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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) Cover

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)

Open Access
|Jun 2023
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Figures & tables

Figure 1:

Virulence of Meloidogyne enterolobii isolates 18-5126 and NC.1 on cotton germplasm lines resistant to M. incognita (RKN) (M240 RNR), resistant to RN (M713 Ren1), or resistant to both RKN and RN (M Rk-Rn-1) in comparison to a greenhouse-maintained RKN race 3 population. Also included were nematode-susceptible obsolete cultivars Deltapine61 (DPL61) and SureGrow747 (SG747). Eggs were used as inoculum and virulence was measured as (A) RF, (B) log10 eggs g−1 root, and (C) gall score index (1–10 scale). Tukey-Kramer multiple comparison was used to determine significant differences between means at α = 0.05 as denoted by different letters (n = 6).

Figure 2:

Virulence of Meloidogyne enterolobii isolates 18-5126 and NC.1 on cotton germplasm lines resistant to M. incognita (RKN) (M240 RNR), resistant to RN (M713 Ren1), or resistant to both RKN and RN (M Rk-Rn-1) using second-stage juveniles as inoculum. Also included were nematode-susceptible obsolete cultivars Deltapine61 (DPL61) and SureGrow747 (SG747). Virulence was measured as (A) RF ± SE, (B) log10 eggs g−1 root ± SE, and (C) gall score index ± SE (1–10 scale) of six replicates.

Table 1.

Effect of Meloidogyne enterolobii infection on cotton growth under growth chamber conditions. Presented are mean ± SE after 6 weeks of growth under uninoculated (control) or inoculated conditions (n = 5).

ControlInoculated
Stem Height (mm)DPL61124.1 ± 3.279.3 ± 3.7**
M240 RNR147.8 ± 4.6133.8 ± 22.8
SG747143.5 ± 2.889.6 ± 2.1**
M713 Ren1144.0 ± 17.0131.0 ± 12.8
MRk-Rn-1157.6 ± 10.5111.6 ± 5.4**
Shoot Fresh Weight (g)DPL612.49 ± 0.131.94 ± 0.23
M240 RNR2.75 ± 0.232.01 ± 0.27
SG7473.23 ± 0.451.48 ± 0.19**
M713 Ren12.58 ± 0.223.39 ± 0.42
MRk-Rn-12.99 ± 0.741.83 ± 0.11
Leaf NumberDPL613.7 ± 0.13.8 ± 0.4
M240 RNR3.8 ± 0.13.5 ± 0.5
SG7473.5 ± 0.22.4 ± 0.3**
M713 Ren13.9 ± 0.33.8 ± 0.3
MRk-Rn-14.1 ± 0.33.1 ± 0.2**
Stem Height/Node NumberDPL6128.9 ± 0.521.1 ± 1.8**
M240 RNR33.2 ± 1.933.2 ± 1.5
SG74740.0 ± 2.326.5 ± 0.9**
M713 Ren131.7 ± 4.727.6 ± 2.2
MRk-Rn-140.5 ± 2.329.5 ± 1.1**

** Significantly different (P ≤ 0.05) from corresponding control mean.

Figure 3:

Time-point dependent reproduction of the Meloidogyne enterolobii isolate NC.1 on cotton germplasm lines M240 RNR and MRk-Rn-1 in comparison to the susceptible cultivar SureGrow747 (SG747). Total eggs were extracted at 35-, 42-, 49-, and 56-days post inoculation (DPI). Isolate NC.1 reproduction is presented as (A) RF (total eggs extracted/initial inoculum) and (B) log10 eggs g−1 root. Significant differences between means at α = 0.05 noted by different letters (n = 6).

Figure 4:

Time-course of Meloidogyne enterolobii isolate NC.1 infection of SureGrow747 and MRk-Rn-1. Infected roots were collected at 4-, 8-, 12-, 16-, 20-, and 24-days after inoculation (DAI) and stained with acid fuchsin.

DOI: https://doi.org/10.2478/jofnem-2023-0021 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X
Language: English
Submitted on: Aug 26, 2022
Published on: Jun 23, 2023
Published by: Society of Nematologists, Inc.
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year

© 2023 Amanda G. Gaudin, Martin J. Wubben, Jack C. McCarty Jr., Johnie N. Jenkins, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.