دراسة مستويات حدود الضرر لنيماتودا الحوصلات Heterodera avenae Wollenweber, 1924 على مح و صلي القمح و الشعير تحت ظروف البيت البلاستيكي و العدوى الاصطناعية

الملخص EN

Pot experiment was conducted at the Center of Scientific Agricultural Research in Al-Hassakah province /Syria under green house conditions and artificial infestation to assess the effects of different levels of initial population densities (Pi) of H.

avenae (1, 3, 5, 7, 9, 10, 15, 20, 25, 30, 35 and 40 second-stage juveniles (J2)/g soil) on growth and yield components of durum wheat (cv.

Sham3), bread wheat (cv.

Sham6) and barley (cv.

Arabi Aswad ) to determine the damage threshold levels of H.

avenae on wheat and barley.

The second-stage juveniles were added one week after planting during the growing season 2010/ 2011.

The different densities of H.

avenae caused reductions in yield components of durum, bread wheat and barley.

The damage threshold levels of H.

avenae for grain yield were found to be 5 J2/g soil for durum wheat and 7 J2/g soil for bread wheat and barley.

The reduction of yield components of each cultivar increased with the increase of Pi of H.

avenae and reached at the greatest initial population density (40 J2/g soil) up to (54.29, 48.68, 45.88)% for number of spikes/plant, (42.4, 43.62, 41.24)% for plant height, (64.23, 58.73, 54.7)% for grain yield, (56.72, 52.09, 49.52)% for straw yield and (53, 50.85, 43)% for weight of 1000 kernels in durum, bread wheat and barley, respectively.

Final population densities (Pf) of H.

avenae were positively correlated with Pi, whereas reproduction factors (Rf= Pf/Pi) were negatively correlated with Pi on durum, bread wheat and barley.