Identification of Resistance to Insect Pests Infestations in Cotton (Gossypium hirsutum L.) Varieties Evaluated in the Field Experiment

Resistance against insect pests is a crucial trait for the stability and sustainability of cotton production. A field trial was conducted to quantify relative tolerance and sensitivity varying in 10 released (new and existing) cotton varieties of Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan, against sucking and bollworm insect pest complexes. In general, it was observed that none of the cultivars were found completely resistant to pests although these originated as least susceptible, moderately susceptible and highly susceptible. Of them, N-777 was rated as more tolerant to white fly attack in comparison to N-Karishma that appeared susceptible. Variety N-9811 and Sitara-10 M carried maximum, and N-Karishma carried minimum jassid load for considering the best source for pest resistance. On the basis of mean bollworms damage values, the varieties N-Karishma, N-846 and N-852 carried less pest pressure than IR-824, Sitara-10 M and N-26 which were the most susceptible. Percent of seedling emergence was variable in most of the test genotypes. The variety N-9811 gave 99% emergence, while N-846 and N-777 conferred 95% emergence. Variety N-852 gave the poorest percent of emergence (72.99%) and the other six varieties conferred an emergence range of 94.05-83.76%. Differences in seed cotton yield were also observed, indicating that minimal and maximal pest injury on cotton influenced the crop yield. The varieties N- Karishma, N-852 and N-846 performed well in respect of higher seed cotton yield. The results suggest that tolerant cotton genotypes might be commercially cultivated extensively in this agro-climatic area and Scientists involving in development of host plant resistant cultivars are encouraged to utilize resistance sources as donar against key pest species.