• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.116-116
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• 2017

Low-temperature is one of the environmental stress factors that affect plant growth and development and consequently limit crop productivity. The control of seed germination under low-temperature is organized by many genes which are called quantitative trait loci (QTLs). High germination rate for low-temperature is an important factor of growing rice. Previously, we identified a major QTL controlling low-temperature germinability in rice using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon (Rufi) and the Korean japonica cultivar, 'Hwaseongbyeo (HS)'. A $BC_3F_7$ line (TR5) showed better low-temperature germinability than its recurrent parent. TR5 was crossed with HS to develop a segregating F2:3 populations for the target QTL. Six SSR markers polymorphic between HS and Rufi were used to screen and fine map the qLTG1. The qLTG1 on chromosome 1, which accounted for 55.5% of the total phenotypic variation, confirmed that Rufi allele enhanced the low-temperature germinability. Intervals between markers CRM16 and CRM15, four candidate genes were identified. The identified candidate genes, which are encoded by a protein of unknown function, showed their direct involvement on seed germination at low-temperature. To identify genes targeted by qLTG1, we investigated the expression profiles of these candidate genes and germination behavior of qLTG1 under different stress conditions and compared to HS, Rufi, and TR5 at $13{\pm}2^{\circ}C$ for 3 days after incubation. Furthermore, transgenic rice plants will also be developed to conduct a detailed investigation on low-temperature germinability. Hence, the QTL for low-temperature germinability would be useful in rice breeding programs especially in the development of lines possessing low-temperature germinability.

• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.477-482
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• 2012

Low-temperature germination is one of the major determinants for stable stand establishment in the rice direct seeding method in temperate regions and at high altitude areas. Quantitative trait loci (QTL) controlling low-temperature germinability in rice were identified using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon and the Korean japonica cultivar, 'Hwaseongbyeo'. The germination rate at $15^{\circ}C$ was measured to represent low-temperature germination and used for QTL analysis. The germination rate at $15^{\circ}C$ for 7 days of Oryza rufipogon and Hwaseongbyeo was 93.3 and 28.7%, respectively, and that of progenies ranged from 0 to 48%. A linkage map was constructed using 135 simple sequence repeat (SSR) markers. Five putative QTLs associated with low-temperature germination were detected on chromosomes 1, 3, 4, 10 and 11. The QTL, qltg10 on chromosome 10 accounted for 19.2% of the total phenotypic variation for low-temperature germinability. Four additional QTL, accounted for 10.4 - 15.1% of the total phenotypic variation. The O. rufipogon alleles in all detected QTLs loci increased the low-temperature germination rate. No QTL associated with low temperature germinability has been detected near the qltg10 QTL in this study suggesting that qltg10 is a new QTL. The locus, qltg10 is of particular interest because of its independence from undesirable height and maturity effects. The DNA markers linked to the QTL for low temperature germinability would be useful in selecting lines with enhanced low temperature germinability in rice breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.37-45
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• 1970

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.192-192
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• 2017

Direct-seeding cultivation of rice is increasing in Asia instead of transplanting system, because of its lower cost and operational simplicity. Low-temperature germinability (LTG) and anaerobic germinability (AG) are important characters for breeding of varieties for wide-spread adoption of direct-seeding cultivation in rice. This study was performed to characterize LTG and AG of seven rice varieties and identify varieties with strong germinability on both low-temperature and anaerobic conditions. The mean germination rate and germination vigor of seven varieties were 51.7% and 6.0 under low-temperature condition, respectively. Among these varieties, Cheongcheongjinmi and Hwanggeumnodeul had the highest germination rate of 80%, indicating that Cheongcheongjinmi and Hwanggeumnodeul have a good LTG. In anaerobic conditions, the germination rate and coleoptile length for all varieties were 47.6% and 3.2 cm, respectively. Of them, the highest germination rate and coleoptile length were observed in Subo and Hopum, respectively, suggesting that these two varieties are tolerant to anaerobic during germination stage. Molecular characterization by SDS-PAGE revealed that the protein patterns differed at 50 kDa, 40 kDa, and 22 kDa between low-temperature and anaerobic conditions. Varieties identified as good LTG or AG in this study may be used for developing new direct-seeding rice cultivars through pyramiding these traits in the breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.711-715
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• 1995

This study was carried out to determine the desirable screeing condition for low-temperature germinability of rice seeds. The germination test was performed with fifty rice varieties from three countries, mainly including the recent Korean rice cultivars. The analyzed result of germination test under three temperature conditions(13$^{\circ}C$, 16$^{\circ}C$, $25^{\circ}C$) pointed out that 11 days after seeding at 13$^{\circ}C$ was the most efficient testing condition for low-temperature germinability in terms of mean and variation in germination rate. Highly significant correlations were observed between germination rates of 11 days after seeding at 13$^{\circ}C$ and germination coefficients, average days of germination at 13 for 20 days. Low-temperature germinability were highly positively associated with days to heading or amylose content, but negatively correlated with grain width.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.283-283
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• 2022

