ABSTRACT
Given that the units of selection are individual plants, practical difficulties encountered in the use of mass selection in sugar beet basically are those related to environmentally caused variation and to variation
arising from interpiani genotypic competition, the latter sometimes accounting for more than half the total phenotypic variance (Lichter, 1972). To reduce unequal environmental influence on the plants, materials undergoing selection should be sown with the best possible precision in highly homogeneous fields. Obviously, when selecting for tolerance/ resistance to a certain disease, the presence of other pathogens is unacceptable. Also, a very useful approach is the stratified (or gridded) mass selection, i.e. partitioning of the entire field into smaller areas and selecting a fixed number of plants from each (Bosemark, 1993). Evaluation in the absence of interplant competition theoretically could be effected through honeycomb breeding designs (Fasoulas and Fasoula, 1995) but no results of relevant work in sugar beet have been reported so far.
