in lamb performance between treatments was much greater than the extent of differences detected in herbage characteristics.

Growth, colonization and productivity of two white clover cultivars strip‐seeded into an upland Festuca‐Agrostis sward

AbstractSmall plots of a Festuca‐Agrostis upland sward on a peaty gley podsol were strip‐seeded during late June 1986 with white clover cvs Aberystwyth S184 or Menna at 4 kg ha−1 and defoliated early (20 August) or late (3 September) and then frequently or infrequently (every 2 weeks or 4 weeks) until the end of September. All plots were defoliated in early November, at 3‐weekly intervals during the growing season in 1987 and then grazed rotationally during 1988.Satisfactory seedling establishment, representing 46% emergence, was achieved 5 weeks after sowing. The differential defoliation regimes had no persistent significant effects on clover development. S184 soon produced more leaves per seedling than Menna and a smaller proportion of its leaf number and weight were removed at each defoliation. Following large losses of leaves over the 1986–87 winter, SI84 had significantly more leaves per stolon than Menna; subsequently it also colonized the sward at a quicker rate. During 1987 amounts of herbage harvested (6.1 t ha−1) were similar with the two clover cultivars, with S184 contributing 47% and Menna 44% of this respectively. SI84 made a larger contribution to yield during May and June but Menna was more productive during September and October. During 1988 clover populations were maintained with rotational grazing without additional fertilizer inputs.The results show that, despite initial soil and climatic contraints, both small and medium‐leaved clovers can be strip‐seeded into upland swards with large subsequent benefits to yield and herbage quality. However, they also indicate the need for further experiments to determine the influence of sward morphology and defoliation regime on stolon branching rates and accumulation of growing points which, in turn, govern sward colonization.

The influence of crown rust (Puccinia coronata) on tiller production and survival of perennial ryegrass (Lolium perenne) plants in simulated swards

AbstractPopulations of Aberystwyth S23 and S24 ryegrass tillers were individually labelled and harvested at intervals to follow their life histories and productivity in response to the effect of infection with crown rust at two levels of nitrogen fertilization.The number of tillers in a population was reduced as a result of infection with crown rust. Increased rates of tiller death due to the pathogen occurred throughout the population age‐range and were most pronounced in the youngest tillers. Population changes were evident following infection and continued to be apparent in the following spring. The disease caused alterations in sward age structure, leading both to a higher proportion of older tillers in the more rust‐damaged treatments and to a decrease in the weight of the herbage produced. It is concluded that rust infection of a sward may lead to changes in population structure with long‐term yield effects, in addition to the immediate direct yield reductions commonly reported. The significance of these results to the ecological and agronomic balance of grassland is discussed.

Assessment of contrasting perennial ryegrasses, with and without white clover, under continuous sheep stocking in the uplands

AbstractPotential lamb production from grass‐clover (75–80 kg N ha−1) swards was compared with that from grass‐only (160–200 kg N ha−1) swards from 1985 to 1987 at the Bronydd Mawr Research Centre in mid‐Wales. Separate pastures of three perennial ryegrass (Lolium perenne L.) varieties; Aurora (very early‐flowering diploid), Meltra (late‐flowering tetraploid) and Aberystwyth S23 (late‐flowering diploid), with and without Aberystwyth S184 small‐leaved white clover (Trifolium repens L.), were continuously stocked with Beulah Speckled Face ewes and their Suffolk cross lambs from spring (late April) until weaning in mid‐July. From late July the pastures were grazed with weaned lambs until early November.Individual lamb liveweight gain was 8% more (P < 0·001) pre‐weaning on grass‐clover than on grass‐only swards and 30% more (p < 0·001) post‐weaning. Averaged over three years, mean stocking rate was 17% higher (p < 0·001) pre‐weaning and 29% higher (p < 0·001) post‐weaning on the grass‐only pastures. Even so, total lamb output (kg ha−1) was similar from the two sward types, although during the pre‐weaning period lamb production was 9% higher (P < 0·05) from grass‐only swards.The results show the potential of grass‐clover (low N) swards to improve the efficiency of lamb production from grassland since better individual lamb growth rate compensated for the lower stock‐carrying capacity. That is, similar output was achieved with lower cost of fertilizer N input and with the lower costs associated with carrying fewer animals.

Assessment of contrasting perennial ryegrasses, with and without white clover, under continuous sheep stocking in the uplands

AbstractComparative sheep production from Aurora (very early‐flowering), Meltra (late‐flowering tetraploid) and Aberystwyth S23 (late‐flowering) perennial ryegrass (Lolium perenne L.) varieties was assessed as both grass‐only (200 kg N ha−1) and grass‐white clover (Trifolium repens L.) (75 kg N ha−1) swards under continuous stocking management. Beulah Speckled Face ewes and their Suffolk cross lambs were used from late April to mid‐July. From late July to early November only lambs grazed the pastures.Mean (1985–87) total annual lamb production per hectare from Aurora and Meltra was 16% and 13% more than that from S23. The magnitude of the differences between these varieties and S23 declined from the first to the third year. Aurora gave 29% more lamb output per hectare than S23 in 1985 but only 10% more in 1987, while the advantage of Meltra over S23 fell from 19% in 1985 to 6% in 1987. Seasonal lamb production per hectare varied between the grasses, especially during spring when lamb output from Aurora was 43% and 22% more than that from S23 and Meltra respectively, with that from the tetraploid being 17% higher than that from S23.It is concluded that the superior spring output from Aurora offers the farmer the opportunity to reduce his dependence on bought‐in feedstuffs, hence improving the efficiency and profitability of lamb production from grassland.

