Screening of Iranian Potato Germplasm for Resistance to the Potato Tuberworm Phthorimaea operculella (Lepidoptera: Gelechiidae) Seyed Mozaffar Mansouri & Seyed Ali Asghar Fathi & Gadir Nouri-Ganbalani & Jabraeil Razmjou & Bahram Naseri & Silvia I. Rondon # Potato Association of America 2013 Abstract The potato tuberworm, Phthorimaea operculella (Zeller), is an important insect pest of potato, Solanum tuberosum L., both in storage and in the field. In this re- search, tubers of eight commercial potato cultivars and four Iranian selections with equal weight and dormancy were exposed to 10 pairs of adult P. operculella in a climate chamber set at 25±1 °C, 65±5 % RH and total darkness. In a free-choice situation, oviposition was lower on 397082–2, Khavaran and Morene compared to the other germplasm that were exposed to adults of P. operculella. Number of mines per tuber, length of mines per tuber, time of development of larvae, number of pre-pupae produced per tuber, weight of pre-pupae and number of eggs developed in ovaries per female were counted and/or measured on each commercial cultivar and selection. There were fewer and shorter mines on tubers of 397082–2, Khavaran and Morene compared to the other potato germplasm. The number of pre-pupae pro- duced per tuber and the weight of pre-pupae were lower when P. operculella was reared on tubers of 397082–2, Khavaran and Morene. Also the development, survival and fecundity were lower when P. operculella was reared on those same germplasm. Flesh firmness was negatively cor- related with larval survival (r 2 =0.87); in addition, the per- centage of starch and macronutrient composition was low on these three germplasm. Thus, tuber flesh firmness of these germplasm could delay larval penetration and lower establish- ment 397082–2, Khavaran and Morene showed promising traits that can be integral component of potato breeding for resistance to P. operculella and pest management programs. Resumen La polilla de la papa, Phthorimaea operculella (Zeller), es una plaga importante del cultivo de la papa, Solanum tuberosum L., en el almacén y campo. En esta investigación, tubérculos de ocho cultivares comerciales de papas y cuatro genotipos Iranís de igual peso y dormancia fueron expuestos a diez pares de adultos de P. operculella en cámaras mantenidas a 25±1 °C, 65±5 % RH y total obscuridad. En un ensayo de selección libre, la oviposición fue baja en 397082–2 y, Khavaran and Morene comparada con las otras nueve variedades. En otro estudio relacionado con los parámetros biológicos de la polilla de la papa, los tubérculos de los doce germoplasmas fueron expuestos a adultos de P. operculella y el número de minas por tubérculo, longitud de la mina, tiempo de desarrollo, número de pre-pupas producido, peso de las pre-pupae y número de huevos por hembra fueron contados y/o estimados para cada germoplasma. Hubieron menos minas y minas más cortas por tubérculos en 397082–2, Khavaran y Morene. El número y peso de pre-pupas producidas por tubérculos fue baja cuando P. operculella fue criada en tubérculos de 397082–2, Khavaran y Morene. También, el desarrollo, sobrevivencia y fecundidad de S. M. Mansouri Department of Ecology, Institute of Science, High and Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran S. A. A. Fathi : G. Nouri-Ganbalani : J. Razmjou : B. Naseri Department of Plant Protection, University of Mohaghegh Ardabili, Ardabil, Iran S. I. Rondon (*) Hermiston Agricultural Research and Extension Center, Crop and Soil Science, Oregon State University, 2121 South First Street, Hermiston, OR 97838, USA e-mail: silvia.rondon@oregonstate.edu Am. J. Potato Res. DOI 10.1007/s12230-013-9325-0