Resistance toTurnip mosaic virusinBrassica rapaandB. napusand the analysis of genetic inheritance in selected lines

Abstract

Forty-two Brassica rapaand Brassica napus lines were tested for resistance to Turnip mosaic virus (TuMV) isolates representing the three major pathotypes in Europe. Of these lines, 11 were susceptible to all pathotypes; nine were resistant to one pathotype; eight were resistant to two pathotypes; and 14 were resistant to all three pathotypes. Of the lines tested, 23 were either able to, or had the potential to, discriminate between two different pathotype-3 isolates. Genetic models for inheritance of resistance were proposed for four B. rapa lines: Jong Bai No. 2 had dominant resistance to pathotype 1 conferred by a single allele; PI418957C and Jin G 55 had recessive resistance to pathotype 4 where a single allele was required; PI418957C also had recessive resistance to pathotype 3 where a model with one of two epistatic, unlinked loci was proposed. Jong Bai No. 1 also had recessive resistance to pathotype 3, apparently conferred by alleles at three loci, where any two of the three loci were epistatic and required for resistance.

Mapping and candidate-gene screening of the novel Turnip mosaic virus resistance gene retr02 in Chinese cabbage (Brassica rapa L.)

“…Resistances have been identified in B. rapa that are effective against a broad range of TuMV isolates (Suh et al 1995;Hughes et al 2002;.…”

Genetic mapping of the novel Turnip mosaic virus resistance gene TuRB03 in Brassica napus

“…In contrast, broad-spectrum (mostly recessive), multigenic (in addition to monogenic) resistance has been identified in B. rapa (Rusholme, 2000;Hughes et al 2002;. The predominance of monogenic resistance in B. napus could be due to an evolutionary bottleneck that occurred during the formation of B. napus from what may have been a limited number of interspecies hybridisation events between B. rapa and B. oleracea.…”

“…The use of insecticides to control the disease has proven ineffective, therefore natural plant resistance is likely to be the most effective and environmentally friendly method of controlling TuMV. Recently identified resistances in Brassica rapa appear to be effective against a broad range of TuMV isolates (Suh et al 1995;Hughes et al 2002;. Several different modes of inheritance of TuMV resistance in B. rapa have been described (Yoon et al 1993;Suh et al 1995;Hughes et al 2002;.…”

“…Recently identified resistances in Brassica rapa appear to be effective against a broad range of TuMV isolates (Suh et al 1995;Hughes et al 2002;. Several different modes of inheritance of TuMV resistance in B. rapa have been described (Yoon et al 1993;Suh et al 1995;Hughes et al 2002;. In contrast, predominantly dominant resistance has been identified in Brassica napus (Shattuck and Stobbs 1987;Walsh 1989;Walsh et al 1999;Jenner et al 2002).…”

Swedes and Turnips

“…pekinesis). Several workers have found resistance in Chinese cabbage and these have been examined by Hughes et al (2002) and Walsh et al (2002). The most promising resistances appear to be those obtained by Liu et al (1996).…”