Inheritance of Increased Sensitivity toN-Phenylcarbamates in Benzimidazole-ResistantVenturia nashicola

Publisher Website
Google Scholar
Abstract
Most of the highly resistant isolates of Venturia nashicola to the benzimidazole fungicide carbendazim showed increased sensitivity in vitro to the N-phenylcarbamate compounds MDPC and diethofencarb, but the intermediately and weakly carbendazim-resistant isolates did not. A segregation ratio of 1:1 was obtained from the cross between MDPC-sensitive and -resistant isolates. In an allelism test, no MDPC-resistant progeny appeared from the cross between two MDPC-sensitive isolates, and no MDPC-sensitive progeny resulted from the cross between two MDPC-resistant isolates. These results indicated that the increased sensitivity to MDPC is controlled by a single chromosomal gene. When a highly carbendazim-resistant isolate (MDPC-sensitive) was crossed with an intermediately carbendazim-resistant or a carbendazim-sensitive isolate (both resistant to MDPC), several progeny strains were doubly resistant, i.e., highly resistant to carbendazim and resistant to MDPC. Such strains also were detected among field isolates, and the double resistance was heritable.