• Asian-Australasian Journal of Animal Sciences
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• v.13 no.10
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• pp.1353-1358
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• 2000

The three-way rotational crossing experiment has been conducted to evaluate heterosis effects on jumping height and body weight. Yonakuni wild mice (Y) and two genetic groups of $CF_{{\sharp}1}$ (C) and C3H/HeNCrj (H) laboratory mice were used as materials. Reciprocal rotational crossing was made by crossing C male${\times}$Y female and Y male${\times}$C female to produce basic group designated $G_0$ and ${G_0}^{\prime}$, respectively. The females of the $G_0$ and ${G_0}^{\prime}$ were mated to the H sire to produce second generation ($G_1$ and ${G_1}^{\prime}$), and at the following generation the replacement females were mated to Y or C sire according to the basic group to produce $G_2$ to $G_3$ and ${G_2}^{\prime}$ to ${G_3}^{\prime}$. Individual jumping height data at Wk6 and body weight data at 1 (Wk1), 3 (Wk3), 6 (Wk6) and 10 (Wk10) weeks of age were analyzed. The results showed that effects of genetic group, sex and interaction of genetic group by sex were significant (p<0.01) for jumping height. For males, 55.34%~79.17% and 54.46%~78.29% of heterosis were reached at $G_1$ to $G_3$ and ${G_1}^{\prime}$ to ${G_3}^{\prime}$, respectively. While for females at $G_1$ to $G_3$ and at ${G_1}^{\prime}$ to ${G_3}^{\prime}$, heterosis effects were 61.53%~80.42% and 47.79%~85.86%, respectively. For body weight, genetic group was a significant source of variation at all ages studied. Sex effect was significant at Wk3, Wk6 and Wk10, and interaction between genetic group and sex was significant at Wk6 and Wk10 (p<0.01). C sires resulted in the highest body weight of offspring, while H sires were the intermediate and Y sires were the lightest. The significant positive and negative heterosis effects for body weight were exhibited. Crossing involved the Y sires in addition to smaller maternal effects of Y dams tended to result in small heterosis.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.181-187
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• 2004

Polyvoltine silkworm breeds/hybrids play an important role in tropical sericulture. In the process of synthesizing more potential polyvoltine hybrids(polyvoltine${\times}$bivoltine) of superior quantity and quality, the Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI) has developed 8 promising polyvoltine breeding lines (SDMG2, APM16, APM15, APM14, APM5, RM2, APM3, APM13). In order to study their hybrid vigour and performance, these breeds were crossed with 4 potential bivoltine testers (SDD1, SDD2, SDD3, APS8), and 32 different hybrid combinations were prepared and evaluated for their mid parent heterosis (MPH) and better parent heterosis (BPH) of silk productivity. Since silk is the ultimate product required for commercial purpose, based on silk productivity and its heterosis, three superior polyvoltine hybrid combinations namely RM2${\times}$APS8 (24.3%), APM3${\times}$APS8 (12.4%) and APM15${\times}$SDD2 (10.8%) were adjudicated as potential heterotic hybrid combinations of superior silk yield and hence recommended for further large scale field trails and commercial exploitation.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.132-135
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• 2005

This experiment was performed to obtain the basic information on heterosis and heterobeltiosis of quantitative characters in the eggplant by crossing of varieties. The heterosis and heterobeltiosis were estimated in Fl generation. The results were as follows, based on the graphical analysis, the characters, plant height, stem diameter, fruit weight, leaf length, leaf width, and fruit number per plant(yield) were assumed to inherit dominance, and fruit length and fruit diameter were found to inherit incomplete dominance. The degree of positive heterosis of plant height, stem diameter, fruit weight, fruit length, fruit diameter, leaf length, leaf width, and fruit diameter, leaf width, leaf length, fruit weight, and stem diameter showed negative heterobeltiosis.

