Natural selection in a mixture of eight barley varieties, grown in six successive years. 1. Competition between the varieties

Blijenburg, J. G.; Sneep, J.

doi:10.1007/bf00028195

Cited by 26 publications

(17 citation statements)

References 12 publications

(13 reference statements)

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“…The initial and harvested proportions of the cultivars changed only little, indicating that competitive interactions among the three cultivars were similar. This is in contrast to other studies with barley (Harlan & Martini, 1938;Blijenburg & Sneep, 1975), oats (Murphy et al, 1982), and wheat (Finckh & Mundt, 1992a), where initial and harvested frequencies usually varied greatly.…”

Section: Disease and Yield In Barley Mixtures 811contrasting

confidence: 87%

Host frequency and density effects on powdery mildew and yield in mixtures of barley cultivars

Finckh

Gacek²,

Czembor

et al. 1999

Plant Pathology

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The effects of frequency and density of susceptible plants on barley powdery mildew epidemics were studied in a combined set of addition and replacement series of field trials. In the addition series, plant densities in pure stands of three cultivars, Rambo, Rodos and Grosso (susceptible, moderately resistant and immune, respectively) were varied six-fold. In the replacement series, the three possible two-way mixtures were analysed at different frequencies but at a density corresponding to the maximum pure stand density. Disease and yield were assessed on a per-plant basis. In the pure stands, tillering reduced the range of densities from six-fold to between three-and four-fold, while in the mixtures, frequencies changed only slightly over time, indicating that competitive interactions among the cultivars were roughly equal. Yield per plant decreased logarithmically with increasing density as expected. However, yield per seed head was not correlated with the final number of heads per plot, indicating low competition among heads even at the highest density. Disease in susceptible pure stands increased strongly with decreasing density in 1994 and to a lesser degree in 1995. These differences could have been caused by differences in plant nutritional status and consequent epidemiological effects. Disease reduction on the susceptible cultivars in mixtures varied between 33% and 71% among years. Depending on the length and strength of the epidemic, the effects of host density and frequency on disease severity varied substantially among years.

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Section: Disease and Yield In Barley Mixtures 811contrasting

confidence: 87%

Host frequency and density effects on powdery mildew and yield in mixtures of barley cultivars

Finckh

Gacek²,

Czembor

et al. 1999

Plant Pathology

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“…There are, however, numerous examples of genetic change within populations of cultivated species. For example, where cultivars of annual crops have been sown together in mixtures, changes in the proportion of the cultivars have occurred within five years (e.g., Harlan and Martini, 1938;Blijenburg and Sneep, 1975). Similar rapid changes have also been found when cultivars of perennial pasture species have been sown in mixtures (e.g., Charles, 1961Charles, , 1964Charles, , 1966Brougham and Harris, 1967).…”

mentioning

confidence: 86%

Rapid Divergence of Plant Populations in Response to Recent Changes in Soil Conditions

Snaydon¹,

Davies²

1982

Evolution

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“…Competition between the components of mixtures have been found to change the composition of the mixture in barley (Blijenburg and Sneep 1975; and wheat (Triticum aestivum L.) (Khalifa and Qualset 1974;Tapaswi et al 1991). Agronomic manipulation of a dominant component will strongly affect the growth of the suppressed component (Fukai and Trenbath 1993).…”

Section: Mots Clésmentioning

confidence: 99%

Three-component barley mixtures: Ratio effects in replacement series

Juskiw¹,

Helm²,

Burnett³

2001

Can. J. Plant Sci.

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. 2001. Three-component barley mixtures: Ratio effects in replacement series. Can. J. Plant. Sci. 81: 651-656. Within a species, cultivar mixtures may offer yield and quality advantages if the cultivars have complementary abiotic and biotic stress tolerances. This study was conducted at Botha, Lacombe and Olds, Alberta, from 1992 to 1994 to determine the effect of relative seeding ratios on yield and other traits of 16 three-component barley (Hordeum vulgare L.) mixtures of Virden:Abee:Tukwa all grown at a standard seeding rate of 250 seeds m -2 . Grain yields of these mixtures fell between the yields of the monocrops, with yields of the 20:40:40 and 50:30:20 mixtures being higher than expected based on the weighted mean yields of the monocrops. When stability of yield was measured using ranking or regression analyses, several mixtures had desirable combinations of high yields and good stability with the 20:40:40 and the 40:20:40 mixtures being identified using either method. Test weights, kernel weights, percent thins, protein contents, and disease levels of the mixtures were intermediate to the monocrops; while lodging levels were as low as the best monocrop. As the proportion of any one cultivar in the mixture increased, the traits it brought to the mixture also increased. These mixtures had no yield advantage over growing a high yielding monocrop. Le poids spécifique, le poids d'amande, le pourcentage de graines minces, la concentration de protéines et le taux de maladie des mélanges se situent à mi-chemin de la valeur correspondante pour la culture pure, mais le taux de verse était égal au plus faible enregistré pour la monoculture. Quand la proportion de graines d'un cultivar augmente dans le mélange, les caractères de ce dernier se démarquent aussi davantage. Les mélanges ne présentent aucun avantage sur la production d'une seule espèce à rendement élevé.

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Natural selection in a mixture of eight barley varieties, grown in six successive years. 1. Competition between the varieties

Cited by 26 publications

References 12 publications

Host frequency and density effects on powdery mildew and yield in mixtures of barley cultivars

Host frequency and density effects on powdery mildew and yield in mixtures of barley cultivars

Rapid Divergence of Plant Populations in Response to Recent Changes in Soil Conditions

Three-component barley mixtures: Ratio effects in replacement series

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