Growth, Water Relation, Yield and Crop Quality of Arabica Coffee in Response to Water Stress and Deficit Irrigation.

Coffee (Coffea Arabica L.) is the single most important commodity crop that comes after petroleum in the world market. It plays a significant role in the economy of Ethiopia, contributing over 60% of the nation's foreign exchange earnings, 30% of the government's direct revenue, 8% output of the agricultural sector and 4% of the gross domestic production. In spite of the importance of the crop in the country's economy, its average national yield is very low primarily because of traditional production technologies. Apart from hereditary characteristics of the trees, seasonal water stress and recurrent drought are among the major factors which account for low yields of the crop in most coffee growing regions of the country. In the present study, attempt was made to identie water stress tolerant Arabica coffee cultivars and deficit irrigation practices that could improve growth, yield, quality and water use efficiency of the crop under both protected environment and field condition in Ethiopia. Both rain shelter and field experiments were carried out in a randomized complete block design with three replications in the rain shelter and four replications in the field. In the first rain shelter ~EWSTAWUN %TAN MJU- SAMAD UWEfirn m MAww than NDI for coffee production particularly in areas where water is scarce and dry spells are prolonged. On the other hand, the effect of supplemental deficit irrigation on plant water relations, crop yield and quality was studied in the field using young coffee stands of three cultivars (F-59, 74110 and 75227). Two irrigation treatments, namely, supplemental full irrigation (SFI) and supplemental deficit irrigation (SDI), applied in the conventional way, were compared against rain fed (RF) control. SF1 consistently increased soil moisture content, leaf RWC and g, during the dry period, but there was no difference between the treatments in the main wet season. Besides, SF1 significantly increased coffee yield, but the difference between SF1