EPISTATIC BIAS IN ADDITIVE AND DOMINANCE VARIATION AND GENETIC ASSOCIATIONS BETWEEN TWO QUALITY TRAITS IN BREAD WHEAT

1972 ◽  
Vol 14 (1) ◽  
pp. 49-55 ◽  
Author(s):  
K. S. Bains ◽  
K. S. Gill ◽  
K. L. Sehgal

Grain protein and Pelshenke value in 8 × 8 diallel crosses and after eliminating the interacting arrays were genetically analysed. All the dominance variation for grain protein was due to epistatic interactions. The dominance component for Pelshenke value was considerably inflated by epistasis. For both characters, the dominance component was affected more by the epistatic bias than the additive component of genetic variance, resulting in considerably low narrow-sense heritability estimates. Covariance between grain protein and Pelshenke value was primarily due to additive gene effects and was attributed to pleiotropic relationships in the absence of genetic linkage. An ambidirectional trend of dominance with an asymmetric distribution of dominant and recessive alleles among the cultivars was observed for grain protein, whereas preponderance of the dominant decreasing genes with more isodirectional gene distribution was operative for Pelshenke value. Correlated responses of these quality traits to selection due to high additive genetic correlation and degree of co-inheritance in relation to their gene action is stressed.

Author(s):  
Alireza Haghighi Hasanalideh ◽  
Mehrzad Allahgholipour ◽  
Ezatollah Farshadfar

This study was undertaken to assess the combining ability of 6 rice varieties, for viscosity parameters and determining gene action controlling Rapid Visco Analyser (RVA) characters. F2 progenies derived from a 6×6 half diallel mating design with their parents were grown in a randomized complete block design with three replications at the research farm of Rice Research Institute of Iran (RRII) in 2015. The diallel analysis by Griffing`s method indicated the involvement of additive and non-additive gene actions controlling RVA traits. For traits PV and FV RI18447-2 and IR50 were the best combiners for increasing and decreasing, respectively. Deylamani and IR50 were the best combiners for increasing and decreasing BV, respectively. Beside, due to more portion of non-additive gene action in controlling trait SV, The Gilaneh × RI18430-46, and Deylamani × RI18430-46 crosses were the best for increasing and decreasing SV, respectively. The high estimates of broad sense heritability and narrow sense heritability for BV and FV, indicated the importance of additive effects in expression of these traits. Therefore, selection base breeding methods will be useful to improve these traits and selection in the early generations could be done to fix the favourable genes. Low estimate of narrow sense heritability for SV revealed that non-additive gene effects play important role in controlling setback viscosity. So, hybrid base breeding methods will be useful to improve this trait.


1975 ◽  
Vol 17 (4) ◽  
pp. 621-629 ◽  
Author(s):  
L. C. Ho ◽  
L. W. Kannenberg ◽  
R. B. Hunter

Pericarp thickness of 16 short-season inbred lines of corn (Zea mays L.) ranged from 35 to 126 μm with an overall mean of 82 ± 5 μm. The mode of inheritance of this trait was studied in two experiments. Two inbreds representing the extremes of pericarp thickness, their F1 and F2 generations, and both first generation backcrosses were included in Experiment 1. The inheritance of pericarp thickness proved to be quantitative in nature. All gene effects were significant, but epistatic effects, particularly dominance × dominance, were the largest in this particular cross. This could have resulted from bias due to linkage disequilibrium. Experiment 2 was a diallel set of 5 inbreds to include the parents and all possible single crosses, but not reciprocals. Diallel graphic analysis of these data indicated partial dominance for thin pericarp with minimal epistasis. Analysis II of Gardner and Eberhart showed that the mean square for line effects was several times larger than the heterosis estimates, indicating a high level of additive gene effects. The narrow sense heritability estimate was 72%. Thus selection for specific pericarp thickness should be effective and relatively rapid.


2010 ◽  
Vol 62 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Yuksel Bolek ◽  
Hatice Cokkizgin ◽  
Adem Bardak

Combining ability and heterosis for fiber quality traits in cotton Combining ability analysis and heterosis for cotton fiber quality traits were studied in a set of diallel crosses involving eight cotton (Gossypium sp.) genotypes. Randomized complete block design was used to test 56 F1 and 8 parents for fiber quality traits; length (Len), strength (Str), micronaire (Mic), uniformity (Unf), elongation (Elg), spinning consistency index (Sci) and short fiber index (Sfi). Analysis revealed significant general combining ability (GCA) and specific combining ability (SCA) effects for all the traits and additive gene effects were important in the inheritance of the traits. Giza-45 had the highest GCA effects for Len, Sci, Unf and Elg while Is-4 had the highest Str value. Mic and Sfi values were lowest for Askabat-100 and Giza-45, respectively. The cross Cukurova-1518 × 108-F and Nazilli-84S × Askabat-100 had the lowest SCA effects for Mic and Sfi, respectively. The highest values for Len (Askabat-100 × 108-F), for Str (Acala Prema × 108-F), for Sci (Is-4 × Giza-45), for Unf (Stoneville-453 × Askabat-100) and for Elg (108-F × Is-4) were also obtained. Hybridizations among Askabat-100 × Nazilli-84S, Is-4 × Giza-45, Askabat-100 × Stoneville-453, Askabat-100 × Giza-45, Is-4 × 108F, Giza-45 × 108F, Giza-45 × Acala Prema, Nazilli-84S × Giza-45, Is-4 × Nazilli-84S and Acala Prema × Askabat-100 crosses yielded the best heterosis and heterobeltiosis values. Aforementioned parents and crosses could be utilized for further selection of high fiber quality and applying 3-way crosses or modified backcross or recurrent selection to genotypes having good combining ability would improve fiber quality.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1172e-1172
Author(s):  
J. H. M. Barten ◽  
J. W. Scott ◽  
J. Elkind ◽  
N. Kedar

