Relationships among Pratylenchus jaehni and P. coffeae populations from Brazil.

The relationships among Pratyleuchus jaehni (C 1 ) and six amphimitic Pratylenchus populations from Brazil (three from banana, PcB 1 , PcB 2 , and PcB 3 ; one from Aglaonema sp., M 2 ; one from coffee, K 5 ; and one from citrus, C 2 ) were studied through morphological and molecular analysis, and pathogenicity test. The analysis of morphometric characteristics of PcB 1 , M 2 , C 2 and K 5 , compared with P. jaehni and P. coffeae (K 6 ) data obtained from literature, delineated three groups: P. coffeae (K 6 ), PcB 1 and M 2 ; P. jaehni (C 1 ) and C 2 ; and K 5 . RAPD analysis of PcB 1 , PcB 2 , PcB 3 , M 2 , C 2 , K 5 and P. jaehni (C 1 ) demonstrated that these populations form three distinct genetic groups: PcB 1 , PcB 2 , PcB 3 and M 2 ; P jaehni and C 2 ; and K 5 . In pathogenicity test, K 5 reproduced well on coffee and caused extensive root necrosis, but C 2 did not. Population C 2 reproduced well on Rangpur lime, which was previously rated as poor host to K 5 . Therefore, the results demonstrated that C 2 is P.jaehni, K 5 is an undescribed species of Pratylenchus, and PcB 1 , PcB 2 and PcB 3 are P. coffeae. The taxonomic status of M 2 remains inconclusive.