• Journal of agriculture & life science
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• v.44 no.5
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• pp.55-64
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• 2010

This study was conducted to estimate genetic parameters for reproductive traits using multivariate animal models in Yorkshire breed. For the study, 4,989 records for litter traits collected between the year 2001 and 2005 from Yorkshire pigs in K GGP were used. The effects of environmental factors such as farrowing year, parity, weaning to estrus interval (WEI), and suckling period were statistically significant (p<0.05), but farrowing season was not significant, for reproductive traits. The estimates genetic correlations and phenotypic correlations in total number of born and number of suckling, was shown to highly correlated. The genetic correlations were higher than phenotypic correlation. The estimates of heritabilities for reproductive traits, considering permanent environment effects (PE) were much lower than those obtained when permanent environment effects were not considered (NPE) in the model. The estimates of heritabilities were 0.240 and 0.076 for total number of born and 0.187 and 0.096 for number of suckling in NPE, and PE, respectively. These results itivcate that PE should be considered in the statistical mode to estimate more acco ate breeding values.

• Journal of agriculture & life science
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• v.51 no.2
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• pp.117-126
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• 2017

Hanwoo young bulls are selected based on performance test using the weight at 12 months and pedigree index comprising marbling score. Pedigree index was not based on the progeny tested data but the breeding value of the proven bulls; resulting a lower accuracy. The progeny testing of the young bulls was categorized into testing at farm and at the test station. The farm tested data was difficult to compare with those from test station data. Farm tested bulls had different slaughter ages than those for test station bulls. Therefore, this study had considered a different age at slaughter for respective records on ultrasound traits. Records on body weight at 12 months, ultrasound measures at 12 and 24 months(uIMF, uEMA, uBFT, and uRFT), and carcass traits(CWT, EMA, BFT, and MS) were collected from steers and bulls of Hanwoo national improvement scheme between 2008 and 2013. Fixed effects of batch, test date, test station, personnel for measurement, personnel for judging, and a linear covariate of weight at measurement were fitted in the animal models for ultrasound traits. The ranges of heritability estimates of the ultrasound traits at 12 and 24 months were 0.21-0.43 and 0.32-0.47, respectively. Ultrasound traits at 12 and 24 months between similar carcass traits was genetically correlated at 0.52-0.75 and 0.86-0.89, respectively.

• Journal of agriculture & life science
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• v.51 no.6
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• pp.89-105
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• 2017

This study utilized 32,312 records of 17 linear type and 10 conformation traits(including final scores) of Hanwoo cows in the KAIA(Korea Animal Improvement Association) ('09~'10), with 60,556 animals in the pedigree file. Traits included stature, body length, strength, body depth, angularity, shank thickness, rump angle, rump length, pin bone width, thigh thickness, udder volume, teat length, teat placement, foot angle, hock angle, rear leg back view, body balance, breed characteristic, head development, forequarter quality, back line, rump, thigh development, udder development, leg line, and final score. Genetic and residual(co) variances were estimated using bi-trait pairwise analyses with EM-REML algorithm. Herd-year-classifier, year at classification, and calving stage were considered as fixed effects with classification months as a covariate. The heritability estimates ranged from 0.03(teat placement) to 0.42(body length). Rump length had the highest positive genetic correlation with pin bone width(0.96). Moreover, stature, body length, strength, and body depth had the highest positive genetic correlations with rump length, pin bone width, and thigh thickness(0.81-0.94). Stature, body length, strength, body depth, rump length, pin bone width, and thigh thickness traits also had high positive genetic correlations.

• Korean Journal of Poultry Science
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• v.47 no.4
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• pp.267-274
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• 2020

This study was conducted to estimate genetic parameters for growth and egg production traits in Black Korean native chicken (L strain) and Korean White Leghorn (F, K strains) using a multi-traits animal model BLUP. Traits used for this study were body weight at 150 days (BW150) and 270 days (BW270), age at first egg (DAY1st), egg weight at first egg (EW1st) and 270 days (EW270), and number of eggs laid by 270 days (EP270), and included 68,688 pedigree and 123,905 performance records collected from 2001 to 2013. In L, F, K strains, heritability estimates of BW150 were high (0.48, 0.52 and 0.50, respectively); of BW270 were high (0.56, 0.57 and 0.56); of DAY1st were medium to high (0.45, 0.39 and 0.31); of EW1st were low (0.15, 0.16 and 0.15); of EW270 were high (0.58, 0.55 and 0.59) and of EP270 were moderate (0.22, 0.21 and 0.20). The genetic and phenotypic correlation of DAY1st with EP270 were highly negative (-0.73 to -0.63 and -0.48 to -0.42). The genetic and phenotypic correlation of EP270 with BW150 and BW270, respectively were low negative (-0.16 to 0.01 and -0.14 to -0.03) and low to moderate positive (-0.08 to 0.07 and -0.13 to 0.04). The genetic and phenotypic correlation of EW270 with BW150 and BW270, respectively were moderate to high positive (0.39 to 0.49 and 0.36 to 0.46) and (0.29 to 0.33 and 0.34 to 0.37). The study showed that there is a potential for genetic improvement of Korean Indigenous chicken through selection program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.499-506
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• 1993

