Abstract
Previous work has shown that the inheritance of ascospore size in certain strains of Neurospora crassa is controlled by a polygenic system with a small cytoplasmic component. Various types of selection lines were set up in strains that had been selected for the large-spored character. The results of these selection procedures are discussed. Experimental work which gives a better estimate of the linkage of part of this polygenic system to the albino locus on chromosome I is reported.