Dominance Type Of Gene Action Research Articles

Genetic Analysis of Fruit Yield and its Components in Bottle Gourd [Lagenaria siceraria (Mol.) Standl.

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.

Genotypic and Phenotypic Behavior for Quantitative Traits of some Wheat Varieties (Triticum aestivum L.) and their Half Diallel Crosses

A field experiment was carried out at the research station of the field crops department college of agricultureuniversity of Tikrit during (2011-2012 and 2013 winter seasons, included crossing according half diallel cross in the first season and evaluating parents and their crosses in the second season to study the genotypic and phenotypic behavior for the traits: days to anthesis, plant height (cm), no. spikes. plant-1, no. grains. spike-1, 1000 grains weight (g) and individual grain weight. Results showed highly significant differences for whole studied traits, many parents have high significant means and agood combiner in many traits especially ACS-W-J19-9148 parents in plant height and grains. spike-1 , ACS-W-J14-9143 parent in days to anthesis and 1000 grain weight and ACS-W-J15-9144 in no.grains.spike-1 and individual grain weight. Many crosses have better performance and affected positively to wards desired direction of significant hybrid vigor (ACS-WJ19- 9148 X sham 6) in no. grains. spike-1 and individual grain yield, (ACS-W-J15-9144) in 1000 grain weight and individual grain weight. Whole traits were controlled by dominance type of gene action and that adequate with the ratio of the degree of dominance which were more than one. Consequently heritability in narrow sense and expected genetic advance were low. The last two crosses can be useful through the application of pedigree selection on the late segregation generations to improve bread wheat cultivars

Estimates of genetic components and regression analysis for grain yield and various morphological traits in bread wheat (Triticum aestivum L.)

The present study was conducted to estimate the gentic components and regression analysis for grain yield and various morphological traits in bread wheat involving 10 parents and their 45 F1s (half diallel) during 2012- 13 and 2013-14. Significant additive (D) and dominance (H1) variance for the traits indicated that expression of these traits is control by both additive and dominance gene action. Average degree of dominance (H1/D)1/2 were more than unity for the traits (peduncle length, flag leaf area, productive tillers, biological yield, grain yield, harvest index) indicating the preponderance of over dominance gene action. The estimates of h2 were positive and significant for days to ear emergence, peduncle length, productive tillers, biological yield and grain yield indicated dominance of genetic components in F1s. Positive and significant values of F were estimated for days to ear emergence, days to 50% flowering, spike length, flag leaf area and grain yield in F1s indicating the preponderance of dominance and positive genes in the parents involved. The theoretical value (0.25) of (H2/4H1) for all the traits indicated asymmetrical distribution of positive and negative genes. The proportion of dominant and recessive alleles indicated presence of dominant alleles in the parents. The traits showing more than 30% narrow sanse heritability could be rewarding for further improvement in grain yield in bread wheat. Regression analysis indicated that the traits (days to ear emergence, days to 50% flowering, peduncle length, flag leaf area, productive tillers, harvest index, biological yield and grain yield) control by over dominance type of gene action. The parent RAJ 4246 contained maximum dominant genes for days to ear emergence and days to 50% flowering; HD 2733 for spike length and flag leaf area and HD 2824 for productive tillers, biological yield and grain yield used as donors in multiple traits breeding programme to develop high yielding wheat genotypes.

Study of genetic architecture through haymen's graphical approach for quantitative and qualitative traits in quality protein maize (Zea mays L.) over environments

Kernel yield is a very complex trait in maize which results from the interaction of various yield contributing characters and it is highly influenced by environmental variation. Therefore, phenotypic selection cannot directly improve the characters in highly cross pollinated crops like maize unless dissected by genetic analysis. The present investigation was carried out for gene action of various quantitative and qualitative traits in a complete set of 10x10half diallel mating designed involving ten elite inbred lines. The results of Variance/Co-variance graphs revealed that preponderance of over dominance type of gene action for days to 50 % tasselling, days to 50 % silking, ear height, kernel rows per ear, 100 kernel weight, kernel yield per plant, shelling percentage and lysine content. Distribution of array points depicted that parents GWQPM 55-2 had the maximum dominant genes while GWQPM 46-2 and GWQPM 26-3 possessed maximum recessive genes for most of the character.

