• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.2
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• pp.97-104
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• 2005

Mass selection (MS) is an efficient selection method to directly improve highly heritable traits. In the present study, two cycles of MS for ear length were conducted on two sweet corn populations, BC2-l0 and $BC1-10{\times}Syn-II$ after introgression of exotic germplasm. The improved populations generated from these selections were evaluated in comparison with the base populations at two locations, to determine the genetic gains and performance of the improved populations. The two base populations showed varied average realized responses to MS. In BC2-l0 derived population, the realized responses were $9.1\%$ in BC2-l0 C1 and $1.2\%$ in BC2-l0 C2, whereas in$BC1-10{\times}Syn-II$ derived population, the realized responses were$ 5.6\%$ in $BC1-10{\times}Syn-II$ C1 and $2.9\%$ in $BC1-10{\times}Syn-II$ C2. All the improved populations showed longer ears than their respective base populations and the check varieties. Ear length, which was used as the selection criterion in this study, showed high broad-sense heritability in the BC2-l0 and $BC1-10{\times}Syn-II$ derived populations, while fresh ear yield revealed low heritability, indicating that selection for ear length in these populations would be more effective than direct selection for yield. Results of this study indicate that MS conducted on BC2­10 and $BC1-10{\times}Syn-II$ had significantly increased ear length and fresh ear yield in both populations. The improved populations obtained would serve as better germplasm sources and further selection in these populations could offer better responses.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.1
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• pp.23-32
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• 2007

The nature of genetic variation and diversity among the 65 multivoltine silkworm genotypes was evaluated for 16 post cocoon characters. The components of genetic variation revealed higher PCV (60.487%) and GCV (44.56%) for evenness (variation 1) followed by cohesion (PCV=55.38%, GCV=40.36%) and non-broken filament length (PCV=32.05%, GCV=31.28%). The higher heritability ($h^2$ in broad sense) was observed for boil-off loss (95.6%) followed by non-broken filament length (95.22%). The both genotypic and phenotypic correlation indicated significant positive correlation of filament length with non-broken filament length, silk recovery, raw silk, neatness, and low neatness; and negative correlation with denier, renditta and silk waste. The principal component analysis (PCA) revealed 75.381 % of total variance from the five principal components extracted. On the basis of Mahalonobis' $D^2$ values (Ward's minimum variance), the sixty-five multivoltine silkworm genotypes were classified in to 9 clusters with substantial inter and intra cluster distances. Number of genotypes included in different clusters varied from 3 to 17. The results indicated that the optimum distance obtained in cluster VII (15.059) along with higher cluster mean values especially for filament length, non broken filament length, renditta, silk recovery, silk waste, and raw silk emphasized the utilization of these genotypes in the conventional silkworm breeding programme for improvement of multivoltine silk fibre quality. The possibility of exploiting genetic variation in post cocoon traits for efficient breeding programme is discussed.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.2
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• pp.149-155
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• 1989

This study was conducted to obtain the breeding information for the leaf breakdown, and correlation coefficients between leaf breakdown and some agronomic characters in flue-cured tobacco at Taegu Experiment Station, Korea Ginseng & Tobacco Research Institute. NC 95 and NC 2326 were used as parents. The bulk method procedure was used from the F2 to the F4 generations, 54 plants were selected among F4, and 11 lines were selected among 54 F5 which based on high resistance to bacterial wilt compared with NC2326. The entries were composed of parents and 11 F6 advanced lines, and designed in randomized block with 3 replications. Plant seedlings were transplanted in 16 April. The number of breakdown leaf were investigated at flowering stage, 18 June. There were significant difference between NC 95 and NC 2326 for the number of breakdown leaf, number and weight of ground suckers, days to flower, yield and resistance to bacterial wilt, and similar results were appeared among lines. Estimated heritability in the broad-sense ranged from 59.3% to 87.4% for all characters. Most of genetic correlations were higher than phenotypic coefficients between characters. Number of breakdown leaf was positively correlated with days to flower, the number and weight of ground suckers, while it was negative to yield. One line among 11 had few breakdown leaf, low producted ground suckers and high resistance to bacterial wilt. Above results suggest that the number and weight of ground suckers can be use as a selection criterion for leaf breakdown even under the condition without leaf breakdown.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.442-446
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• 2003

The Gene action for eight quantitative characters related to the plant type was estimated using diallel cross among three different plant types of sesame (Sesamum indicum L.) in 2001. The parental varieties used for diallel cross were Ahnnam and Yangbaeck as indeterminate type, ksan22 as semi-determinate type, and dt-45 and Suwon131 as determinate type. In variance and covariance analysis (Wr-Vr) for eight characters the mean square of array except for capsule length, 1,000 seed weight were significant, which suggest that varieties involved in diallel set cross may have epitasis. Complete dominance was observed in the flowering periods, and ratio of matured grains while partial dominance was observed in the plant height, no. of capsules per plant, and no. of branch per plant. Broad sense heritability for flowering periods, plant height, no. of capsules per plant, and no. of branch per plant ranged from 0.91 to 0.99. Narrow sense heritability for flowering periods, capsule length, ratio of matured grain, 1,000 seed eight were 0.18 to 0.34, and plant height, no. of capsules per plant and no. of branch per plant were ranged 0.77 to 0.81.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.198-203
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• 2007

