Breeding varieties for increased disease resistance is a major means to control epidemics. However, the deployment of resistance genes through space and time drives the genetic composition of the pathogen population, directionally altering pathotype frequencies. In France, Leptosphaeria maculans causes stem canker on Brassica napus oilseed rape crops but not on B. juncea condiment mustard. Prior to the deployment of winter B. napus varieties with Rlm6 resistance gene introduced from B. juncea, the aim of our study was to investigate if this deployment could impact disease control in condiment mustard. We assessed the presence of resistance genes against the disease in a set of current French B. juncea varieties and breeding lines with a set of five differential L. maculans isolates carrying know Avr/avr genes. Rlm6 was detected in all 12 condiment mustard varieties. Rlm5 was also detected in eight varieties. No additional resistance genes were detected with the set of isolates used. Because the frequency of isolates virulent on Rlm6 is very low in France, these results indicate that Rlm6 gene is a major component of disease control in the French B. juncea mustards tested. Using Rlm6 in oilseed rape varieties will very likely induce an increase in frequency of Rlm6 virulent isolates. This raises the acute concern of a wise deployment of oilseed rape around the condiment mustard growing area. Scientific knowledge on adaptation dynamics, spatial segregation of crops and cooperation between actors is currently available in order to mitigate the risk and advert negative consequences of the introduction of Rlm6 resistance gene in oilseed rape varieties.

选育品种以提高抗病性是控制流行病的主要手段。然而，抗性基因通过空间和时间的部署驱动了病原体种群的遗传组成，从而定向改变了病态频率。在法国，Leptosphaeria maculans导致甘蓝型油菜油菜油菜茎枯萎，而芥菜型芥菜酱芥子油不引起茎枯病。在部署来自芥菜油菜的带有Rlm6抗性基因的冬季油菜品种之前，我们研究的目的是调查这种部署是否会影响调味芥末的疾病控制。我们评估了一组当前的法国芥菜B.juncea品种和带有五个带有已知Avr / avr基因的五个斑节状黄斑分离株的育种系中对该病的抗性基因的存在。在所有12种调味芥末品种中均检测到Rlm6。还在八个变种中检测到Rlm5。使用该组分离株未检测到其他抗性基因。由于在法国对Rlm6有毒力的分离株的频率非常低，因此这些结果表明Rlm6基因是法国B. juncea疾病控制的主要组成部分。芥末测试。在油料油菜品种中使用Rlm6，极有可能导致Rlm6强毒分离株频率增加。这引起了人们对在调味芥子生长区周围明智地部署油菜的强烈关注。目前可利用的有关适应动力学，作物空间隔离和行动者之间合作的科学知识，可减轻在油菜品种中引入Rlm6抗性基因的风险并减轻其负面影响。