Jujube Flowering and Pollen Germination, Poster Board #310

Jujubes, also called Chinese dates, are native to China and have been cultivated in China for more than 4000 years. Jujubes have small, fragrant, and greenish-yellow colored flowers. As the deciduous fruiting branches (branchlets) grow, single flower or flower clusters start to initiate at the leaf axils. Unlike other tree fruit species, jujube completes its flower bud initiation, blooming, fruit setting, and fruit maturation all within one growing season. Fifty-two jujube cultivars were observed for their blooming type at the NMSU Alcalde Center; in addition, several cultivars were also examined for their pollen release and pollen germination. Among the 52 observed cultivars, 21 cultivars are morning-blooming type with flower buds slitting around 9:00–10:00 a.m. The remaining 31 cultivars are afternoon-blooming type with flower buds slitting around 2:00–4:00 p.m.  The pollen release period for the morning-blooming type is 10:00 a.m.–2:00 p.m., while for the afternoon blooming type it is from 3:00–4:00 p.m. of the same day to 10:00 a.m. of the next day. There were very limited pollens left in the anther after 4:00 p.m. of the same day for the morning type and after 12:00  p.m. of the next day for the afternoon type. The pollen germination rates ranged from 0% to 68% depending on the cultivar and sampling time. In general, the afternoon-blooming cultivars had higher pollen germination rate in the morning, while the morning-blooming cultivars had higher pollen germination rate from 11:00 a.m.–4:00 p.m. ‘Fitzgerald’ (morning-blooming) and ‘Sihong’ (afternoon-blooming) had the highest pollen germination rates among the 24 cultivars examined. The cultivar ‘Sugarcane’ had very low pollen germination rate and high aborted pollen rate, which partially contributed to its low fruit set at Alcalde. ‘Sherwood’ was another cultivar with very low fruit set and its high aborted pollen rate could be one of the reasons for its low fruit set.