Graft, Pollen, and Seed Transmission of an Agent Associated with Top Spotting inKalanchoe blossfeldiana

Abstract

Top spotting was caused by a graft-transmissible agent(s), which was also seed-borne and transmitted through pollen from diseased plants. Seed transmissions occurred in about 30-63% of the progeny if the pollen parent had top spotting. Bacilliform particles measuring 20-25 .times. 50-100 nm were observed in ultrathin sections of 3 of 4 diseased plants used as a source of scions in graft-transmission tests and in 3 of 5 diseased but none of 5 healthy progeny examined from seed-transmission tests.