The contents of sulfur, sulfur-containing protein and amino acids of soybean seeds of 518 genotypes as well as their inheritance and selection efficiency in early breeding generation were measured to facilitate breeding for soybean with high sulfur-containing amino acids. Average seed sulfur content of 518 cultivars was 0.33%, and ranged from 0.20 to 0.45%, and that of 30 wild soybeans was 0.35%, and ranged form 0.19 to 0.62%. Correlation coefficients between seed sulfur content and sulfur-containing protein and amino acids were 0.924$^{**}$ and 0.974$^{**}$, respectively. Seed sulfur content was tended to be high in soybean genotypes with late maturity, seed coat bloom, or green cotyledon. Sulfur content had -0.312$^{**}$ correlation coeficient with sugar content and -0.384$^{**}$ with 100 seed weight. Seed sulfur content was inherited quantitatively, in which additive effect was greater than dominant one, and proportion of genes with positive effects was similar to those with negative ones. Estimated narrow- and broad-sense heritabilities were 0.75 and 0.88 for seed sulfur content, respectively. Heritability measured from selection in early breeding lines for high or low seed sulfur content was 60～62.5% or 50～62,5%, respectively. And selection for high sulfur content increased by 14.7～18.8%, whereas that for low one decreased by 8.8～15.6%, when compared to that of random population. Therefore selection in early generation seemed to be clearly effective.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.1-8
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• 1992

This study was conducted to obtain the basic information on salt-tolerance of rice cultivars in relations with growth retardation and cation content. As the salt-level increased, less retardation in plant height and dry weight were shown in salt-tolerant than salt-susceptible rice cultivars. Salt tolerant cultivars showed lower N $a^{+}$ and higher $K^{+}$ content and lower N $a^{+}$ / $K^{+}$ ratio at each salt-levels than salt-susceptible ones, while there were no significant differences in $Ca^{++}$ and $Mg^{++}$ content. At the tillering stage, the plant height and dry weight of the salt-treated plots were significantly correlated with N $a^{+}$ and $K^{+}$ content and N $a^{+}$ / $K^{+}$ ratio, implying that N $a^{+}$ and $K^{+}$ content could be an indicator of salt-tolerance of a rice cultivar. There were no tiller-depending differences in cation content in all cultivars. N $a^{+}$ content and N $a^{+}$ / $K^{+}$ ratio in leaves were lower at the top and higher at the bottom. In three $F_1$ hybrids between salt tolerant parent Pokkali and three salt susceptible parents, plant height, dry weight, $K^{+}$ content and N $a^{+}$ / $K^{+}$ ratio were similar to those of Pokkali parent, while N $a^{+}$ content was intermediate of the parents. So, it seemed that salt tolerance is dominant over salt susceptibility. In $F_2$ of Pokkali/wx817 cross, genetic segregation of plant height, dry weight, $K^{+}$ content and N $a^{+}$ / $K^{+}$ ratio varied continuously and was biased onto Pokkali side, while that of N $a^{+}$ content showed normal distribution with intermediate mode. Broad-sense heritability of the characters ranged from 0. 604 to 0. 811. Genotypic and phenotypic correlation coefficients among them were relatively high.fficients among them were relatively high.h.h.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.70-79
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• 2002