Frequency of stocking rate adjustments required on contrasting upland perennial ryegrass pastures continuously grazed to a sward height criterion from May to July

AbstractThe use of sward height as a criterion for determining the time and extent of stocking‐rate changes on continuously grazed swards was investigated over a 2‐year period (1985–86) in a sheep production experiment. Swards of three contrasting perennial ryegrass (Lolium perenne L.) varieties were established with and without Aberystwyth S184 small‐leaved white clover (Trifolium repens L.) at an upland site (310–363 m) in mid‐Wales. From spring (late April) until weaning (mid‐July) the pastures were continuously stocked with Beulah Speckled Face ewes and Suffolk cross lambs. During this period sward heights of 4 ± 0.5 cm were obtained and maintained by regular adjustment of animal number on individual paddocks. Grass‐only swards received 160 and 200 kg N ha−1 and the grass clover swards were given 80 and 75 kg N ha−1 in 1985 and 1986 respectively.Differences were observed between the treatments in sward height profiles over the season necessitating contrasting adjustments to stocking rates. Mean stocking rate necessary on early flowering Aurora (22 6 ewes ha−1) was respectively 27% and 17% higher than on late‐flowering Aberystwyth S23 and Meltra (tetraploid) ryegrasses; mean stocking rate on grass‐only swards was 19% higher than on the grass‐clover pastures.It is concluded that sward height is a useful criterion on which to make adjustments to stocking rates to compare the potential performance of contrasting swards, under continuous grazing. The infrequent adjustments required to maintain a constant sward height, especially on the late flowering diploid perennial ryegrass variety on which many upland pastures are based, suggest that the criterion of sward height could be successfully employed on farms as an aid to efficient grazing management.

Water‐soluble carbohydrates in perennial ryegrass breeding

AbstractWater‐soluble carbohydrate (WSC) contents of the early heading perennial ryegrass cultivar Aurora and five late heading cultivars were assessed in samples from 1 m × 2 m plots cut eight times in 1983 and five times in 1984. Despite fluctuations due to effects of the environment and plant development, the ranking of the cultivars in terms of WSC generally remained constant. Aurora had the highest overall WSC content. Majestic and Aberystwyth S23 had the lowest while Perma, Melle and Ba 9795 were intermediate. In the same trial, the ranking of the F2 hybrids between the late heading cultivars and Aurora was also consistent with that obtained previously in F1 and F2 spaced plants. Melle F2 families had the highest WSC followed by Perma F2, Ba 9795 F2, S23 F2 and finally Majestic F2 families. This ranking also remained constant over a generation of intense selection for uniformity of heading date. It was concluded that WSC is a consistent and heritable trait in breeding perennial ryegrass. Aurora was a good resource for improving WSC but the turf‐type perennial ryegrass. Majestic, had a strong negative effect on WSC content in hybrid material.

Water‐soluble carbohydrates in perennial ryegrass breeding

AbstractWater‐soluble carbohydrate (WSC) contents of the early heading perennial ryegrass cultivar Aurora and five late heading cultivars were assessed in samples from spaced plants cut five times in 1982. Aurora had the highest overall WSC content. Majestic and Aberystwyth S23 had the lowest while Perma, Melle and Ba 9795 were intermediate. Samples from F1 and F2 spaced plants derived from crosses between Aurora and the five late heading cultivars were also analysed for WSC contents and heading dates were recorded. As expected, heading date behaved as a polygenic character controlled mainly by additive gene effects. However, WSC contents behaved in a more complex way with evidence of non‐additive gene effects comprising dominance, overdominance (heterosis) and epistasis. It was concluded that by crossing contrasting cultivars, significant improvements in WSC content could be achieved, which may be more stable than those obtained by within‐cultivar selection.

