جستجوی مقالات مرتبط با کلیدواژه « واریانس افزایشی » در نشریات گروه « کشاورزی »

Sesame is one of the oldest crops and probably the oldest oilseed in the world. In most regions, the landrace and local masses of sesame are used. To increase production and yield, the production of modified cultivars for different agricultural climates is extremely important.

Seven genotypes included Isfahan, Sirjan, Fars, Oltan, Jiroft, Sabzevar, TS-3 and 21 hybrids that were obtained from them were studied in the research farm of the Faculty of Agriculture of the University of Birjand under the drought stress conditions during 2015-2018. The experiment was conducted in a randomized complete block design with three replications as a 7 × 7 one-way diallel. In this study, several traits were measured. These traits were including plant height, height to the first fruiting capsule, number of capsules per plant, number of sub-branches, number of leaves, leaf length, number of seeds per capsule, capsule length, capsule weight, capsule width, days to 50% and 90% flowering, days to physiological maturity, thousand seed weight, oil percentage, protein percentage, amount of chlorophyll a, chlorophyll b, total chlorophyll, biological yield, economic yield and harvest index.

The investigation of the adequacy of the additive-dominance model showed that the model was sufficient in the traits including plant height, capsule length, capsule weight, number of leaves, number of sub-branches, number of capsules per plant, economic yield, biological yield, days to 50 flowering, days to 90% flowering and days to physiological maturity, and therefore diallel analysis was done on these traits. Hayman's variance analysis showed that were significant component a (additive effects of genes) in all traits and component b (dominant effects of genes) in all traits except plant height. Also, were significant the component b1 (mean dominance effects) in most traits except plant height, number of auxiliary branches, number of capsules and seed yield, the component b2 (other dominance deviation due to the parents) in most traits except plant height, number of auxiliary branches and number of capsules, and the component b3 (residual dominance variation) in all traits except plant height. The investigation of genetic parameters showed significant additive genetic component (D) and dominanant genetic components (H1 and H2) in most traits. Also were significant the component F (average covariance of additive and dominance effects) and the component h2 (the overall dominance effect of heterozygous loci) in half of the traits. The average degree of dominance (√ (H1/D)) in different traits was observed as additive, incomplete, and over dominance. In all characteristics, except capsule weight, the ratio of genes with positive and negative effects (H2/(4H1)) was not equal to 0.25; therefore, in all traits, increasing and decreasing genes did not have symmetrical distribution among parents. The ratio of dominant and recessive genes in parents ((√(4DH1)+F)/(√(4DH1)-F)) was more than unity in most of the traits, so there was an uneven distribution of dominant and recessive genes in most of the traits. The number of dominant gene groups (h2/H2) was obtained from 0 to 2.04; therefore, all traits were controlled by one or two gene blocks. Broad sense (hb2) and narrow sense (hn2) heritability were high in all traits.

In the traits studied, the type of action of genes controlling the traits, the ratio of dominant and recessive genes, the ratio of genes with increasing and decreasing effects, additive effects and dominance were variable and were different in most of the traits. Generally, most traits were controlled by genes with additive and dominant effects. The high heritability estimate indicates the promising news of the studied genetic materials in future studies. Therefore, among these materials, better genotypes can be selected for the climatic conditions of Birjand, so that it can be further investigated in the future.

Tomato is a self-pollinated crop and has a high potential for heterosis production. Tomato has a wide range of diversity in terms of vegetative and fruit traits. Therefore, learning information about the genetics of the tomato plant and the inheritance of its various traits to the next generation will help plant breeders to use appropriate breeding methods to improve them. One of the methods that is used to know the genetic structure of plants, identify parental lines and determine their combining ability is line × tester analysis. Line × tester analysis provides information about general and specific combining of parents and can be useful in estimating different types of gene effects such as additive and non-additive effects. In most of the developed countries, many researches have been done in relation to hybrid production and combining ability among tomato lines, and sometimes the inferred results are different from each other. In Iran, few studies have been done about crossing cultivars and their hybrids, and most of the seeds used by farmers are imported from other countries. Therefore, this study intends to evaluate genetic variance components, general and specific combining ability of some quantitative traits in a number of tomato lines and testers and their hybrids by using line × tester analysis.
 
This research was conducted in Sari Agricultural Sciences and Natural Resources University, Mazandaran Province, Iran in 2022. Two modified cultivars SC and V as lines and three modified cultivars L, R and MZ as testers were crossed with each other to create F1 hybrids. Six F1 genotypes and their parents (11 treatments in total) were cultivated in the farm in a randomized complete block design with three replications. The evaluated traits included the number of days to the first flowering, earliness, number of fruits per plant, fruit weight per plant (g), fruit yield (g), fruit length and width (cm). In order to analyze the variance of the experimental design to search for diversity between treatments, to separate the effects of treatments into their components based on line × tester analysis, to mean comparison with Duncan's test, and also to calculate the general and specific combining ability, R statistical software was used. Also, in order to calculate additive and non-additive variances, Singh and Chaudhary's method was used.
 