This study was conducted to determine correlations and combining abilities of leaf lengths, leaf widths, petiole lengths, number of branches, number of leaves, leaf areas, fresh weights, dry weights and number of flowers in F₁ crosses made with the partial seven-parent diallel cross in Viola tricolor. Leaf lengths and leaf widths showed highly positive correlation with petiole length and negative correlation with number of branches, number of leaves and number of flowers. There was positive correlation between the number of leaves and flowers as well as between leaf area and fresh weight. Mean squares of general combining ability(GCA) and specific combining ability(SCA) were highly significant for all the parameters. Variance component values of SCA were greater than those of GCA for all the parameters except leaf length, implying preponderance of non-additive gene actions for these characters. The lines C and G for leaf lengths and widths, the lines A and F for number of leaves, the lines A, B and G for leaf areas, and the lines B and F for number of flowers showed relatively high GCA effects. The crosses of A×B and B×D exhibited high SCA effects on increasing leaf lengths, leaf widths, number of leaves, fresh weights and number of flowers. And also the crosses of B×E and D×G exhibited high SCA effects on decreasing leaf lengths, leaf areas and fresh weights as well as increasing number of flowers. The broad sense heritabilities of most characters were high compared with the narrow sense one. Those of leaf length, leaf width, petiole length and number of leaves were high in both the broad and narrow sense heritabilities.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.167-178
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• 2016

This study was conducted to estimate genetic parameters for milk production and linear type traits in Holstein dairy cattle in Korea. The data including milk yields, fat yields, protein yields, fat percent, protein percent, somatic score and 15 linear type traits for 10,218 first parity cows collected by Dairy Cattle Improvement Center, National Agricultural Cooperative, Korea, which were calving from January 2009 to April 2013. Genetic and error (co)variances between two traits selected form 19 traits were estimated using bi-trait pairwise analyses with WOMBAT package. The estimated heritabilities for milk yield(MY), fat yield(FY), protein yield(PY), fat percent(FP), protein percent(PP), somatic cell score(SCS), udder depth(UD), udder texture(UT), median suspensory(MS), fore udder attachment(FUA), front teat placement (FTP), rear attachment height(RAH), rear attachment width(RAW), rear teat placement(RTP), front teat length(FTL), foot angle(FA), heel depth(HD), bone quality(BQ), rear legs side view(RLSV), rear legs rear view(RLRV) and locomotion(LC) were 0.128, 0.144, 0.100, 0.273, 0.333, 0.090, 0.179, 0.066, 0.104, 0.109, 0.127, 0.099, 0.059, 0.069, 0.154, 0.014, 0.010, 0.052, 0.065, 0.175 and 0.031, respectively. Among the genetic correlations, UD, UT, FTP, RAW, FTL, FA and RLSV with MY were -0.334, 0.271, 0.445, 0.544, 0.076, -0.281 and -0.228, respectively, and MS, FTP, RTP, FTL, FA, BQ, RLSV, RLRV and LC with PP were -0.147, -0.182, -0.262, -0.136, 0.355, 0.311, 0.135, 0.233 and 0.143, respectively. Especially, MY had the highest positive genetic correlation with RAW (0.544), while SCS had the highest negative genetic correlation with LC (-0.603). FP had negative genetic correlation with most udder traits, whereas, FP had positive genetic correlation with leg and hoof traits (0.056 - 0.355).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.1-43
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• 1971

