A nursery with 184 entries including French, European, North African and CIMMYT/ICARDA lines, was phenotyped for its resistance in field trials inoculated with wheat leaf rust, in 4 locations in France and 2 locations in Mexico, in 2009 and 2010. Moreover, the 184 entries were phenotyped for their resistance to 9 pathotypes in the glasshouse. Genes Lr27+31 and Lr3 were effective in France, but given their breakdown in Mexico, they are unlikely to be durable sources of resistance in France. Genes Lr61, LrCamayo, Lr19 and Lr47 were efficient both in Mexico and in France, and could represent valuable sources of resistance. Some lines displayed a high level of resistance in all locations, likely due to an unknown major gene. Four French entries, as well as several slow rusting lines from CIMMYT, displayed a good level of partial resistance in all environments tested. Association mapping, using 1300 DArT markers and 34 variables from the phenotyping studies, revealed two QTLs and one locus corresponding to a major gene: i) on chromosome 2B, a QTL was tagged by wPt-1064, wPt-6477 and wPt-0408 ii) on chromosome 6B, a QTL was tagged by wPt-8059, wPt-7065 iii) on chromosome 7B, a major gene was tagged by wPt-0465, wPt-3700 and wPt-9515, which corresponded to Lr14a. This gene is not effective in France, whereas it is still efficient in Mexico.