• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.346-350
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• 2009

The cultivated radish (Raphanus sativus L.) is a major vegetable crop in the world wide and fast-growing species that grows inhabitats of six continents. It is very important to determine hybrid seed purity in the production of hybrid Brassica vegetable seeds to avoid unacceptable contamination with self-inbred (sib) seeds. The use of random amplified polymorphic DNA (RAPD) markers for evaluating seed purity in $F_2$-hybrid radish cultivars demonstrated. One hundred eighty seeds from the F1 male and female harvest were subsequently screened for seed purity using 13 primers. The 13 primers result in 17 cultivar-specific bands and 23 variable RAPD bands scored for cultivar. RAPD analysis of hybrid seeds from the harvest revealed 128 seeds tested except underdevelopment and decayed seeds were sibs. Especially, $F_2$ hybrids of radish, OPC13, OPD20 were presented clear hybrid bands. It maintains higher than average level of genetic diversity compared with their correspondent parents. RAPD amplification of DNA extracted from germinated individuals from the female harvest reveal that 10 of 208 seeds tested were self-inbred (4.8%). RAPD analysis of hybrid seeds from the male harvest revealed 7 of the 208 seeds tested were sibs (3.4%). The RAPD may lead to a better insight in to the hybrid seed purity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.373-380
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• 2004

The production of sweet (su) and super sweet corns (sh2) has been economically feasible in Korea in recent years. Major factors limiting super sweet corn production are low germination and low seedling vigor. Since seed quality is closely related to seed maturity, the optimum harvest time for the seed production of sweet and super sweet corns was studied and the quality of seeds with varying maturities was investigated in 2001 and 2002 cropping seasons. The parents of the sweet corn seeds were Hybrid Early Sunglow and 'Golden Cross Bantam 70' and those of super sweet corn were Xtrasweet 82 and 'For­tune'. Seeds were harvested at 21, 28, 35, 42, 49, and 56 days after silking (DAS). As the seeds developed, seed weight of sweet corn increased and the seed moisture content decreased faster than that of super sweet corn. Germination rates of sweet corn seeds harvested 21 and 28 DAS at $25^{\circ}C$ and emergence rates in the cold soil test were significantly lower than those of seeds harvested after 42 DAS in both years. Although the germination rates of super sweet corn seeds with varying maturities showed similar patterns as sweet corn seeds at $25^{\circ}C$, the emergence rate of super sweet corn seeds in cold soil test continuously increased with seed maturity. This suggests that seed quality of super sweet corn should be tested in a cold soil test to estimate field emergence. As the seeds developed, leakage of total sugars and electrolytes from the both sweet and super sweet corn seeds decreased up to 42 or 49 DAS. The $\alpha-amylase$ activities of both sweet and super sweet corn seeds increased with seed maturity from 21 to 35 or 49 DAS depending on genotype and year. The optimum harvest time for the seed production of sweet corn was 42 DAS and 49 DAS for super sweet corn considering emergence rate and plumule dry weight in the cold soil test, leakage of sugars and electrolytes from the seeds, and $\alpha-amylase$ activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.258-261
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• 1983

This experiment was conducted to evaluate the effect of early seed harvest on germination of tobacco(Nicotiana tabacum L.) seeds. Seeds of seven burley tobacco were harvested every two days from 8 to 30 days after pollination and tested for germination. The results are; 1. Seeds harvested 12days after pollination germinated but germination rates were low and varied across cultivars. These seeds will provide viable seeds adequate for breeding program. 2. Germination rates of seeds harvested 24-28 days after pollination were high and showed none significant differences among cultivars. 4. Over-ripen seeds showed low germination rates cused by after-harvest or temporary dormancy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.70-74
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• 2008

To determine an optimum harvest time for chinese milk vetch (CMV) seed production, the seeds were harvested at 4 times, according to 25, 30, 35, and 40 day after flowering (DAF), in Miryang, southern part of Korea. CMV plants were manually harvested at each time and seed threshing was done by rice threshing machine. Seed yield, 1,000-seed weight, germinability, and hard coat ratio were investigated. Seed yield was the highest, 53.9 kg/300 kg by dry weight (DW) of CMV plant, at 35 DAF. 1,000-seed weight increased according to seed harvest time from 25 DAF to 40 DAF when it was 3.10 g. The germination ratios of seeds harvested at 4 times were not significantly different when the seeds stored until August 1. In case of long period of CMV seeds stored, the seeds harvested later showed higher germination rate. On the other hand, because the hard coat ratio causing germination inhibition was declined with an increase of storage period, it was higher in the seeds harvested later. There was no difference among the seeds harvested at 4 times at October 1. In conclusion, it was presumed that an optimum harvest time for CMV seed production should be at 35 DAF considering seed yield, weight and germinability.

