Response of Allium Tissue Cultures to Filtrates of Pyrenochaeta terrestris

Abstract

Allium cepa L., A. fistulosum L., A. galanthum L., and A. cepa × A. fistulosum reciprocal interspecific hybrids were grown in vitro as calluses, shoots, and plantlets, and exposed to the filtrate of the pink root disease-causing fungus, Pyrenochaeta terrestris (Hansen) Gorenz, Walker, and Larson. Tissue culture reponses to the filtrate were assessed by visible damage ratings and fresh weights. Calluses exposed to the filtrate incorporated into the culture medium reflected the degree of whole plant susceptibility among the tester lines. However, in vitro shoot and plantlet culture responses did not reflect this correlation. Filtrate action appeared to be localized in meristematic cells. This in vitro approach may prove useful in screening or selection for onion pink root disease resistance.