Uses neryl diphosphate to catalyze the cis-prenyl chain elongation and produce the 15 carbon product (2Z,6Z)-farnesyl diphosphate. dimethylallyl diphosphate + 2 isopentenyl diphosphate = (2Z,6Z)-farnesyl diphosphate + 2 diphosphate dimethylallyl diphosphate + isopentenyl diphosphate = diphosphate + neryl diphosphate isopentenyl diphosphate + neryl diphosphate = (2Z,6Z)-farnesyl diphosphate + diphosphate Localizes in punctuate patterns inside the chloroplasts. Expressed in roots and red fruits. Belongs to the UPP synthase family.