Growth responses of arabica coffee (Coffea arabica L.) varieties to soil moisture deficit at the seedling stage at Jimma, Southwest Ethiopia.

摘要

Increasing trends towards dry weather affect coffee cultivation in Ethiopia through high seedling mortality and poor plant growth, but very limited research has been conducted on the response of coffee varieties to water deficit stress. This study was conducted in Jimma, Southwest Ethiopia, to investigate the growth responses of seedlings of six Coffea arabica varieties to 15 or 30 days of moisture deficit followed by 15 days of re-watering. Growth responses were assessed by measuring morphological characteristics and growth rate after stress and re-watering. Repeated measures analysis revealed that differences among varieties depended on water stress and recovery periods for lateral root number (LRNo), root volume (RV) and net assimilation rate (NAR). Significant differences between 15- and 30-day stress, as well as 15-day recovery were also obtained for majority of measurements. Particularly, specific leaf area (SLA), leaf area ratio (LAR), and stem and leaf area growth rate of all varieties decreased significantly, whereas total dry matter (TDM) increased in response to 30-day stress. Plant height, girth, TDM, RV and NAR showed significant increase in response to the 15-day recovery. The highest values for plant height, internode length, leaf area and SLA were recorded during both stress and rewatering for Variety 741, followed by Varieties 7487, 744 and 7440 in that order, and the lowest values were recorded for Variety 74148.