Effects of Random Intercrossing in a Naturally Self‐Fertilizing Species, <i>Nicotiana tabacum</i> L.¹

Abstract

Eight varieties of Nicotiana tabacum L. were crossed into an eight‐line synthetic population. This population was random mated for an additional five generations and each random mated generation was selfed for one generation. Comparisons of generation means indicated the presence of epistatic effects for six of eight characters studied. A decrease in yield and narrower leaves with increased generations of random mating suggested that internally balanced chromosomal effects were being disrupted. However, the magnitude was low and this effect would be expected to be more than offset by one generation of selection.