부산대학교 도서관

Rotylenchulus reniformisLinford & Oliveira is increasing in incidence in cotton‐growing areas throughout the southern USA east of New Mexico. Cotton (Gossypium hirsutumL.) cultivars resistant to R. reniformisare currently unavailable. Management depends on a crop sequence with nonhosts of the nematode. In South Texas, the sequence of cotton with grain sorghum [Sorghum bicolor(L.) Moench] or corn (Zea maysL.) has become a standard practice. To improve farm efficiency, the implementation of rotation crops that are economically superior to grain sorghum is desirable. Eighteen cultivars of soybean [Glycine max(L.) Merr.] were tested in nonfumigated and in fumigated sandy loam soil infested with R. reniformisto evaluate nematode resistance of soybean under field conditions. Shank application of 1,3‐dichloropropene at a 38‐cm depth reduced R. reniformispopulation densities at the 15‐ to 60‐cm depth compared with preseason counts. The effect of each soybean cultivar on the growth and yield of a subsequent cotton crop was compared with the impact of grain sorghum and fallow. High‐yielding cultivars of soybean (HY574, Padre, DP7375RR, and NK83‐30) with reniform nematode‐suppressing potential were identified among cultivars within maturity groups 5, 6, 7, and 8. In contrast, cotton yields following the susceptible cultivars Santa Rosa‐R, Vernal, and DP6880RR were on average 25% lower than those following grain sorghum. The enrichment of cotton sequences with reniform nematode‐resistant soybean cultivars is viable when the proper cultivars are chosen, whereas the use of reniform nematode‐susceptible soybean cultivars is discouraged. The effective use of R. reniformis‐resistant soybean cultivars to manage R. reniformisin cotton will depend on a number of additional economic parameters not studied in these experiments.