جستجوی مقالات مرتبط با کلیدواژه « heritability » در نشریات گروه « زراعت »

The reduction of genetic diversity in tomatoes (Solanum lycopersicum L.), caused by domestication and breeding, has necessitated the use of all available genetic resources. Limiting cultivated tomato cultivars to modified cultivars and reducing genetic diversity are not desirable and cause production vulnerability and instability. Native populations can be used as genetic resources to improve and introduce superior crop varieties. Local populations are one of the most important genetic resources that are often non-uniform and consist of different and mostly pure genotypes. Breeding tomatoes means transferring desirable traits from parents to progeny and causing the variety and quality of tomatoes. Considering the great variety of tomato cultivars found in Iran, they can be used to select high-quality cultivars and produce desirable hybrids. This research aimed to select accessions for purposeful crossings to investigate the heritability of fruit traits, and the amount of heterosis in the F1, and to select progeny with small fruit and non-determinate growth.

In this research, seeds were collected from nine identified local accessions of native cherry tomatoes in Iran, including Kafshgiri from Gorgan, 2) Darklate, 3) Kurdistan, 4) Varamin, 5) Rasht, 6) Gorgan, 7) Rafsanjan, 8) Sari, and 9) Kermanshah. These accessions were subjected to 17 crosses, and the results of their first generations were analyzed afterward. After collecting pollen from the male parent and removing the stamens of the female parent flowers, the pollen was placed on the stigma of the female in the early morning before opening the flowers. In each mass, 6-10 plants were selected for crossing. In one cluster, 2-4 flowers were considered for crossing. Crossing was repeated in the case of no successful pollination and no fruit formation. After crossing and to control and prevent unwanted crossing by insects, the bushes were completely enclosed with a thin net (mosquito net). The formed fruits were harvested 30-40 days after mating. The fruits obtained in the laboratory were evaluated in terms of fruit volume, fruit weight, fruit length, fruit diameter, number of seeds in the fruit, Brix, acidity, and vitamin C. The experiment was based on a randomized complete block design with 17 treatments (17 crossings) in three replications. One-way analysis of variance (ANOVA) for the measured traits was performed using SAS software version 9.1. Other calculated parameters were variance components, general heritability, phenotypic, genotypic, environmental diversity coefficients, and the degree of trait heterosis.

The results of ANOVA for different fruit traits showed a significant difference between the studied crosses in terms of fruit volume, fruit length, fruit weight, fruit diameter, number of fruit seeds, Brix, acidity, and vitamin C at the probability level of 1%. The comparison of the average traits showed that fruit weight, fruit diameter, and fruit length traits were the highest in the progeny of the Kermanshah × Rasht cross with values of 28.16 g, 3.29 mm, and 2.71 mm, respectively. The highest fruit volume (18.8 ml) was recorded in the offspring of the Sari × Rasht cross. The highest number of seeds per fruit was counted at 141 and 140, respectively, in the cross between Gorgan × Varamin and Shoghgiri × Kurdistan. The highest Brix (8.67%) belonged to the crossbreed of Rafsanjan × Kurdistan, the highest acidity (11.03 mg/100 ml of water) to the crossbreed of Rafsanjan × Rasht, and the highest vitamin C (1.6 mg per 100 ml of water) to the progeny of Kafshgiri × Rafsanjan.  In the fruit size, fruit weight, number of fruit seeds, Brix, acidity, and vitamin C traits, the genetic variation coefficient was higher than the phenotypic variation coefficient, indicating the lesser effect of environmental factors on these traits. In fruit length and diameter, the phenotypic diversity coefficient was higher than the genetic diversity coefficient. The estimated heritability (h2) of traits revealed that fruit volume, fruit weight, acidity, and vitamin C traits had general h2 from 80 to 99%. The Brix value showed the lowest general h2 of 59%. The results showed positive heterosis in fruit diameter and volume. Negative heterosis was observed in fruit length, fruit weight, and number of seeds. All crosses showed positive and high heterosis regarding fruit size, and the highest fruit size heterosis with 10.71 was obtained in the progeny of the Kurdistan × Kafshgiri cross. The superior cross in terms of fruit diameter was identified in the Kermanshah × Rasht cross, with a heterosis of 7.53.

