Late blight resistance in the British Neo-Tuberosum potato population

Summary Development of the British Neo-Tuberosum population included selection for resistance to late blight. High levels of foliage resistance are most often found in later-maturing clones but some early-maturing clones have good resistance. Resistance of foliage to Race 4 and to a complex race is associated. Some clones give variable results in tests for resistance in tubers. While those consistently displaying resistance are most frequent among those with resistant foliage, some have rather susceptible foliage. Tuber resistance appears most common among early maturing clones but this could be misleading, perhaps being due to tubers of later-maturing clones tending to be immature when tested (resistance often increasing as tubers mature). However some ‘lates’ are resistant, suggesting that genes for resistance in immature tubers occur. Selections are being used experimentally as parents in breeding for blight-resistant cultivars, and controlled breeding within Neo-Tuberosum to produce superior parents has commenced.