SIN1, A MUTATION AFFECTING FEMALE FERTILITY IN ARABIDOPSIS, INTERACTSWITH MOD1, ITS RECESSIVE MODIFIER

In Arabidopsis thaliana, a mutation in the SIN1 gene causes aberrant o vule development and female-specific sterility. The effect of the sin1 mutation is polymorphic and pleiotropic in different genetic backgrou nds. The polymorphism concerns morphology of the mutant ovules. The pl eiotropism involves internodal distance and inflorescence initiation t ime. The particular ovule phenotype and the length of internodes are d ependent on an interaction of sin1 with a second recessive gene, which we term mod1. The recessive mod1 allele in a homozygous sin1 mutant p lant reduces internode length and ovule integument size. The mutation sin1, but not mod1, has a demonstrable effect on ovule morphology when acting idependently. In our crosses mod1 was inseparably linked to th e well known mutation erecta that is known to cause a reduction in int ernode and pedicel lengths.