Experiment I: The objective of this study was to know variation in some selected agronomic characters of sweet sorghum when planted in several growing seasons. The 17 different sweet sorghum varieties having various maturities, and plant, syrup and sugar types were used in this study which had been carried out for the period of two years from 1968 to 1969 at Industrial Crops Division of Crop Experiment Station in Suwon. These varieties were planted at an interval of 20 days from April 5 to August 25 both in 1968 and 1969. The experimental results could be summarized as follows: 1. As planting was made early, the number of days from sowing to germination was getting prolonged while germination took place early when planted at the later date of which air temperature was relatively higher. However, such a tendency was not observed beyond the planting on August 25. In general, a significant negative correlation was found between the number of days from sowing to germination and the average daily temperature but a positive correlation was found between the former and the total accumulated average temperature during the growth period. 2. The period from sowing to heading was generally shortened as planting was getting delayed. The average varietal difference in number of days from sowing to heading was as much as 30.2 days. All the varieties were grouped into early-, medium and late-maturing groups based upon a difference of 10 days in heading. The average number of days from sowing to heading was 78.5$\pm$4.5 days in the early-maturing varieties, 88.5$\pm$4.5 days in the medium varieties and 98.5$\pm$4.5 days in the late-maturing varieties, respectively. The early-maturing varieties had the shortest period to heading when planted from July 15 to August 5, the medium varieties did when planted before July 15 and the late-maturing varieties did when planted before June 5. 3. The relationship between the sowing date (x) and number of days from sowing to heading could be expressed in an equation of y=a+bx. A highly positive correlation was found between the coefficient of the equation(shortening rate in heading time) and the average number of days from sowing to heading. 4. The number of days from sowing to heading was shortened as the daily average temperature during the growth period was getting higher. Early-maturing varieties had the shortest period to heading at a temperature of 24.2$^{\circ}C$, medium varieties at 23.8$^{\circ}C$ and late-maturing varieties at 22.9$^{\circ}C$, respectively. In other words, the number of days from sowing to heading was shortened rapidly in case that the average temperature for 30 days before heading was 22$^{\circ}C$ to $25^{\circ}C$. It prolonged relatively when the temperature was lower than 21$^{\circ}C$. 5. There was a little difference in plant height among varieties. In case of early planting, no noticeable difference in the height was observed. The plant height shortened generally as planting season was delayed. Elongation of plant height was remarkably accelerated as planting was delayed. This tendency was more pronounced in case of early-maturing varieties rather than late-maturing varieties. As a result, the difference in plant height between the maximum and the minimum was greater in late-maturing varieties than in early-maturing varieties. 6. Diameter of the stalk was getting thicker as planted earlier in late-maturing varieties. On the other hand, medium or early-maturing varieties had he thickest diameter when they were planted on April 25. 7. In general, a higher stalk yield was obtained when planted from April 25 to May 15. However, the planting time for the maximum stalk yield varied from one variety to another depending upon maturity of variety. Ear]y-maturing varieties produced the maximum yield when planted about April 25, medium varieties from April 25 to May 15 and late-maturing varieties did when planted from April 5 to May 15 respectively. The yield decreased linearly when they were planted later than the above dates. 8. A varietal difference in Brix % was also observed. The Brix % decreased linearly when the varieties were planted later than May 15. Therefore, a highly negative relationship between planting date(x) and Brix %(y) was detected. 9. The Brix % during 40 to 45 days after leading was the highest at the 1st to the 3rd internodes from the top while it decreased gradually from the 4th internode. It increased again somewhat at the 2nd internode from the ground level. However, it showed a reverse relationship between the Brix % and position of internode before heading. 10. Sugar content in stalk decreased gradually as planting was getting delayed though one variety differed from another. It seemed that sweet sorghum which planted later than June had no value as a sugar crop at all. 11. The Brix % and sugar content in stalk increased from heading and reached the maximum 40 to 45 days after heading. The percentage of purity showed the same tendency as the mentioned characters. Accordingly, a highly positive correlation was observed between. percentage of purity and Brix % or sugar content in stalk. 12. The highest refinable sugar yield was obtained from the planting on April 25 in late-maturing varieties and from that on May 15 in early-maturing varieties. The yield rapidly decreased when planted later than those dates. Such a negative correlation between planting date(x) and refinable sugar yield(y) was highly significant at 1% level. 13. Negative correlations or linear regressions between delayed planting and the number of days from sowing to germination. accumulated temperature during germination period, number of days to heading, accumulated temperature to heading, plant height, stem diameter, stalk weight, Brix %. sugar content, refinable sugar yield or Purity % were obtained. On the other hand, highly positive correlations between the number of days from sowing to heading(x) and Brix %, sugar content, purity %, refinable sugar yield, plant height or stalk yield, between Brix %(x) and purity %, refinable sugar yield or stalk yield, between sugar content(x) and purity% or refinable sugar yield(y), between purity %(x) and refinable sugar yield and between daylength at heading(x) and Brix %. number of days from sowing to heading, sugar content, purity % or refinable sugar yield (y), were found, respectively. Experiment II: The 11 varieties were selected out of the varieties used in Experiment I from ecological and genetic viewpoints. Complete diallel cross were made among them and the heading date, stalk length, stalk yield, Brix %, syrup yield, combining ability and genetic behavior of F$_1$ plants and their parental varieties were investigated. The results could be summarized as follows: 1. In general, number of days to heading showed a partial dominance over earliness or late maturity or had a mid-value, though there were some specific combinations showing a complete dominance or transgressive segregation in maturity. Some combinations showed relatively high general or specific combining abilities in maturity. Therefore, a 50 to 50 segregation ratio in heading date could be estimated in this study and it might be positive to have a selection in early generation since heritability of the character was relatively high. 2. A vigorous hybrid vigor was observed in stalk length. A complete or partial dominant effect of long stalk was obtained. The general combining ability and specific combining ability of stalk length were generally high. Long and short stalks segregated in a ratio of 50:50 and its heritability was relatively low. 3. Except for several specific combinations, high stalk yield seemed to be partial dominant over the low yield. Some varieties demonstrated relatively high general as well as specific combining abilities. It was assumed that several recessive genes were involved in expression of this character. The interaction among regulating recessive genes was also obtained. Accordingly, the heritability of stalk yield seemed to be rather low. 4. The Brix % of hybrid plants located around mid-parental value though some of them showed much higher or lower percentage. It could be explained by the fact that such behavior might be due to partial dominance of Brix %. The varieties with, relatively higher Brix % were high both in general. and specific combining abilities. Therefore, it could be recommended to use the varieties having higher sugar content in order to develop higher-sugar varieties. 5. The syrup yield seemed to be transgressively segregated or completely dominant over low yield. Hybrid vigor of syrup yield was relatively high. No-consistent relationship between general combining ability and specific combining ability was observed. However, some cases demonstrated that the varieties with relatively higher general combining ability had relatively lower specific combining ability. It was assumed that the frequencies of dominant and recessive alleles were almost same.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.371-384
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• 1982