The results of line × tester variance analysis showed that the mean squares of parents and testers were significant for all traits except fruit length and width, and the mean squares of crosses and lines were significant for all traits except fruit length. The effect of line × tester was significant for all traits except the number of fruits per plant and fruit length. The line of SC to improve the number of days to first flowering, earliness, plant height, fruit weight per plant, and fruit width, and the line of V to improve the number of fruit per plant were the best general combiners with testers. The tester of L for improve all traits except yield, and the tester of MZ for improve plant height were the best general combiners with the maternal lines. Among the crosses, the SC×L cross for improve earliness and fruit width, and the SC×R and V×MZ crosses for improve plant height and fruit weight per plant, respectively, were favorable specific combiners. The mean comparison of the genotypes for some important traits showed that among the parental cultivars, the line of SC and among the crosses, the SC×L genotype had the lowest means for the number of days to first flowering and earliness. Also, the line of SC for the number of fruits per plant and the SC×L genotype for fruit weight per plant, yield and fruit width had the highest means. Also, the estimation of additive and non-additive variances indicated that in plant height and fruit weight per plant traits, additive variance plays the main role. While for the traits of the number of days to first flowering, earliness and yield, the contribution of non-additive variance was more than the additive variance.
 
According to the results obtained from this study, in future projects it is recommended to use parents that have significant general combining ability (GCA) for traits. Because such parents easily transfer the trait to their next generation. In this way, the line of SC was a good general combiner for the number of days to first flowering, earliness, plant height, fruit weight per plant and fruit width, and the line of V was a good general combiner for the number of fruits per plant. Among the testers, the tester of L was a good general combiner for improve the number of days to first flowering, earliness, number of fruits per plant, fruit weight per plant, and fruit width, and the tester of MZ recorded a high GCA for the plant height. Also, for the improvement of earliness and fruit width, the SC×L cross and for plant height and fruit weight per plant, SC×R and V×MZ crosses were favorable specific combiner. Mean comparison of genotypes showed that the SC×L cross is superior to its parents for the number of days to first flowering, earliness, fruit weight per plant, fruit yield, and fruit length and width. The traits of plant height and fruit weight per plant are more affected by additive variance, so the best breeding method to improve plant height and fruit weight per plant is selection from among the segregating population. The traits of number of days to first flowering, earliness and yield were affected by non-additive variance, so hybrid production is recommended to improve the mentioned traits.

Gynociouce hybrids have the advantage of high yield; therefore, gynociouce trait should always be considered in the production of cucumber hybrid cultivars. There are at least five genes that affect the expression of gynociouce. In order to improve cucumber for production new cultivars with higher yield and better quality, using of genetic diversity and cucumber germplasm is extremely essential. Knowing the importance and extent of controller genetic effects the inheritance of traits can lead to the selection of appropriate corrective methods. Therefore, the present study took with this goal how inheritance of the gynoeciouc trait and to investigate the effects of controller genes on this trait and other performance components in cross between a commercial hybrid and a selected line, Finally a proper amendatory plan is adopted.

In order to evaluate genetic and determinate heritability of gynoecioucy in cucumber seven generation including P1, P2, F1, F2, BC1, BC2 and F3 from a cross between two gynoeciouc and androeciouc cucumber lines N10×A11, were supplied and number of female flowers and number of male flowers, number of fruit per plant, length of plant and length of internode were evaluated in a randomized complete block design with three replications. Cause on create populations, experiments were carried out in the spring and autumn of 2017 to 2018 in three stages in the greenhouse of the college of Agricultural Sciences, University of Guilan and population assessment was performed in 1398 in the research farm of the Faculty of Agricultural Sciences, University of Guilan. First year, in order to produce hybrid seeds, a cross was made between gynoecious N10 and androecious A11 lines. After producing and cultivating hybrid seeds in the second stage, self-pollination and hybrid cross-breeding with parents were carried out and F2 populations and backcrosses were created. In the second year, samples of second generation seeds were planted in greenhouses for creating self-pollination and third-generation populations. In the greenhouse, hydroponic cultivation system was used and fertilization and irrigation of plants were did at regular intervals. In the field cultivation system, Growing Phases were carried out using drip irrigation system and cover mulch for planting and necessary agricultural care in the cultivation stages. Data normality was tested by SPSS software and data analysis was performed by SAS software. Generation mean comparison was also performed using LSD test at 5% and 1% probability levels.

about the gynoecioucy there was a significant differences among case study generations. Examination of scale tests for this trait also showed that there may be inallele interactions among the genes controlling this trait. Examination of genetical parameter and doing scale tests showed for all of study traits there are different epistasis. the results showed about number of female flower all of the genetic parameters was significant and for number of male flower, number of fruit per plant and length of internode traits simple six parametric was in charge of controlhing the traits such as all of genetic parameters without dominance-dominance epistasis, whereas for length of plant trait simple six parametric model such as all of genetic parameters without additive-additive epistasis was the best of genetic model vindication for diversity.

