• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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• pp.20-25
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• 2000

Viviparous germination causes yield loss and quality deterioration of rice. This study was conducted to investigate varietal differences of the viviparous germination with different days after heading (DAH) and different temperatures. In the laboratory examination, the averaged germination rate of all varieties at 45DAH and at 25DAH was 79.9%, and 27.5% under the incubation at the temperature of 3$0^{\circ}C$/2$0^{\circ}C$ (day/night) for 12 days. Andabyeo, Da- sanbyeo, and Nonganbyeo showed the lowest viviparous germination rates among the tested varieties. The shoot length of the viviparous germination measured 12days after incubation at 30/2$0^{\circ}C$ ranged from 21 to 53mm, indicating significant deterioration of rice quality. In the field test, the averaged viviparous germination rates of rice varieties at 25, 35, 45DAH with the underwater conditions for 4 days were 2.2, 6.2 and 9.2%, respectively, while their rates at 12 day after underwater conditions increased to 17.6, 44.2 and 43.8%, respectively. A variety that showed the highest viviparous germination rate at 25 and 35 and 45DAH was Heukjinjubyeo. When standing rice panicles without lodging were examined after consecutive raining for 7 days Juanbyeo showed the highest viviparous germination (45.5%), followed by Odaebyeo (16.0%), Jinbubyeo (14.5 %), Bongkwangbyeo (14.2 %) and Obongbyeo (12.6%). The viviparous germination of rice was greatly affected by variety, days after heading and temperature settings. Bongkwangbyeo, Juanbyeo, Dongjinbyeo, Hwasunchalbyeo, Naepoongbyeo and Heukjinjubyeo were classified as the most susceptible varieties to the viviparous germination in the field conditions.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.15-18
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• 1984

This experiment was conducted to find out the factors governing the viviparous germination of In. $\times$ Ja. type rice varieties. Six varieties, i.e., Milyang 21, Raekyeong, Milyang 30, Yeongnamjosaeng, Nopoong and Mansuk, were used for this experiment. The viviparous germination easily occurred between 40 to 45 days after heading, and was easier in yellow-ripe stage or full-ripe stage than dough-ripe stage. The use of exceeding fertilization induced more viviparous germination than ordinary one. The early varieties such as Yeongnam-josaeng and Milyang 21, easily occurred the viviparous germination. The local conditions of viviparous germination were usually poorly drained soils and narrow alluvial valleys where were high humidity prevailed.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.421-427
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• 2006

To investigate the relationships among the traits related seed dormancy in rice, viviparous germination, dry-heat tolerance and seed longevity were tested using 164 M/G RILs ($F_{17}$) derived from the cross between Milyang 23 (Indica/Japonica) and Gihobyeo (Japonica). At 40 days after heading, the viviparous germination rates of Milyang 23 and Gihobyeo were 0.0 and 7.0%, respectively. The averaged viviparous germination rate of 164 MIG RILs was 3.2%, and their range was from 0.0 to 50.9%. In dry-heat treatment at $90^{\circ}C$ for 24 h followed by the pre-drying at $40^{\circ}C$ for 2 days, Milyang 23 showed higher germinability (98.6%,2.7 days to $T_{50}$) than Gihobyeo (37.6%, 12.9 days to $T_{50}$), and the mean germination rate of 164 M/G RILs was 72.4%. In 54 months after harvest, the germinability in Milyang 23 and Gihobyeo were 90% and 0%, and 71 lines among 164 M/G RILs showed the germinability over 90%. The relationship between seed longevity and dry-heat tolerance was linearly correlated with high positive correlation coefficient. The relationships between seed longevity and viviparous germination, and viviparous germination and dry-heat tolerance were linearly correlated with high negative correlation coefficient. Milyang 23 had higher tolerance against high dry-heat, viviparous germination and long-term storage than Gihobyeo, and 164 M/G RILs showed the medium values of parents.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.241-248
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• 2009

Varietal differences on viviparous germination of newly released rice varieties were investigated to provide selection criteria for the high quality rice production. Laboratory and field tests were conducted on 20 different rice varieties in 2007. Varieties which showed below 10% of viviparous germination at the laboratory test were Odaebyo, Hitomebore, Koshihikari, Hwasungbyo, Hopyongbyo, Ilpumbyo, Chuchungbyo when they were treated 35 days after heading (DAH) at the temperature of 25/$15^{\circ}C$ (day/night) for 8 days, and were Hitomebore, Koshihikari, Hwasungbyo, Hopyongbyo under diurnal temperature of 30/$20^{\circ}C$ (day/night). At the field test with artificial lodging, there were 12 varieties including Hopyongbyo, Hitomebore that showed lower viviparous germination below 10% when they were treated at 35DAH and measured 8 days after lodging treatment but there was only four varieties (Ilpumbyo, Hwasungbyo, Chuchungbyo, Hopyongbyo) when lodging treatment was made at the 45DAH. Among newly released rice varieties, viviparous germination rate of Hopyongbyo was below 10% and was 11 to 20% at Hithomebore and Samgwangbyo, 21 to 40% at Koshihikari, Odae-No.1, Josaengheukchalbyo, Chonghobyo, 41 and 60% at Suean-No.1, Whongwangbyo, Bosukchalbyo, and 61 to 90% at Gopumbyo when it was examined 8 days after lodging treatment at 45DAH.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.113-119
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• 1995