A half diallel including 11 parents was conducted under high temp. conditions in Florida and low temp. conditions in Israel. Blossom scar (BS) size was measured relative to the fruit size for 20 mature fruits per plot. Griffing's analysis showed that both GCA and SCA effects were highly significant at both locations (p< 0.0001). Analysis according to Hayman indicated no epistatic effects. In both environments, additive and dominant gene action was significant (p < 0.0005), although the additive gene effects were most important. Averaged over all loci, the incomplete dominance was in the direction of small BS. Narrow sense heritability estimates were 0.62 and 0.57 for Florida and Israel, respectively. Combined analysis showed that the genetic system was unstable over the 2 environments, as both additive and dominant gene effects interacted significantly with environment (p < 0.0001). The implication for breeding programs is that hybrid performance should be tested at several locations to insure stability of small BS.


2014 ◽  
Vol 63 (1-6) ◽  
pp. 15-23 ◽  
Author(s):  
Q. Weng ◽  
X. He ◽  
F. Li ◽  
M. Li ◽  
X. Yu ◽  
...  

Abstract Interspecific hybrids of Eucalyptus urophylla × E. tereticornis in a factorial-mating design were used to analyze general hybridizing ability (GHA), specific hybridizing ability (SHA) and heterosis for height (H; 0.5, 1.5, 2.5, 4 and 7.5 years in age), diameter at breast height (D; ages 1.5, 2.5, 4 and 7.5) and wood density (WD; age 7.5) across two environments. The GHA variances were significant for all traits, and those of the SHA were also significant for most of the traits but with less magnitude, indicating the greater importance of additive gene effects in explaining the phenotypic variation among hybrids. The narrow-sense heritability (h2) and dominance (d2) estimates with hybrid growth and wood density ranged between 0.02±0.05 (d2 in D7.5) and 0.23±0.10 (d2 in H1.5) over the different ages, suggesting weak additive and dominant effects on these traits. Additive genetic correlations of growth with wood density were weak at age 7.5. Female general combining ability (GCA) based on maternal open-pollinated families was not necessarily a good indicator of GHA as their correlations were 0.48 (P=0.17), 0.65 (P=0.04) and -0.56 (P=0.10) for H7.5, D7.5 and WD7.5, respectively. A great proportion of hybrids showed positive female-parent heterosis (FPH) at age 7.5, with the highest relative FPH of 47.2% in D7.5. This study demonstrates the heterosis between inter-sectional species and could have implications for E. urophylla × E. tereticornis hybrid breeding.


1984 ◽  
Vol 103 (3) ◽  
pp. 543-547 ◽  
Author(s):  
S. Singh ◽  
M. S. Dahiya

SummaryThe data obtained from 360 progeny families produced by crossing 40 F2 plants from each of three wheat crosses HD 2009 × HD 1949, Raj 821 × WH 147 and NP 876 × HD 1949, to three testers (the testers being the two parents of each original cross and their F1 in each case) were subjected to triple test cross analysis for detecting and estimating additive, dominance and epistatic components of genetic variation and interaction of these components with environment for plant height, spike length, number of tillers per plant, number of spikelets per spike, number of grains per spike, 1000-grain weight, number of days from sowing to heading and to maturity, grain yield per plant and grain yield/above ground dry matter ratio (harvest index). Epistasis was an important element for plant height, number of tillers per plant, number of grains per spike and grain yield per plant in all three crosses. Both the i type and j and l type epistasis were equally important. In general, the magnitude of additive component was larger than that of dominance component. The additive gene effects were more sensitive to environmental change than the dominance gene effects. Similarly, j and l type epistasis was relatively more sensitive to environment than the i type epistasis.