Estimates of combining ability and standard heterosis for grain yield and various agromorphological traits in rice (Oryza sativa L.)

A study was conducted for estimating combining ability and standard heterosis for grain yield and various agromorphological traits involving 10 parents and their 45 F1s (half diallel) during 2012-13 and 2013-14. The results of present investigation revealed that additive gene action played a predominant role in the inheritance of most of the traits under study. On the basis of general combining ability (GCA) effects and specific combining ability (SCA) effects, three parents (Vallabh Basmati 21, Pusa Basmati 1, CSR 13) and three crosses (Vallabh Basmati 21 x Pusa 1121, Pusa 1121 x CSR 13 and Pusa Basmati 1 x CSR 13) were found good general and specific combiners. The best combinations mostly involved good x good and good x poor parental GCA effects suggesting that there is addi-tive x additive and additive x dominance type of gene action for yield and other component traits. The cross showing additive gene action can be improved by pedigree breeding and selection can be postponed to later generations. The most appropriate breeding method for the exploitation of non additive gene action will be heterosis breeding. The six best cross combinations (Vallabh Basmati 21 x CSR 30, CSR 30 x CSR 13, Vallabh Basmati 21 x CSR 13, CSR 30 x Pusa basmati 1, Pusa basmati 1 x CSR 13 and Vallabh Basmati 21 x Pusa basmati 1) had significant standard heterosis for grain yield and other component traits. The crosses which showed significant standard heter-osis is highly suitable for commercial exploitation of heterosis in rice crop.

Inheritance of Resistance to Sorghum Shoot Fly, Atherigona soccata in Sorghum, Sorghum bicolor (L.) Moench.

Sorghum production is affected by a wide array of biotic constraints, of which sorghum shoot fly, Atherigona soccata is the most important pest, which severely damages the sorghum crop during the seedling stage. Host plant resistance is one of the major components to control sorghum shoot fly, A. soccata. To understand the nature of gene action for inheritance of shoot fly resistance, we evaluated 10 parents, 45 F1's and their reciprocals in replicated trials during the rainy and postrainy seasons. The genotypes ICSV 700, Phule Anuradha, ICSV 25019, PS 35805, IS 2123, IS 2146, and IS 18551 exhibited resistance to shoot fly damage across seasons. Crosses between susceptible parents were preferred for egg laying by the shoot fly females, resulting in a susceptible reaction. ICSV 700, ICSV 25019, PS 35805, IS 2123, IS 2146, and IS 18551 exhibited significant and negative general combining ability (gca) effects for oviposition, deadheart incidence, and overall resistance score. The plant morphological traits associated with expression of resistance/susceptibility to shoot fly damage such as leaf glossiness, plant vigor, and leafsheath pigmentation also showed significant gca effects by these genotypes, suggesting the potential for use as a selection criterion to breed for resistance to shoot fly, A. soccata. ICSV 700, Phule Anuradha, IS 2146 and IS 18551 with significant positive gca effects for trichome density can also be utilized in improving sorghums for shoot fly resistance. The parents involved in hybrids with negative specific combining ability (sca) effects for shoot fly resistance traits can be used in developing sorghum hybrids with adaptation to postrainy season. The significant reciprocal effects of combining abilities for oviposition, leaf glossy score and trichome density suggested the influence of cytoplasmic factors in inheritance of shoot fly resistance. Higher values of variance due to specific combining ability (σ2s), dominance variance (σ2d), and lower predictability ratios than the variance due to general combining ability (σ2g) and additive variance (σ2a) for shoot fly resistance traits indicated the predominance of dominance type of gene action, whereas trichome density, leaf glossy score, and plant vigor score with high σ2g, additive variance, predictability ratio, and the ratio of general combining ability to the specific combining ability showed predominance of additive type of gene action indicating importance of heterosis breeding followed by simple selection in breeding shoot fly-resistant sorghums. Most of the traits exhibited high broadsense heritability, indicating high inheritance of shoot fly resistance traits.

