Biomass Mass Production and Partitioning in Seedling of Harerghe Coffee Genotypes Under Deficit Irrigation at Jimma, Southwest Ethiopia

In Ethiopia, the coffee production is highly constrained by drought. To overcome such problem, knowing the behavior of coffee genotype’s biomass accumulation pattern to different parts under contrasting moisture stress is important in selection of drought tolerant genotypes. Therefore, the objectives of the present study were to evaluate and characterize the biomass partitioning patterns of Harerghe coffee genotypes as influenced by deficit irrigation in rain shelter at Jimma agricultural research center. An experiment was conducted in completely randomized block design with three replications, where treatments consisted of three deficit level (40, 80 and 120% of ETc) and six genotypes (H-674/98, H-739/98, H-823/98, H-981/98, H-929/98 and H-857/98). The result showed that the coffee dry-biomass partitioning patterns were significantly varied due deficit irrigation and genotypes as well as their interactions. Overall, the biomass assimilation and allocation were higher for roots (37%) under 40% ETc and finally dropped to 23% under well watered seedlings, the investment made in root at the expense of shoot in drought conditions, enables the plants to extract more water from dipper soil layers, if water is limited in upper soil layers Conversely, the dry matters portioned to leaf were greater (48%) under well watered seedlings and finally dropped to 26% under water stressed conditions. The accumulation of more dry-mater to leaf in well irrigated environment enables the plants to enhance photosynthetic capacity and thereby improve plant growth. Lastly, the study of dry biomass partitioning patterns in different parts of coffee plant is crucial important to decide appropriate watering amount and identifying drought tolerant genotypes for future breeding program under variable climatic conditions.