Abstract:

Comparisons of chromosome ploidy，DNA fingerprint，fruit and leaf morphology，and fruit nutrition index were carried out among the common‘Dongzao’cultivated in Zhanhua County，Shandong，and three bigger-fruit variants，i.e.‘Zhandong 2’，variant No.1 and No.2. The results showed that the three bigger-fruit variants were all mixoploids（2x + 4x）according to flow cytometry analysis，and their mother plants were pure diploids. No differences of DNA fingerprint were observed using 74 pairs of SSR primers between the three bigger-fruit variants and their diploid controls（common‘Dongzao’），indicating that they were really originated from the common diploid‘Dongzao’and their 4x parts were autotetraploids. Compared to their diploid controls（common‘Dongzao’），the three mixploid variants had bigger and broader fruits with smaller fruit shape index，wider leaves with smaller leaf shape index，and significant higher content of vitamin C in fruit. However，the soluble sugar and titrable acid contents in fruits did not 

always change in accordance with the variations of ploidy. Compared to‘Zhandong 2’having been released as a new excellent cultivar，the average fruit weight of variant No.1 and No.2 increased by 22.95% and 15.90% and reached 27.05 g and 25.50 g，repectively.

Key words: Chinese jujube, variant, tetraploid, mixoploid