Susceptibility and tolerance in red skinned potato (Solanum tuberosum L.) to root-knot nematode, Meloidogyne spp.

Abstract

Susceptibility and tolerance to Meloidogyne, root-knot nematode (RKN), can be different among potato cultivars. These differences extend to different species of RKN within a potato cultivar. Most red skinned potato cultivars have not been studied in terms of susceptibility and tolerance to Meloidogyne spp. This thesis examined susceptibility and tolerance of eight red skinned potato cultivars to M. incognita at 4 population densities in a 6-liter pot in Hawaii. Damage threshold of M. incognita was determined in cultivars Desiree, Mountain Rose, Pink Pearl and Red Thumb. In the second experiment, susceptibility and tolerance to M. javanica and M. konaensis were determined forthese cultivars. Penetration and development rate of M. incognita and M. javanica were compared in Mountain Rose and Red Thumb. At Pi 20, 200, or 2,000 nematode eggs/plant, cultivars 'Red Thumb', 'Durango', and 'Colorado Rose' were susceptible and intolerant, while 'Rote Ersting' was resistance but intolerant to M. incognita. Although 'Desiree' was susceptible to all RKN species tested, it was moderately tolerant to both M. javanica and M. konaensis, despite intolerant to M. incognita. 'Mountain Rose' was moderately resistant and tolerant to M. incognita, and resistant/tolerant to M. konaensis. However 'Mountain Rose' was susceptible and intolerant to M. javanica. TW of 'Mountain Rose' was reduced due to M. javanica infections compared to TW of uninoculated plants (P≤ 0.05). 'Pink Pearl' was susceptible/intolerant to M. incognita, but susceptible/tolerant to both M. javanica and M. konaensis. 'Red Thumb' was the most susceptible/intolerant cultivar to M. incognita, and the most resistant/intolerant to both M. javanica and M. konaensis, among all cultivars tested. This research provides important information on red skinned potatoes for breeders to develop new cultivars and for growers in choosing cultivars for fields infested with Meloidogyne. Crop response information to this nematode can be efficiently used to develop effective crop rotation in order to control Meloidogyne spp. in the tropics and subtropics.