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

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.117-126
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• 1997

This study was conducted to estimate the hatching and growing performance, and heterosis of Korean Native Chicken(KNC), Rhode Island Red(RIR) and KNC XRIR crossbred. A total of 1,274 female pullets were produced from KNC, RIR and KNC x RIR crossbred kept in National Live-stock Research Institute, Korea. The experiment was conducted for 20 weeks from Sep. 2, 1995 to Jan. 20,1996. Hatchabilities of KNC dark brown strain x RlR(DR), KNC light brown strain x RlR (LR) and KNC dark black strain x RlR(BR) were 77.3%, 73.6% and 72.5%, respectively. Viabilities up to 20 weeks of age were not significantly (P>0.05) different among purebreds and crossbred. Body weights of DR, LR and BR were 1,890 g, 1,849 g and 1,967 g, respectively, at 20 weeks of age. The feed conversion ratio(feed /gain) of DR, LR, and BR were 5.88, 6.07 and 5.87, respectively, up to 20 weeks of age. Average shank lengths of DR, LR and BR were 97.1 mm, 98.9 mm and 99.4 mm, respectively, at 20 weeks of age. The heterosis effects were estimated to be -0. 48%, and 12.58%, respectively, in fertility and hatchability. Up to 20 weeks of age, the heterosis effects were estimated to be 0.07%, 13.49%, -5.77%, and 3.52% in viability, body weight, feed conversion ratio, and shank length, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.767-771
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• 2005

In order to understand the molecular basis of chicken heterosis in reproduction traits, mRNA differential display (DDRT-PCR) methods were used to analyze the differential gene expression of ovary tissue between hybrids and their parental lines in a 4${\times}$4 diallel cross, involving 4 chicken breeds, which were White Plymouth Rock (E), CAU Brown (D), Silkies (C) and White Leghorn (A). Total of 331 differential displayed cDNA bands from 1,161 were displayed in the 4${\times}$4 diallel cross combinations with 30 pairs of primers, which shows the differences of gene expression between hybrids and their parental lines were very obvious in quantity and quality. Seven types of differential expression patterns were found: Co-dominance expressed pattern (T1), under-expression of parental fragments in hybrids (T2), over-expression of parental fragments in hybrids (T3), hybrid-absence expressed pattern (T4), single parentspecific expressed pattern (T5), dominant expression fragments of single parent in hybrids (T6), hybrid-specific expressed pattern (T7). Correlation analysis indicated that there were significant correlations between the pattern of T3 and the heterosis percentage of egg number of 32-week and 42-week old chickens(p<0.01), while there were negative significant correlations between the pattern of T7 and the heterosis percentage of egg number of 32-week and 42 week-old birds (p<0.01).

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.325-330
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• 2008

In order to understand the molecular mechanism of heterosis of reproduction traits in chickens, we used the quantitative real-time reverse transcriptional polymerase chain reaction (Quantitative real-time RT-PCR) technique to investigate the differential expression of estrogen receptor (ESR) and follicle stimulating hormone receptor (FSHR) genes in 32-week-old ovaries of inbred chickens and their hybrid offspring in $4{\times}4$ diallel crosses, which involved White Plymouth Rock (E), CAU Brown (D), Silkies (C) and White Leghorn (A). We found that there were significant differences in mRNA expression of ESR and FSHR genes not only between hybrids and their parental lines (p<0.01), but also among different crosses (p<0.01). Furthermore, positive correlations between differential expression of both ESR and FHSR in hybrids and heterosis percentages of 32-week-old and 42-week-old egg number traits were significant at p<0.05. Our results suggested that differential expression of ESR and FSHR genes in the ovaries of inbred chickens and their hybrids could play roles in the formation of heterosis of egg number traits to some extent.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.888-893
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• 2000

The present study was conducted to evaluate heterosis effects of body weight and jumping height for successive generations of rotational crossing using two subspecies of mice which are very different in body weight and in genetic relationship from each other. Domesticated laboratory mouse $CF_{{\sharp}1}$ (C) and Yonakuni wild mouse (Y) were used as materials. Two groups of rotational crossing was made according to the parent used at the beginning of crosses, C male$\times$Y female and Y male$\times$C female. These crosses were done to produce the first ($G_1$ and $G_1{^{\prime}}$), second ($G_2$ and $G_2{^{\prime}}$) and third generations ($G_3$ and $G_3{^{\prime}}$) with sire used was alternated. Individual body weights were weighed at 1 (wk1), 3 (wk3), 6 (wk6) and 10 weeks of age (wk10) and jumping heights were measured at six weeks of age (wk6). Only the first litter used. For body weight, results of this study showed that genetic group effects were significant (p<0.01) source of variation at all ages studied. Sex effects were significant (p<0.01) at wk3, wk6 and wk10, but not at wk1. Significant interaction effects (p<0.01) between genetic group and sex were found at wk6 and wk10. The C mice with large maternal effects produced heavier offspring body weight and crosses using sire of this subspecies maintained heavy weight compared to wild Y mouse sire that has small body size. Heterosis tended to exist at the rotational crossing started from Y male C female. For jumping height, effects of genetic group and sex were significant, sire and dam effects (heterosis) exhibited from the first to third generations, and no maternal effects were observed.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.1
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• pp.34-48
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• 1993

