The article highlights potential features for the varieties of vegetable bean and actual losses of yield subject to the total amount of photosynthetically active radiation (PAR) received over the vegetation period in the Forest-Steppe of Ukraine. It is established that the potential of the vegetable bean yield in Ukraine depends on PAR received over the vegetation period. All the varieties had their yield upon receiving PAR higher by 0,26-0,41 t / ha compared to that of control. Potential yield of vegetable bean varieties when PAR is used by 2% amounted to 57.25–59.30 t / ha, which was 2.2–3.6 times more than their actual yield. The smallest actual yield loss compared to that potential was inherent in the varieties of Bartoli and Windsor (2.2–2.3 times). The actual yield losses for Karadag and Karestyno varieties were the highest, namely 3.6 times higher compared to the potential prospect.