Evaluation of tolerance and resistance to southern root-knot nematode in sweetpotato

摘要

Southern root-knot nematode(Meloidogyne incognita)(SRKN)causes severe damage to sweetpotato(Ipomoea batatas).Tolerance and resistance to SRKN are useful characters for sustainable cropping and SRKN management.In this study,we evaluated the tolerance and resistance of five cultivars in a field experiment.Vine cuttings were transplanted on May 18 in the field naturally infested with rootknot nematode(Meloidogyne spp.).Tuberous roots were harvested on August 29 and October 11.Their yield was lower in the plot of high root-knot nematode density(HD)before cropping than in that of low density(LD)and number of tuberous roots per plant was also lower in the HD plot than in the LD plot in most plots.Root-knot nematode did not propagate and few root galls were observed in two resistant cultivars,Tamaotome and J-red.But Murasakimasari,despite being considered a resistant cultivar,was infected by root-knot nematode and it propagated.The results of this study suggest that the characters oftolerance and resistance differ for each cultivar.