Competition between cultivars of fodder kale (Brassica oleracea L.) in yield trials with single-row plots

Bradshaw, J. E.

doi:10.1007/bf00021851

Cited by 17 publications

(14 citation statements)

References 7 publications

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“…In these trials, interplot competition may lead to biased estimations of yield performances [9] and particularly to the overestimation of the value of aggressive genotypes. Several authors have noted very low or even no correlations between yields of genotypes in singlerow plots and their yield in larger plots due to competition [6,10,15].…”

Section: Introductionmentioning

confidence: 99%

Correction models for intergenotypic competition in winter wheat

et al. 2000

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Section: Introductionmentioning

confidence: 99%

Correction models for intergenotypic competition in winter wheat

et al. 2000

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“…However, with single-row plots inter-plot competition can bias the results . In cereals (Jensen .& Federer, 1964), cassava (Kawano et al ., 1978), field beans (Kempton & Lockwood, 1984) and kale (Bradshaw, 1986) inter-plot competition has been associated with plant height, and in potatoes (Kempton,198 ) and sugar beet (Kempton, 1982) with plot yield .…”

Section: Introductionmentioning

confidence: 99%

Inter-plot competition in yield trials of swedes (Brassica napus ssp. rapifera L.)

Bradshaw

1989

Euphytica

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Two experiments were done to evaluate the use of single-row plots for assessing dry-matter yield of swedes .In the first experiment the correlation between the dry-matter yields of 20 cultivars in unguarded single-row plots and those in guarded double-row plots was poor (r = 0 .39) . It was improved (r = 0 . 8) by adjusting the single-row plot fresh-weight yields for inter-plot competition, through an analysis of covariance in which the covariate was the mean of the adjacent plot yields, and then estimating the pure stand dry-matter yields . However, the correlation was still lower than that between unguarded double-row plots and the guarded double-row plots (r = 0 .73), and this latter correlation was also improved (r = 0 .82) by adjusting the fresh-weight yields of the unguarded plots for inter-plot competition .The second experiment provided an explanation for the partial success of the covariance adjustment . The individual neighbour effects of six cultivars were determined . Doon Major and Ruta Otofte decreased the yields of adjacent cultivars whereas Dryden and Melfort increased them . Angela and Magres had little effect . The correlation between the dry-matter yield neighbour effects of cultivars and their fresh-weight yields was high (r = -0.81), but not complete . So although competitive ability was associated with root fresh-weight yield, other factors must also be involved .It was concluded that a two-replicate trial with unguarded double-row plots is preferable to a fourreplicate trial with unguarded single-row plots for dry-matter yield assessment of early generation families in a pedigree swede breeding programme .

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“…Their assessment in single-row plots would not require unrealistically high levels of resources if there were few replicates. Interplot competition is unlikely to be a serious problem in an outbreeding root crop such as turnip, where the aim is an open-pollinated cultivar, in contrast to kale, where competition arises from height differences and very tall cultivars are undesirable (Bradshaw 1986), and swede, which is a root crop where inbred cultivars are grown in pure stands (Bradshaw 1989). The formula for the response to selection given earlier was used to determine the optimum balance between the intensity of selection and heritability as affected by the number of trials and replicates within trials for a fixed total number of plots.…”

Section: Discussionmentioning

confidence: 99%

Turnip (Brassica rapa L. ssp. rapifera Metzg.) population improvement and cultivar production

Bradshaw¹,

Gemmell²,

Gowers³

et al. 2002

Plant Breeding

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In 1977, a fodder turnip breeding programme was started from seven cultivars with the primary aim of increasing dry-matter yield. The breeding method chosen was population improvement by half-sib family selection on a biennial cycle. Seed production in polythene tunnels with blowflies as pollinators was followed by assessing the resulting progenies in replicated yield trials and observation plots from which plants were selected for the next cycle. Six generations of selection resulted in a population with a yield that was 25% higher than the mean of the initial seven cultivars. This was remarkably close to the predicted superiority of the population, despite a significant discrepancy in one generation. It is concluded that the greatest response to selection per year would be achieved by selecting eight families from 128 assessed for 1 year in trials at two or three sites with an overall total of six replicates, given a resource limit of 800 plots.

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Competition between cultivars of fodder kale (Brassica oleracea L.) in yield trials with single-row plots

Cited by 17 publications

References 7 publications

Correction models for intergenotypic competition in winter wheat

Correction models for intergenotypic competition in winter wheat

Inter-plot competition in yield trials of swedes (Brassica napus ssp. rapifera L.)

Turnip (Brassica rapa L. ssp. rapifera Metzg.) population improvement and cultivar production

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