Genetic analysis of water-deficit response traits in maize.

A set of sixty inbred lines of maize (Zea mays L.) were screened in the greenhouse at the seedling stage under both normal and water-deficit conditions. Six water deficit-tolerant inbred lines were selected based on root to shoot ratios. These selected lines were crossed in a diallel pattern. The parental, F1, and reciprocal cross plants were planted in a field under both normal and water-deficit conditions. Normal irrigation was applied to the control set, while the water-deficit set received 50% of normal irrigation levels. Analyses of variance of various morpho-physiological parameters identified significant differences among the selected lines under both conditions, indicating the presence of significant genetic variability. Variance components for general combining ability (GCA), specific combining ability (SCA), and reciprocal effects for all the parameters were estimated to determine the relative importance of additive and non-additive or dominance type of gene action. Variance components for GCA were larger than for SCA indicating the preponderance of additive types of gene action for all the traits under study. Hybrids developed from inbred lines W-10 and W-64SP proved to have the best grain yield under normal and water-deficit conditions. Under water-deficit conditions, the best performing cross was B-34 x W-10. Hence, these inbred lines and the hybrids might be of value in future breeding programs.

Evaluation of inbred lines of maize (Zea mays L.) through line × tester method

Maize inbred lines were evaluated by using line × tester method involving 11 lines and 3 testers for grain yield and its components through estimation of general combining ability (gca) and specific combining ability (sca) effects. Highly significant genotypic differences were observed indicated wide range of variability present among the genotypes. The crosses with high sca effect for grain yield were evolved from high × low general combiner parents which reveled additive × dominance type of gene action. The cross combinations 9MS4-1 × L22, 9MS4-1 × L486, 9MS4-2 × L431, 9MS4-11 × L486 and 9MS4- 15 × L431 with high positive sca effect having high mean values might be used for obtaining high yielding hybrids. The information on the nature of gene action with respective variety and characters might be used depending on the breeding objectives. DOI: http://dx.doi.org/10.3329/bjar.v39i4.22547 Bangladesh J. Agril. Res. 39(4): 675-683, December 2014

Evaluation of Inbred Line Through Line X Tester Method

Early generation evaluation of inbred lines through line × tester method was conducted at Regional Agricultural Research Station, Rahmatpur during rabi 2013-14 in maize involving 12 S4 lines and 2 testers (BIL 28 and BIL 29) for grain yield, yield components and other characters to estimate the general combining ability of the lines and specific combining ability effects of the crosses. Highly significant genotypic differences were observed indicated wide range of variability present among them. The crosses with high SCA effect for grain yield evolved from high × low general combiner parents were revealed additive x dominance type of gene action. The cross combinations E-7 X BIL-29, E-11 X BIL-29, E-10 X BIL-28 and E-9 X BIL-28 with high positive SCA effect having high mean values might be used for obtaining high yielding hybrids. The information on the nature of gene action with respective variety and characters might be used depending on the breeding objectives.DOI: http://dx.doi.org/10.3329/jesnr.v7i2.22211 J. Environ. Sci. & Natural Resources, 7(2): 79-84 2014

ESTIMATION OF GENE ACTION FOR FIBRE TRAITS IN UPLAND COTTON

The experiment was laidout in randomized complete block design with four replications in the experimental field of Botanical Garden, Department of Plant Breeding and Genetics, Sindh Agriculture University, Tandojam for assessing the gene action for quality traits in a 5x5 complete diallel cross having five varieties of Gossypium hirsutum L. The genetic components of variance revealed that dominance components (H1 and H2) and additive component (D) were highly significant for all the traits except staple length in dominance components. It was further observed that dominance components were greater in magnitude than additive components. The average degree of dominance for lint index, GOT%, staple length and fibre strength were more than a unity, displaying over dominance type of gene action, the positive non-significant F-value revealed that the dominant genes were less frequent than recessive genes in the parents and that they were in decreasing position as exhibited by h2 value. Estimated ratio of h2/H2 indicated that there were at least one group of genes controlling GOT%, two group of genes controlling lint index and fibre strength and three group of genes controlling staple length. ——————————  ——————————

