In this test,‘Chuannong 1 loquat’ (C1) was taken as the experimental material which was derived from a low seediness line of degenerated seeds of‘Dawuxing’ loquat.The self-pollination of ‘Dawuxing’ loquat was the control treatment.The growth of pollen tubes in the styles was observed with fluorescence microscopy.The results showed that:(1)Pollens germination and pollen tube growth were normal in cross-pollination of C1 and it took about 48 hours for pollen tubes to reach the base of style.(2)The pollens could germinate on stigma and the pollen tubes could growth in the styles after self-pollination of C1,but it took quite a long time.Most pollen tubes could reach the upper or middle of style but stopped growing 36 hours after self-pollination of C1,and meanwhile there were some incompatibility-phenomenon that the form of tube apex was abnormal and fluoresced more obviously,and only few pollen tubes could reach the base of style.C1 behaved gametophytic self-incompatibility (GSI).The self-incompatibility of C1 was one of the important reasons for its seed abortion.