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)
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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.
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.
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).