• Journal of the Korean Society of Tobacco Science
• /
• v.7 no.2
• /
• pp.99-109
• /
• 1985

The present studies were carried out to obtain some basic informations of the breeding of tobacco varieties. Genetically divergent 8 varieties, 3 flue-cured, 2 burley and 3 sun-cured tobaccos, were used in half diallel cross. In order to analyze the heterosis, combining abilities, modes of inheritance and correlations for some agronomic and chemical characters, 8 parents and 28 $F_1$ were tested. The results obtained were summarized as follows: The percentages of heterosis for stem diameter, internode length and total sugar content in $F_1$ hybrid were 3.6%, 3.1% and 10.6%, whereas these for days to flower, total alkaloids and leaves per plant were -6.3%, -6.9% and -5.0%, respectively. Yield had significant positive genotypic correlations with plant height, days to flower and leaf length, but negative with internode length and total sugar content. It also had significant prositive phenotypic correlations with plant height, days to flower, leaves per plant, leaf length, leaf width and leaf shape index (Leaf length/leaf width). General (GCA) and specific combining abilities (SCA) for all characters of $F_1$ hybrid were significant. The effects of GCA were positive on yield, plant height, stem diameter, leaves per plant and days to flower of Burley 21. And those were positive on yield, leaf shape index and plant height, but negative on leaves per plant and total nitrogen of Hicks. The effects of SCA for yield and leaves per plant were greater than those of others on the combinations of Coker 139 and Burley type, respectively.

• Journal of Sericultural and Entomological Science
• /
• v.29 no.2
• /
• pp.7-14
• /
• 1987

Extensive studies were undertaken to analyze the genetic basis of economically important quantitative characters in the silkworm by diallel crosses of four inbred lines differing widely in silk yielding ability. Some differences between the reciprocal corsses were detected in cocoon weight, cocoon shell weight, cocoon filament length and cocoon filament weight in case the parental lines were greatly differenent each other in silk yielding ability. The general combining ability (GCA) varied with the inbred lines and M242, a Chieese sexlimited larval marking variety showed high GCA value in the economic characters, such as cocoon yield, cocoon weight, cocoon filament length and weight, and raw silk percentage. The highest heterosis effect, about 13% to 14% was seen in cocoon and raw silk yield and it was low in cocoon reelability and raw silk percentage with less than 1%. It is advisable to improve highly heritable quantitative characters such as larval duration, cocoon shell weight, cocoon filament length and raw silk percentage by means of selection, and to select single crosses with high heterosis effect for cocoon weight and cocoon yield which show overdominance. Genetic correlation should be considered when more than two characters are targets for improvement and selecting high cocoon shell weight is effective to breed high silk yielding varieties. It is difficult to improve cocoon reelability because of low heritability (0.11) and its negative correlation with cocoon-silk quality.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.28 no.4
• /
• pp.473-480
• /
• 1983

To obtain basic information on the Korean local com lines a total of 57 lines were selected from 1,000 Korean local collection at Chungnam National University, and classified by principal component analysis, and genetic nature was investigated. There were a great variation in mean values of plant characters of the lines. The mean values of plant characters except for density of kernels varied with types of crossing. All characters except for tasselling dates were reduced in magnitude when selfed, while those characters were increased when topcrossed. The inbreeding depression varied with plant characters and lines. The characters such as yield, kernel weight per ear, ear weight and plant height showed great degree of inbreeding depression. Group I showed high inbreeding depression in such characters as 100 kernel weight, leaf number, plant height and days to tasselling, while group II showed high inbreeding depression in other plant characters. Heterosis of plant characters varied also with lines. The ear weight, kernel weight per ear, yield, 100 kernel weight, and plant height were some of the plant characters showing high heterosis. Group II showed high values of heterosis in such characters as ear length, ear diameter, ear weight, kernel weight per ear, 100 kernel weight and leaf length, while group I was high in heterosis in other plant characters. The degree of homozygosity was highest in ear weight (79.1%) and lowest in ear number per plant (-2.1%). Group II showed higher degree of homozygosity than group I. Correlation coefficients between characters of sibbed and topcrossed lines were positive for all characters. Highly significant correlation coefficients between sibbed and topcrossed lines were obtained especially for characters such as ear number per plant, plant height, leaf length and yield per plot.

