Phosphorus Use Efficiency and Yield Performance of Haricot Bean (Phaseolus vulgaris L.) in South Omo Zone, Southern regional state, Ethiopia

Haricot bean (Phaseolus vulgaris L.) is an important pulse crop in Ethiopia, serving as a major source of food, income, and soil fertility improvement. Despite its importance, haricot bean productivity in many parts of the country remains low, mainly due to phosphorus (P) deficiency in soils and the use of low-yielding varieties. This study was conducted to evaluate the phosphorus yield efficiency of fifteen haricot bean varieties under contrasting phosphorus conditions in two districts (Ben Tsemay and Bako Dawula) of South Omo Zone, Southern Ethiopia. The experiment was laid out in a randomized complete block design with three replications at each location. Each variety was grown under two phosphorus treatments: with the recommended rate of phosphorus fertilizer and without phosphorus application. Data were collected on phenological traits (days to 50% flowering and 90% maturity), growth parameters (plant height and number of branches), and yield and yield components, including number of pods per plant, number of seeds per pod, thousand seed weight, biological yield, grain yield, and harvest index. Analysis of variance was conducted for individual locations and combined across locations. The results revealed significant differences among the haricot bean varieties in terms of phosphorus yield efficiency, grain yield, and other yield-related traits under both phosphorus conditions. Under the recommended phosphorus application, varieties Sere 119, Nasir, and Sere 125 produced the highest grain yields. In contrast, under no phosphorus application, Sere 125, Sere 119, Dinknesh, and Nasir performed better than the other varieties. Moreover, DRK, SAB 736, and Sere 125 exhibited superior phosphorus yield efficiency. These varieties show strong potential for improving haricot bean productivity in phosphorus-deficient soils and in low-input farming systems where phosphorus fertilizer use is limited.