• Journal of Life Science
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• v.18 no.7
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• pp.907-911
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• 2008

Radish (Raphanus sativus L.) is one of very important crop plants in the world. It is very important to determine hybrid seed quality in the production of hybrid Brassica vegetable seeds to avoid unacceptable contamination with self-inbred (sib) seeds. The allozyme for evaluating seed purity in a commercial $F_1-hybrid$ radish cultivar is demonstrated. Three hundred sixty seeds from the male and female harvest were subsequently screened for seed purity using 27 isozyme loci. Especially, F1 hybrids of radish, Per-1 ($aa{\times}bb$), Lap-1 ($aa{\times}bb$), Est-1 ($aa{\times}bb$) were presented clear hybrid bands. Est-1 locus revealed that 15 (8.3%) seeds from the female harvest and 26 (14.4%) seeds from the male harvest were sibs. It maintains higher than average level of genetic diversity compared with their correspondent parents. Shannon's index of phenotypic diversity (I) of hybrids was the highest of all accessions (R. sativus L. cv. Daepeng, R. sativus L. cv. Backza, and their hybrids). The allozyme may lead to a better insight into the hybrid seed purity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.1
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• pp.22-26
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• 2014

This research was implemented to investigate pre-harvest sprouting characteristics in two Korean rice cultivars, Shindongjin (SDJ) and Hopum (HP). The panicles of both varieties were sampled after 15 days after heading (DAH) to 60 DAH at intervals of 5 days. As soon as sampled, the panicles were imbibed in water for 14 days at $25^{\circ}C$ to determine the vigor and germination ability of seeds according to location on panicle. To investigate the cause of non-germination of seeds in panicles, tetrazolium test and dormancy breaking were performed. The preharvest sprouting of HP started at 20 DAH while that of SDJ began at 30 DAH. The germination of seeds located in high rank branches within a panicle and the terminal seeds within a branch were earlier and faster and the germination patterns were same in both cultivars. The times at more than 50% of germination in a panicle were 35 DAH (57.0%) in HP and 45 DAH (56.8%) in SDJ. Preharvest sprouting was more than 80% at 50 DAH (82.6% of HP, 92.3% of SDJ) and more than 99% at 60 DAH (99.5%, 99.4%, HP and SDJ). These results indicated that the rate of PHS in a panicle increased with accumulation of the days after heading. The cause of non-germinated seeds at 15-25 DAH in panicle was immature embryo. After 30 DAH, however, when the non-germinated seeds were hulled, they started to germinate due to dormancy breaking, in which the germination percentage was higher in SDJ than HP. In conclusion, the pre-harvest sprouting varied according to days after heading, the seed position on panicle, and the dormancy intensity of varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.361-367
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• 2002

In order to determine the optimum harvest time for the seed production of inbreds and hybrids in silage corn, the ears of sib-pollinated 'KS5', 'KS7rhm', and 'Ga209' and cross-pollinated 'KS5' $\times$ 'KS6' (Suwon19), 'KS7 rhm' $\times$ 'KSl17' (Suwonok), and 'Ga209' $\times$ 'DB544'(Kwanganok) were harvested at the one-week intervals from 4 to 10 weeks after silking. The optimum harvest time for the seed production for 'KS5', 'KS5' $\times$ 'KS6', 'KS7 rhm', and 'KS7rhm' $\times$ 'KS117' was 7 weeks after silking considering both emergence rate and plumule growth in cold test. Although earlier harvested seeds showed similar germination rate as the seeds harvested at the optimum time at $25^{\circ}C$, their emergence rate were lower in cold test. Seed weight and $\alpha$-amylase activity of earlier harvested seeds were lower compared to those of seeds harvested at the optimum time, while leakage of total sugars and electrolytes were higher. However, the later harvested seeds showed lower germination rates at $25^{\circ}C$ and emergence rates in cold test probably due to the lower $\alpha$-amylase activity although they showed increased seed weight and reduced leakage of total sugars and electrolytes. In contrast, the emergence rate of 'Ga209' and 'Ga209' $\times$ 'DB544' in cold test increased up to 10 weeks after silking probably due to the increased seed weight and $\alpha$-amylase activity and reduced sugar and electrolyte leakages during the germination. The cross-pollinated F$_1$ hybrid seeds showed higher germination and emergence rates at $25^{\circ}C$ and in cold test, and higher plumule growth and $\alpha$-amylase activity compared to those of sib-pollinated inbreds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.705-710
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• 1995

