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Identification of a Brassica juncea-derived recessive gene conferring resistance to Leptosphaeria maculans in oilseed rape

Saal, B., Brun, H., Glais, I., Struss, D.
Plant breeding 2004 v.123 no.6 pp. 505-511
Brassica juncea, recessive genes, disease resistance, fungal diseases of plants, Leptosphaeria maculans, plant pathogenic fungi, chromosome addition, introgression, plant breeding, Brassica nigra, Brassica carinata, inheritance (genetics), seedlings
Screening of 212 spring type Brassica napus lines carrying B genome chromosome additions and introgressions from B. nigra, B. juncea and B. carinata resulted in the identification of one line segregating for resistance to Leptosphaeria maculans (anamorph Phoma lingam) at the seedling (cotyledon) stage. This line was derived from an interspecific hybrid containing the B genome of B. juncea. Trypan blue staining of cotyledons from resistant individuals demonstrated a hypersensitive response which is delayed in plants with intermediate lesion size. Genetic analysis supported the hypothesis of a monogenic recessive inheritance of resistance. The resistance gene, termed r(j)lm2, is effective in spring and winter type oilseed rape backgrounds against all tested virulent pathotypes, including two isolates which have been shown to overcome two dominant (race-specific) B genome-derived resistance genes in B. napus.