As the fruits of loquat (Eriobotrya japonica, 2n = 2x = 34) carry large seeds, the breeding of seedless loquat has long been a goal. The recent creation of
triploid cultivars (2n = 3x = 51) and the application of
gibberellins allow commercial production of seedless loquat, but the possibility of seed formation in
triploid loquats has not been carefully investigated. Through crossing experiments and cytological observations of meiosis and pollen tube growth, we found that the
triploid line 3N-N28 was essentially self-sterile, but developed seeds on pollination with pollen from diploid cultivars at rates of up to 5.5%. Almost half of the seedlings survived to 5 months, and carried diploid (2n = 34),
tetraploid (2n = 68), or
aneuploid chromosome numbers. Our results suggest that
triploid loquat cultivars might retain the risk of seed formation. Protection from pollination by diploid cultivars or the development of new
triploid cultivars will be necessary to ensure the production of seedless loquat fruits.