Reniform nematode, Rotylenchulus reniformis, has been known to cause yield losses in cotton of 20 to 30% compared with yields on non-infested soils or yield from fields protected by nematicides. About 30% of the finer textured soils of the Lower Rio Grande Valley are infested with reniform nematodes and infestations have been reported in the Brazos River Valley and the Southern High Plains of Texas. Reniform nematode is the second most damaging nematode to cotton with root-knot, Meloidogyne incognita, being the more wide spread.

A high level of resistance has been found in Gossypium longicalyx, a wild diploid relative of upland cotton. Direct introgression of this trait is not easily obtained because of ploidy level differences in the wild relative and commercial cotton. However, a set, minus one, of germplasm lines have been developed in which each of the twelve contain a different chromosome of G. longicalyx. This research will identify plants of each monosomic addition line of G. hirsutum carrying a unique monosomic chromosome of G. longicalyx and determine if any monosome confers resistance to the reniform nematode in G. hirsutum.