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Research Conducted
Twenty soybean cultivars that are commercially available in ND were evaluated for resistance to a new species of root-lesion nematode (RLN) identified in ND. The experiment was conducted under greenhouse conditions and repeated twice to confirm research findings. Since RLN can occupy either soil or roots, habitat preference of this nematode was evaluated by comparing the numbers of nematodes present in roots and in soil.
Why the research is important to ND soybean farmers
Root-lesion nematodes are one of the destructive groups of plant-parasitic nematodes worldwide. This soil-borne pathogen is widely distributed in the U.S. and has a wide host range which includes soybean. One of the most effective control practices against such plant-parasitic nematodes is the use of resistant cultivars. Results of this research helps us identify resistance or susceptibility of soybean cultivars used in ND to suppress this new RLN species.
Final findings of the research
Two soybean cultivars (NS 1911NR2 and NS 60083NXR2) were found to be susceptible to the new RLN species across all three repetitions of the experiment. The cultivars S12-R3, NS 0081NR2, NS 1291NLL and the positive control Barnes were moderately susceptible whereas the cultivars S06-Q9 and NS 61493NXR2 were moderately resistant across all the three experiments. Although a cultivar that is resistant in all the experiments was not identified in this study, the cultivars 3408RR2YN and NS 0651NR2 were found to be resistant in one repetition and moderately resistant in the remaining repetitions. The variation in resistance ratings between the experiments could be attributed to different inoculum concentrations and time of the year on which the experiments were conducted. Our results also demonstrated that more than 50% of the nematodes can be present in roots compared with soil habitat, indicating the importance of extracting nematodes from both soil and roots for quantification purposes.
Benefits/Recommendations to North Dakota soybean farmers and industry
Such research findings provide an insight into the virulence of this new species identified in ND against commercial soybean cultivars. The susceptible cultivars identified can be used in future studies to culture this new species and increase the population for determining its impact and economic threshold on soybean. The resistant/moderately resistant cultivars identified should be better options than susceptible/moderately susceptible cultivars for the nematode management. However, further research is necessary to assess the performance of these cultivars against the new RLN species under field conditions.