• Journal of Life Science
• /
• v.12 no.3
• /
• pp.256-263
• /
• 2002

This study was carried out to estimate the degree of heterosis and heterobeltiosis, and the heritability and genetic correlation in F$_1$hybrid produced by reciprocal crosses between two six-rowed hulled barley (Gangbori and Olbori) and three six-rowed naked barley (Saechalssalbori, Saessalbori, and Moodeongssalbori). Heterosis was observed positively in traits such as cults length, spike length, awn length, leaf length, leaf width, number of spikes per plant, number of grains per spike, and 1000 grain weight. Heterosis and heterobeltiosis from the crosses with hulled barley as a material parent showed higher performance in culm length, leaf length, leaf width, number of spike per plant, number of grains per spike. The hulled grain characteristics is dominant over the naked one. The highest heritability was confirmed in leaf width with a value of 94.5% and overall high heritability was observed in most traits with the range from 76.7% to 94.5%. In an analysis of correlation coefficient, higher genetic correlations were observed between leaf length and number of spikes per plant(0.970), between cults length and number of grains per spike(0.963), and between awn length and leaf length(0.862) in the forward crosses in which hulled barley was maternal. In the reverse crosses, higher genetic correlation was observed between culm length and spike length(0.926), between awn length and leaf length(0.922), and between number of spikes per plant and number of grains per spike(0.713).

• Korean Journal of Poultry Science
• /
• v.22 no.2
• /
• pp.97-104
• /
• 1995

Recently, DNA fingerprinting has been utilized as the most powerful tool for genetic analysis and improvement of poultry. This technique enables us to solve several problems of poultry breeding ; traits of low heritability, difficulty in keeping the performance records, measuring in late of life, and sex limited traits. Application of DNA fingerprinting is chiefly focused to individual and population identification, evolution force, quantitative trait marker, introgression of new gene, and prediction of heterosis. Thus, research work on DNA fingerprinting will he accelerated to analyze genetic components exactly and improve the performance of poultry.

• Journal of the Korean Society of Tobacco Science
• /
• v.4 no.2
• /
• pp.23-30
• /
• 1982

Six flue- cured cultivars of Nicotiana tabacum L., 15 possible $F_1$ hybrids and $F_2$ Populations among them, and 15 haploid Populations from Fl hybrids and haploids from Parents, were evaluated. Comparisons of the $F_1$, hybrids and $F_2$ Populations with the Parents indicated that heterosis values were small but significant for yield, plant height, days to flower, leaf length and width and total alkaloids from-6.0% to 5.4% in $F_1$ hybrids, and from -3.4% to 3.6% for Plant height days to flower leaves per plant in $F_2$ populations, respectively. There were positive correlations for yield, plant height, days to flower, leaves per plant and total alkaloids between diploid and haploid populations. Increase or decrease ratio of haploids to diploids of total alkaloids was appeared to 30.3%. Those for yield, leaf length and width, value arid reducing sugar were ranged from -4.1% to -27.6%.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.26 no.2
• /
• pp.67-73
• /
• 2013

Antheraea mylitta Drury is basically a crossbreeding species, as such it seems to be potentially a good material for the exploitation of heterosis. In the present study F1 hybrid of wild ecorace Laria (L) and semi-domestic Daba (D) was raised and evaluated for various quantitative traits and biochemical parameters during larval stage. Improved fecundity ($+18{\pm}1.8%$ and higher egg hatching rate ($+10.96{\pm}1.3%$) was recorded in the F1hybrid ($L{\times}D$). Biochemical parameters studied in the hemolymph, midgut and fatbody of the larva showed significantly higher (P<0.05) total proteins and carbohydrate concentration besides digestive enzyme activity. Correspondingly SDS-PAGE revealed more number of protein bands in the hemolymph sample of F1s, ranging between 29 kDa to 66 kDa compared to parental lines. The present study demonstrates the positive heterosis effect in the F1 hybrid of Laria ${\times}$ Daba. Biochemical analysis indicates that, there is possibilities of exploitation of hybrids with specific parents targeted for desirable commercial traits (silk yield and fecundity). Moreover, most of these biochemical parameters can be used as markers to analyze the genetic improvement in the tasar silkworms.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.4
• /
• pp.447-454
• /
• 2001

