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Showing 9 results for Dominance
Pariya Dorri, Saeed Khavari Khorasani, Mahmood Vali Zadeh, Parisa Taheri,
Volume 1, Issue 2 (2-2015)
Abstract
Selection of breeding methods for plant genetic improvement largely depends on the genetic basis of selected traits. This research was carried out in order to study the genetic parameters of phenological and morphological traits , yield and yield components of maize using generation mean analysis of inbred lines derived from crosses KE72012 (P1) × K1263 / 1 (P2) inbred lines. This study was conducted at Torough Station of Khorasan Razavi Agriculture and Natural Resources Research Center, Mashhad, Iran, during 2012. Six maize generations include BC2, BC1, F2, F1, P2 and P1 was evaluated in a randomized complete block design (RCBD) with three replications. Analysis of variance showed higher dominance gene effects than additive effects. Average dominance gene effects (H / D) ½ in all measured traits, showed complete and over dominance gene effects indicating the importance of dominance effect in studied traits. A simple additive-dominance model performed using weighted least square analysis. Results showed not it’s adequacy for traits, indicating the importance of epistatic effects in controlling genetic variations. Broad sense heritability for all measured traits in crosses KE72012 (P1) × KE1263 / 1 (P2) ranged between 0.10 to 0.88 and the range of narrow sense heritability in this cross was between 0.02 to 0.59. Estimation of number of genes controlling grain yield showed that the one to five genes are involved in KE72012 (P1) × K1263 / 1 (P2).
Davoud Sadeghzadeh-Ahari, Peyman Sharifi, Rahmatollah Karimizadeh, Mohtasham Mohammadi,
Volume 2, Issue 1 (5-2015)
Abstract
To estimate the genetic components and the mode of inheritance for some morphological traits, six rainfed durum wheat genotypes (Chehel daneh, Gerdish, Zardak, Syrian-1, Waha and Knd1149//68/ward) and their complete diallel progenies were grown in a randomized complete blocks design with two replications in 2005-06 cropping season in Maragheh Dryland Agricultural Research Station. Results of diallel analysis revealed that additive variance were important for inheritance of grain yield, number of grain per spike, spike length and number of fertile tiller than dominance variance. The positive value of ‘F’, indicated that there were excess of dominant alleles in comparison to recessive ones in the parents for all of the studied traits. The average degree of dominance (H1/D) 0.5 showed partial dominance for grain yield, number of grain per spike, spike length, 100 grains weight and number of fertile tiller and over-dominance for peduncle length. Graphic analysis indicated that increase of grain yield, number of grain per spike, spike length, 100 grains weight and number of fertile tiller were under the control of combination of recessive and dominance alleles. Predominance of additive effects for grain yield demonstrated that breeding methods based on selection may be advantageous in improving of this trait. The highest value of this trait relevant to Gerdish (10.33 g/plant), therefore this genotype can be used as cross parent in breeding programs for receiving to lines with high yield and yield components. The cross of Waha × Knd1149//68/ward with high value of GY and GCA for this trait can be used as a suitable cross for hybrid production.
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Volume 4, Issue 1 (9-2017)
Abstract
Drought is a worldwide risk seriously influencing production of agricultural plants such as coriander. In order to evaluate heritability and gene action for important quantitative traits in coriander in three irrigation regimes, including well water (WW), mild water stress (MWS) and severe water stress (SWS), a cross between two genotypes of TN-59-158 (Sensitive parent) and TN-59-230 (Tolerant parent) was done. Parents and progenies of triple test cross were evaluated in filed condition through a randomized complete block design with three replications. Days to 50% flowering (DTF), days to harvest (DTH), fruit yield (FY), thousand fruit weight (TFW), harvest index (HI), relative water content (RWC), essential oil yield (EOY) were measured. Results showed that total epistasis effect was observed for all traits except RWC in WW. Also, total epistasis effect was observed for all traits except DTF in MWS and SWS. Partitioning of total epistasis revealed that [i] type of epistasis was contributed to determining DTF and TFW in WW and MWS treatments, DTH, FY and RWC in MWS and SWS treatments, and HI and EOY in WW, MWS and SWS treatments.
