SELECTIVE FERTILIZATION IN LIh/IA BEANS

ELECTIVE fertilization or incompatibility has been reported to exist in many S plant species. The usual reaction which results in these phenomena is one between the diploid style and the haploid pollen tube so that selective fertilization occurs. Selective fertilization in lima beans appears to be similar to that reported in maize by EMERSON (1925) and MANGELSDORF and JONES (1926) where the effect of the dominant gametophyte factor Ga is operative only when gcc and Ga pollen are competing on stylar tissue which is Ga/Ga or Ga/ga. Under these conditions pollen gametes with the recessive ga factor fail to effect fertilization, or effect only a small percentage of the fertilizations. In a species such as lima beans where controlled pollination is restrictive in producing large backcross populations, such a gametophyte factor can be detected only when it is linked with a qualitative factor in progenies of self-fertilized heterozygous plants. Qualitative factors when linked with the gametophyte factor will be detected by having either a deficient or excess class depending on whether the linkage is in the repulsion or coupling phase.