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Logo of annbotAboutAuthor GuidelinesEditorial BoardAnnals of Botany
 
Ann Bot. 2010 June; 105(7): 1199–1210.
Published online 2009 October 8. doi:  10.1093/aob/mcp253
PMCID: PMC2887060

Genetic analysis of potassium use efficiency in Brassica oleracea

Abstract

Background and Aims

Potassium (K) fertilizers are used in intensive and extensive agricultural systems to maximize production. However, there are both financial and environmental costs to K-fertilization. It is therefore important to optimize the efficiency with which K-fertilizers are used. Cultivating crops that acquire and/or utilize K more effectively can reduce the use of K-fertilizers. The aim of the present study was to determine the genetic factors affecting K utilization efficiency (KUtE), defined as the reciprocal of shoot K concentration (1/[K]shoot), and K acquisition efficiency (KUpE), defined as shoot K content, in Brassica oleracea.

Methods

Genetic variation in [K]shoot was estimated using a structured diversity foundation set (DFS) of 376 accessions and in 74 commercial genotypes grown in glasshouse and field experiments that included phosphorus (P) supply as a treatment factor. Chromosomal quantitative trait loci (QTL) associated with [K]shoot and KUpE were identified using a genetic mapping population grown in the glasshouse and field. Putative QTL were tested using recurrent backcross substitution lines in the glasshouse.

Key Results

More than two-fold variation in [K]shoot was observed among DFS accessions grown in the glasshouse, a significant proportion of which could be attributed to genetic factors. Several QTL associated with [K]shoot were identified, which, despite a significant correlation in [K]shoot among genotypes grown in the glasshouse and field, differed between these two environments. A QTL associated with [K]shoot in glasshouse-grown plants (chromosome C7 at 62·2 cM) was confirmed using substitution lines. This QTL corresponds to a segment of arabidopsis chromosome 4 containing genes encoding the K+ transporters AtKUP9, AtAKT2, AtKAT2 and AtTPK3.

Conclusions

There is sufficient genetic variation in B. oleracea to breed for both KUtE and KUpE. However, as QTL associated with these traits differ between glasshouse and field environments, marker-assisted breeding programmes must consider carefully the conditions under which the crop will be grown.

Key words: Arabidopsis, Brassica oleracea, genetics, potassium (K), potassium use efficiency (KUE), quantitative trait loci (QTL), shoot

Articles from Annals of Botany are provided here courtesy of Oxford University Press