Achbani E H, Hafidi M, Abdellatif B, Lamaaraf N, Kouta B, Nafie N, Corbière R, Andrivon D
Laboratoire de Phytobactériologie, INRA Centre Régional Saïs-Moyen Atlas BP 578, 50000 Méknès, Morocco.
Commun Agric Appl Biol Sci. 2005;70(3):247-52.
Late blight caused by Phytophthora infestans, is the most important disease of potato in Morocco. Use of partially resistant cultivars should be an essential component of a sustainable management strategy of potato late blight, provided the durability of this form of resistance. It is therefore important to determine the nature of P. infestans Moroccan populations. Mating types were determined for 91 strains of P. infestans collected in the northern (Larache-northern plain), north western (Kénitra) and north eastern (Méknès, Middle Atlas) potato cropping areas of Morocco in 1999-2000, 2000-2001 and 2003-2004. They showed a clear regional structure of these populations, with the presence of both mating types (A1 and A2). Of all isolates collected since 1999, A2 mating type constituted 56% (54 isolates), following by A1 mating type (40.7%, 31 isolates) and A1-A2 (self-fertile) mating type (3.30%, 3 isolates). Populations from Méknès and Kénitra consisted mainly of A2 mating type, whereas populations from Larache predominantly included A1 mating type. Physiological race study revealed the presence of 19 races of P. infestans in the first collection of 25 isolates tested between 1999 and 2001. All known virulence genes were detected in western and northern Moroccan isolates, except virulence for resistance genes R2, R5, and R6 which were absent. All isolates were able to overcome two or more R genes except one isolate (5-1) corresponding to race 1.
由致病疫霉引起的晚疫病是摩洛哥马铃薯最重要的病害。使用部分抗病品种应成为马铃薯晚疫病可持续管理策略的重要组成部分，前提是这种抗性形式具有持久性。因此，确定摩洛哥致病疫霉种群的性质很重要。对1999 - 2000年、2000 - 2001年和2003 - 2004年在摩洛哥北部（拉腊什 - 北部平原）、西北部（凯尼特拉）和东北部（梅克内斯，中阿特拉斯）马铃薯种植区收集的91株致病疫霉菌株进行了交配型测定。结果表明这些种群具有明显的区域结构，同时存在两种交配型（A1和A2）。自1999年以来收集的所有分离株中，A2交配型占56%（54个分离株），其次是A1交配型（40.7%，31个分离株）和A1 - A2（自育）交配型（3.30%，3个分离株）。来自梅克内斯和凯尼特拉的种群主要由A2交配型组成，而来自拉腊什的种群主要包括A1交配型。生理小种研究表明，在1999年至2001年测试的首批25个分离株中存在19个致病疫霉小种。在摩洛哥西部和北部的分离株中检测到了所有已知的毒性基因，但不存在对抗性基因R2、R5和R6的毒性。除了一个对应于小种1的分离株（5 - 1）外，所有分离株都能克服两个或更多的R基因。