The obtained results showed that the highest level of general h2 and genetic progress were found for the vitamin C, fruit acidity, fruit weight, and fruit volume traits, respectively, which were found in the crossings of Kafshgiri × Rafsanjan, Rafsanjan × Rasht, and Kermanshah × Rasht. In terms of fruit size, fruit weight, number of fruit seeds, soluble solids, acidity, and vitamin C, the genetic variation coefficient was higher than the phenotypic variation coefficient, indicating less influence of environmental factors on these traits. In other words, high heritability, genetic progress, and genetic diversity for quantitative and qualitative traits can help breeders choose the best combination and reach an optimal level of performance potential.

Lentil (Lens Culinaris Medik.) belongs to cool season pulses. It is annual, self pollinated and diploid crop and its seed is rich in protein. Lentil, such as other legumes that are in symbiosis with nitrogen-fixing bacteria plays an important role in reducing fertilizer consumption and increasing the productivity of other crops that are in rotation with lentil. Success in breeding programs depends on genetic diversity, heritability and selection. Investigating the genetic diversity is the basis of breeding and releasing high-yielding cultivars with high quantitative and qualitative characteristics and capacities. Therefore, the evaluation of genetic diversity in crops is essential for breeding programs and the protection of genetic resources. For this purpose, it is necessary to collect plant germplasm to be evaluated as a base population, and genotypes with yield potential and other desirable traits are identified and exploited. Due to the low yield potential of the exsistance cultivars, investigating the genetic diversity among native lentil lines and comparing them with control cultivars could assiste the breeder in selecting superior lines in terms of yield potential and agromorphological triats.

To select and introduce new cultivars, native lentil lines collected from the target areas in Zanjan province were evaluated in the two cropping years of 2017-2018 and 2018-2019 in the experimental farm of Zanjan University's Faculty of Agriculture. In both years of the experiment, improved cultivars such as Kimia, Sabz Koohin, Gachsaran, Maragheh and Bilehsavar were used as control cultivars. The first year, the experiment was conducted in the augmented design based on randomized complete bloke design with 200 lines. Each experimental unit consisted of one metere row. The distance between the rows was 25 cm, the distance on the rows was 5 cm, and the planting depth was 5 cm. At the beginning and end of each block, two rows of Sabz Koohin were planted as borders. The second year, Due to echeaving enough seeds from the first year, the experiment was carried out in square lattice design with tow replications and larger experimental units for the selected lines from the first year. Each experimental unit consisted of two one-meter rows. The distance between the rows, the distance on the rows and the planting depth were similar to the first year experiment. At the beginning and end of each incomplete blocks, two rows of Sabz Koohin were planted as borders.

