Screening Lycopersicon spp. for New Genes Imparting Resistance to Root-Knot Nematodes (Meloidogyne spp.). M. Ammati, Former Graduate Student, University of California, Riverside 92521. I. J. Thomason, Professor of Nematology and Plant Pathology, University of California, Riverside 92521, and P. A. Roberts, Extension Nematologist, University of California Kearney Agricultural Center, Parlier 93648. Plant Dis. 69:112-115. Accepted for publication 9 July 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-112.

Lycopersicon peruvianum, L. glandulosum, L. cheesmanii, L. parviflorum, and L. pimpinellifolium accessions were tested for root-knot nematode resistance. L. peruvianum accession 270435 and L. glandulosum accessions 126440 and 126443 were resistant to Meloidogyne hapla. Six L. peruvianum accessions tested were resistant to M. incognita and M. arenaria. Variations in the level of resistance to four M. incognita races were observed among L. peruvianum accessions. Variation also occurred within the same accession. Race 3 of M. incognita reproduced less than other M. incognita races on L. peruvianum and L. glandulosum accessions. Results from greenhouse tests were complemented by laboratory isozyme studies of the variant in locus 1 of acid phosphatase (Aps-1¹). Results of our work suggested the possibility of a new resistance gene(s) to M. hapla and to the other Meloidogyne spp.

Keyword(s): breeding, tomato.