Antixenosis and antibiosis resistance of 9 wheat cultivars (Triticum aestivum) to the sunn pest, Eurygaster integriceps (Hem.: Scutelleridae) in the field conditions in Naghadeh region, west Azarbaijan

The Sunn pest, Eurygaster integriceps Put. is the most important pest of the wheat in Iran and neighbouring countries that can considerably reduce its yield. One way to control this pest is deployment of resistant cultivars. Field experiments were conducted to evaluate the antixenosis and antibiosis resistance of nine wheat cultivars to this pest. In a field choice test, the numbers of attracted overwintered adults to the cultivars were determined as antixenosis index. Also, number of eggs per m2 and numbers of damaged hills, buds and spikes were used as antixenosis indices. To evaluate the antibiosis, wheat seeds were planted in pots under the field conditions in which second instar nymphs were released and reared. Nymphal weight on the 14th day after releasing, mortality of nymphal stage and the duration of this stage were considered and analyzed as the antibiosis indices. Significant differences were observed in studied traits (P≤0.05). Using cluster analysis, UPGMA procedure based on Euclidean distance, nine experimental cultivars were grouped in five distance groups that cultivars Alvand, Sardari and Azar2 by replacing in the same group, had the highest resistance to the Sunn pest.