In order to find out the effect of rainfall at harvesting season on germination of malting barley, the seeds sampled from Cheju island and southern part of Korea were examined. The germination rate of seeds from Cheju island where rainfall was frequent at harvesting season, ranged from 46 to 71%, even though disease infection of the seeds was not that serious as would be expected. High sugar content of seed was resulted from the degradation of carbohydrates during the harvest season. From TZ test the rainfall - affected seeds were found to be highly viable but in the state of secondary dormancy. Results of cold germination test showed that the seeds were recovered from the secondary dormancy. Therefore, it was recommended that the seeds affected by the rainfall at harvesting season should be utilized after 12 months when the dormancy period terminated. The germination percent of the seeds was significantly enhanced by prechilling and / or 1 ppm gibberellic acid treatment. Different seed lots showed different rate of germination and the degree of dormancy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.311-318
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• 2002

Planting date of soybeans [Glycine max (L.) Merr.] is one of production components in cultural systems. The objective of the current study was to identify the components of soybean production and cultural practices encompassing planting dates and cultivars that respond to dry matter accumulation, harvest index and yield components. Three determinate soybean cultivars were planted on May 13 (early), June 3 (mid), and June 24 (late). Planting density was 60$\times$15cm with 2 seeds (222,000 plants per ha). Soybean plants were sampled every 10 days interval from the growth stages of V5 to R8 and separated into leaves including petioles, stems, pods, and seeds. Dry matter accumulations, harvest indices, and yield components were measured. Early planting had taken 55 days from VE to R2 and late planting taken 39 days indicating reduced vegetative growth. Early planting showed higher leaf, stem, pod and seed dry weights than late planting. However, late planting appeared to be higher harvest index and harvesting rate. Vegetative mass including leaf and stem increased to a maximum around R4/R5 and total dry weight increased to a maximum around R5/R6 and then declined slightly at R8. The highest seed yield was obtained with mid planting and no difference was found between early and late plantings. Cultivar differences were found among planting dates on growth characteristics and yield components. The results of this experiment indicated that soybean yield in relation to planting dates examined was mainly associated with harvest index and harvesting rate, and planting date of cultivars would be considered soybean plants to reach the growth stage of R4/R5 after mid August for adequate seed yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.2
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• pp.223-229
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• 1996

To investigate the effect of seeding date, seeding rate, and sprouted seeds on seedling establishment, yield and its components of rice in barley /rice reley cropping as a minimum tillage, Gancheokbyeo rice seeds sowed by hand broadcast in various overlapped days befer barley harvest. The highest rice seedling stand was at sowed on the day just before barley harvest and l00kg per hectare of seeding rate with sprouted seeds. Also number of tiller and panicle showed the similar tendency. Delayed rice heading dates were found 2 days at l0-day overlap, 2 days at 5-day overlap, and 4 days at 0-day overlap before barley harvest compared with machine transplanting rice at just after barley harvest using l0-days old seedling. The culm length of broadcast rice shortened 2∼4cm compared with the transplanting rice. The rice plants lodged slightly at seeding rate l00kg per hectare and at sowed on the day of barley harvest. The rice panicle number increased with later date sowing and higher seeding rate. Number of spikelets per panicle and ripened grains decreased at higher seeding rates. Sprouted seeds and higher seeding rates showed higher rice yield at later sowing dates.