Antixenois Studies in Helicoverpa armigera(Hubner) Oviposition towards certain Sunflower Genotypes

A study on the ovipositional preference of Helicoverpa armigera females on certain sunflower genotypes was conducted at the Faculty of Agriculture, Annamalai University, Tamilnadu during 2014-2017. The head borer, Helicoverpa armigera, is one of the most important pests of sunflower, and host plant resistance is an important component for minimizing the extent of losses caused by this pest. To develop insect‐ resistant cultivars, it is important to understand the contributions of different components of resistance, and therefore, we studied the antixenosis mechanism of resistance to H. armigera in a diverse array of sunflower genotypes under no choice, and multi‐ choice conditions. Antixenosis for oviposition was observed in case of AHT 02, AHT 14, KBSH 1, GMU 631, and GHU 615 under no‐ choice; and GMU 631, AHT 02, GHU 615, IHT 751, and KBSH 1 under multi‐ choice conditions. The susceptible check, Morden was highly preferred for oviposition in both the antixenosis tests. The genotypes AHT 02, KBSH 1, GMU 631, and GHU 615 can be used as sources of non‐ preference mechanism of resistance in sunflower improvement programs to breed for resistance to H. armigera.