EFFECT OF HUMIC ACID AND CYTOKININ CPPU SPRAYS IN SOME GROWTH STANDARDS NAVEL ORANGE AND LOCAL LEMON

Abstract

his study was carried out at research station affiliate for department of Horticulture and landscape gardening science/ Agriculture college- Diyala University during the period 1/10/2014 to 1/7/2015. study included effect of spraying of humic acid and cytokinin (CPPU) on some parameters of shoot and root growth for seedlings (navel orange and local lemon) grafted on 2 years old sour orange rootstock. Randomized Complete Block design (RCBD) in a factorial experiment was used with three replications and three seedlings per experimental unit. The experiment included humic acid in two levels (3, 6 ml l- 1) and CPPU in two levels (4, 8 mg l-1) and the control (spray with water only), were sprayed in this experiment at 21 day intervals, and started from15/10/2014 up to 21/5/2015. Results were analyzed according to (SAS) and differences between means were compared using Duncan's Multiple Range test at 5% probability level. Results showed that CPPU treatment at 8 mg l-1 led to significant increase in number of branches, leaves area and dry weight for shoot system, while humic acid treatment at 6 ml l-1 caused an increase in main root length, dry weight for root system, leaves content of N, total carbohydrates in branches. As for intervention, the treatment of Navel orange with 8 mg l-1 led CPPU to get on the highest values for number of branches, leaf areas and dry weight for shoot system both types. As for concentration 4 mg l-1 it gave the highest content of the leaves from chlorophyll. The treatment of lemon by humic acid Concentration 6 ml l-1 led to get on the highest values for Total carbohydrates in branches, while same the treatment on the orange navel gave highest average major root length and dry weight for root system.