Genetic Analysis for Yield and Some Yield Traits in Spring Wheat

A 5x5 diallel cross involving five wheat varieties/lines (Kohistan-97, Chakwal-86, 6529-11, 6544-6 and 7086-1) was conducted. Twenty hybrids along with five parents were planted in randomized complete block design with three replications in order to find out the gene action controlling some vital polygenic yield related attributes like plant height, spike length, peduncle length, number of tillers per plant and grain yield per plant. Highly significant differences among genotypes were observed for all traits. Plant height has only significant differences. The graphical presentation demonstrated that number of tillers per plant was ruled by partial dominance with additive type of gene action. While over-dominance was observed in plant height, spike length, peduncle length and grain yield per plant. It showed the potential for the availability of transgressive segregates in later filial generations. The prevalence of partial dominance type of gene action for number of tillers per plant showed that it can be gradually improved by selection.

English

The genetic effect of grain yield plant-1 and its correlation with yield components were investigated in a 7 × 7 incomplete diallel cross of seven wheat parents during the crop season of 2009 to 2010. Mean square of general combining ability (GCA) effect was 2.90 for grain yield plant-1, which was highly significant (P<0.01), indicating that additive effect played important role in the inheritance of the trait. Specific combining ability (SCA) effect was highly significant (P<0.01) for grain yield plant-1 (0.68), suggesting that the trait was also controlled by non-additive effect. The estimates of GCA showed that the best combiner for grain yield plant-1 was Ningmai 9. The additive-dominance model was partially adequate for grain yield plant-1 and it was controlled by the over dominance type of gene action. Ningmai 8 possessed maximum dominant genes, whereas Yangmai 9 had maximum recessive genes. Grain yield plant-1 might be controlled by two groups of genes and exhibited moderately high value of narrow sense heritability (h2N=69.51%). The statistical analysis revealed that grain yield plant-1 was positively and significantly correlated with tillers plant-1 (rp=0.584, rg=0.595) and number of grains spike-1 (rp=0.528, rg=0.507) at phenotypic and genotypic levels. The information obtained from the study might be helpful for wheat breeders trying to develop new varieties with high-yielding potential.   Key words: Combining ability, diallel cross, grain yield, inheritance, Triticum aestivum L.

Inheritance of Graın Yield and Its Correlation with Yield Components In Bread Wheat (Triticum aestivum L.)

The inheritance of grain yield plant-1 and its correlation with other yield components were investigated in a diallel cross of seven wheat parents during the crop season of 2011-2012. Mean square of GCA effect was 2.90 for grain yield plant-1, which was highly significant (P<0.01), indicating that additive effect played important role in the inheritance of the trait. SCA effect was also highly significant (P<0.01) for grain yield plant-1 (0.68), suggesting that the trait was also controlled by non-additive effect. The estimates of GCA showed that the best combiner for grain yield plant-1 was Ningmai 9. The additive-dominance model was partially adequate for grain yield plant-1 and it was controlled by the over dominance type of gene action. Ningmai 8 possessed maximum dominant genes, whereas Yangmai 9 had maximum recessive genes. Grain yield plant-1 might be controlled by two groups of genes and exhibited moderately high value of narrow sense heritability (h2N=69.51%). The statistical analysis revealed that grain yield plant-1 was positively and significantly correlated with tillers plant-1 (rp=0.584, rg=0.595) and number of grains spike-1 (rp=0.528, rg=0.507) at phenotypic and genotypic levels

Genetic analysis of various morpho-physiological traits inZea maysL. using graphical approach under normal and water stress conditions