Evaluation of inheritance and dominance degree showed additive variance was more important in number of female flower and number of fruit per plant traits that means Superior genotypes can be select to modify these traits in the study population

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.

Assessment of general and specific combining , heterosis and genes action for traits until the advention of the first female flower, time to first harvest, the number of fruit branch main and plant height up to first fruit the were experiment half diallel 7×7 second and fourth Griffing method using a fixed model for a number cucumber lines in 2014. Result of variance analysis showed significant differences among genotypes. Mean squares of general combining and specific combining revealed significant differences for all traits. These reflects the importance of both addative and dominance effects genes of inheritance traits. Specific combining for traits until the advention of the first female flower and number of fruit branch main was futher general combining which reflects the non - addative genes action. For traits time to first harvest and fruit plant height up to first fruit due to the high general combining controlled by addative and non -addative genes action. Line B10 and B12 due to general and specific combining ability for seed production of hybrid cucumber is desirable and recommended.

This experiment was conducted to investigate heritability, combining ability and genetic control of important traits of greenhouse cucumber inbred lines in 2015-2016. The genetic materials used in this experiment were 52 hybrids from 10 male and 27 female cucumber inberd lines which were examined in two separate experiments. These experiments were carried out as North Carolina Design I using randomized complete block design with three replications. The results showed that male parents 1, 2 and 13 had the highest values of vegetative traits in both experiments. Estimation of genetic parameters for vegetative traits also indicated low levels of additive variance and narrow-sense heritability. The highest total number of fruits in the first experiment was observed in male parent number 7. Regarding fruit yield related traits, male lines number 7 and 15 in the first experiment had higher fruit yield. The results of second experiment showed that the longer fruit production duration and higher number of fruit per node belonged to male parents 10 and 3, respectively. There was no significant differences for other fruit related traits. Estimation of genetic parameters showed that in many of traits associated with fruit such as fruit diameter, fruit firmness, fruit number and yield, the additive variance and narrow-sense heritability were high, therefore, it is possible to select successfully for these traits. In general, male inbred lines number 7, 13, 15, and 24 contributed to increasing of fruit-related traits and fruit yield in progenies.

Five CMS lines and four restorer lines (tester) were crossed in a line × tester designe in order to analyze general and specific combining abilities and gene effects in sunflower for some agronomic traits. Hybrids were evaluated in a randomized complete block design, with three replications under optimum and limited water conditions in the Agriculture Research Station, Khoy, during 2014 and 2015 growing seasons. Plant height, head diameter, seeds per head, days to beginning of flowering, days to maturity, proline percent, protein percent, and Chlorophyll b were found to be controlled mainly by dominance effects. CMS lines AGK30 and testers RGHK25 and RGHK50 turned out to be the best general combiners for seed and oil yield. The highest positive and significant GCA for plant height, head diameter, and the number of seeds per head were achieved for RGHK25. The hybrid combination of AGK44 × RGHK56 showed high specific combining ability for seed and oil yield. At grain yield AGK30 line had the highest positive and significant GCA and AGK2 had the highest negative and significant GCA it trait. At evaluation of tester, RGHK50 tester had the highest positive and significant GCA and RGHK56 had the highest negative and significant GCA it trait. At evaluation of specific combining ability RGHK56×AGK44 hybrid had the highest positive and significant SCA and RGHK25× AGK110 hybrid had the highest negative and significant GCA it trait.

Satureja rechingeri, belonging to the family Lamiaceae, has been recently used in the pharmaceutical industry due to its high level of carvacrol in the essential oil. The domestication and breeding of suitable S. rechingeri variety has been started since few years ago in Iran. The initial screening of natural populations, grown in the same environment, was performed and 58 talent clones were selected. In the present study, half-sib (HS) progenies of the 58 parent clones were obtained by polycross and were evaluated in a randomized complete block design (RCBD) with six replications. Different production biological traits as plant height, main branches number, lateral branches number, leaf width and length, fresh and dry weight, dry weight of leaves and flowers and essential oil content and yield were evaluated at full flowering stage. Narrow sense heritability values based on measurement at the individual plant level (H1) and based on plot mean (H2), additive variance and general combining ability were calculated for each trait. Highest narrow sense heritability was observed for plant diameter, plant height and main branches number while lowest value was obtained for the number of lateral branches. Additive variance was significant for main branch number, fresh weight, and dry weight, weight of leaves and flowers and plant height. By selection of 20 percent of the half-sib families, based on general combining ability for essential oil yield, families of F27, Z12, Z37, F14, E59, E37, Z26, Z28, K56 and G27 clones can be selected as parents of a synthetic variety.