This experiment were conducted to investigate heterosis and combining ability for several mutant characters by analyzing dialled crosses of flue-cured tobacco. In a dialled cross of 3 flue-cured varieties and the mutant line 83H -5, the heterosis was somewhat higher in Fl than in F2. For growth character, the heterosis was 0.28-6.03% in plant height, leaf number, leaf shape index and yield, and was 43.2% for bacterial wilt disease index. The mutant line 83H-5 showed significantly negative GCA effect for plant height, leaf width and bacterial wilt disease index in Fl and F2, leaf length in F2, and positive GCA effect for total alkaloids, total nitrogen in Fl and days to flower in F2, respectively. Specific combining ability(SCA) in 83H-5 x Hicks was significant in negative effect for leaf length(F2), number of leaves(F2), leaf shape(F1, F2), bacterial wilt(F2) and alkaloids(F1), and in 83H-5 x NC 2326 in positive effect for leaf length(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in positive effect for plant height(F1, F2) and leaf width(F2), and for 83H-5 x NC 82 in Positive effect for Plant height(F1, F2), leaf length(F2) and yield(F1, F2).

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.8-25
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• 1994

The study was conducted to obtain the genetic information on heterosis and combining ability of the quantitative characters for F1 hybrid breeding in silkworms. Six parental varieties and each set of 30 diallel crosses in F1's were used as materials, and bred on the randomized complete block design with three replications. Fourteen characters were observed with the twenty samples in each tray. The data were analyzed for (1) heterosis and combining ability in F1 hybrid. The heterosis in the weight and the length of cocoon showed positively high at 24.51%, and 23.4%, respectively and the weight of the whole cocoon as well as the weight of the whole cocoon layer showed a siginificant heterosis ranging from 15.56% to 15.71% and from 17.14% to 19.01%, but the fifth and the total instar period showed negative heterosis. It was found that the combination between, C70XRomogua and N9 X Romogua showed highly a negative heterosis on the fifth instar period and for the cocoon weight. The female of N9+Sansuian and the male of Romogua X Sansurian have a high heterosis effect, on the cocoon shell weight, and Sansurian X Romogua(reciprocal) on the length and the weight of cocoon filament with no regard to sexuality. The significant maternal and cytoplasmic effect on heterosis of the cocoon weight and the cocoon shell weight were observed with the combinations, N9 X C5, N63 X C70 and on the length of the cocoon filament with the combinations, Sansurian X N63, Sansurian X C5, Sansurian X C70 and N9 X C70, N63 X C70 on the weight of cocoon filament. As mean squared of GCA, SCA and RCA were significant with these combining ability for all characters resulted from additive and non-additive altogether and there is a significant difference between reciprocals. Sansurian showed a negative GCA effect on the fifth and total larval duration, but the higher positive GCA effects took places with varieties N9 and C5 on the length, width, weight of cocoon, cocoon shell weight, percentage of cocoon shell weight, length and weight of cocoon filament, percentage of raw-silk with no regard to both generations and silkworm sexuality. The values of SCA between the cross combinations varied generation-wise and sex-wise. It was shown that SCA value for the fifth instar period was highly negative for Sansurian X C70, Romogua X C70, Sansurian X C5, Romogua X C5, but it was positive effect on the cocoon weight, cocoon shell weight with N9 X C5, and C70 X Sansurian, on the length of cocoon filament with N9 X C5, Romogua X Sansurian on the weight of cocoon filament between Romogua and N63 and on the percentage of raw-silk between the combination of Sansurian X Romoga.