Gynodioecy in Plantago lanceolata L.: II Inheritance of three male sterility types

Abstract

Inheritance of male sterility has been studied in Plantago lanceolata. Crosses between plants, obtained from a 50 m2 area, yielded the entire array of possible sex phenotypes. Emphasis is put on nuclear inheritance of two nuclear-cytoplasmically determined male sterility types. In both types multiple interacting genes are involved. For MS1 a combination of two recessive and three dominant male sterility genes is proposed, for MS2 three recessives. These are minimum estimates as the exact numbers could not be determined. One of the loci for MS2 is probably linked to the self-incompatibility locus. Not all results can be explained this way, which emphasizes the complexity of nuclear inheritance. Intermediates between the completely male steriles of both types and hermaphrodites constitute two continuous series, each consisting of multiple genotypes with overlapping phenotypes. Segregation patterns indicate genetic determination by incomplete dominance at the male sterility loci. A third male sterility type (MS3) is described whose expression appears to be independent of plasmon type. Preliminary results indicate two duplicate recessive male sterility genes. The stability of the complexity of nuclear inheritance for gynodioecy is discussed. © 1983, The Genetical Society of Great Britain.