RESPONSE OF CLONAL AND SEEDLING ROOTSTOCK OF AVOCADO (Persea americana) TO DIFFERENT LEVEL OF SALINITY AT DARA WOREDA SIDAMA REGION

The avocado tree (Persea americana Mill.)Is a fruit tree native to Mexico classified in to the flowering plants family Lauraceous, along with cinnamon, camphor and bay laurel. It is known in having high nutritive value containing: monounsaturated fatty acids (MUFA), dietary fiber, essential nutrients and phytochemicals. However, productivity is reduced due to biotic and abiotic factors. Salt stresses are one of the most important a biotic factors that adversely affect avocado productivity. The purpose of the study was to evaluate the growth response of clonal and seedling root stock under different salinity levels. For these clonal root stock and seedling root stock of Guatemalan race was used. The experiments were laid down in randomized complete design with four salt stress treatments (control, 1.3ds/m,2.6ds/m and 3.9ds/m)in three replication. The results revealed that most of the morphological growth parameters for clonal rootstocks were significantly affected by salt stress level. The result showed that root stock diameter, the highest stem greenness, and sucker development significantly decreased with the increase of salt concentrations on seedling rootstock similarly showed that significant variation for most of the morphological parameters considered under this study. Accordingly, the tallest leaf length, the highest bud number, the highest leaf fresh and dry weight, the widest leaf area, maximum total fresh and dry weight, shoot height, number of plants, tap root length and lateral root length significantly decreased with the increase of salt concentrations. Similarly, physiological parameters highest photosynthetic rate, the transpiration rate, the stomata conductance and the maximum instantaneous water use efficiency were maximum from seedlings grafted on seedling rootstock treated with control and 1.3ds/m salinity. Overall results indicate that high salinity condition was not suitable for avocado plant. However, this is a one season experiment that may need further verification. This is therefore further studies that are replicated at least over seasons are needed to get reliable information and to give conclusive recommendation.