The F1 hybrids along with the parents were evaluated in field under normal and water stress regimes to determine the nature and magnitude of genetic variances and heritability estimates at Dezful Research Station in Safi Abad, from 2011 to 2012 using RCBD with three replications. Results analysis of variance showed that variations among genotypes were highly significant for all the traits studied under both the regimes. Therefore, variations were partitioned into additive and non-additive components according to Hayman and Hayman & Jinks methods. Based upon the results of tests, simple genetic model was fully adequate for analyzing the data set for all traits except RWC under water stress condition. It was observed that a and b components which are due to additive and dominant gene effects, respectively, were significant for all studied characteristics under both the conditions. Considering the average degree of dominance as well as Vr/Wr graphs revealed that the yield potential traits like plant height, harvest index, RWC and grain yield per plant were controlled by over dominance type of gene action, while traits like ASI and 100kernel weight were under the control of partial dominance with additive type of gene action under both the conditions. Over-dominance for most of the parameters reveals that selection in later generations may be more effective and the selection in early generations will be more effective for the trait which is additively controlled.

Study on gene action and combining abilities for thermotolerant ablilities of corn (Zea mays L.)

High temperature reduces the pollen viability and silk receptivity of corn resulting in poor seed set and reduced yield. Continuously increasing temperature and less frequency and distribution of rainfall coupled with usual canal–closure particularly in Pakistan have significantly been decreasing the grain yield. This problem could be overcome by developing heat tolerant maize hybrids. For this purpose, five heat tolerant (lines), five heat susceptible (lines) and four heat susceptible (testers) corn inbred lines were hybridized artificially in a line × tester mating design. The 40 hybrids and 14 parents were evaluated for heat tolerance under moderate temperature field conditions (by sowing on March 31) using triplicated randomized complete block design during spring 2004. Large differences in heat units (111 to 326) utilized by the parents and crosses under normal and moderate temperature conditions to mature physiologically suggested that inbred lines as well as crosses were photosensitive as they were not utilizing similar thermal units in both the environments. Highly significant differences (P ≤ 0.01) were observed among 54 corn genotypes, 14 parents, 40 crosses, parent vs crosses and interaction term of lines × tester (L × T) for 14 maize plant traits. The inbred lines L1, L2, L3, L5 (lines), T1, T3 (testers) and hybrids L1×T3, L2×T4, L3×T3 and L5×T1 were proved to be the excellent combiners with high GCA and SCA effects respectively, for most of the traits. The dominance type of gene action was observed to be predominant for all the traits. The proportional contribution of lines was more for seven very crucial parameters. The estimates of heritability in broad sense were high for all the traits. Hybrid breeding is suggested as hybrid plants have higher capacity to tolerate heat stress in field conditions than their parents.

Breeding potential of the basmati rice germplasm under water stress condition

Eight parents were selected on the basis of phenotypic and genotypic screening for the development of F 1 . All the possible combinations were made between the parents excluding reciprocals in diallel mating design. Data were analyzed by using Hayman graphical approach and Griffing’s approach to study the genetics of the parents and their F 1 hybrids. Based on the genetic component analysis, both additive and non-additive components appeared which is important in the inheritance of most of the traits. Both additive and dominance type of gene action were found important in inheritance for different traits under study. Most of the traits showed constant gene action in both environments, but the gene action of some traits was affected by the environment. Morphological traits like plant height, productive tillers per plant and 1000 seed weight showed over dominance type of gene action in both environments (control and drought environments), while seeds per panicle and seed length width ratio showed this type of gene action only in drought conditions. The seeds per panicle and length width ratio showed additive type of gene action with partial dominance only in normal irrigation conditions. From Griffing analysis, genotypes CB-17, CB-32 and Basmati-198 were found to be good general combiners for productive tillers per plant, primary branches per panicle and yield per plant, especially under water stress condition. Also, maximum specific combining ability was found in Basmati-198 × CB-17 for productive tillers per plant, Basmati-198 × CB-42 for primary branches per panicle and CB-32 × CB-14 for yield per plant. Key words: Oryza sativa L., gene action, combining ability, stress, yield traits.