Mohammad Zabet, Amir Ebrahimzade, Zohreh Alizadeh, Ali Reza Samadzadeh,
Volume 6, Issue 2 (3-2020)
Abstract
The production of new and compatible cultivars to different environments is one of the most important goals for the breeders. The crossing new cultivars and the selection of superior genotypes for desirable traits among their offspring is a method that has always been used by breeders. 28 genotypes obtained from the crossing of a 7 × 7 one-way diallel experiment consisting of seven parents (Alvand, Anfarm9, Chamran2, BC Roshan, Qods, Ofogh, local variety Sorkh-dane) and their 21 hybrids were investigated in a randomized complete block design with three replications in the research field of the Faculty of Agriculture of University of Birjand (Iran) under non-stress and drought stress conditions. The analysis of variance showed a significant difference among genotypes for all traits. Mean squares of GCA and SCA were significant for all traits under non-stress and stress conditions, so, there were additive and non-additive components of heritable variance in all traits. The BC Roshan parent had the high combining ability and Ofogh parent had the lowest combining ability in most traits in non-stress and stress conditions. In both conditions, BC-Roshan × Chamran2, Sorkh-dane × Qods and Ofogh × Anfarm9 hybrids had the highest yield and yield dependent traits. Hayman's variance analysis showed that component a (additive genetic diversity), component b (dominance genetic diversity), component b1 (heterosis), component b2 (heterosis specifically for each parent), and component b3 (specific dominance deviation per cross) were significant in both conditions in all traits.The Hayman's analysis confirmed the results of Griffing's analysis.
Jamal Rahimi Darabad, Varahram Rashidi, Hossein Shahbazi, Mohammad Moghaddam Vahed, Ebrahim Khalilvand,
Volume 7, Issue 2 (3-2021)
Abstract
In order to determine the heritability and genetic parameters of some agronomic traits in barely (Hordeum vulgare L.) cultivars, a seven-parent half diallel (F1 crosses + parents) was conducted in the non-stress and salt stress (8 and 12 ds m-1) conditions in a randomized complete block design with three replications. Genetic analysis was performed by Hayman’s method and Griffing’s fixed model, method 2. The slope of linear regression of Wr on Vr were significantly higher than 0 and had not significant difference with 1 indicating the additive-dominant model was satisfied in all cases. The narrow-sense heritability of traits was medium to high (0.4-0.8) but their broad-sense heritability was estimated relatively high (0.7-0.9). Results of regression graphs showed that Afzal parent had the most dominant allele. The significance of “a” component in most of the studied traits indicated the presence of the additive effects in controlling of traits. The significance of “b” component in most of the studied traits indicated the presence of the dominance effects in controlling of traits. The proportion of positive and negative genes was lower than 0.25 in all of the traits (except for grain weight per spike in 12 ds m-1 salinity), indicating the presence of asymmetry in the distribution of the positive and negative alleles in the parents. Based on general combining ability effects, it was concluded that under salinity, cultivar “Kavir” had favorable alleles in plant height, grain weight per spike and 100 grain weight traits and can be used as a general parent in breeding programs. Estimates of high broad-sense heritability and narrow-sense heritability in most traits indicated that these genetic materials were promising for breeding under normal and salinity stress conditions.
Mehdi Rahimi,
Volume 7, Issue 2 (3-2021)
Abstract
The diallel mating design is an important tool used by plant breeding programs to obtain information on trait inheritance. Knowledge of gene action, heritability and genetic advance from selection is a prerequisite for starting a breeding program for developing varieties of maize. Five maize S7 lines and their F2 progenies were studied in a 5 × 5 half-diallel crossing design to evaluate the gene action and the heritability of biochemical and physiological traits. Parents and their F2 hybrids were planted in a randomized complete block design with three replications at the Research Farm of Graduate University of Advanced Technology (Kerman, Iran) in 2017 cropping year, and chlorophyll (Chl), proline, protein, carotenoid and reducing sugars traits were evaluated. Analysis of variance showed significant differences among genotypes for the studied traits at 1% probability level. The graphical results of Hayman's analysis showed the role of over-dominance genes effects in controlling proline content, sugars content, Chl a, Chl b, total Chl and carotenoids traits whiles the protein content trait was controlled by the incomplete dominance of genes. The narrow-sense heritability for carotenoid and proline content traits were 0.14, for protein content was 0.44 and for other traits were varaied in this range. The results of this study showed that the use of heterozygosity and the production of hybrid varieties can be used to breeding traits such as proline content, sugars content, Chl a, Chl b, total Chl and carotenoids. However, for breeding of protein content, use of both methods (selection and production of hybrid) are proposed.
