An effective strategy for fertility improvement of indica-japonica hybrid rice by pyramiding S5-n, f5-n, and pf12-j
- 50 Downloads
Though inter-subspecific hybrids from indica and japonica rice have gained great success for yield increases over the recent decade, there are severe sterility problems in such hybrids. To overcome hybrid sterility, we previously obtained the line PL-(S5-n + f5-n) in the genetic background of an elite indica restorer line 9311, via breeding strategy for construction of wide compatibility line, which was proven to be an effective strategy in improving the seed setting rate of indica-japonica hybrid rice. Here, a novel strategy for developing japonica-compatible indica lines was employed by introducing the japonica allele pf12-j into 9311. The obtained NIL-(pf12-j) could significantly improve pollen and embryo-sac fertility by 29.7% and 28.6% in indica-japonica hybrids, thus leading to 20.9% improvement of spikelet fertility. In addition, we achieved the pyramiding line PL-(S5-n + f5-n + pf12-j) by a combinational strategy using both wide compatibility line and japonica-compatible indica line. Compared to PL-(S5-n + f5-n) with 38.9% increase of spikelet fertility, the pyramiding line PL-(S5-n + f5-n + pf12-j) showed 49.7% increase of spikelet fertility, suggesting cumulative effect of wide compatibility alleles S5-n + f5-n and japonica allele pf12-j to shape normal fertility of inter-subspecies hybrid. Interestingly, these lines also showed compatibility to indica. Hence, our results demonstrate that the two strategies could be simultaneously applied for indica-japonica hybrid breeding, and S5-n + f5-n + pf12-j are the optional allelic combination for overcoming hybrid sterility. This finding will greatly enhance our understanding for breeding indica-japonica hybrid rice by molecular-assisted selection strategy.
KeywordsOryza sativa L. indica-japonica hybrids Hybrid sterility japonica-compatible indica Wide-compatibility line
We are indebted to Dr. Lin Zhang from Yangzhou University for discussion.
J.M., Y.O., and T.M. conceived and designed the experiments; J.M. and Y.L. performed the experiments, including artificial crossing, genotyping, and selecting for breeding in the field; J.M. and G. P. analyzed the data; S. K., G. P., Y.O., and J.M. wrote the paper.
This research was supported by grants from the National Key Research and Development Program of China (2016YFD0100803), the China Postdoctoral Science Foundation, and the Science and Technology Major Projects of Genetically Modified Organisms Breeding of China (High Yield Transgenic Rice Breeding, Grant No. 2016ZX08001004-001-007).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Chakraborty S (2001) Rice breeding and genetics. New Delhi, IndiaGoogle Scholar
- Ikehashi H, Araki H (1986) Genetics of F1 sterility in remote crosses of rice. In: IRRI (ed) Rice genetics. IRRI, Manila, pp 119–130Google Scholar
- Lin J, Song X, Wu M (2012) Biological characteristics and heterosis utilization of four indica-japonica intermediate type restorer lines with wide compatibility. Chin J Rice Sci 26:656–662Google Scholar
- Lu Y, Ma R, Wang X, Li X, Zhou H, Zhang Z, Hua G (2007) SSLP-based SSR fingerprinting and indica/japonica classification of Yongyou series hybrid rice (in Chinese with English abstract). Chin J Rice Sci 21:443–446Google Scholar
- R Development Core Team (2018) R: A language and environment for statistical computing. R foundation for statistical computing, Vienna, Austria. Retrived from https://www.R-project.org/. Accessed 9/11/2019
- Siddiq EA, Singh S (2005) Wide-compatibility system for yield enhancement of tropical rice through inter-subspecific hybridization. Advancesin Agronomy 87:157–209Google Scholar
- Wan J (2010) Utilization in heterosis of indica-japonca crosses (in Chinese). Proceed First Hybrid Rice Congress China 9:3–6Google Scholar
- Yuan L (1996) Hybrid rice breeding in China. In: Virmani SS, Siddiq EA, Muralidharan K (ed) Advances in hybrid Rice technology, proceedings of the third international symposium on hybrid Rice 26-33Google Scholar
- Zhang G, Lu Y (1999) Breeding of the Indica compatible Japonica lines and their use in the breeding of super high yield hybrid rice (in Chinese with English abstract). Hybrid Rice 14:3–5Google Scholar
- Zhu W, Li W, Ding X, Zhang Z, Zeng R, Zhu H, Zhang G (2008) Preliminary identification of F1 pollen sterility gene S-e in Oryza sativa. J S China Agric Univ 29:1–5Google Scholar