In the first year, the results of analysis of variance</strong> showed that there is significant difference among lentil lines in terms of canopy temperature difference, podding period, number of seed per plant, seed yield per plant, harvest index per plant, number of seed per area, seed yield per area and 1000-seed weight at 0.01and 0.05 level. in this year, canopy temperature difference, podding period, first branch height, number of pod per plant, number of vacant pod per plant, number of seed per plant, seed yield per plant, harvest index per plant, number of seed per area, seed yield per area and 1000-seed weight had high value of genetic variation coefficient, heritability and genetic advance. lines 14, 68 and 165 were the superior lines in terms of phonological traits. The height of the plant and the height of the first pod in lines 85, 92, 193 and 195 were higher than other lines. Lines 32, 90 and 156 had the highest number of full pods. Lines 122, 163, 165 and 200 had the highest seed yield per plant. The 1000- seed weight in lines 163, 166, 171 and 174 was higher in compared with other lines. The highest seed yield was observed in lines 23, 150, 192 and 200. Finaly, based on the results of comparison of mean with superior control cultivar for each trait by LSD method and considering the degree of importance of traits, the 95 superior lentil lines from 200 examined lines were selected. In the second year, the results of analysis of variance</strong> indicated a significant variation among lentil lines in terms of all studied traits except for the first branch height at 0.01 and 0.05 levels. The canopy temperature difference, number of vacant pods per plant and number of seed per plant had high value of genetic variation coefficient. High heritability was observed in the days to 50% flowering, flowering period, days to 50% podding, days to 50% physiological maturity, seed filling period and straw yield per plant. The canopy temperature difference, flowering period, first pod height, number of vacant pod per plant, seed yield per plant, biomass per plant and straw yield per plant had high genetic advance. lines 150, 155, 173 and 176 were the superior lines in terms of phonological traits. The highest plant height and the highest height of the first pod was observed in lines 146 and 180 and lines 12, 47 and 130 respectively. Lines 1, 131 and 176 had the highest number of full pods. In terms of yield and yield components per plant, lines 1, 131 and 176 had the highest number of seeds and seed yield. The 1000- seed weight in lines 23, 52, 163 and 178 was higher in compared with other lines. In terms of yield and yield components, lines 55, 69, 86, and 176 were recognized as the superior lines. Finally, based on the results of comparison of mean lines with superior control cultivar for each trait by LSD method and considering the degree of importance of traits, the 44 superior lentil lines from 100 examined lines were selected.  <span style="font-family:"Times New Roman",serif">

The evaluated lines were significantly different from each other in terms of most traits. High heritability was observed in the days to 50% flowering, flowering period, days to 50% podding, days to 50% physiological maturatry, seed filling period and straw yield per plant. Comparing to the control cultivars, the evaluated lines had a higher mean in most of the studied traits. Therefor by selecting superior lines in terms of yield potential and agromorphological traits this genetic potential can be used to create superior population and introduce high yield cultivars. 

Lentils are one of the most important legumes, which have a high amount of protein and vitamins A and B, fiber, potassium and iron, and are an inexpensive food for low-income people. The objective of this study was the determination of variability, heritability, correlations between yield and yield components in 14 Lentil (Lens culinaris L.) genotypes using a randomized complete block design with three replications. The results showed that secondary stem per plant and productivity degree had the highest GCV and PCV but the lowest GCV and PVC was found for a number of pod/ m2 and number of the plant. Maximum heritability was estimated for 100-seed weight, number two-seed pod, biological yield, grain yield, productivity degree and plant height respectively. The high genetic advance and heritability were observed for the number of the two-seed pod and biological yield. The phenotypic correlation revealed that rainwater productivity, biological yield and plant height had the greatest, positive and significant association with seed yield. By performing path analysis based on stepwise regression, rainwater productivity had the most direct effect on seed yield, while the number of secondary stems per plant through rainwater productivity had the most indirect and negative effect on seed yield. That means with increasing number of the secondary stem, rainwater productivity is decreased which results in reduced grain yield. As a result, it was concluded that rainwater productivity and biological yield can be good selection criteria for improving seed yield per plant in Lens culinaris.

In order to investigate phenotypic and genotypic correlations between Characteristics affecting the germination stage and genetic variation and estimating the genetic parameters of these indices in Drought and normal conditions, 19 genotypes of bread wheat were cultivated inCompletely randomized design with three replications in the Laboratories, Department of Agronomy and Plant Breeding of Agricultural Research Campus Natural Resources of Razi University of Kermanshah, Iran In the germination stage was evaluated. The results of variance analysis (ANOVA) showed significant differences for the Germination Percentage (GP), coleoptile Length (KL), Mean Germination Time (MGT), Cofficent of Velocity of Germination (CVG), Average Velocity of Germination (AVG) and Vigor index (SV) under stress and normal condition indicating. The presence of a considerable genotypic variation and possibility of selection of drought tolerant genotypes. The presence of a considerable genotypic variation and possibility of selection of drought tolerant genotypes. According to the biplot obtained in the laboratory conditions (germination test) genotype (16) was located in group A. A high positive genetic and phenotypic relation was observed between GP, AVG, SV and RL, which is completely in line with results of the relation between traits by GTbiplot. High heritability and genetic gain were observed for GP, AVG and SV that reflect the additive gene action. Accordingly, the selection method for studied traits in examined genotypes effective. Cluster analysis using Ward method, based on the traits, classified the genotypes in three different groups.