This excperiment was conducted to investigate relation on seed dormancy and vi-viparous germination with sucrose content, fatty acid composition and abscisic acid content of rice seeds. The following results were obtained by this experiment. Sucrose content of brown rice harvested at 20 and 40 days after heading was higher in Japonica and Sare type varieties than in Tongil and Indica type rices. Positive relationship was found be-tween sucrose content of brown rice and viviparous germination rate of rice varieties tested.J aponica and Sare type rice varieties showed low proportion of oleic acid and higher proportion of linoleic acid in brown rice harvested at 20 and 40 days after heading than Tongil and Indica rices tested. Viviparous germination was negatively correlated with the proportion oleic acid and positively with that of linoleic acid. Abscisic acid content in hull of rice seeds stored for 30 days at 25/15$^{\circ}C$ fluctuation temperature condition was decreased more rapidly than 4$^{\circ}C$, and Japonica varieties tested showed lower con-tent of abscisic acid in rice hull than Tongil and Indica varieties used.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.3
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• pp.262-269
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• 1988

Experiments were conducted to find out the method of reducing viviparous germination of rice seeds using growth regulators during grain filling period. Among the recommended varieties, early Japonica type showed higher rate of viviparous germination, while late Japonica type and Tongil type varieties did not show viviparous germination in field condition. Grain showed high germination ability from 30 days of grain filling period in Daeseongbyeo of Japonica type and 35 days in Taebackbyeo of Tongil type. Growth regulators, NAA, CMH and Reglone were effective for reducing viviparous germination to the two rice varieties and three treatment stages in this experiment. NAA and CMH were most effective at 100 ppm and Reglone was at 0.4-0.6% concentration. Germination rates of rice seed were not different from non-treatment when NAA CMH were treated, while Reglone lowered germination rate. NAA and CMH had no effects on grain filling rate for both varieties, which showed high grain filling rate as the non-treatment, but Reglone results low grain filling rate. Grain color was not changes when NAA was applied, while CMH and Reglone made a lot of grain to dark brown as the concentration became higher. When grain were hulled, NAA had no difference with the non-treatment whereas CMH and Reglone had lower rate of perfect brown rice when they were applied at 20-30 days after heading.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.15-18
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• 2008

This study was conducted to analyze the rice yield and grain quality of viviparous germinated seeds caused by long period rainy days. In the yield characteristics, the milled/brown rice rates in two cultivars, Unkwangbyeo and Gopumbyeo were 86.0 and 80.9%, respectively, in viviparous germinated seeds, showing the decreased rates by 3.2 and 6.2%, respectively, as compared to 89.2 and 87.1% in normal seeds. Rice yield in Unkwangbyeo and Gopumbyeo also decreased by 5 and 7%, respectively, in viviparous germinated seeds as compared to normal seeds. Peak viscosity and set back of viviparous germinated seeds were decreased, and the hardness of them was increased compared to normal seeds. Color value (a) of viviparous germinated seeds was 0.90, showing lower value than that (1.65) of normal seeds of Gopumbyeo. The results demonstrated that as the viviparous germinating rate was increased, the grain quality was deteriorated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.565-570
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• 2006

The viviparous germination (VG) with lodging caused the yield reduction and quality deterioration in rice. We carried out the evaluation of VG tolerance (on the 40th day after heading) and mapping QTLs associated with VG tolerance using the recombinant inbred lines (M/G RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). The VG rates of Milyang 23 and Gihobyeo were 0.0 and 7.0%, respectively. The averaged VG rate of 162 M/G RILs was 7.7%, and their range was from 0.0 to 50.9%. Of the 162 RILs, 144 lines were tolerant less than 10%, and 18 lines were susceptible more than 10%. Using the M/G RIL Map, three QTLs associated with the viviparous trait were detected on chromosome 2 (qVG 2-1 and qVG 2-2) and 8 (qVG 8). qVG 2-1 was linked to RM 32D and RZ 166, and had LOD score of 2.97. qVG 2-2 was tightly linked to E13M59.119-Pl and E13M59.M003-P2, and showed higher LOD score of 3.41. qVG 8 was linked to RM33 and TCT116, and had LOD score of 2.67. The total phenotypic variance explained by the three QTLs was about 24.4% of the total variance in the population. The detection of new QTLs associated with VG tolerance will provide important informations for the seed dormancy, low temperature germination, or comparative genetics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.434-440
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• 1996

This experiment were conducted to elucidate the damage by viviparity during grain filling on grain quality and hulling recovery and to understand the varietal differences of viviparity and the effect of extractive from rice hull of hardly viviparous varieties on seed germination and seedling growth. Ten rice cultivars, such as three indica, four japonica and three Tongil-type rices, were used in this study. The brown rice yield was decreased along with increasing the artificial viviparous treatment periods. At six days after treatment, brown rice yield of Daeseongbyeo was reduce 20% as compared with control. The ratio of head rice was 41.3% at six days after viviparous treatment with $25^{\circ}C$ temperature and over 95% relative humidity, while it was 99.5% in control. Varietal differences of viviparity in three rice groups were ranged from 1.1 to 5.2% in indica rices, 9.2 to 79.7% in japonica rices and 2.1 to 63.7% in Tongil-type rices. Methanol extractives from rice hull of IR36, Shinunbongbyeo and Jungwonbyeo inhibited significantly the germination of Deaseongbyeo.