Author(s):  
MK Alam ◽  
UK Nath ◽  
MAK Azad ◽  
MA Alam ◽  
AA Khan

A 10×10 half diallel experiment was conducted on groundnut (Arachis hypogaea L.) to ascertain the gene action and genetic parameters of ten traits including 50% flowering, no. of pods per plant, plant height, harvest index, pod index, 100 pod weight, 100 kernel weight, pod size, diseases infection and yield per plot. The experiments were carried out in the Department of Genetics and Plant Breeding, Bangladesh Agricultural University (BAU), Mymensingh during the cropping season of 2010-2011. The estimates of gene effects indicated that significance of both additive and non-additive variance for pod size, 100 pod weight and diseases infection among the traits and presence of over dominance satisfying assumptions of diallel except dormancy. However, both the additive and non-additive gene affects together importance to control of most quantitative traits in the groundnut. The average degree of dominance (H1/D) 1/2 (H1 = dominance variance, D = additive variance) was higher than one, indicating over dominance for all the traits. The narrow-sense heritability was high for 50% flowering (38%), harvest index (35%), pod size (52%), 100 pod weight (35%) and yield per plot (41%) indicating that great genetic gain could be achieved for them. DOI: http://dx.doi.org/10.3329/ijarit.v3i2.17841 Int. J. Agril. Res. Innov. & Tech. 3 (2): 31-35, December, 2013


2019 ◽  
Vol 11 (4) ◽  
pp. 755-761
Author(s):  
A.K. Singh ◽  
A.K. Mall ◽  
P.K. Singh

The study subjected to estimate gene effects and inheritance of quantitative traits of rice with Generation Mean Analysis (GMA). Segregation analysis and estimation of genetic parameters under epistatic model indicated partial dominance and importance of additive effects in the inheritance of drought tolerance, respectively. In present study, absence of epistasis by scaling tests was recorded only for plant height in cross NDR-359 x P0 1564, grains per panicle in cross DSL- 63-8 x NDR- 359, test weight in cross Sarjoo-52 x P0 359, harvest-index in cross NDR-359 x P0 1564 and spikelets per panicle in cross Sarjoo-52 x P0 359 and NDR-359 x P0 1564 in irrigated condition and days to 50 per cent flowering in cross P0 359 x Sonam and harvest-index in cross NDR-359 x P0 1564 in drought condition. In remaining cases, existence of epistasis was observed in either one or both conditions by one or both types of scaling tests. The presence of complementary epistasis in cross P0 359 x Sonam and P0 1564 x Sarjoo-52 would make progress through selection procedures exploiting additive gene actions faster while existence of duplicate epistasis in cross NDR-359 x P0 1564 would have reverse impact. The non-additive gene effects in NDR-359 x P0 1564 for grain yield plant-1may also be utilized for facilitating development of pureline cultivars by involving population improvement methods. Our study concluded that for a large number of traits in six crosses, dominance gene effects and epistatic interactions were significant under drought and irrigated conditions implying that utilization of heterosis through hybrid varieties will act as a budding choice.


2020 ◽  
pp. 1589-1594
Author(s):  
Josephine T. Pasipanodya ◽  
Rob Melis ◽  
Deidre Fourie

Angular leaf spot (ALS) caused by Pseudocercospora griseola (Sacc.) is one of the serious fungal diseases affecting dry bean in Africa, including South Africa. Host plant resistance is the best management strategy, of which its effectiveness requires knowledge of the genetics underlying the resistance in guiding breeding efforts. In this study, the inheritance of ALS resistance was studied through the generation mean analysis biometrical procedure. Six generations consisting of the two parents Ukulinga and Gadra, and its cross derived filial progenies (F1), second-generation (F2), and backcrosses of F1 to Ukulinga (BCP1) and Gadra (BCP2) were planted in a net-house and later inoculated using a mixture of P. griseola isolates. Leaf lesions (% disease severity) were rated using a CIAT 1-9 scale and analysed using SAS macros in Proc GLM of SAS version 9.3. Results of ANOVA for a full model displayed significant additive effects (P<0.05) and highly significant (P<0.001) additive x dominance effects. Segregation analysis indicated 9:7 ratio, implying the involvement of complementary gene effects. The number of genes was estimated to be 1.79; however, due to epistasis two or more genes possibly govern the resistance in this cross. Broad and narrow sense heritabilities were 0.40 and 0.33, respectively. Therefore, the estimated narrow-sense heritability, additive gene effects, and epistatic interaction imply that it is prudent to delay selections until later stages, in which homozygosity could be achieved and additive effects fixed.


Author(s):  
J.R. Balat ◽  
J.B. Patel ◽  
I.R. Delvadiya ◽  
A.V. Ginoya

Background: The choice of parents to be incorporated in hybridization is a crucial step for breeders for the improvement of complex quantitative characters, such as fruit yield and its components. It requires extensive and detailed genetic assessment of existing germplasm and newly developed promising lines. The magnitude and type of gene action serves as criteria for selection of parents, which after hybridization are likely to produce the best recombinants for desirable traits. Methods: Forty five bottle gourd genotypes comprising 36 hybrids and 9 parents were evaluated in four different environments. Genetic components of variation were estimated for 12 different characters including fruit yield per plant. Result: The additive as well as dominant components were significant for fruit yield per plant and its components, revealing equal importance of both additive as well as non-additive gene effects. However, fruit yield per plant is under the control of dominance variance. Over dominance type of gene action, considerable degree of gene symmetry over all the loci, excess of dominant alleles in parents and high narrow sense heritability was found for most of the traits studied.


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