• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.135-139
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• 1987

The influence of ploidy level on agronomic characteristics in italian ryegrass, Lolium multiflorum Lam, italicum, was studied using diploids (2x) and tetraploids (4x) on the upland of Livestock Experiment Station, Suweon. The results are summarized as follow: 1. Tetraploid cultivars are in general dark green in leaf color and strong glittered. 2. Diploid cultivars are more resistant to cold than tetraploids but degree of resistance to cold depends on cultivars. The di-and tetraploids did not differ in summer survival and coldand heat resistance of di-Itetraploid cultivars were not related. 3. Tetraploid cultivars have larger leaf-blades, more rapid growth and higher leaf ratio to stem by heading than diploids. 4. Tetraploids possess significantly lower dry matter content than diploids. 5 . Fresh- and dry weight of tetraploids are similar with that of diploids but tetraploids are more leafy than diploids. 6. Seasonal yield depends more on the type of the cultivar than on its tetraploid nature.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.290-293
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• 2000

The main grape producing regions in Korea were surveyed for the occurrence and relative incidence of crown gall disease on grapevine. The results of the survey showed that the disease tended to affect tetraploid cultivars, which produce a large and sweet fruit but are very weak to cold weather. Incidence of crown gall disease was high on the tetraploid cultivars, Kyoho (Gerbong), Daebong, and Black Olympia while it was low on the diploid cultivars, Cambell Early and Sheridan. The disease incidence was very high on Anseong, Cheonan, and Chincheon, where the major growing areas of tetraploid cultivars and grapevines were burried in the winter to protect from freeze injury, whereas it was low in Yungdong, Kimcheon, and Nonsan. Crown gall disease did not increased with grapevine age on both Cambell Early and Kyoho. It remained low in Cambell Early, but high for all ages on Kyoho, Galls were found on the crown region and mid part of the trunk, but more galls were on small branches and canes on Kyoho grapevines. More than one third of ZKyoho grapevines inspected had galls on multiple locations on grapevines. On Kyoho, 56.3% of the galls covered more than 50% of the crown gall disease affects severely on the cultivar.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.340-350
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• 1995

This study was conducted to obtain the basic information for the salt stress of Italian Ryegrass. Fourteen cultivars including 7 diploid and 7 tetraploid were subjected to eight levels of NaCl treatments during germination and early seedling stages. Germination percentage decreased remarkably over 300mM of NaCl concentration. The NaCl concentration that inhibited germination of 50% of the viable seeds in the cultivars was 344mM. The decreasing degree of germination percentage was higher in tetraploid type than in diploid type. The varietal difference of germination percentage was shown to be very conspicuous as the NaCl concentration increased. Top dry weight in 166 mM NaCl was decreased by 50% compared with that of control. Inhibition of NaCl appeared to be more in early seedling stage than in germination stage. Top dry weight of cultivars in NaCl stress was not related with germination capacity. Root dry weight in 148mM NaCl decreased by 50% compared with that of control. Root dry weight of cultivars was significantly correlated with top dry weight in NaCl treatment. Top dry weight and root dry weight was higher in diploid type than in tetraploid type at each 8 levels of NaCl concentration. Total chlorophyll content increased with the increase of NaCl concentration and the degree of increase in chlorophyll a was higher than that in chlorophyll b. Chlorophyll a was higher in tetraploid type than in diploid type. But chlorophyll b was higher in diploid type than in tetraploid type. There were significant correlation between chlorophyll a and top dry weight of cultivars over 150mM of NaCl concentration. Free proline content accumulated remarkably in NaCl treatment compared with control and was not difference between diploid type and tetraploid type. Free proline content of cultivars was not related with top dry weight in NaCl treatment.

• Journal of Plant Biology
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• v.39 no.3
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• pp.185-188
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• 1996

Randomly amplified polymorphic DNAs were employed to study the genetic variation and gene introgression in potato dihaploids (2n=24) which were generated after interspecific pollination of tetraploid cultivars (2n=4X=48, Solanum tuberosum cv Irish Cobbler, Superior and Dejima) by haploid inducer clones (2n=2X=24, Solanum phureja 1.22, Hes-5 and Hes-6). Genetic variation and DNA marker segregation among dihaploids were observed. Most dihaploids contain S. tuberosum specific RAPD markers but haploid inducer-specific RAPD markers were also found in some dihaploids. Of six different arbitrary 10-mer oligonucletide primers which showed polymorphism betwen tetraploid cultivars and haploid inducers used, three generated amplification products which seemed to be derived from the S. phureja parent. Our results indicate that chromosomes of dihaploids may not be pure S. tuberosum and the dihaploids may not be produced by parthenogenesis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.365-370
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• 1995

This study was conducted to obtain the basic information on salinity tolerance in Italian Ryegrass. Seeds of 20 cultivars that contained diploid(9 cultivars) and tetraploid(l1 cultivars) types were exposed to eight levels of NaCl concentration ranging from 0 to 350 mM under three levels (15$^{\circ}C$, 2$0^{\circ}C$ and $25^{\circ}C$) of temperature. There were highly significant differences in germination percentage among the levels of NaCl concentration, levels of temperature and cultivars, respectively. Average germination percentage of cultivars in control(no NaCl was higher at 2$0^{\circ}C$(90.1%) than that of $25^{\circ}C$(87.8%) or 15$^{\circ}C$(87.5%). Average germination percentage of cultivars began to decrease over 200mM of NaCl concentration. The degree of decrease in germination was higher at $25^{\circ}C$ than that of 15$^{\circ}C$ or 2$0^{\circ}C$. At 2$0^{\circ}C$, the germination percentage and gemination speed were gradually decreased as NaCl concentration increased. The average germination day was lengthened by the increase of NaCl concentration and temperature. The germination percentage in diploid types were higher than that of tetraploid types but the average germination day in diploid types was shortened more than that of tetraploid types, regardless of temperature and NaCl concentration.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.656-664
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• 2015