This study was carried out to obtain basic informations for gene action of quantitative characters including shattering resistance. The parental varieties used for $5{\times}5$ half diallel crosses were 'Yangbaek' and 'Ansan' of normal type, 'Suwon177' and 'Suwon195' of placenta adhesion type (PA) and 'SIG960320-5-1-1' of indehiscent type (ID). PA and ID type are shattering-resistant sesames, and Yangbaek and Ansan are shattering sesames. All the characters were sufficient to the assumption for diallel analysis in this experiment. Over dominance was exhibited by the number of capsules per plant, while partial dominance by plant height, capsule setting stem length, grain yield per plant and shattering rate, complete dominance by the number of branches per plant. Additive effect was higher than dominance in shattering rate. High shattering rate was dominant over low shattering rate. Suwon 195, shattering resistant sesame, showed to have the many recessive genes which reduced the shattering rate of sesame seed. Broad sense heritability for all the characters was more than 0.8. Narrow sense heritability for the number of branches per plant, the number of capsules per plant, grain yield per plant and shattering rate was 0.45 to 0.63, and plant height and capsule setting stem length was more than 0.8.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.429-438
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• 2007

Early growth vigor(EGV) is one of the physiological characteristics that may contribute to the increase of genetic yield potential and radiation use efficiency by closing the canopy earlier. To estimate the genotypic variation of EGV, determine the relationships among the related traits, and identify the rapidly growing genotypes and indirect indicator for selection in breeding program, the evaluation of EGV and EGV-related traits was conducted for a total of 140 rice varieties consisting of 101 Korean, 25 Northern China and 14 IRRI-bred rice varieties in a serial sowing experiment in plastic rain shelter and plastic-covered nursery bed in 2003. EGV defined as the amount of leaf area and/or dry weight produced early in the season and the EGV-related traits such as length and breadth of the $2^{nd}\;and\;3^{rd}$ leaves showed highly significant positive correlation with the embryo and seed weight. Especially, the genotypic variation in the length of the third leaf was explained over 90% of genotypic variation in the seed weight. Owing to a large effect of seed size on EGV and its related traits, vigor measurements were adjusted based on their linear or exponential relationships with seed weight for excluding the seed weight effect. EGV and its related-traits adjusted for seed weight also showed big variation among genotypes. Increased EGV was genetically correlated with increases in breadth and length of early leaves. The broad-sense heritability for EGV was significantly high(81%), but lower than those of leaf breadth(90% for the $2^{nd}$ leaf and 93% for the $3^{rd}$ leaf) and length(87% for the $2^{nd}$ leaf and 89% for the $3^{rd}$ leaf). Significantly positive genetic correlations were found between EGV and the breadth and length of early leaves. The high heritability of early leaf breadth and length coupled with their strong genetic correlation with EGV indicated that the breadth and length of the $2^{nd}\;and\;3^{rd}$ leaf would be used as good indirect indicators for EGV selection in rice breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.84-88
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• 1984

To obtain basic information on the breeding of early maturing, short plant height rapeseed varieties, the following 7 varieties, Isuzu, Miyuki, Norin 25, Rang, Yongdang, Cresus and Tower were used in diallel crosses in 1979. Maturing date, plant height and grain weight per plant for the parents, $F_1$'s and $F_2$'s of the 7 x 7 partial diallel crosses were measured in 1981 for analysis of their genetic behavior. The results obtained are summarized as follows: 1. The days to maturing of $F_1$'s showed complete dominance for early maturing, and both additive and dominance genetic variances were significant. Number of effective factors in $F_1$'s was 3, but in $F_2$'s was 1. The degree of dominance in $F_1$'s was partial, while in $F_2$'s was complete. Both broad and narrow sense herita-bilities in $F_1$'s was high, while in $F_2$'s was low. 2. Yield per plant in $F_2$'s was controlled by additive component of genetic variance only, but $F_1$'s was different. The degree of dominance in $F_1$'s was complete, while in $F_2$'s was partial. The direction of dominance showed almost complete dominance over high yield and three effective factors was estimated. Yield per plant was controlled by recessive genes. 3. The plant height was controlled by both dominance and additive variance. Dominance was directed toward tall plant height. Number of effective factors was 2, and broad and narrow sense heritability were high in the plant height.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.142-146
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• 2003

