EFFECT OF SHADING, ROOTSTOCK TYPE AND FOLIAR SPRAYING WITH AMINO ACIDS ON SOME GROWTH TRAITS OF SWEET ORANGE (CITRUS SINENSIS L. OSBECK) SAPLINGS

Abstract

ABSTRACT : This study was conducted in the experiments field belonging to the Department of Horticulture and Landscape Gardening, College of Agriculture, University of Anbar, Iraq for the period frommid-April 2018 tomid-October 2018 in order to study the effectof shading levels (50 and 75%) and types of citrus rootstocks (Sour orange, Swinglecitrumelo and Rough lemon), in addition to foliar spraying with a mixture of amino acids (Amino PlusTG) at threeconcentrations of (0, 2, 4 mlL-1) in some growthcharacteristics of Local sweet orange saplings, where 162 saplings were selected at the age of three years, homogeneous in their growth as much as possible, a factorial experiment was conducted within the Nested Factorial Design, with three replicates for each treatment.The results showed that the level of shading had a significant effect in all studied traits, where shading at a percentage of 50% was significantly excelled in the average increase in main shoots number, average increase in leaves number, leaves area, dry weight of vegetative parts, shoots content of total carbohydrateand percentage of nitrogen in leaves,while shading at a percentage of 75% has excelled in the average increase in main shoots length and the leaves content of total chlorophyll. The type of rootstock and spraying with amino acids showed a significant effect in all studied traits, especially the rootstock of rough lemon and spraying with amino acids at a concentration of 4 ml L-1, which achieved the highest values for these traits. Interactions between the study factors significantly affected all growth traits and their significant effect varied depending on the type of traits and the interaction factors.