Effect of Eight Cucumis Genotypes on Life Table and Population Growth Parameters of Melon Aphid: An Approach to Assess Antibiosis Resistance

Abstract

The effect of eight Cucumis L. (Cucurbitaceae) genotypes, including native cuc umber genotypes (Hormozgan, Bushehr and Gilan), greenhous e cucumber genotypes (Girtap, Negeen, Sepehr and Pouya) and Armenian cucumber ( Cucumis melo var. flexuosus ) was studied on the life table and population growth par ameters of Aphis gossypii Glover to evaluate antibiosis resistance. The experiment was conducted at 25±1°C, 60±10% RH and a photoperiod of 16:8 hour (L:D). The data were ana lyzed by Two-Sex MSChart program. The most pre-adult mortality (22.6 %) and the shortest total life span (14.5 days) were recorded for ‘Bushehr’. The net Reproduc tive rate (R 0 ) ranged from 43.70 for ‘Bushehr’ to 92.39 nymphs per individual in the cas e of ‘Pouya’. The lowest value of the intrinsic rate of increase (r) and the finite rate o f increase ( λ ) was observed in ‘Gilan’ (0.378 and 1.460 day −1 , respectively) and the highest in ‘Pouya’ (0.471 a nd 1.602 day −1 , respectively). The maximum and minimum mean generat ion Times (T) were 10.20 and 9.23 days in ‘Gilan’ and ‘Negeen’, respectively. On the basis of these parameters, ‘Gilan’ had the highest antibiosis resistance to A . gossypii . Information on life table of pests and subsequent host resistance evaluation improves IPM programs and leads us to genotype selection for crop breeding programs. Keywords: Antibiosis, Aphis gossypii , Cucumis , Life table, Plant resistance.