Barham, W. S. and N. N. Winstead.
Tomato breeding lines received from Gilbert and McGuire of the Hawaii Station and from Harrison of the Texas Station were found resistant to 4 species of root-knot nematodes. Gilbert's conclusion that resistance to Meloidogyne incognita is monofactoral was confirmed; however, it has been concluded that resistance is incompletely dominant. In addition, resistance to M. javanica, M. arenaria, and M. incognita acrita was found to be controlled by the same gene. It is concluded that even though this factor is incompletely dominant, the level of resistance of hybrids resulting from crosses between homozygous resistant and homozygous susceptible tomato lines is sufficient to warrant the use of such F1 hibrids in tomato production in soils infested with one or more of these four nematode species.