For determining the relative genetic effects of Duroc (D) and Taoyuan (T) breeds on the economic traits of their hybrids, 72 litters of pigs, from four mating types, namely TT (T♂$\times$T♀), DD (D♂$\times$D♀) and D-T hybrids (TD, T♂$\times$D♀ and DT, D♂$\times$T♀) were used in this study. The various crossbreeding parameters were estimated by comparisons among mating types using linear contrasts of least-square analysis. The results of reproductive traits analysis showed that T breed had contributed superior genetic effects on the total number of piglets at birth (TBN) (p<0.10) and number of live piglets at 21 days (LP21) (p<0.05) to the D-T hybrids. Estimates of maternal genetic effects showed that the T females were superior in TBN (p<0.05), but inferior in average birth weight (ABW) and average litter birth weight (LBW) (p<0.01) to the D females. Direct heterosis effects were significant for LBW, LP21 and LWT21 (p<0.01). Least-squares analysis of other economic traits showed that T breed had relative negative effects on all growth traits, withers height (WH), body type index (BTI), average backfat thickness (ABF), carcass length (LENG), loin eye area (longissimus) (LEARA), and lean percentage (LEAN) of D-T hybrids (p<0.05). Estimates of direct genetic effects showed that the D breed was superior to the T breed in all growth and carcass traits except the average backfat (BF). Estimates of maternal genetic effects showed that average body weight at 180 days (WT180) of progenies from T sows were lighter than from D sows. Progenies from D females had larger and leaner carcass than those from T females. Direct heterosis effects were significant for average daily weight gains from 150 to 180 days ($ADG_{150-180}$) (p<0.05) and for average body weights at 150 (WT150), and 180 days (WT180), average daily weight gains from birth to 150 and 180 days ($ADG_{150}$ and $ADG_{180}$, respectively), WH, body length (BL), ABF, BTI, and LENG (p<0.01). The results showed that D-T hybrids tended to have superior TBN and LP21 than D breed, and to be superior in all growth and most conformation and carcass traits to the T breed.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1998.04a
• /
• pp.35-36
• /
• 1998

• International Journal of Industrial Entomology and Biomaterials
• /
• v.8 no.1
• /
• pp.101-106
• /
• 2004

The process of removal of gummy proteinous material sericin from silk is commonly called as degumming loss or boil-off loss ratio. In the present study, the boil-off loss ratio in the cocoon shells of twelve multivoltine${\times}$bivoltine hybrids and their parents were analysed. Inheritance pattern of boil-off loss ratio was analysed in crosses involving high and low boil-off loss parents, F$_1$s, F$_2$s and back-crosses by parent off spring regression analysis. Heterosis and heterobeltiosis was also analysed for this character, Highly significant (P＞0.01) variations were observed in eight out of ten multivoltine and two out of five bivoltine parents indicating the presence of genetic variation in the expression of boil-off loss ratio. Among F$_1$ hybrids, ten hybrids expressed significant (P＞0.01) variations when compared with control hybrid PM${\times}$NB$_4$D$_2$. Significant negative heterosis was expressed in three multi ${\times}$ bi hybrids viz., BL67${\times}$CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{19}$, which is desirable for this character, whereas expression of heterobeltiosis was significant only with one hybrid, 96C${\times}$CSR$_{18}$ in desired direction. Studies on inheritance pattern showed that the character is heritable and contribution percentage of female and male in the ratio of 50.9: 49.1 and it appears that both the parents are influencing in the expression of boil-on loss ratio in silkworm. Based on the overall performance and evaluation by multiple trait evaluation index and also considering the expression of the boil-off loss ratio three hybrids vix., BL67 ${\times}$ CSR$_{101}$, 96A${\times}$CSR$_{19}$ and 96C${\times}$CSR$_{18}$ were found superior and recommended for commercial exploitation.n.ion.n.