In order to investigate the combining ability of sunflowers lines under normal conditions and drought stress، a study was conducted at the Seed and Plant Improvement Institute، Karaj، Iran in 2006. A total of 41 treatments including 2 CMS and 13 restorer lines as well as their 26 corresponding hybrids were evaluated in two irrigation conditions، in a line x tester approach. The analysis of variance indicated that significant differences existed among genotypes، parents، parents against crosses، crosses and testers for most of the studied traits. The effects of lines were significant for days to maturity، plant height and grain yield in non-stress conditions، and for most of the traits in stress condition s. The effect of line × testers was significant for seed weight in non-stress condition، and for days to flowering، seed yield، plant height and oil yield in stress condition. Assessment of general and specific combining abilities showed that CMS19 (tester) and CMSb × R7 were best line and hybrid in both conditions، respectively.

Determining general and specific combining ability of lines is necessary to use them as parents of hybrid varieties. In addition, estimates of the heritability of characters helps in selecting suitable breeding methods and predicting genetic gains of the traits. To determine general and specific combining abilities and gene effects of agronomic characters, five CMS lines and four restorer lines (tester) were crossed in a line × tester scheme. Hybrids were evaluated using a randomized complete block design with three replications. The results showed that CMS lines 52, 330, 344 and testers R25 and R50 had high general combiners for seed and oil yield. Hybrids R25 × 222 and ­R23 × 52 also showed high specific combining ability for seed and oil yield. For head dry weight, seed weight per head, seed yield with hull, seed yield, oil percentage and oil yield, non-additive genetic effects were important. Plant height and seed number per head were controlled by both additive and dominance effects.

Partial diallel design can be used to investigate the general and specific combining ability, and heterosis. Combining ability and heterosis were studied in a 6×6 partial diallel cross to see the nature of gene action for fruit quality indices in cucumber (Cucumis sativus L.) during 2007 to 2009. Analysis of variance revealed highly significant differences among all the F1 hybrid means and their respective six parental values for all the traits examined. The mean squares of general combining ability (GCA) and specific combining ability (SCA) were also highly significant. SCA genetic variances were greater than GCA and more important for the seedcell size, showing the additive and non-additive gene action. Fruit color was controlled by additive type of gene action due to high GCA variances. Fruit shape and overall performance were controlled additively and non-additively due to high general combining ability. Line 605 and 118 were found to be the best general combiner and its utilization produced valuable hybrids with desirable SCA F1 hybrids.

A study was conducted to investigate the genetic variance components and the combinig ability of sunflowers lines at the Seed and Plant Improvement Institute, Karaj, IRAN in 2006. A total of 41 genotypes including 2 CMS, 13 restorer and their 26 corresponding hybrids were evaluated in a line × tester approach. The analysis of variance indicated that significant differences existed among genotypes for all of the studied traits except the days from sowing to emergence. The significance of the parents vs crosses variance indicated the presence of heterosis for days to maturity, diameter of head, grain yield and oil yield. The effect of parents was significant for most of the traits except for number of leaves, grain and oil yield. The effect of lines was significant for days to 5%, 50% and 75% flowering, days to maturity, number of leaves, length and width of leaf, plant height and grain yield. The testers effect was significant for plant height, grain yield, 1000 ‎grain weight and oil content. The effect of line × testers was significant only for 1000 ‎grain weight and days to 5% flowering. Based on general and specific combining abilities, CMS19 (tester) and CMSB × R7 were the best line and hybrid, respectively. The additive genetic effect was important in controling grain yield while dominance gene effect was important in controling 1000 grain weight and oil yield.

Combining ability and heterosis were studied in a 6×6 partial diallel cross during 2007-2009 to see the nature of gene action in cucumber (Cucumis sativus L.). Analysis of variance revealed high significant differences among all the F1 hybrid means and among their respective six parental values for all the traits examined. The mean squares attributed to General Combining Ability (GCA) and Specific Combining Ability (SCA) were also highly significant. SCA genetic variances were greater than those of GCA and more important for the traits of Marketable Yield as well as Simple Weight Index, showing the dominance of non-additive gene action. Early yield and nonmarketable yield were controlled by additive and non-additive type of gene action due to high GCA variances. Line 504 with its bearing of high general and specific combining ability is finally found desirable regarding cucumber hybrid seed production and therefore is recommended.