Acquisition of triploid germplasms by controlled hybridisation between diploid and tetraploid in Chinese jujube

ABSTRACT

‘Chenguang’ is the first released tetraploid cultivar (2n = 4x = 48) of Chinese jujube (Ziziphus jujuba Mill.) induced by colchicine. The purpose of this study was to create triploid germplasms by using ‘Chenguang’ as a parent. The controlled crosses between autotetraploid ‘Chenguang’ and diploid ‘Dongzao’ were carried out from 2013 to 2015 by maintaining the 2 parents in a nylon net and employing bees as pollinator. A total of 606 fruits were produced, yet only 17 seeds were obtained from ‘Dongzao’ and none from ‘Chenguang’. Direct sowing of the seeds in greenhouse showed a higher seedling rate than embryo culture. Four progeny plants were eventually obtained in the greenhouse and all of them were confirmed as authentic hybrids by SSR marker technique. At last, 3 triploids and 1 diploid were identified by flow cytometric analysis. Consequently, tetraploid ‘Chenguang’ with high pollen vitality and pollen number per anther could be used as a reliable 2n pollen provider, and the 2x × 4x cross combination type is more suitable for triploid creation in Chinese jujube. This is the first successful production of triploid hybrids by controlled cross between diploids and tetraploids in jujube.

KEYWORDS:

• Chinese jujube
• triploid hybrids
• 2n pollen provider
• SSR marker
• flow cytometric analysis

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Science Technology Support Program (2013BAD14B03) and the Beijing Municipal Education Commission (CEFF- PXM2017_014207_000043).