Variation in spring temperatures, grass production and response to nitrogen over twenty years in the uplands

AbstractLarge between‐year variation was observed in spring air and soil temperatures at Pant‐y‐dwr Hill Centre (305 m altitude) from 1967 to 1984 and at Bronydd Mawr Research Centre (330 m) from 1985 to 1986 in Powys. The mean date of attaining T‐sum 200°C accumulated air temperature was 13 March (range 9 February to 23 April) and that of soil temperature at 100 mm depth permanently above 5 5°C was 9 April (range 7 March to 4 May). Net herbage accumulation and response to applied N from Aberystwyth S23 perennial ryegrass (Lolium perenne L.) swards during April were also highly variable and were correlated with the date of reaching target soil temperatures of above 5 5°C for 5 consecutive days (r=−0·68, P < 0·001 for net herbage accumulation and r=−0·70, P < 0·001 for response to N).The use of early flowering varieties of perennial ryegrass gave a significant increase of herbage growth in spring compared with late varieties. From 1979 to 1980 net herbage accumulation during April from the early variety Frances was 94% more than from Perma (late) and 55% more than from Talbot (intermediate) varieties. Under conservation management more winter hardy and persistent varieties of Italian and hybrid ryegrasses (L. multiflorum L. and L. multiflorum X L. perenne) gave higher quantities of firstcut silage crops in early June than RvP Italian ryegrass.After the severe winters of 1978–79 and 1985–86, subsequent spring production from a wide range of ryegrasses was shown to be affected by sward survival, highlighting the value of winter hardy varieties when resowing in the uplands

Comparative sheep production and herbage characteristics on four perennial ryegrass varieties in the uplands

AbstractEwe and lamb performance, herbage production and feed quality components on four late‐flowering perennial ryegrass (Lolium perenne L.) varieties were assessed under a fixed stocking management at an upland site (305 m OD) in mid‐Wales. Averaged over four years (1981–84) there was no significant difference (P>0·05) between Aberystwyth S23, Aberystwyth Ajax, Perma and Meltra (tetraploid) in ewe and iamb liveweight gains. There were, however, considerable differences between varieties during individual years and their relative ranking also changed substantially over the four years. Lamb production on Perma was 22% more than on S23 in the first year but by the fourth year it was 21 % less than on the latter variety.Differences between varieties were observed in herbage production. Net herbage accumulation was 15% more on Meltra than on Ajax whilst the calculated quantity of OM consumed was 19% higher from Meltra than from both Ajax and S23. Net animal liveweight gains were positively correlated with herbage production (r = 0·95, P < 0·05) and DOM consumed (r=0·96. P<0·05).

Slot‐seeding investigations. 6. A comparison of the spread and productivity of different white clover varieties introduced into permanent pasture

AbstractSeeds of six cultivars of white clover were sown in 1983 in slots in tares of permanent pasture in soil‐filled tanks in spring and in small plots in the field during midsummer. The clover cultivars investigated were the large‐leaved Olwin and Milk nova, the medium‐leaved Grasslands Huia and Aberystwyth S100, and the small‐leaved Kent Wild White and Aberystwyth S184. Seeds from an indigenous clover population were also sown in the tanks. All herbage was defoliated at three‐ to six‐week intervals to simulate rotational grazing and assessments were made until autumn 1984.Leaf and stolon production and spread of stolons from the slots were more rapid in Milkanova, S184, Huia and Kent than in Olwen and S100 In the tanks, harvested yields of clover leaf and petiole were largest for Milkanova and Olwen and least for the indigenous population; both Olwen and S100 had a smaller percentage of their total weight outside the slot area than had the other varieties. In the field, Milkanova greatly out yielded all other varieties and S100 yielded the least, contributing 48 and 27%, resf actively, to total herbage yield. The yield of grass differed little between varieties in tanks but in the field it tended to be higher with the smaller than with the larger‐leaved varieties. Total herbage yield was largest for Olwen and Milkanova in tanks and for Milkanova in the field. The greatest weight of stolons in tanks was produced by Olwen and in the field by Olwen and Kent, but the greatest length of stolons and number of nodes in both environments occurred in the smalt‐leaved varieties, especially Kent. Least length of stolons and fewest nodes in the tanks were produced by Olwen and in the field by Milkanova.It was concluded that all the varieties investigated could be successfully slot‐seeded into permanent pastures but that the choice of variety will depend on subsequent use and management of the resulting swards.

A comparison of two cultivars of Holcus lanatus with Lolium perenne, under cutting

AbstractThis work examined whether or not Holcus lanatus, cv. Massey Basyn, is an improvement on plants from German Commercial seed of this species and whether either could outyield Lolium perenne cv. Aberystwyth S23. The three grasses were sown in monoculture in a field near Oxford and received a total of either 250 or 500 kg N ha‐1 over two years. They were also sown with Tri‐folium repens cv. Blanca. The plots were cut 11 times over the 2‐year period at a height of 50 mm from ground level.At the high rate of nitrogen Lolium perenne always gave the highest yields of DM and DOM. In the second year, both types of H. lanatus gave higher yields than L. perenne at the low level of N. The L. perenne and T. repens mixture yielded more than that with H. lanatus and T. repens. H. lanatus depressed the yield of T. repens more than did L. perenne. H. lanatus h lanatus; Massey Basyn was affected less by rust infection than was German Commercial H. lanatus. At the final harvest, plots with r. repens contained more unsown grass than did N‐fertilized plots sown to grasses only.