• 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%.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.12
• /
• pp.1684-1690
• /
• 2005

Using mRNA differential display technique, we investigated differential gene expression in hybrids relative to their parents in a diallel cross involving four chicken breeds in order to provide an insight into the molecular basis of heterosis in chicken. The results indicated that there was extensive differential gene expression between chicken F1 hybrids and their parents which was classified into four kinds of patterns as following: (1) bands only detected in hybrid F1; (2) bands only absent in hybrid F1; (3) bands only detected in parent P1 or P2; (4) bands absent in parent P1 or P2. Forty-two differentially expressed cDNAs were cloned and sequenced, and their expression patterns were confirmed by Reverse-Northern dot blot. Sequence analysis and database searches revealed that genes showed differential expression between hybrid and parents were regulatory and functional genes involved in metabolism, mRNA splicing, transcriptional regulation, cell cycles and protein modification. These results indicated that hybridization between two parents can cause changes in expression of a variety of genes. In conclusion, that the altered pattern of gene expression in hybrids may be responsible for heterosis in chickens.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.3
• /
• pp.176-179
• /
• 2001

To obtain the basic information of high yielding ability for varietal improvement and cultural practice, reciprocal grafts were made analyzed among five sweet potato cultivars. Five cultivars were characterized with the different in whose source and sink capacities. Grafting decreased main vine length, number of tuberous roots per plant, but its effects were different among grafting combinations. The growth of vines was affected more by scion, while growth and yield of under-ground were influenced more by stock. Grafting effects, interactions between stock and scion for main vine length and number of tuberous roots were highly significant in diallel grafting. The percentage of marketable tuberous roots was higher in the order of stem cutting＞self grafting＞reciprocal grafting.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.11 no.1
• /
• pp.27-36
• /
• 2005

Successful silkworm breeding attempts were made at Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI), Hindupur, India in developing productive bivoltine silkworm hybrids. One hundred hybrid combinations involving 10 parents (five each of oval and peanut) were evaluated in complete diallel pattern and identified the combination APS$_{83}$ $\times$ APS$_{102}$ as most promising. This hybrid showed economic merit for the characters fecundity (524 eggs/laying), pupation percentage (96.0$\%$), cocoon yield per 10,000 larvae by weight (19.0 kg), cocoon weight (1.85 g), shell weight (41.7 cg), shell ratio (22.5$\%$), filament length (1,004 m), reelability (88.4$\%$), raw silk recovery (18.4$\%$) and neatness (92 point) over the control hybrid APS$_{9}$ $\times$ APS$_{8}$ The breeding process and identification of APS$_{83}$ $\times$ APS$_{102}$ is discussed in the paper.

• Journal of the Korean Society of Tobacco Science
• /
• v.4 no.1
• /
• pp.7-13
• /
• 1982

Six orient varieties of N.tabacum and 15 $F_1$ hybrids, not including reciprocal crosses, were evaluated for the degrees of heterosis and the combining abilities of 6 characteristics in Suweon, Korea, 1981. The values 9f general combining abilities tiers greater than those of specific combining abilities in all traits but significant SCA was also observed for Plant height, days to flowering and yield. In general, CCA effect was large in Samsun, Kavala and Izmir varieties. Large SCA values were observed for number of leaves in Samsun x Izmir, days to flowering in Samsun x Serves, leaf shape in Basma x Xantlli, and yield in Basma x Kavala and Xanthi x Izmir. Heterosis of favorable directions in $F_1$ was generally observed for all traits. Especially the $F_1$ of Samsun x Kavala flowered earlier than its midparents. Large heterosis effects were manifested for the number of leaves in Samsun x Izmir and yield in Samsun x Izmir as well as Xanthix Izmir.

• Journal of the Korean Society of Tobacco Science
• /
• v.7 no.2
• /
• pp.111-121
• /
• 1985

The present study was 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 $F_2$ were tested. The results obtained were summarized as follows: The percentages of heterosis for yield, stem diameter, internode length and total sugar content in $F_2$ hybrid were positive , where-as those for the other characters were negative. Yield had significant positive genotypic and 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 $F_2$ hybrid were significant. In the effect of GCA, yield was greater in combinations of Bulgaria and Xanthi, days to flower and leaves per plant were those of Burley 21 and Va 528, leaf length and width were those of Coker 139, respectively. In the effect of SCA, the major part of characters were greater than those of others in the combinations of Burley 21, Va 528, Hicks.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.5
• /
• pp.424-427
• /
• 2001

