Abstract: Nymphal development time and fecundity of Sitobion avenae (F.) were determined on nine widespread wheat varieties cultivated in Tekirdağ Region in Turkey. Tests were carried out in controlled environment chambers (25±1°C, 65±5 % R.H. and 16:8 light and dark cycle). Developmental time ranged from 5.75±0.25 to 7.20±0.20 day. Fecundity was found the highest (12.87±1.50) on cv. Sana. Cv. MV-17, cv. Miryana, cv. Pehlivan and cv. Saraybosna were found particular resistant wheat varieties against S. avenae.
Introduction
Aphids are major agricultural pests and cause reduction in crop yield by direct feeding damage and by transmission of viruses. The wheat aphids and their natural enemies were determined by previous researches in Tekirdağ (Özder and Toros, 1999a,b). English grain aphid Sitobion avenae (F.) was found the most common species on the wheat in this region. It is also known as the wide spread aphid over the world (Dean, 1974; Kiechefer, 1975; Kolbe and Linke, 1974; Markkula, 1980; Robinson and Hsu, 1963). Biology and effect of wheat varieties on main life parameters of Sitobion avenae have been studied separately (Araya et al., 1987; Celis et al., 1997; Di Pietro and Akli, 1987; Dixon, 1973; 1987; JunXiang et al., 1999; Leszczynski et al., 1995; Markkula and Myllymaki, 1963; Markkula and Roukka, 1972; Theime and Heimbach,1996; Watt, 1979; Watt and Dixon, 1981). The nymphal development duration, longevity and fecundity are the most important indices identifying the resistance of wheat varieties (JunXiang et al., 1999). In addition to the quantification of the impact of resistance varieties on the aimed pest is important for the effective use of plant resistance as a part of management strategy.
This research was conducted at Agricultural Faculty of Tekirdağ to determine the effects of wheat varieties on S. avenae development and fecundity using nine wheat varieties on S. avenae and determining particular resistant wheat varieties for Tekirdağ Region of Turkey.
S. avenae adults were obtained from wheat cultivar Kate-A-I in the field of the Faculty. S. avenae was cultured as a stock culture on each wheat variety in laboratory conditions after they collected from the field. Kate-A-I, Miryana, Pehlivan, Flamura 85, MV-17, Saraybosna, Sana, Primoretz, Prostor are the most widespread cultivated Triticum aestium varieties in Tekirdağ. The experiments were conducted on this wheat varieties at 25±1°C, 65±5 % R.H. and 16:8 light and dark cycle. Each wheat variety was grown up individually in 10 cm diameter plastic pots. In order to determine nymphal development newly born nymph were settled individually on two plant leaves of each wheat variety. Afterwards, they nymph was observed daily for molting and survivoship. The presence of exuviae was used to determine molting. Daily reproduction per adult and adult mortality were recorded every day after they reached adult stage still they died. There were 35 replicates for each wheat variety and each traits.
For the analysis of nymphal development all of the data were normalized by
the arcsine
Wheat varieties had significant effects on total nymphal development period, preoviposition period and the mean nymph number of reproduction of S. avenae (P<0.5).
There were no significant differences in 1, 2 and 3 nymphal development period among the wheat varieties. But 4 nymphal period was found the shortest on cv. Pirimoretz. Total nymphal developmental time of S. avenae was shortest on cv. Pehlivan (5.75±0.25) and cv. Primoretz (5.80±0.20). The maximum development time were found on cv. Saraybosna (7.20±0.209). Mean nymph number were found the highest on cv. Sana (12.87±1.50). The lowest nymph number was found on Pehlivan (6.50±1.55) for S. avenae.
| Table 1: | Nymphal development period and mean of nymph number of Sitobion avenae on different wheat varieties |
| X Within columns, mean followed by the same letter do not differ significantly P<0.05. Y Figures are values ± S.E.; in parantheses, the range of minimal and maximal values. | |
The shortest preoviposition period was found on Flamura 85 (1.33-0.58) and Kate-A-I (1.33-0.58). There were no significant differences on oviposition period among the wheat varieties (Table 1).
Hasn’t been found any literature on the developmental time and fecundite of S. avenae for the wheat species studied in this research. The total nymphal development time values of these aphids was similar to what has been reported for these species (Simon et al., 1991). The mean total fecundity in this study was lower than others research (Dean, 1974; Markkula and Myllymaki, 1963). But they also obtained sometimes very different values in his studies (Dean, 1974). Fecundity of S. avenae are dependent on aphid-plant genotype and between the aphid–plant interactions, differences of clones and vegetative parts of plant where aphids placed on it (Dixon, 1987; Gianoli et al., 1997; Griifths and Wratten, 1979; Lowe, 1980; Radchenko, 1987; Soroka and Mackay, 1991). It is also concluded that S. avenae reproduced more faster on ears than leaves (Acreman and Dixon, 1989; Vereijken, 1979). The differences of the value in this study may be happened due tospecies of wheat cultivar, rearing techniques, the part of plant where this study was conducted, aphid-plant interactions and clonal factor.
As a result of this investigation, cv. MV-17, cv. Miryana, cv. Pehlivan and cv. Saraybosna were found resistant varieties against S. avenae. Moreover cv. MV-17 and cv. Pehlivan were found resistant wheat varieties against R. padi among the same wheat varieties in the Thrace Region (Özder, 1999; Özder and Bayhan, 1998). Antibiosis to S. avenae was observed in cultivar Regina between five winter wheat cultivars under greenhouse conditions (Havlikova, 1995).
Acknowledgments
The author thanks to Prof. Dr. Muhsin Doğaroğlu for his kind editorial comments.