The feasibility of selecting potato tolerance, in the pollen stage, toVerticilliumwilt was evaluated using a phytotoxicVerticillium dahliaeprotein-lipopolysaccharide complex which was isolated from culture filtrates of a fungal isolate pathogenic to potato. The toxin, at concentrations of 10 mg/ml and above, significantly reduced both germination and tube growth in vitro of pollen from the disease-susceptible potato genotypes, Promesse andSolanum phurejaIvP35, but not from the tolerant genotypes, Alpha and WA-85-4-5. Vital staining showed that inhibition of germination was not due to pollen death. Although toxin-sensitivity of pollen mirrored that of excised potato leaves or cultured roots, cell suspensions, and plantlets, reduction in germination occurred only at toxin concentrations 100-fold higher than that required to cause damage to vegetative potato tissue. The results suggested that this bioassay may be useful for selection in pollen before pollination.
展开▼