Combining ability study was carried out on the components of synchronization in maturity and determinate growth habit in mungbean, using 6$\times$6 diallel cross. Both additive and non-additive gene effects were found conditioning the inheritance of days to first flower, days between first pod and 90% pod maturity (DDd1), plant height from first pod stage to 90% pod maturity (DDhl, DDh2, and DDh3). Only non-additive gene action was important in degree of determination from first pod stage to 90% pod maturity (DDd2). While only additive action was important in plant height at first flower. The predominant additive gene action was observed in all traits but non-additive was significant in only DDd$_2$. For synchronization in maturity, determinate growth habit, and their components, the best combiners were NM92, VCl560D, and NM89, whereas the best indeterminate combinations were NM92 $\times$ NM89, NM92 $\times$ VCl560D, and NM92 $\times$ ML-5.

• Journal of the Korean Society of Tobacco Science
• /
• v.22 no.1
• /
• pp.31-38
• /
• 2000

Seven flue-cured tobacco(Nicotiana tabacum) varieties and their 21 progenies in Fl and F2 generation, half diallel crosses(no reciprocal), were tested for the degree of heterosis and combining abilities in sucker producing character according to topping and suckering treatment. Significant difference in number and weight of sucker was observed among seven cultivars. The values of general combining ability(GCA) were greater than those of specific combining ability(SCA) in weight and number of sucker in F$_1$ generation. In topping and suckering plot, Cocker 86, McNair 944, and Va 115 revealed the significant negative GCA effects for number and weight of sucker, but By 104 and Speight G-28 did positive GCA. Without topping and suckering, GCA effects for sucker weight in Cocker 139 and Cocker 86 were negative and those for sucker number in Va. 115 were also negative. Negative SCA values in sucker weight could be observed in F$_1$ generation of Cocker 86 X BY 104 and Speiht G-28 X Cocker 86, in F$_2$ of Hicks $\times$ Speight G-28 and McNair 944 $\times$ BY 104 in topping and suckering plot. SCA in F$_1$ of McNair 944 X Cocker 86 and Speight G-28 X Cocker 139 was negative without topping and suckering. The value of heterosis in sucker producing character of F$_1$ hybrids was positive

• The Korean Journal of Zoology
• /
• v.20 no.1
• /
• pp.1-8
• /
• 1977

Several hundred flies of Drosophila melanogaster collected in Anyang City were selected for positive, negative and neutral directions during 15 generations. The population responded effectively to the artificial selection. The realized heritability estimated for the first 10 generations was $2 \\sim 4%$ per generation in the positive and negative phototaxis. The results of diallel crosses among selected populations indicated that some polygenes showing a negative phototaxis were partially dominant over polygenes controlled the positive phototaxis, and the dominant effect became greater in later generations. The populations selected for positive and negative phototaxis were relaxed after 15 generations of selection, and their phototactic responses were completely returned to their original states. Such phenomena would be explained by the genetic homeostasis resulted from an action of natural selection. It seems reasonable to assume that the phototactic neutrality of a natural population was maintained as an adaptive trait under natural environment.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2002.11a
• /
• pp.140-142
• /
• 2002

This study was conducted to obtain some genetic information for developing superior Korean native chickens. Heterosis and combining ability effects were estimated with 1,080 progenies of full diallel crosses of 3 strains in Korean Native Chicken. The traits of egg productivity were Investigated, and heterosis effect, general combining ability, specific combining ability and reciprocal effect were analyzed model I of the Griffing's method 1. The general performance were 147.0 days in age at first egg laying, 71.8 eggs in egg numbers to 270 days, 50.1g in egg weight at 270 days, 75.6 in egg shape index, 356$\mu\textrm{m}$ in egg shell thickness, and 4.27kg/$\textrm{cm}^2$ in egg shell strength, respectively. According to result, heterosis effect revealed comparatively high in age at first egg laying, egg numbers, egg weight, and egg shell strength. The effects estimated highly in general combining ability for age at first egg laying, egg numbers, egg weight, egg shape Index and egg shell thickness, and in specific combining ability were egg numbers, egg weight and egg shell thickness, and in reciprocal effects for egg numbers, egg shape index, and egg shell thickness. This result could be used for developing Korean native chicken.