The Relationship Between Cotyledon and Adult Plant Resistance to Downy Mildew (Peronospora Parasitica) in Brassica Oleracea

Coelho, Paula S.; Leckie, Donald G.; Bahćevandžiev, Kiril; Valério, Luísa; Astley, D.; Boukema, I.W.; Crute, I. R.; Monteiro, António A.

doi:10.17660/actahortic.1998.459.39

Cited by 41 publications

(24 citation statements)

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“…The gradual increases in leaf resistance from the bases to the apices of the plants in Experiments 1, 2 and 3 agrees with field observations of susceptible Brassica plants, where the lowest leaves are the first to show disease symptoms with larger lesions and heavier sporulation (Coelho et al 1998;Jensen et al 1999). Our results agree with those found by Agnola et al (2003), who compared downy mildew susceptibility of leaf discs from fully-developed leaves occupying 17 leaf positions on 10-18 week-old Brassica plants and showed that discs collected below the sixth leaf are susceptible, and those collected above the sixth leaf are moderately susceptible to resistant.…”

Section: Resultssupporting

confidence: 86%

Leaf position, leaf age and plant age affect the expression of downy mildew resistance in Brassica oleracea

Coelho¹,

Valério

Monteiro

2009

Eur J Plant Pathol

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Downy mildew caused by the oomycete Hyaloperonospora parasitica (formerly Peronospora parasitica) is a worldwide foliar disease of Brassica vegetables, which may cause seedling loss in the nurseries and damage to adult plants in the field. Disease symptoms start from the lower leaves and progress upwards. Three experiments were conducted under controlled environment conditions, using inoculated leaf discs, to determine the influence of leaf position, plant age, and leaf age on the expression of resistance to downy mildew in various Brassica oleracea genotypes. The upper leaves were more resistant than the lower leaves when 7-19 week-old plants of broccoli and Tronchuda cabbage were tested. Broccoli lines 'PCB21.32' and 'OL87123-2' were fully susceptible at the cotyledon stage, showed a clear resistance increase from lower to upper leaves at 6 weeks and 'PCB21.32' was fully resistant 16 weeks after sowing. Immature leaves were more resistant than adjacent fully expanded mature leaves. Susceptibility increased with leaf age when the same leaf was tested at two to 4-week intervals. Leaf age and upper-leaf position on the stem had opposite effects on disease score, since younger leaves collected from lower positions and older leaves collected from upper positions tended to score similarly in compatible interactions. The progression of downy mildew from the base of the plant upwards on B. oleracea in the field could be due to differences in leaf resistance in addition to environmental variation. To maximise the expression of a compatible reaction in adult plants lower leaves of Brassica plants that are at least 12 weeks-old should be used.

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Section: Resultssupporting

confidence: 86%

Leaf position, leaf age and plant age affect the expression of downy mildew resistance in Brassica oleracea

Coelho¹,

Valério

Monteiro

2009

Eur J Plant Pathol

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“…tronchuda is resistant to the seven Portuguese isolates of P. parasitica at cotyledon stage. Coelho et al (1998) verified that DM resistance in 'Couve Algarvia' is also effective at adult-plant stage in the field.…”

Section: Introductionmentioning

confidence: 62%

“…There is evidence that DM resistance is dependent on plant age (Dickson & Petzoldt, 1993;Coelho et al, 1998). Coelho & Monteiro (2003a) compared cotyledon with adult-plant resistance in several B. oleracea accessions and found that the two types of resistance are very poorly correlated, but they were unable to determine whether cotyledon and adult-plant resistance are under an independent genetic control.…”

Section: Introductionmentioning

confidence: 99%

Inheritance of downy mildew resistance at cotyledon and adult-plant stages in ‘Couve Algarvia’ (Brassica oleracea var. tronchuda)

et al. 2005

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“…italica) (Coelho et al 1998), whose resistance is determined by a single major gene (Coelho and Monteiro 2003a).…”

Section: Plant Materialsmentioning

confidence: 99%

“…1967;HoserKrauze et al 1995;Jensen et al 1999) and adult plant stages (Natti and Atkin 1960;Dickson and Petzoldt 1993;Mahajan et al 1995;Coelho et al 1998), thereby generating confidence that genetic resources are available for the genetic control of this disease and, consequently, the use of pesticides can be reduced. Coelho et al (1998) identified a new source of resistance to downy mildew in mature broccoli plants. This resistance is dominantly inherited and controlled by a single locus (Coelho and Monteiro 2003a) and shows good potential for direct use in commercial broccoli breeding.…”

Section: Introductionmentioning

confidence: 99%

Mapping of a locus for adult plant resistance to downy mildew in broccoli (Brassica oleracea convar. italica)

et al. 2004

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The identification of the gene Pp523, conferring downy mildew resistance to adult plants of broccoli (Brassica oleracea convar. italica), led to the construction of a genetic map that included this resistance locus, 301 amplified fragment length polymorphisms, 55 random amplified polymorphic DNAs, 46 inter-simple sequence repeats, three simple sequence repeats, four other PCR markers and a flower colour locus, all gathered into nine major linkage groups. Nineteen additional molecular markers were clustered into one group of four markers, one group of three markers and six pairs of markers. The map spans over 731.9 cM, corresponding to 89.5% of the 818 cM estimated to be the total genome length. A significant number of the mapped markers, 19.3%, showed distorted segregation. The average distance between mapped adjacent markers is 1.64 cM, which places this map among the densest published to date for this species. Using bulked segregant analysis, we identified a group of molecular markers flanking and closely linked in coupling to the resistance gene and included these in the map. Two markers linked in coupling, OPK17_980 and AT.CTA_133/134, are located at 3.1 cM and 3.6 cM, respectively, at each side from the resistance gene. These markers can be used for marker-assisted selection in breeding programs aiming at the introgression of this gene in susceptible B. oleracea genotypes. The fine mapping of the genomic region surrounding the Pp523 resistance gene is currently being carried out, a basic condition for its isolation via positional cloning.

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The Relationship Between Cotyledon and Adult Plant Resistance to Downy Mildew (Peronospora Parasitica) in Brassica Oleracea

Cited by 41 publications

References 0 publications

Leaf position, leaf age and plant age affect the expression of downy mildew resistance in Brassica oleracea

Leaf position, leaf age and plant age affect the expression of downy mildew resistance in Brassica oleracea

Inheritance of downy mildew resistance at cotyledon and adult-plant stages in ‘Couve Algarvia’ (Brassica oleracea var. tronchuda)

Mapping of a locus for adult plant resistance to downy mildew in broccoli (Brassica oleracea convar. italica)

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