Evaluation of resistance of some wheat varieties to Sitobion avenae (F.) in the laboratory conditions.

Ramazani, Shirzad and Razmjou, Jabraeil and Nouri Ganbalani, Gadir and Naseri, Bahram and Rafiee Dastjerdi, Hoshang (2010) Evaluation of resistance of some wheat varieties to Sitobion avenae (F.) in the laboratory conditions. Other thesis, University of Mohaghegh Ardabili.

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Abstract

The population what grain aphid Sitobion avenae (F.) regarded as one the most important pests of cereal, particularly wheat has distributed in recent years. To carry out the screening experiment 23 varieties of wheat were evaluated in two-leaf stage. In spite of high correlation among measured characteristics (percentage of leaf rolling, leaf chlorosis and mean number of aphid), screening was conducted on the base of these three characteristics. Antibiosis, antixenosis and tolerance experiments were conducted to assess the existence of resistance or tolerance among six varieties that had been selected by screening and are mostly cultivated in Ardabil province. Based on this, the highest and lowest mean nymphal development time was occurred on Saysonz (10.8±0.2) and Zagros (7.5±0.2) respectively. The highest and lowest mean number of progeny during reproductive time was observed on Zagros (35.2 nymph) and Saysonz (15.2 nymph) respectively. The highest amount of intrinsic rate of natural increase (rm) was observed on Shirodi (0.210) and the lowest on Saysonz (0.133). The highest net reproductive rate was observed on Shirodi (22.6 nymph per aphid) and the lowest amount of this parameter was occurred on Saysonz (7.5 nymph per aphid). The highest amount of doubling time (DT) was found on Saysonz (5.2 day) and lowest on Shirodi and Zagros (3.3 day). Also, the highest and lowest finite rate of increase (λ) was observed on Shirodi (1.231) and Saysonz (1.145) respectively. Antixenosis experiments were carried out through counting the number of aphids attracted to each variety. The results showed that there is a significant difference among varieties with regard to the number of aphids attracted to each variety (P<0.05). Based on this, the highest number of aphids was attracted to Zagros and the lowest number to Saysonz. Tolerance mechanism was calculated based on Du Toit scale as well as effect of aphid’s feeding on plant height. The results of this experiment indicated that among varieties Shirodi and Zagros are the least tolerance and Saysonz is the most tolerance one. According to this study, Saysonz, Arta and Moghan3 have higher level of partial resistance to English grain aphid among studied varieties.

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