Field reactions of lentil lines and cultivars to isolates of Ascochyta fabae f sp. lentis

The reactions of lentil lines and cultivars (differentials) to seven isolates of Ascochyta fabae f. sp. lentis were studied in 1994 and 1995 in separate field experiments using artificial inoculation. Disease was assessed as initial disease severity, area under the disease progress curve (AUDPC), and percent seed infection. In all experiments significant differences occurred among differentials in their reactions to the isolates based on initial disease severity. Based on combined analyses of variance of AUDPC for all experiments in a year, differentials and isolates were significantly different in both years, but the interaction was significant only in 1995. Similarly, differentials and isolates showed significant differences in percent seed infection but the isolate X differential interaction was nonsignificant in both years. The Line ILL358, moderately resistant at the seedling stage according to previous growth chamber experiments, showed much higher susceptibility in the field as judged by all three disease measurements. On the other hand, the widely grown cv. Laird was equally susceptible in the growth chamber and field. The correlation between initial disease severity and AUDPC was high compared to those between initial disease severity and percent seed infection and between AUDPC and percent seed infection.