Seyede Sharare Arianezhad, Hamid Hamid Najafi Zarini, Mehdi Ghaffari, Gholamali Ranjbar,
Volume 9, Issue 1 (9-2022)
Abstract
This research was carried out to estimate the genetic variance components for sunflower fatty acids in two separate optimum and drought stressed conditions in Karaj during 2020 and 2021 growing seasons. The plant materials consisted of 12 hybrids derived from crossing of four restorer lines by three cytoplasmic male sterile lines (Testers) that were evaluated in two separate experiments as randomized complete block design with three replications. Drought stress made a reduction in oil yield (34 percent), oil content (six percent), stearic acid (4.7 percent) and oleic acid (10.6 percent) and an increase in palmitic acid (12 percent) and linoleic acid (2.8 percent). Line × tester interaction effect had a major role in explanation of the variance of the hybrids in terms of fatty acid content in both conditions, indicating the critical role of non-additive effects in genetic control of these traits. Under optimum irrigation, oil yield, oil content and stearic acid content were under control of both additive and dominant gene action and palmitic, oleic and linoleic acids were under control of dominant gene action. Under drought stress, except oil content which was under control of additive effects, all the other traits were under control of dominant gene action. According to the results of this study, fatty acid composition of sunflower was under control of non-additive genetic effects and the crossing-based methods and hybrid breeding could be used for improvement of sunflower in terms of fatty acid composition.
Mohammad Zabet, Fahime Barazandeh, Alireza Samadzadeh,
Volume 10, Issue 1 (9-2023)
Abstract
To investigate the genetic structure of different sesame traits, 7 genotypes, including Ardestan, Sirjan, Fars, Sabzevar, Jiroft, Oltan and TS-3 were studied in the form of a 7 x 7 one-way diallel design in the research farm of the Faculty of Agriculture at University of Birjand during 2015-2018.The traits measured included plant height, height to the first capsule, number of auxiliary branches, number of leaves, leaf length, days to 50 % flowering, days to 90 % flowering, days to physiological maturity, number of capsules per plant, biological yield, grain yield, harvest index, number of seeds per capsule, capsule weight, capsule length, capsule width, chlorophyll a, b and total chlorophyll, oil and protein percentage.Hayman′s variance analysis showed that there were significant components a, b and b3 in all traits and components b1 and b2 in most traits. Parameters D, H1, and H2 were significant and the parameters F, h2 and E were not significant for most traits. The average degree of dominance (√H1/D) showed incomplete dominance and over dominance for all traits. The H2/(4H1) parameter was less than 0.25 in all traits except the day to 50 % flowering, suggesting that increasing and decreasing genes did not have symmetrical distribution among the parents. The parameter (√(4DH1)+F)/√(4DH1)-F ) showed symmetrical and asymmetrical distributions for the studied traits. In most of the traits, there was a dominant gene block controlling the traits. Broad sense and narrow sense heritabilities ranged 0.47-0.99 and 0.17-0.98, respectively. In general, all traits were controlled by genes with additive and dominance effects, so it is possible to select and produce hybrids in sesame. Considering that Fars, Oltan and TS-3 genotypes had the most dominant alleles, it is recommended that in future studies, attention should be paid to these three genotypes.
Ramezanali Pourali, Mohammadhadi Pahlevani, Khalil Zeinalnejad,
Volume 10, Issue 2 (2-2024)
Abstract
Increasing grain yield and improving the quality of bread are among the most important goals of wheat breeding programs in Iran. Understanding the genetic control of traits and finding molecular or morphological markers associated with them are also prerequisites for any genetic engineering program. In this study, 100 progenies of a 10 × 10 diallel cross were used to analyse the genetics of grain yield and bakery values using STS markers associated with HMWG subunits. This research was carried out during 2018 and 2019 cropping season at Gorgan University of Agricultural Sciences and Natural Resources experimental fields. In the first year, 10 wheat cultivars, including Gonbad, Morvarid, Kalate, Ehsan, Sirvan, Baharan, Chamran2, Shush, Mehrgan and Brat collected from different geographical regions of Iran were planted and crossed in the field. In the second year, the parents and crosses were planted in the form of a randomized complete block design with three replications. The grain yield, number of spikes per plant, number of seeds per spike, seed weight, days to emergence and plant height were recorded. The results of this study indicated significant genetic differences between the parents. Narrow-sense heritability analysis revealed that the crossing of cultivars is the best breeding method to enhance seed yield, number of spikes per plant and days to emergence. Also, to improve the number of seeds per spike, seed weight and plant height, classical breeding methods may offer higher efficiency. Marvarid and Gonbad were ranked 1st and 2nd, respectively with respect to general combining abilities for grain yield, attributed to their positive and significant general combining ability effects. The highest specific combining ability was observed for Ehsan×Gonbad, Marvarid×Chamran 2 and Shush×Sirvan crosses. The results of molecular markers analysis showed that the STS markers were able to identify the difference in the baking value of cultivars. The quality score of the cultivars ranged 6 and 10 and to this end, Kalate and Brat were the top cultivars. Therefore, due to superiority in terms of both quantity and quality for yield, these cultivars can be used as parents with desirable genes for future breeding programs. Overall, the STS markers employed in this study proved to be valuable markers for enhancing the genetic background of bread wheat, particularly when employing marker-assisted selection for bakery value.
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