Hospedabilidade e resistência de cultivares de alface {Lactuca sativa L) aos nematóides das galhas Meliodogyne incógnita (raças 1, 3 e 4) e Meloidogyne javanica

Abstract

Evaluation of lettuce (Lactuca sativa L.) cultivars for resistance to root knot nematodes Meloidogyne incógnita (races 134) andMeloidogyne javanica. Lettuce cultivars are often susceptible to both Meloidogyne incógnita and Meloidogyne javanica, the most widespread root knot nematode species in Brazil. No emphasis has been placed so fer in breeding lettuce for nematode resistance. Four trials were carried out atthe Experiment Station ofIjaci-MG , Brazil, toevaluate the leveis ofresistance of28 lettuce cultivars to race 1, 3 and 4.ofM incógnita andtoMeloidogynejavanica. Plants were grown oninoculated substrate in speeling trays, in randomized complete block design with nematode eggs of each of races L, 3 and 4 ofMeloidogyne incógnita or ofthe specie Meloidogyne javanica. Number ofgalls and egg masses per root system, as well asnumber ofnematode. oggs. per plant weie recorded for each plant. Correlation between these traits were rather low, but nonetheless significant. No differences among. lettuce cultivars were fòund relativa to the responses to race 1 of Meloidogyne incógnita. Cultivar Crespa Grande Rápida (Agroflora) was consistenrly resistant to race 3 and 4 of Meloidogyne incógnita as well as to Meloidogyne javanica, whereas Regina 71 proved to be susceptible to these nematodes.