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.

Rice is one of the oldest and most important cereals in the world and is a desirable model plant for genetic and molecular studies. Drought is one of the important risks for the successful production of crops, especially rice, in the world, which can be created at any time during the growing season. One of the main challenges in agriculture is to produce more food with less water consumption, and therefore, the production of rice genotypes that can have more tolerance to drought stress is one of the main goals of breeding projects.

In order to evaluate the effect of drought stress (zero (control), -3 and -5 bar using Polyethylene Glycol) on some genetic, morphological, and biochemical characteristics of rice at the germination stage, 38 lines with their parents (MousaTarom and 304) were investigated in randomized complete block design with three replications during 2022.

Morphological traits were decreased under -5 bar drought stress compared to the control. The germination rate and percentage were increased by 9.6 and 1.1% under -3 bar stress, and 37.8 and 33% under -5 bar stress, respectively. The rootlet length, rootlet fresh weight, and dry weight increased under - bar stress compared to the control, indicating that the rice plant can tolerate such a stress intensity, and it may even be used as a priming. Catalase, peroxidase and superoxide dismutase enzyme activities increased by 59, 51 and 81%, respectively, by increasing the stress to -5 bar compared to the control. This increase shows the increase of the plant's resistance to the active oxygen and drought tolerance. The highest phenotypic correlation in non-stressed conditions was between seedling weight and length vigor (0.92), under -3 bar stress was detected between shootlet length and fresh weight (0.91), and under -5 bar stress the highest one was between seed germination percentage and rate (0.94). The factor analysis for each of the zero, -3 and -5 bar drought stress levels introduced three factors that explained 73.68, 81.13 and 81.73 percent of the variance, respectively.

The high diversity of traits at the -5 bar drought stress indicates that it is possible to use germination rate and percentage, length and weight indices, and shootlet length and fresh weight as criteria for genotype selection under -5 bar drought stress. Such traits could be used as effective ones in the selection of tolerant rice genotypes at the germination stage and in order to establish the rice plant optimally.

In crop breeding programs, comprehensive information is needed regarding the genetic structure of plant materials and their combinability. In this regard, the present study was carried out with the objectives of evaluating the general combining ability of parents and the specific combining ability of crosses, determining the nature and extent of gene action, and finally estimating the heritability of quantitative and qualitative traits of sugar beet hybrids by the analysis of line-tester crosses.

The study was conducted as a line-tester crossing using nine lines and two testers of sugar beet. For this purpose, maternal lines were planted in the middle lines and pollinator lines were cultivated in two lateral lines and all the crossings were done by observing the points related to isolation. A number of 18 hybrids obtained from the line-tester cross were cultivated and investigated in the agricultural research station of Shiraz in randomized complete block design with four replications during the crop season of 2019-2020.

The results of analysis of variance of root yield, sugar yield, white sugar yield, sugar content, white sugar content, sodium, potassium, harmful nitrogen, alkalinity coefficient, extraction coefficient of sugar and molasses sugar percentage showed that among studied hybrids, there is a significant difference at the 1% probability level in terms of all the traits except the two traits of sugar content and white sugar content. Line-tester analysis confirmed that the additive and non-additive effects of genes are involved in the expression and inheritance of root yield and sugar yield; However, in the genetic control of white sugar yield, sugar content, white sugar content, sodium, potassium, nitrogen, alkalinity coefficient, extraction coefficient of sugar and molasses sugar percentage, genes with non-additive effect have not played a role, and according to the significance of the general combining ability effect of the line or tester for the mentioned traits, only genes with additive effect are involved in the control. In total, from the used lines in the present study, 950123 and from the experimental testers, F-21121 had positive effects with regard to the improvement goals of sugar beet. S1-24 and F-21122 were associated with negative effects and caused a decrease in the breeding value of the traits.

