Physiology and genetics of self-incompatibility in Echinopsis chamaecereus (Cactaceae)

Abstract

The self-incompatibility (SI) system of a geophytic cactus (Echinopsis chamaecereus Friedrich & G. Rowley) was examined in a series of experiments. Pollination tests indicated that E. chamaecereus is an obligate outbreeding species with a functional SI system. Incompatible matings were characterized by stylar inhibition of pollen tube growth and lack of fruit set. Two S1 seedlings were recovered when plants of one clone were exposed to 42°C for 16 h and flowers were selfed immediately after incubation. The two S1 seedlings and the parental (S0) clone were crossed in a full diallel. Results were consistent with a one-locus, gametophytic SI system with two different S alleles. Disturbed segreg..