Morpho-physical and biochemical traits associated with potato (Solanum tuberosum L.) genotypes conferring resistance to potato tuber moth, Phthorimaea operculella (Zeller)

Potato is a nutrient dense crop providing livelihoods to millions in developing countries and has become an important non-cereal crop worldwide. Potato is a versatile crop grown for food and industrial purposes. The Potato Tuber Moth, Phthorimaea operculella is a destructive pest of potato both on field and storage. Its damage threatens potato production and livelihoods of many potato growers particularly small landholder farmers. In this study, nine local and six commercial potato varieties were screened for resistance to potato tuber moth based on their ovipositional and feeding preferences in the foliage parts of potato plant. The role of the associated morpho-physical and biochemical traits of the potato varieties in conferring the resistance was assessed. The local varieties were comparatively resistant to potato tuber moth than the commercial varieties. Local varieties Phan San Minit and Lah Ksain were less preferred for both oviposition and feeding by potato tuber moth. Expression of resistance was found positively correlated with higher glandular and non-glandular trichome density on leaves, higher trichome length, high concentration of glycoalkaloids α-solanine and α-chaconine; and phenolic compounds chlorogenic acid, caffeic acid and flavonoids compared to the susceptible Kufri Jyoti and Kufri Megha varieties. Whereas, total soluble sugars had little role in conferring resistance to potato tuber moth. The resistant potato varieties with these traits may be used as sources of resistance in future breeding programs to enhance resistance to potato tuber moth in cultivated potato varieties.