Genetic analysis of physio-morphological traits in bread wheat (Triticum aestivumL.) under water stress conditions

A diallel cross involving six wheat varieties, namely Sehar 06, Punjab 96, GA 2002, Barani 83, Kohistan 97 and Chakwal 86 was carried out to determine the mode of gene action for some physio-morphological traits under water stress conditions. Analysis of variance showed highly significant differences among genotypes for all the traits studied. Additive type of gene action with partial dominance was observed for flag leaf area, stomatal frequency, leaf venation, days to heading and spike density while 100-grain weight was controlled by over dominance. Additive type of gene actions shows the fruitfulness of early selection for the traits while over dominance type of gene action indicates selection in later generations. Epistasis was absent for all the traits studied.

Inheritance of stem strength and its correlations with culm morphological traits in wheat (Triticum aestivumL.)

Yao, J., Ma, H., Zhang, P., Ren, L., Yang, X., Yao, G., Zhang, P. and Zhou, M. 2011. Inheritance of stem strength and its correlations with culm morphological traits in wheat ( Triticum aestivum L.). Can. J. Plant Sci. 91: 1065–1070. The genetic effect of stem strength and its correlation with culm morphological traits were investigated in a 7×7 diallel cross of wheat involving seven parents (Ningmai 8, Ningmai 9, Yangmai 5, Yangmai 9, Yangmai 11, Sumai 3, and Wangshuibai) during the crop season of 2009–2010. Significant differences were observed among genotypes for stem strength. The estimates of general combining ability (GCA) pointed out that the best general combiners for stem strength were Ningmai 8 and Yangmai 9. The additive-dominance model was adequate for stem strength, and it was controlled by the over dominance type of gene action. Ningmai 8, followed by Yangmai 5, possessed maximum recessive genes, whereas Wangshuibai had maximum dominant genes. Stem strength could be controlled by three genes with low narrow sense heritability. A statistical analysis showed that stem strength is highly significantly correlated with nine culm morphological traits except for diameter of the first basal internode.

Inheritance of stem strength and its correlations with culm morphological traits in wheat (Triticum aestivum L.)

Yao, J., Ma, H., Zhang, P., Ren, L., Yang, X., Yao, G., Zhang, P. and Zhou, M. 2011. Inheritance of stem strength and its correlations with culm morphological traits in wheat ( Triticum aeestivum L.). Can. J. Plant Sci. 91: 1065-1070. The genetic effect of stem strength and its correlation with culm morphological traits were investigated in a 7×7 diallel cross of wheat involving seven parents (Ningmai 8, Ningmai 9, Yangmai 5, Yangmai 9, Yangmai 11, Sumai 3, and Wangshuibai) during the crop season of 2009-2010. Significant differences were observed among genotypes for stem strength. The estimates of general combining ability (GCA) pointed out that the best general combiners for stem strength were Ningmai 8 and Yangmai 9. The additive-dominance model was adequate for stem strength, and it was controlled by the over dominance type of gene action. Ningmai 8, followed by Yangmai 5, possessed maximum recessive genes, whereas Wangshuibai had maximum dominant genes. Stem strength could be controlled by three genes...

Genetic dissection of yield and its components in upland cotton ( Gossypium hirsutum L.)

A 4x4 diallel cross experiment involving three exotic lines that is DPL-775, 71-821 Bulk-OP and Coker-100/A-2 and one local line that is MNH-53, was conducted for genetic analysis of yield and its components in upland cotton, to evaluate the gene action for different agronomic and fiber characters in upland cotton. Additive gene action with partial dominance appeared to control plant height, number of sympodial branches, number of bolls, yield of seed cotton, boll weight and lint percentage, where as over dominance type of gene action was noted for number of seeds per boll, seed index, lint index, staple length, fiber fineness. On over all basis 71-82 Bulk-OP has maximum dominant genes for number of sympodial branches, yield of seed cotton, seed index, lint index and fiber fineness while dominant genes for number of seeds per boll, boll weight, lint percentage and staple length are present in Coker-100/A-2. MNH-53 has maximum dominant genes for plant height and number of bolls while DPL-775 did not possess and dominant genes for any character. Key words: Gene action, diallel cross agronomic traits, cotton.