Variability in Crop Plants, Its Use and Conservation

Simmonds, N. W.

doi:10.1111/j.1469-185x.1962.tb01620.x

Cited by 211 publications

(104 citation statements)

References 52 publications

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“…It was uncommon for a mixture to yield less than the mean of its components. These results agree well with the earlier works reviewed by Simmonds (1962), Trenbath (1974) andWolfe (1985). The present results are also in accordance with recently published studies of barley varietal mixtures by Baker andBriggs (1984), Houmoeller et al (1986), Karjalainen and Hiivola (1987), Gieffers andHesselbach (1988), Ibenthal et al (1988) and Aufhammer and Stutzel (1989).…”

Section: Yield Advantagessupporting

confidence: 94%

Competition and yield advantage in barley-barley and barley-oats mixtures

Jokinen¹

1991

AFSci

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Competition and yield advantage in barley varietal mixtures and in barley-oats mixtures were investigated. The trials were based on replacement series, but in a few cases the overall density of the stand was varied on the basis of an addition series. Both models of competition, one based on the de Wit model and the other upon a linear regression model, agreed as to which component was the dominant and which was the subordinate in the mixture. The competition coefficients from regression analyses depicted competition between components better in a dense than in a sparse stand. The competitive ability of a genotype did not depend directly upon individual characters of the genotype, such as rate of initial development, earliness, culm height, tillering capacity or grain yield in monoculture (adaptation), A good combination of characters from the viewpoint of competition was provided by the barley cv. Arra with its rapid initial development and rapid culm growth (earliness), the variety being dominant irrespective of number of components in the mixture, stand density, level of nitrogen fertilization or growing season. This suggests that competitive relations and distribution of resources within a mixture are determined at an early stage in the growing period. In other cases the competitive ability of a genotype varied from one environment to another with the competitive relations between components being inconsistent. The dominance of an aggressor usually increased with increasing nitrogen fertilization especially when the total density of the stand was high. As a rule, competition affected all the components of yield with the kernel weight being least affected. The grain yield of varietal mixtures did not differ from the yield of the highest yielding component grown alone, i.e., mixtures did not over yield. The relative yield total of varietal mixtures was higher at low (RYT > 1) than at optimal densities (RYT =1). Also the relative yield total was higher under conditions where the nitrogen fertilization was not optimal. The results of a varietal trial repeated during three successive years indicated that the relative yield total of a given mixture varied from one growing season to another, fluctuating around unity. Thus highly adapted barley varieties appear to compete for the same resources, and the grain yield advantage of such mixtures is marginal. The results of the barley-oats mixture trials revealed that the mixture may over yield. The relative yield totals of barley-oats mixtures were usually equal to or greater than unity the latter suggesting that the mixtures of barley and oats may use resources more efficiently than monocultures, and some grain yield advantage could be achieved with such mixtures. The protein yield of the barley-oats mixtures did not differ from the yield of the highest yielding component grown alone. The ratio of actual and expected protein yield and the relative protein yield total were usually slightly greater than one. The grain yields of mixtures were not consistently more stable than monocultures as determined by the coefficient of variation.

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Section: Yield Advantagessupporting

confidence: 94%

Competition and yield advantage in barley-barley and barley-oats mixtures

Jokinen¹

1991

AFSci

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“…Fumigation (Taylor 197ti (Clark 1980 For personal use only. These results agree with earlier reports (Simmonds 1962 …”

supporting

confidence: 83%

Experiments With a Barley-Oat Mixture and Its Components

Fejer¹,

Fedak²,

Clark³

1982

Can. J. Plant Sci.

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Soil treatments with nitrogen, lime and fumigation of mixed grain seeded in a 1:1 ratio of barley and oats were applied for 2 yr. They induced relatively few changes in agronomic characters even though a sloping terrain was employed the first year compared with a flat area the second year. Fumigation reduced spot blotch development the first year but not the second year. Kernel yield and protein content were relatively higher in mixtures when compared with average values for pure stands but they were not as high as the highest component.

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“…Toutefois, un des m6langes a donn6 un rendement significativement inf6rieur d celui attendu selon les rendements en peuplements purs. La diff6rence de (Allard l96l ;Simmonds 1962), and (iii) more stable resistance to disease (Browning and Frey 1969 (Roy 1961) and barley (Hordeum vulgare) (Gustafsson 1953 (Stringfield 1959;Eberhart et al. Funk and Anderson 1964, Kannenberg and Hunter 1972Juroda-Tovar and Compton 1974;Thompson 1977),but in one study mixtures have given yields both above and below their component means (Kannenberg 1974 (Kannenberg and Hunter 1972) and potato clones (Doney et al 1965) were stronger in competitive influence as the ability to yield increased.…”

Section: -72mentioning

confidence: 99%