Highly cold tolerant varieties are requested not only at high latitute cool area but also tropical high elevated areas, and the required tolerance is different from location to location. IRRI identified 6 different types of cold tolerance required in the world for breeding purpose; a) Hokkaido type, b) Suweon type, c) Taipei 1st season type, d) Taipei 2nd season type, e) Tropical alpine type and, f) Bangladesh type. The cold tolerance requested in Korea is more eargent in Tongil group cultivars and their required tolerance is the one such as the physiological activities at low temperature are as active as in Japonica group cultivars at least during young seedling stage and reproduction stage. With conventional Japonica cultivars, such cold tolerant characters are requested as short growth duration but stable basic vegetative growth, less sensitive to high temperature and less prolonged growth duration at low temperature. The methods screening for cold tolerance were developed rapidly after the Tongil cultivar was reliesed. The facilities of screening for cold tolerance, such as, low temperature incubator, cold water tank, growth cabinet, phytotron, cold water nursery in Chuncheon, breeding nursery located in Jinbu, Unbong and Youngduk, are well established. Foreign facilities such as, cold water tank with the rapid generation advancement facilities, cold nurseries located in Banaue, Kathmandu and Kashimir may be available for the screening of some limitted breeding materials. For the reference, screening methods applied at different growth stages in Japan are introduced. The component characters of cold tolerance are not well identified, but the varietal differences in a) germinability, b) young seedling growth, c) rooting, d) tillering, e) discolation, f) nutrition uptake, g) photosynthesis rate, h) delay in heading, i) pollen sterility, and j) grain fertility at low temperature are reported to be distinguishable. Relationships among those traits are not consistent. Reported studies on the inheritance of cold tolerance are summarized. Four or more genes are controlling low temperature germinability, one or several genes are controlling seedling tolerance, and four or more genes are responsible for the pollen fertility of the rice treated with cold air or grown in the cold water nursery. But most of those data indicate that the results may come out in different way if those were tested at different temperature. Many cold tolerant parents among Japonicas, Indicas and Javanicas were identified as the results of the improvement of cold tolerance screening techniques and IRTP efforts and they are ready to be utilized. Considering a) diversification of germ plasm, b) integration of resistances to diseases and insects, c) identification of adaptability of recommending cultivars and, d) systematic control of recommending cultivars, breeding strategies for short term and long term are suggested. For short term, efforts will be concentrated mainly to the conventional cultivar group. Domestic cultivars will be used as foundation stock and ecologically different foreign introductions such as from Hokkaido, China or from Taiwan, will be used as cross parents for the adjustment of growth durations and synthsize the prototype of tolerances. While at the other side, extreme early waxy Japonicas will be crossed with the Indica parents which are identified for their resistances to the diseases and insects. Through the back corsses to waxy Japonicas, those Indica resistances will be transfered to the Japonicas and these will be utilized to the crosses for the improvement of resistances of prototype. For the long term, efforts will be payed to synthsize all the available tolerances identified any from Japonicas, Indicas and Javanicas to diversify the germ plasm. The tolerant cultivars newly synthsized, should be stable and affected minimum. to the low temperature at all the growing stages. The resistances to the diseases and insects should be integrated also. The rapid generation advancement, pollen culture and international cooperations were emphasized to maximize the breeding efficiency.