Maize Tolerance to Western Corn Rootworm Larval Feeding: Screening through Five Years of Investigation

Research on maize tolerance to rootworm larval feeding was conducted in Osijek, Croatia in period from 2001 to 2005. Seven Croatian commercial maize hybrids were evaluated by measuring traits associated with resistance: root injury, root size and root regrowth. Hybrids were grown in monoculture in field trials in four replicates. Root injury was rated according to Iowa Node Injury Scale (0-3), and the Eiben 1-6 Scale, reversed, was used for root size and regrowth assessment. No significant differences were observed for root injury between the hybrids. However, injury was significantly different across the years and more damaged roots were observed in 2003 (1.606), 2004 (1.281) and 2005 (0.940) compared to 2001 (0.081) and 2002 (0.099). Root size and root regrowth differed significantly across the years of investigation, while differences between the hybrids occurred only for root regrowth. Hybrids OsSK 617, OsSK 602 and OsSK 596 appeared to be the most tolerant through all years of investigation measured by root regrowth