Abstract

This study was conducted to evaluate the effect of five inoculium levels (0,2,4,8 and 16 gm/kg ) of three isolates of Trichoderma spp. (T.9,T.26 and T.28) on seed germination and seedling growth of sour orange (Ctrus arantium ) . The results revealed the variation among tested isolated in their effect on sour orange seeds germination as manifested by the period required for germination (PRG) and the percented of germinal . The all tested isolates (T.9,T.26 and T28) )at 2 and 4 gm/kg soil showed significant reduction in PGR (20.3,23.6),(19.6,22.3) and (21.6,26.3) days respectively as compared to (28)days in control treatment ,significant increment in seed germination percentye also was recorded for these inoculium levels (77.3 ,68.6 ) , (80.00 , 68.00) and (73.30 , 73.30) respectively . Inoculium levels more than 8gm/kg soil showed different ability rated from no effect to harmful effect. The results also showed that the tested isolates ( T.9 ,T.26 ,T.28) showed no significantly defference in enhancement seedling growth for all tested growth parameters . The highest increment in plant high rat,root long ,shoot fresh weight ,root fresh weight ,shoot dry weight and root and dry weight when (16,4,16,16,8,4)gm/kg inoculium levels used as compared to both ther tested treatment and control un treated treatment .the optimum inoculation level was varied according to used isolate and tested growth parameter