The Effect of Frequency of Defoliation on the Yield of Mixtures of S22 (Oiploid) and Tetra (Tetraploid) Italian Ryegrass in Early Establishment

Alcock, M. B.; Morgan, E. W.

doi:10.1111/j.1365-2494.1966.tb00448.x

Cited by 15 publications

(17 citation statements)

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“…These techniques have been applied by Gardner and Hunt (1963) and England (1968) to demonstrate competition effects. Alcock and Morgan (1966) examined competition between S22 (diploid) and Tetra (tetraploid) Italian ryegrass in early establishment following the de Wit (1960) model of plant competition and suggested a yield advantage from mixing. However, van den Bergh (1968), from a comprehensive study of grass yields in mixed and pure stands, largely discredited the possibility of obtaining increased yields from mixing grasses.…”

Section: Introductionmentioning

confidence: 99%

Competition among pasture plants

Harris

Thomas²

1970

New Zealand Journal of Agricultural Research

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Simulated swards forming a replacement series of the ryegrass cultivars 'Grasslands Manawa' and 'Grasslands Ruanui' consisting of two monocultures and three mixtures were cut during establishment to two heights and at two frequencies. The cutting frequencies were continued for a year after the first cut, after which all swards were cut uniformly until the experiment was concluded 2 years after sowing.Yields, tiller numbers, and plant survival were recorded separately for the cultivars. These data were used to fit parameters to the twospecies competition model of de Wit (1960).Manawa was initially dominant in all cutting systems, and this dominance was greatest where cutting was infrequent. Initial lax cutting reduced the suppression of Ruanui. The suppression of Ruanui during establishment is largely attributed to shading by Manawa, and where hard cutting removed stubble, Ruanui tiller numbers were reduced and Ruanui plants died in the mixtures with Manawa. This effect hindered the transition to dominance of Ruanui in the summer and autumn after sowing.The results indicate that mixing of the cultivars would be advantageous as a function of both herbage yield and quality under the frequent lax cutting system, because the cutting did not markedly suppress Ruanui initially, allowing Ruanui to contribute substantially to the yields of the mixtures in the post-reproductive period when yields of Manawa were low. With infrequent hard cutting the yield contribution of Ruanui in mixture during the post-reproductive period was small and, because Manawa was unable to utilise the space made available by the death of Ruanui plants, depressed yields from mixing were observed. It is concluded that no advantage is gained by mixing Ruanui and Manawa where the management system in the first year tends to maximise the yield of Manawa.

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Section: Introductionmentioning

confidence: 99%

Competition among pasture plants

Harris

Thomas²

1970

New Zealand Journal of Agricultural Research

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“…In the present work the components in both of the highly productive mixtures were of similar height, but in each case one component was of lax or prostrate habit while the other was erect. It has been observed that during the first one or two years of a sward, where higher production has been obtained from grass mixtures than from their highest yielding component in monoculture, these mixtures have consisted of essentially similar types, for example, mixtures of similar varieties (1,6,7,10) or genotypes from within a single variety. Studies on mixtures of contrasting grass species (2, 3) have failed to reveal increased production in comparison with monocultures, even with all bispecific combinations of five contrasting species grown with high nutrient and water input (Rhodes, unpublished results).…”

Section: Lai At Complete Light Interceptionmentioning

confidence: 99%

“…Several recent studies have indicated that mixtures of certain grass varieties may outyield their highest yielding component in monoculture, when subjected to precisely defined and controlled management practices (1,6,7,10).…”

Section: Introductionmentioning

confidence: 99%

“…It has been suggested on theoretical grounds that complex ecosystems, such as mixtures of grass species or varieties, might be more efficient in utilizing the available environmental resources than simple ones (4). Several recent studies have indicated that mixtures of certain grass varieties may outyield their highest yielding component in monoculture, when subjected to precisely defined and controlled management practices (1,6,7,10).…”

Section: Introductionmentioning

confidence: 99%

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THE PRODUCTION OF CONTRASTING GENOTYPES OF PERENNIAL RYEGRASS (LOLIUM PERENNE L.) IN MONOCULTURES AND MIXED CULTURES OF VARYING COMPLEXITY

Rhodes

1970

Grass and Forage Science

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An experiment was set up to measure the production from donally propagated micro-swards of four contrasting ryegrass genotypes, grown in monocultures and in all possible combinations of mixed cultures consisting of two, three and all four genotypes. Water and nutrients were supplied frequently in non-limiting quantities and the swards were subjected to two cutting frequencies.The yield ranking of the monocultures and mixed cultures diifered at the two cutting frequencies. Under infrequent cutting, though not under frequent cutting, two mixtures, each containing two genotypes, were more productive than their highest yielding components in monoculture. The physiological basis of this apparent synergy is hriefly discussed and it is suggested that the increased yield may he due to more efficient light utilization hy the mixtures. In general, yields of other mixtures, including those consisting of 3 or 4 genotypes were intermediate between the highest and lowest yielding components in monoculture.The agronomic and plant-hreeding implications of the results are discussed.

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“…There have been recent reports of competition studies with herbage grasses in which mixtures gave higher yields than monocultures under certain conditions (1,8,11). Also there appeared to be a different relationship between yields and tiller numbers of grasses in monocultures and mixtures (7,10).…”

Section: Introductionmentioning

confidence: 99%

Analyses of Yield From a Competition Trial With Perennial Ryegrass

Thomson

1970

Grass and Forage Science

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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 ofthe 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 hetween 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 tahle only at the first harvest. The change in the competitive ahility of the four varieties throughout the season was examined. The relative ranking order of varieties for competitive ability altered as the season progressed.

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The Effect of Frequency of Defoliation on the Yield of Mixtures of S22 (Oiploid) and Tetra (Tetraploid) Italian Ryegrass in Early Establishment

Cited by 15 publications

References 1 publication

Competition among pasture plants

Competition among pasture plants

THE PRODUCTION OF CONTRASTING GENOTYPES OF PERENNIAL RYEGRASS (LOLIUM PERENNE L.) IN MONOCULTURES AND MIXED CULTURES OF VARYING COMPLEXITY

Analyses of Yield From a Competition Trial With Perennial Ryegrass

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