ASSESSING PROGENIES OF POTATO FOR RESISTANCE TO EARLY BLIGHT

Progenies from crosses between cultivars varying widely in resistance to early blight (Alternaria solani Sor.), were assessed for resistance as true seedlings in a glasshouse in Scotland. The resistance of a re presentative sample of surviving genotypes from each progeny was compa red with samples of the same progenies not previously exposed to the f ungus, both in the glasshouse in Scotland and in the field in Israel. The exposed population was more resistant. Resistance was identified m ore effectively in adult plants from tubers in the glasshouse than in true seedlings and agreement between glasshouse and field assessment w as better when progenies were compared rather than individual genotype s. The mid parent and progeny mean scores of the unexposed population were correlated at both sites, thus confirming that the resistance is heritable. Selecting resistant individuals at the seedling stage is su ggested as a useful tool for resistance breeding, having first chosen the best parents for crossing.