Evaluation of dihaploid populations from potato varieties and breeding lines

Summary Dihaploid populations from 20 varieties and 11 breeding lines ofSolanum tuberosum differed greatly in the occurrence and frequency of mutant phenotypes, in tuberization, flowering, pollen stainability, 2n-pollen production and resistance toGlobodera rostochiensis pathotype Ro-1. One population contained up to 61.7% lethal mutants: 39.1% of the total of 5377 dihaploids obtained did not tuberize, and 32.4% of 825 vigorous dihaploids did not flower. Of 825 vigorous dihaploids, 26.9 and 3.9% respectively had a pollen stainability higher than 20 and 60%. Among 222 dihaploids with a pollen stainability higher than 20%. 23.0% produced some 2n-pollen and none of these had a stainability higher than 60%. Among the dihaploid populations investigated the proportion of resistant to susceptible dihaploids ranged from 8:26 to 62:8.