Effect of DL-β-amino-n-butyric acid on okra plants infected with different initial populations of Meloidogyne javanica

Habiballah Chadegani

DL-β-amino-n-butyric acid (BABA) induces resistance in plants against root-knot nematodes (Meloidogyne spp.) by activating natural defense mechanisms. This study evaluated the effect of BABA on the resistance of okra (Abelmoschus esculentus cv. Clemson Spineless) to M. javanica under greenhouse conditions. Seeds were sown in 1 kg plastic pots and maintained at 27 ± 3℃ under a 16:8 hours of light-dark cycle and with daily irrigation. At the four-leaf stage, seedlings were foliar-sprayed with BABA at concentrations of 0 (control), 0.5, 1, and 2 mM. After 24 hours, plants were inoculated with M. javanica at initial population densities of 0 (control), 1, 2, 4, and 8 second-stage juveniles (J2s). Sixty days post-inoculation, plant growth and nematode reproduction indices were assessed. Results showed that higher BABA concentrations significantly improved plants growth and reduced nematodes populations. Plants treated with 2 mM of BABA and inoculated with 8, 4, 2 and 1 J2s showed increases in shoot length by 43.9%, 45.1%, 32.5%, and 32.2%, respectively; shoot fresh weight by 37%, 38.2%, 69%, and 61.5%; and shoot dry weight by 23.5%, 24.5%, 37.4% and 39.7% compared to untreated control. Meanwhile, the nematode reproduction factor decreased by 25.1%, 25.9%, 14.1% and 38.4%, respectively. This study demonstrated that BABA application improves okra growth against M. javanica. Although BABA had no significant effect on the reproduction factor at the highest nematode population level, all concentrations improved plant growth, even under severe nematode pressure. Foliar application of 2 mM BABA effectively enhances okra resistance to M. javanica under greenhouse conditions.

Plant Pathology Science

Effect of DL-β-amino-n-butyric acid on okra plants infected with different initial populations of Meloidogyne javanica