To obtain information on the inheritance of grain weight and grain size of japonica cultivar, Sobibyeo which has high yielding potential and large grain in rice, the genetic variation, heritability and phenotypic correlation of 1,000 grain weight, grain length, width and thickness were investigated in two crosses, Iksan 429/Sobibyeo and Iksan 430/Sobibyeo. The gram characteristics of $\textrm{F}_1$ hybrids exceeded mid-parental values, while grain length: width ratio was intermediate between the parents. In $\textrm{F}_2$ populations, the average grain length, width and thickness were intermediate as mid-parental values, but grain weight exceeded the mid-parental values. In $\textrm{F}_2$ populations of Iksan 429/Sobibyeo and Iksan 430/Sobibyeo, mean 1,000 grain weights were 24.86g and 25.04 g on the average, and ranged 18.4g-32.2g and 19.5g-33.4g, respectively. The segregation mode for grain weight was regarded as a nearly normal distribution in two crosses of $\textrm{F}_2$ populations. Estimates of broad sense heritabilities for grain weight in Iksan 429/Sobibyeo and Iksan 430/Sobibyeo were high as 89.00% and 89.06%, and grain length showed the highest heritability among grain characteristics as 97.45% and 97.35%, respectively. Grain weight was highly correlated with grain length, width and thickness, and grain length was highly correlated with grain width and thickness. These grain characteristics were apparently controlled by polygenes. Accordingly, these traits will be readily improved through selection in the early segregating generations.

• Journal of Sericultural and Entomological Science
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• v.24 no.1
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• pp.28-31
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• 1982

Flacherie virus (FV) is an important pathogen in the silkworm, which often gives serious damage to farmers for cocoon production. The inbred parents and F$_1$'s from an eight-parent diallel were examined to determine the inheritance of resistance to flacherie virus in the silkworm. Three resistant (R), two intermediate (M) and three susceptible (S) inbreds were used in the diallel with no reciprocals. Mean resistance was measured by survival rates of larvae which were fed on mulberry leaves sprayed with diluted mid-gut homogenate of FV infected larvae. Broad-sense heritability was obtained according to inbreds and F$_1$ family performance. Estimation of general (GCA) and specific combining ability (SCA) was made according to Griffing's Model 1, Method 2. Mean FV resistance of F$_1$ family displayed additive effect of the major gene, while heterotic effect was not significant. Considerable variation in FV resistance within F$_1$ groups of R$\times$S and S$\times$S indicated that action of minor genes for FV resistance may have been involved. FV resistance of inbreds perse and predominant effect of the major gene over minor gene(s) satisfactorily predicted the FV resistance of the hybrids. Broadsense heritability value of FV resistance on the basis of F$_1$ family performance averaged 93%, which suggested that environmental effects might have not been important in this experiment. GCA was highly significant for FV resistant among inbreds. GCA effect of 13.1 in Jam 108 was highest and -17.7 in Gyeongchu lowest. Effective selection for high FV resistance would be possible, using inbreds with high GCA effect and low GCA variance. SCA was significant among hybrids. High SCA effect in the hybrid of Geumho$\times$Mudeung (13.7) and Hansaeng #4$\times$Jam 115 (11.6) indicated that the interaction effect of minor genes for resistance to FV in the silkworm could be exploited by standard silkworm breeding procedures.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.2
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• pp.89-101
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• 2019

The variation of content of 12 soybean seed isoflavone components was determined in the aglycone, glucoside, malonylglucoside and acetylglucoside groups of 44 Korean soybean cultivars grown in 2016 as well as in 2017. The total isoflavone content of the 44 cultivars averaged at $2935.4{\mu}g/g$ and was in the range of 950.6 to $5226.3{\mu}g/g$ for two years. Malonylglucoside group averaged at $2437.2{\mu}g/g$ with the highest proportion of isoflavone composition (83.0%). Significant differences were observed between cultivars, years and their interactions for both the total isoflavone and each composition group contents (P < 0.0001); however, no year-wise differences were observed for daidzein and genistin. The broad-sense heritability ($h^2$) within the set of 44 Korean soybean cultivars was as high as 0.93 for the total isoflavone content and was in the range of 0.8-0.92 for each composition group of isoflavone except for acetylglucoside. The total isoflavone content in cultivar group for soy-sprout was higher ($3850.4{\mu}g/g$) than that for the other cultivar groups of soy-paste and tofu ($3082.8{\mu}g/g$), black or green soybean cooked with rice ($2345.8{\mu}g/g$), and early maturity group ($1298.6{\mu}g/g$). The total isoflavone content of 'Sowonkong', a soybean cultivar for soy-sprout, was the highest ($5226.3{\mu}g/g$). In the cultivar group for soy-paste and tofu, the average isoflavone contents of 'Daepung', 'Daepung2ho', 'Saegeum', 'Uram', and 'Jinpung' were higher than $4000{\mu}g/g$. With the exception of small seeded cultivars with low isoflavone contents such as 'Sohwang' and 'Socheongja', the seed size and total isoflavone content were significantly negatively correlated in 2016 and 2017, respectively ($r=-0.47^{**}$ and $-0.49^{**}$). The number of days of growth from flowering to maturity did not affect the variations observed in isoflavone content.