Assessment of reaction to Cereal cyst nematodes (Heterodear filipjevi) to different bread wheat accessions under greenhouse conditions

 Cereal cyst nematodes (CCNs) are acknowledged globally as a biotic constraint for wheat production, particularly under rain-fed conditions and drought stress. Among species of CCNs, Heterodear filipjevi is the dominant species in most cereal growing areas of Iran and is widespread in different regions of the country. The use of resistant wheat cultivars is considered the most effective and economical method for managing cereal cyst nematodes. The effectiveness of resistance to CCNs depends on the efficiency and durability of the sources of resistance, and on the correct identification of the nematode species and pathotype(s) present in each region. The objective of this study was to assess the reaction of common accessions of bread wheat to H. filipjevi under greenhouse conditions. The reaction of common accessions of bread wheat, including some cultivars and lines (20 accessions) to H. filipjevi was assessed according to used method for screening of wheat accessions under controlled conditions. Single wheat seeds were planted in standard small tubes. After plant emergence, tubes were inoculated with 300 freshly hatched J2 in 3 holes around the stem base. Experimental units were arranged in a randomized complete block design with 5 replicates. Plants were harvested 8 weeks after juvenile inoculation. Extracted Cysts from both root and soil counted under a stereomicroscope. The data were analyzed and the genotypes were divided into different groups based on their reactions. The results showed that Back-cross Rowshan cultivar with mean 30.2 and Silverstar cultivar with mean 6.8 had the most and the least number of cysts in soil and root of each plant, respectively. Cluster analysis divided all accessions into 4 groups. Back-cross Rowshan, Pishtaz and Pishgam cultivars were identified as highly susceptible according to higher mean of the cyst number in soil and root, in comparison to Bezostaya cultivar (Susceptible check). Mahdavi, Bam, Dena, Bahar, Sivand, Ofogh, Arg and Bezostaya cultivars were categorized as susceptible. Rowshan, Alvand, Parsi, Es-93-95 and Marvdasht accessions were grouped as moderately susceptible, and, Sirvan, M-90-9, M-90-7 and Silverstar (Moderately resistant check) accessions were identified as moderately resistant. This study revealed that Back-cross Rowshan, Pishtaz and Pishgam are highly susceptible cultivars to H. filipjevi. However, the cultivation of these wheat cultivars is common in the country. In order to impeding the damage of this nematode, it is essential to avoid cultivating these cultivars and other susceptible cultivars in infested fields to H. filipjevi.