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<p><italic>Meloidogyne enterolobii</italic> [the guava root-knot nematode (RKN)] is an emerging plant-parasitic nematode that poses a threat to Upland cotton (<italic>Gossypium hirsutum</italic>) production in the southeastern United States. Like other RKN spp., <italic>M. enterolobii</italic> has a wide host range and proven ability to overcome resistance sources that have helped protect crops from other <italic>Meloidogyne</italic> spp., including the southern RKN (<italic>Meloidogyne incognita</italic>). In this study we evaluated the virulence of two North Carolina <italic>M. enterolobii</italic> isolates on Upland cotton germplasm lines having resistance quantitative trait loci (QTL) to RKN (M240 RNR, MRk-Rn-1) and/or reniform nematode (<italic>Rotylenchulus reniformis</italic>) (M713 Ren1, MRk-Rn-1) in comparison to their susceptible recurrent parents (DPL61, SG747). Multiple assays using eggs or J2 as inoculum demonstrated that both isolates reproduced equally well on all germplasm lines, producing reproductive factor (RF) values ≥ 6 on the otherwise nematode-resistant lines. Measurements of seedling growth in control and inoculated containers suggested that existing nematode-resistance QTL may offer a level of tolerance to <italic>M. enterolobii</italic> infection that should be further explored in greenhouse and field environments. <italic>Meloidogyne enterolobii</italic> infection of SG747 and MRk-Rn-1 showed nearly identical stages of symptom and nematode development over a time-course of 24 days. These data demonstrate that existing RKN and RN resistance QTL available in elite cotton varieties to producers are most likely insufficient in preventing yield loss due to <italic>M. enterolobii</italic> and that future research should focus on (i) understanding the <italic>M. enterolobii</italic>–cotton interaction at the molecular level, and (ii) screening novel germplasm collections to identify resistance loci.</p>
</abstract>

Meloidogyne enterolobii [the guava root-knot nematode (RKN)] is an emerging plant-parasitic nematode that poses a threat to Upland cotton (Gossypium hirsutum) production in the southeastern United States. Like other RKN spp., M. enterolobii has a wide host range and proven ability to overcome resistance sources that have helped protect crops from other Meloidogyne spp., including the southern RKN (Meloidogyne incognita). In this study we evaluated the virulence of two North Carolina M. enterolobii isolates on Upland cotton germplasm lines having resistance quantitative trait loci (QTL) to RKN (M240 RNR, MRk-Rn-1) and/or reniform nematode (Rotylenchulus reniformis) (M713 Ren1, MRk-Rn-1) in comparison to their susceptible recurrent parents (DPL61, SG747). Multiple assays using eggs or J2 as inoculum demonstrated that both isolates reproduced equally well on all germplasm lines, producing reproductive factor (RF) values ≥ 6 on the otherwise nematode-resistant lines. Measurements of seedling growth in control and inoculated containers suggested that existing nematode-resistance QTL may offer a level of tolerance to M. enterolobii infection that should be further explored in greenhouse and field environments. Meloidogyne enterolobii infection of SG747 and MRk-Rn-1 showed nearly identical stages of symptom and nematode development over a time-course of 24 days. These data demonstrate that existing RKN and RN resistance QTL available in elite cotton varieties to producers are most likely insufficient in preventing yield loss due to M. enterolobii and that future research should focus on (i) understanding the M. enterolobii–cotton interaction at the molecular level, and (ii) screening novel germplasm collections to identify resistance loci.

Virulence of Two Isolates of <italic>Meloidogyne enterolobii</italic> (Guava Root-Knot Nematode) from North Carolina on Cotton Lines Resistant to Southern Root-Knot Nematode (<italic>M. incognita</italic>) and Reniform Nematode (<italic>Rotylenchulus reniformis</italic>)

Genetics and Sustainable Agriculture Research Unit

Journal of Nematology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Virulence of Two Isolates of  (Guava Root-Knot Nematode) from North Carolina on Cotton Lines Resistant to Southern Root-Knot Nematode () and Reniform Nematode ()

Meloidogyne enterolobii [the guava root-knot nematode (RKN)] is an emerging plant-parasitic nematode that poses a threat to Upland cotton (Gossypium hirsutum)...

Virulence of Two Isolates of Meloidogyne enterolobii (Guava Root-Knot Nematode) from North Carolina on Cotton Lines Resistant to Southern Root-Knot Nematode (M. incognita) and Reniform Nematode (Rotylenchulus reniformis)

Article Category: Research Paper

Published Online: Jun 23, 2023

Page range: -

Received: Aug 26, 2022

DOI: https://doi.org/10.2478/jofnem-2023-0021

Keywords
Cotton, resistance, root-knot nematode, Meloidogyne

© 2023 Amanda G. Gaudin et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Virulence of Two Isolates of Meloidogyne enterolobii (Guava Root-Knot Nematode) from North Carolina on Cotton Lines Resistant to Southern Root-Knot Nematode (M. incognita) and Reniform Nematode (Rotylenchulus reniformis)

Article Category: Research Paper

Published Online: Jun 23, 2023

Page range: -

Received: Aug 26, 2022

DOI: https://doi.org/10.2478/jofnem-2023-0021

KeywordsCotton, resistance, root-knot nematode, Meloidogyne

© 2023 Amanda G. Gaudin et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
Cotton, resistance, root-knot nematode, Meloidogyne