In vitro induction of auto‑allotetraploid in a newly developed wild rice line from Oryza alta Swallen
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Date
2019
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Abstract
Oryza alta Swallen is an important germplasm for rice resistance breeding; however, its CCDD genome (2n = 48) resulted in
low crossability when the wild rice was crossed with O. sativa and restricted the success of transferring the desirable traits
into cultivated rice. Induction of polyploidy is an efficient way for overcoming the low crossability among different species.
A new O. alta line, Huaye 5, was developed by our group in 2016, which had high fertility (64.93%) and photoperiod-insensitive.
Huaye 5 was used to induce auto-allotetraploidy using tissue culture in the present study. The tissue culture system
was established by comparing five basic media (N6, B5, MS, NB and MB), two hormones (2,4-D and 6-BA) for induction
and two differentiation media (MS and NB), and then induced auto-allotetraploid in the wild rice line by colchicine. The
medium and hormone combinations of NB + 2,4-D (2.5 mg/L) + 6-BA (1.0 mg/L) produced the induction rate of 20%, and
MS medium was found to be a suitable medium for callus induction with a differentiation rate of 10.15%, and the treatment
of 600 mg/L colchicine for 24 h was the best protocol for inducing auto-allotetraploid. Subsequently, auto-allotetraploid
plants (2n = 96) were obtained in the present study and their ploidy levels were detected by using flow cytometry, stomata
size and chromosomes count methods. Many inclusions in the parenchyma cells surrounding vascular bundle were observed
in auto-allotetraploid rice compared to the parent. We developed a new germplasm from O. alta, and established a protocol
of in vitro induction of auto-allotetraploid, which can be used for crossing with autotetraploid rice.
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Wild rice
Citation
Zhang, L., et al. (2019). In vitro induction of auto‑allotetraploid in a newly developed wild rice line from Oryza alta Swallen. Plant Cell, Tissue and Organ Culture, 139, 577-587.