Induced resistance in groundnut by jasmonic acid and salicylic acid through alteration of trichome density and oviposition by Helicoverpa armigera (Lepidoptera: Noctuidae) uri icon

abstract

  • Jasmonic acid (JA) and salicylic acid (SA) are important phytohormones involved in plant resistanceagainst insect herbivory and pathogen infection. Application of JA and SA induces several defensive traits in plants.Here we investigated the effect of JA and SA on trichome density in five groundnut genotypes (ICGV 86699, ICGV86031, ICG 2271, ICG 1697 (resistant) and JL 24 (susceptible)). The effect of JA- and SA-induced resistance on the ovipositionbehaviour of Helicoverpa armigera on different groundnut genotypes was also studied. Pre-treatment with JAincreased numbers of trichomes in the insect-resistant genotypes, ICGV 86699, ICGV 86031, ICG 2271, and ICG 1697.The induction was greater at 10 days after treatment. Jasmonic acid- and SA-treated plants showed a substantialeffect on the oviposition behaviour of H. armigera. Jasmonic acid application and herbivory reduced the number ofeggs laid by H. armigera in all the groundnut genotypes tested. However, a greater reduction was recorded on plantspre-treated with JA. More egg layingwas recorded in JL 24 in all the treatments as compared to the insect-resistant genotypes.These results suggested that pre-treatment with JA increased trichomedensity in groundnut plants, which conferredantixenosis for oviposition by H. armigera

publication date

  • 2013
  • 2013