Abstract:
Drought stress is a major abiotic factor affecting crop production worldwide. Coffee cultivation
in Ethiopia has been highly affected by drought stress. However, very limited research has been
conducted on Screening Arabica Coffee genotypes in the country in general, and in vitro
screening of Hararghie Coffee (Coffea arabica L.) accessions for drought stress tolerance using
Polyethylene Glycol (PEG) solution in particular. Hence, this study was conducted in
Agricultural Biotechnology Research Laboratory at Jimma Agricultural Research Center
(JARC), Southwest Ethiopia, to see the response of 13 Hararghie Coffee genotypes (Coffea
arabica L.) to various levels of PEG concentrations (0, 2, 4, 6, 8 and 10%) under in vitro
condition at an interval of 15 days and, thus, to understand drought stress tolerance capacity of
the accessions in MS medium. Seeds of the accessionswere obtained from JARC and growth
parameters like number of leaves(NL), number of roots(NR), root length(RL), shoot length(SL)
and leaf area(LA) of in vitro grown plantlets were measured. Completely Randomized Design
(CRD) with two replications was used to run the experiment. It was observed that differences
among accessions were significant for NL, NR, RL, SL and LA. Significant differences between
15 and 45 days of stress were observed for majority of the measurements in 6, 8, and 10% PEG
concentrations. Particularly, LA, SL, NL and NR of all accessions significantly decreased with
increasing concentrations of PEG. The highest values for NL, NR, RL and SL were recorded
during the stress time for accession H-674/98, followed by accession H-618/98, H-822/98 and
H-
739/98, whereas the lowest values were for accession H-980/98. The reduction was mainly
caused at PEG concentration of 8 and 10%. On the basis of the present study, it was concluded
that drought stress at earlier stages severely reduced growth attributes of Hararghie coffee
genotypes and some accessions (H-674/98, H-618/98, H-822/98 and H-739/98) have shown the
capacity of tolerance to drought stress.
