Effect of spraying with Gibberellic acid and seaweed extract on seedling growth of olive ( Olea europaea L.cv.Khudheiry )

Abstract

The experiment was conducted in lath house at the College of Agriculture Kerbala University during the growing season of 2009 to study the effect of Gibberellic acid and seaweed extract on shoot system and root growth of olive seedling .The latter was imported from Syria and represented an oil riched cultivar called khudairi .Three replicates `were used for each treatment and the seedlings were completely wetted with either the acid or extract .the Gibberellic acid was used at three levels :0,150,and200 mg/l while the levels of the seaweed extract were 0,100,125 ml/l .The seedling were sprayed at three interval :1/4,1/5,and 1/6 /2009 and they were also sprayed with urea (1g/l) one day before each of the three dates of spraying .The experiment was conducted according to the Randomized Complete Block Design (R.C.B.D) and analysis of variance (ANOVA) was based on the least significant difference (p=0.05) .All measurements were taken at mid October and results were as follows :1.the concentration of 200 mg/l of Gibberellic acid significantly surpassed all other concentrations regarding.(root length , dry weight of root system ). Mean root length reached 66.44 cm/seedling and mean dry weight of root system reached 15.22g/seedling .on the other hand ,the concentration of 150mg/l was the most effective regarding the height of seedling for the mean height reached 6.33 cm/seedling .There was no significant effect of the GA3 on the total content of chlorophyll.2.The extract of seaweed at 125 ml/l concentration significantly surpassed all other concentrations regarding all studied growth characters .Mean stem length ,total Chlorophyll content ,root length ,and dry weight of root system at this concentration . reached 7.56 cm /seedling ,173.3mg /100g of wet weight ,64.67 cm/seedling ,and 15.11g/seedling ,respectively.3.The interaction between Gibberellic acid and seaweed extract had no significant effects on the most characters of growth . However ,the only significant effect of this interaction was on the character of dry weight of root system where its highest mean was 19 g/seedling at the concentration of 200 mg/l .of Gibberellic acid and 125ml/l of seaweed extract compared with the mean of control treatment which reached only 7.67 g/seedling