Abiotic stresses such as high/low temperature, drought, salinity, and submergence directly or indirectly influence the physiological status and molecular mechanisms of rice which badly affect yield. Especially, the low temperature causes harmful influences in the overall process of rice growth such as uneven germination and the establishment of seedlings, which has become one of the main limiting factors affecting rice production in the world. It is of great significance to find the candidate genes controlling low-temperature tolerance during seed germination and study their functions for breeding new rice cultivars with immense low-temperature tolerance during seed germination. In this study, 120 lines of Cheongcheong/Nagdong double haploid population were used for quantitative trait locus analysis of low-temperature germinability. The results showed significant difference in germination under low different temperature conditions. In total, 4 QTLs were detected on chromosome 3, 6, and 8. A total of 41 genes were identified from all the 4 QTLs, among them, 25 genes were selected by gene function annotation and further screened through quantitative real time polymerase chain reaction. Based on gene function annotation and level of expression under low-temperature, our study suggested OsGPq3 gene as a candidate gene controlling viviparous germination, ABA and GA signaling under low-temperature. This study will provide a theoretical basis for marker-assisted breeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.766-777
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• 1997

The purpose of this study was to investigate inheritance modes of low temperature germinability(LTG) on rice. Two experiments were carried out: In experiment I, the seeds of 10 rice varieties yielded at the different cultivation conditions which were transplanted in a paddy field from May 20 to July 5 with 15-day interval, were tested at fixed temperature (13$^{\circ}C$) in-door and at field with natural conditions to find out the change of LTG according to different cultivating condition among the each variety, In experiment II, F$_1$ seeds of full diallal cross from six parents, were analyzed for combining ability and reciprocal differences of low temperature germinability. The results are summarized as follows. The seeds of 10 varieties showed significant differences of LTG at the different cultivation conditions, varieties and their interaction. And the relationship between LTG coefficient at 13$^{\circ}C$ and low temperature emergence(LTE) coefficient at field was highly significantly positive(r=0.511). From the analysis of the diallel cross, high significance was found at reciprocal difference and alpha inheritance. The mean squares of general combining ability(GCA) and specific combining ability of LTG were highly significant with higher mean squares of GCA. Seventeen out of 30 cross combinations showed transgressive segregation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.187-192
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• 1994

This study was conducted to investigate varietal difference in viviparous germinability at different days after heading and temperature conditions. Three Japonica rice varieties, Sobaekbyeo, Odaebyeo and Hwaseongbyeo, and Sare type rice variety, Jakwangdo, showed higher viviparous germination rate from 20 days after heading, while a Tongil type rice, ]ungwonbyeo, and a Indica varieyt, IR-20, showed still low viviparous germination at 40 days after heading. Viviparous germination rate of rice varieties observed at 4 and 10 days after incubation was greately increased with increasing temperature from 15$^{\circ}C$ to 3$0^{\circ}C$ , and germination rate less than 5% was observed at 4 days after incubating at 15$^{\circ}C$ in all rice varieties teased. Viviparous germination pattern of rice varieties was divided into two types. Three Japonica and Sare type rice varieties showed higher and faster in viviparous germination than a Tongil type and Indica rice verieties. Viviparous germination was delayed under day /night fluctuation of incubation temperature compared with day /night fluctuation of incubation temperature compared with day /night constant condition at the same average temperature. The optimum incubation temperature and duration to evaluate viviparous germinability of rice varieties were 25/15$^{\circ}C$ and 6 days, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 1996.05a
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• pp.12-13
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• 1996

• Plant Biotechnology Reports
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• v.3 no.1
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• pp.103-109
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• 2009

In this study we established reliable methods for conservation of seeds of Phaius tankervilleae as an orchid genetic resource. The seeds, which were dehydrated to 5% water content and preserved at $4^{\circ}C$, showed no decrease in viability and germinability after three months. After storage for six months, however, the seeds showed a drastic decrease in germinability, even though survival rate was high. For long-term preservation of seeds of P. tankervilleae, cryopreservation is applied to the freshly harvested seeds. When the seeds were cryopreserved by the vitrification method for up to 12 months there was no apparent deterioration effect of storage time. These results indicate that cryopreservation by the vitrification method is useful for long-term conservation of P. tankervilleae seeds, which are difficult to preserve for more than three months under dry and low-temperature conditions.