Evaluation of Potato Varieties for Yield, Quality, and Late Blight Resistance

This study provides the first long-term, cross-border evaluation of Lithuanian potato (<i>Solanum tuberosum</i> L.) cultivars, integrating agronomic performance, tuber quality, and resistance to major pathogens across diverse environments. Field and controlled trials conducted in Lithuania and Ukraine from 2014 to 2024 revealed substantial genetic variability among 14 national cultivars, enabling their classification into five distinct maturity groups. Maincrop cultivars outperformed others in yield and starch accumulation, with 'VB Meda', 'Goda', and 'VB Aista' exhibiting a superior balance of productivity (up to 49 t ha^-1), starch content (>19%), and moderate-to-high resistance to <i>Phytophthora infestans</i>. A broader genetic screening of 287 accessions-including varieties, breeding lines, and hybrids-demonstrated wide diversity in phenological development, disease resistance, and reproductive traits. Notably, Ro₁ pathotype resistance was identified in 85 genotypes, predominantly with yellow-skinned tubers, while genotypic sterility in flowering and berry set was associated with both parental lineage and elevated temperatures. Although no complete immunity to <i>P. infestans</i> was detected, several genotypes displayed stable polygenic field resistance, suggesting the presence of horizontally inherited defense mechanisms effective under variable agroclimatic conditions. These results underscore the strategic breeding potential of Lithuanian potato germplasm for developing high-performing cultivars with enhanced resilience to late blight and nematodes and offer valuable insights for climate-adapted potato breeding in Northern and Eastern Europe.