<i>Ex-situ</i> Performance Evaluation of Coffee (<i>Coffea arabica</i>) Seedlings under Different Management Conditions: I. Relationship between Hydraulic Resistances and Growth Characters

Abstract

The study was conducted with the aim of determining the variations in growth and hydraulic resistances and identifying the relationship between these traits in seedlings of Arabica coffee populations. Coffee accessions collected from four wild coffee forests in Ethiopia (Harenna, Bonga, Berhane-Kontir and Yayu) were ex situ evaluated under controlled nursery conditions at the Jimma Agricultural Research Center, southwest Ethiopia. One-year-old coffee
seedlings were used to record growth and hydraulic characteristics. The results revealed highly significant differences among coffee populations for most
morphological and destructive growth characteristics. The Harenna and Yayu coffee populations had maximum growth values as opposed to the lowest
response from the Berhane-Kontir population. Coffee populations also exhibited significant variations in the hydraulic resistance of main stem-cut and its
contribution to whole-shoot resistances. The hydraulic resistance contributions across seedling root and shoot components followed the order of
root>leaf>whole-shoot>branch>petioles. Seedling growth characters and root hydraulic resistance were correlated strongly and indirect in optimum nursery conditions. Main stem diameter had highly significant inverse relationships with hydraulic resistance components in stem-cut, whole-shoot, leaf and root growth parts. Stem and leaf growths are the most useful traits to describe the extent of variability among Arabica coffee genetic resources in hydraulic resistances. As a whole, coffee population of varying geographical origins in Ethiopia, seedling growth habits and segments are important in determining hydraulic resistance patterns and hence can be used as selection and characterization criteria in the local coffee variety development program of the country.