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

• Korean Journal of Breeding Science
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• v.42 no.1
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• pp.28-34
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• 2010

Diversity of 30 Korean potato cultivars was evaluated using 14 microsatellite markers. Twelve microsatellite markers representing 12 loci in the potato genome detected 84 polymorphisms among 30 cultivars and revealed alleles with a mean of 7.00 alleles per primer. The polymorphism information content (PIC) value ranged from 0.57 to 0.93 with average of 0.82. Based on polymorphism, cluster analysis was conducted by the unweighted pair-group method with arithmetic average (UPGMA) methods. Thirty potato varieties were distinctly separated into 2 groups and similarity coefficient of cluster ranged from 0.58 to 0.95. Thirty tetraploid cultivars were evaluated for six important agronomic traits. One-way analysis of variance was done to look for the degree of relationships between individual markers and traits. K1 and K2 markers showed a significant association with amylose contents, starch contents, and specific gravity.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.163-171
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• 2016

We investigated the intensity and pattern of the scent produced by diploid and tetraploid Cymbidium flowers, using an electronic nose with 6 metal oxide sensors (MOS). The MOS responses were evaluated by principal component analysis, discriminant function analysis, and sensor data. These analyses revealed that tetraploid flowers had a stronger scent than diploid flowers in Cymbidium Golden Elf 'Sundust'. Furthermore, among the different flower parts-column, lip, and petals-the column produced the strongest scent. There was no significant difference between the flowering periods of diploid and tetraploid potted Cymbidium Golden Elf 'Sundust' and Cymbidium Elma 'Orient Toyo' grown in a greenhouse. Moreover, there were no significant differences between the number of flowers per flower stem and the length of flower stems on the diploid and tetraploid plants of these two Cymbidium cultivars. This study provides potentially useful information for the breeding of polyploidy Cymbidium in the floriculture industry.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.343-352
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• 2012

This experiment was carried out to report some data such as survival rate, tetraploid production efficiency, and agronomic characteristics of offspring from the induced tetraploid by the colchicine treatment in rye. The colchicine was soaked with 0.05%, 12 hours in dark condition and at two growth stages (green seed and 2nd leaf stage) in diploid ryes. Flow cytometry (FC) was proved to be efficient and rapid tool for screening ploidy levels in rye, showing around 40 to 60 in DNA amount (DAP1) corresponding to diploid and 80 to 110 tetraploid. There were 18.5% of survival rate at green seed treatment and 78% at 2nd leaf stage in average of two rye cultivars, Gogu and Jogreen, but in reverse 50.9% and 1.1% in the ratio of tetraploid to total tillers among the plants survived, respectively, resulting in 9.42% of tetraploid production rate in green seed treatment and 0.86% at 2nd leaf stage, respectively. In green seed treatment, there were 33% of survival rate in Gogu, 4% in Jogreen in 1st year, but 56% in Gogu, 21% in Jogreen and 49% in Charmgreen, respectively. The rate of tetraploid to total spikes among survived was 53.7% in Gogu, 32.4% in Jogreen, and 50.9% in average in 1st year, and 64.1% in Gogu, 51.5% in Jogreen, 60% in Charmgreen, and 60.5% in average in 2nd year. In green seed treatment, tetraploid production rate (survival rate ${\times}$ tetraploid ratio ${\times}$ 100) was 17.7% in Gogu and 1.3% in Jogreen and 9.42% in average in 1st year, and 35.9% in Gogu, 10.8% in Jogreen, 29.4% in Charmgreen, and 25.4% in average of three diploid rye cultivars. By the colchicine treatment with 0.05% for 12 hours in Gogu and Jogreen, 35 tetraploid plants were obtained and they produced 2,673 seeds with 148 spikes. There were 3.3-4.4 in the number of spikes per plant, 15.6-18.3 in grain number per spike, and 37.6 g in Gogu and 46.8 g in Jogreen in the 1,000-grain weight.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.761-770
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• 2016

This study investigated the variation in fruit characteristics between different triploid progenies derived from a cross between tetraploid and diploid grape cultivars, with the aim of developing high quality, labor-saving triploid grapes. No differences were found in fruit quality traits such as soluble solids content and titratable acidity, whereas significant variation was noted in cluster weight induced by a one-time application of GA3 (100 ppm) on the triploid progeny of different cross combinations. The cluster weight was higher in progeny obtained from 'Kyoho' ${\times}$ 'Sekirei' than for offspring derived from other cross combinations; deviation in the mean cluster weight was also small for 'Kyoho' ${\times}$ 'Sekirei' progeny. These results suggest that specific cross combinations, such as 'Kyoho' ${\times}$ 'Sekirei', can be used to efficiently breed new, labor-saving seedless grape cultivars.