Periodically members ask about poor fruiting behaviour with feijoa. This species is protogynous & mostly self-incompatible to encourage cross-pollination. Although some varieties have partial self-fertility sufficient to set an acceptable crop, it's usually best to have multiple plants of different genetic diversity, or use grafts. Additionally with our most common pollinator the honeybee, flower attractiveness has to rely on pollen as they don't produce nectar, & bees are too small for much pollen to dust off on the central stigma as it's 1-2cm above the anthers. Larger insects or birds have to do the job, or you hand-pollinate.