P-438 - Field performance of several maturity group IV and V soybean cultivars in a Meloidogyne incognita infested field

The southern root-knot nematode (Meloidogyne incognita) is one of the most important yield-limiting pathogens of soybean in Arkansas.  Host plant resistance is an effective management tool; however, there is limited information on the susceptibility of available cultivars to M. incognita. The objective of this study was to evaluate 56 maturity group IV and V cultivars that were marketed as having resistance to the southern root-knot nematode.  Soybean cultivars were selected and grouped based on herbicide tolerance and maturity group.  Soybean cultivars were planted in a field with a high population density of M. incognita (averaged 648 J2/100 cm³ of soil at harvest).  Eight root systems from each of the four replications were rated based on the percentage of root system galled at R4-R5 growth stage. Soybean cultivars with less than 9% root system galled were considered resistant compared to cultivars with the greatest percentage of root galling.  Of the maturity group IV cultivars with tolerance to glyphosate, glufosinate, dicamba, or 2,4-D choline salt, 18 were identified as moderately resistant.  Of the maturity group V cultivars, 20 cultivars were identified as moderately resistant to the Meloidogyne incognita.   These data indicate at least a few soybean cultivars were resistant, which would be a better option in fields with a damaging population density of Meloidogyne incognita.