Assessment of Susceptibility of Potato (Solanum tuberosum L.) Cultivars to Root Lesion Nematode, Pratylenchus penetrans, and Disease Impact on Plant Growth and Tuber Weight

The root lesion nematode (RLN), Pratylenchus penetrans (Cobb) Filipjev and Schuurmans-Stekhoven, a migratory endo-parasite has impacted potato yield and tuber's quality across the world including Pakistan. The present study was designed to investigate the susceptibility of 16 potato cultivars to P. penetrans under screen house and field conditions. Population densities of P. penetrans in roots, soils and tuber peels of each cultivar were assessed. Findings revealed that three potato cultivars Lal Moti, Rodeo, and Raco were found "Resistant", six cultivars Semi, Pirol, Ronaldo, Abelia, 5-Zena red and L-R were found "Moderately Resistant" and remaining cultivars were found "Moderately Susceptible or Susceptible". Significantly (P = 0.00) lower number of nematode larvae or adults was observed within roots (53.75) and 100 g tubers peel (10.0) of cultivar Lal Moti. A marked reduction in the number of necrotic lesions per root system (1.25), 100 g tuber peel (3.0) and minute size necrotic lesions on tubers (1.06) and root system (0.62) were evident in cultivar Lal Moti. It was the only cultivar that sustained high inoculum pressure under field conditions, restricted the reproduction factor (Rf = 0.02) of RLN in roots and yielded significantly higher number of tubers (13.1 per plant) with maximum yield (35.5 g per three random tubers) as compared to Rodeo, Raco and L-R cultivars. A strong negative correlation between the number of egressed nematodes from peels or soil and weights of potato cultivars was evident with r = - 0.97 and - 0.87 under screen house and field conditions, respectively. Cultivar resistance offers a potential sustainable solution for the migratory RLN in potatoes and could be effectively integrated into nematode management strategies.