• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.1
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• pp.8-17
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• 2021

As rice originates from tropical regions, low temperature stress during the germination stage in temperate regions leads to serious problems inhibiting germination and seedling establishment. Identifying and characterizing quantitative trait loci (QTLs) for low-temperature germination (LTG) resistance help accelerate the development of rice cultivars with LTG tolerance. In this study, we identified QTLs for LTG tolerance (qLTG5, qLTG9) and germination coefficient of velocity under optimal conditions (OGCV) (qOGCV7, qOGCV9) using 129 recombinant inbred lines (RILs) derived from the cross between a low-temperature sensitive line Milyang23 and a low-temperature tolerant variety Gihobyeo. qLTG9 and qOGCV9 were detected at the same location on chromosome 9. At both LTG QTLs (qLTG5 and qLTG9), the alleles for LTG tolerance were contributed by the japonica variety Gihobyeo. At qOGCV7 and qOGCV9, the alleles for low temperature tolerance were derived from Milyang23 and Gihobyeo, respectively. The RILs with desirable alleles at two or more QTLs, i.e., GroupVII: qLTG5+qLTG9 (qOGCV9) and GroupVIII: qLTG5+qOGCV7+qLTG9 (qOGCV9), showed stable tolerance under low-temperature stress. Our results are expected to contribute to the improvement of tolerance to low-temperature and anaerobic stress in japonica rice, which would lead to the wide adoption of direct-seeding practices.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.4
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• pp.209-214
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• 1991

The germination of seeds is developmentally complex process requiring water uptake, which is regulated by both genotypic and environmental factors. The present study was undertaken to determine the difference in germination characteristics, and to compare the ability of the logistic and Weibull functions to describe the cumulative germination curve when two levels of osmotic potential(0, -5 bar) were put to seeds of alfalfa, tall fescue, orchardgrass, and Kentucky bluegrass. The effects of grass type, osmotic potential, and their interaction on the total germination and coefficient of germination velocity were significant(P<0.01). The Weibull equation for predicting percent cumulative germination curve of alfalfa had significantly lower residuals than the logistic equation regardless of osmotic potential(P<0.01), indicating that the Weibull equation was more efficient than the logistic equation to fit the data of the percent cumulative germination of alfalfa. The rate parameter from the logistic equation was decreased under water stress, whereas the scale and shape parameters were increased. There were significant differences in days to 20% germination estimated from the logistic and Weibull equations.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.31-35
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• 2010

Several experiments were conducted to investigate the germination characteristics among the Rumex crispus, R. japonicus, R. obtusifolius, and R. nipponicus. The germination point of R. japonicus was started 4 days after application, and then R. obtusifolius (5th), R. crispus (6th), R. nipponicus (10th) with appeared order. The optimum temperatures for germination of all tested Rumex spp. occurred at the $15^{\circ}C$. Especially, R. obtusifolius will have the widest germination range at $10^{\circ}C{\sim}30^{\circ}C$. To compared with 1996 and 2004 year selected R. japonicus germination were did not significantly difference, otherwise, all tested Rumex spp. on dark condition was not germinated. The parameters of germination characteristics of Rumex spp. were investigated mean germination rate (MGR, %), mean germination time (MGT, day), mean germination velocity (MGV, No./day), and coefficient of germination uniformity (CGU). The R. japonicus compared in tested Rumex spp. showed the highest MGR. The MGT and MGV of R. obtusifolius was appeared the earliest compared with R. obtusifolius and R. crispus.