Comparison of Reproductive Efficiency of Meloidogyne chitwoodi on Solanum bulbocastanum in Soil and In Vitro Tests. C. R. Brown, Research Geneticist, Vegetable and Forage Crops Production, Agricultural Research Service, U.S. Department of Agriculture. H. Mojtahedi, and G. S. Santo. Research Associate, and Professor, Nematology, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser 99350. Plant Dis. 73:957-959. Accepted for publication 25 June 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1989. DOI: 10.1094/PD-73-0957.

The reproductive efficiencies (R = final population of eggs [Pf]/initial population of eggs [Pi]) of races 1 and 2 of Meloidogyne chitwoodi, the Columbia root-knot nematode, were tested on 22 clones of Solanum bulbocastanum derived from five plant introductions. Twenty clones showed nonhost reactions (R = <0.1) for race 1, and 13 were poor hosts (0.1 <R <1.0) for race 2. Two clones were nonhosts to both races. The host reactions of excised roots of potato, tomato, and 13 clones of S. bulbocastanum to races of M. chitwoodi were also tested in monoxenic culture. The reproductive efficiencies of both races on host genotypes in pot vs. root culture were significantly correlated. However, the two screening methods measured different levels of resistance to race 2 in the case of three clones of S. bulbocastanum.

Keyword(s): germ plasm enhancement.