Overall, obtained results showed the existence of diversity among hybrids derived from crossing between lines and testers. Based on the results, genes with both additive and non-additive effects are involved in the control of root yield and sugar yield, but in the inheritance of sugar yield, sodium, potassium, harmful nitrogen, alkalinity coefficient, extraction coefficient of sugar, and molasses sugar percentage, only genes with additive effect are involved. Considering that general combinability shows the additive effects of genes, so parents with high general combining ability also have a large additive effect that can be used in cultivar production.

Selection efficiency requires complete and accurate knowledge of genetic parameters such as heritability, phenotypic and genotypic variation coefficient, environmental variance, selection response, genetic gain, genetic and phenotypic variance, genetic and phenotypic correlation between traits that the breeder consciously chooses the appropriate selection method in breeding populations. In this study, some genetic parameters for yield and soybean agronomic and reproductive period characteristics under normal and stress conditions were estimated and drought tolerant genotypes are determined by the Ideal Genotype Selection Index (SIIG).

In 2013, in an experimental farm in Karaj, 50 soybean genotypes were cultivated in two normal and drought stress conditions in a randomized complete block design with three replications. Irrigation cycle was determined based on the amount of evaporation from the surface of Class A pan. During the growth period, the reproductive period characteristics and after the ripening agronomic traits were evaluated. After collecting experimental data, analysis of variance, mean, minimum, maximum values of traits, heritability, phenotypic and genotypic variation coefficient, environmental variance, selection response, genetic gain, genetic and phenotypic variance, genetic and phenotypic correlation, and SIIG index method was used for grouping genotypes based on drought tolerance.

Among the the reproductive period characteristics the highest and lowest genetic gain in normal conditions were 21.40 and 3.95% for day to the beginning of seed filling and the Reproductive relative duration respectively and in stress conditions were 21.9 and 7.3% for day to the beginning of seed filling and the Reproductive relative duration respectively.In normal conditions, the highest genetic gain was 0.52 for the number of pods per plant and the number of branches and the lowest genetic genetic gain was 0.14 for the number of nodes per stem. In stress conditions, the highest and lowest genetic gain were 104% and 0.14 for the number of pods per plant and the number of nodes per stem, respectively. In normal conditions, among the agronomic traits, the highest values of response to indirect selection of grain yield were 1.6 and 1.41 g, through 100-grain weight and number of seeds per plant respectively and in stress conditions, the highest values of response to indirect selection of grain yield were 1.04, 0.89 and 0.87, through The number of branches, number of seeds per plant and weight of 100 seeds were obtained respectively. Also, according to the Ideal Genotype Selection Index (SIIG), five genotypes were in the tolerant group, seven genotypes in the semi-tolerant group, 11 genotypes in the semi-susceptible group and 27 genotypes in the susceptible group. Roanak, Kabalovskaja and TMS genotypes were identified as the most drought tolerant and AGS 363, Hermen and Kuban as the most drought sensitive genotypes.

Based on the results, acceptable phenotypic and genotypic diversity in terms of agronomic traits was observed among the studied genotypes. Most of the genetic parameters measured were almost identical under both normal and stress conditions. The characteristics of the reproductive period had higher e selection response (direct and indirect), higher broadsense heretability and higher genetic gain than the agronomic characteristics. The highest indirect to direct selection efficiency for grain yield were obtained from number of seeds per plant and 100-seed weight under normal conditions,and The highest indirect to direct selection efficiencies were obtained from number of sub-branches, number of seeds per plant and 100-seed weight in stress conditions. Also in this study, based on the ideal genotype selection index (SIIG), Roanak, Kabalovskaja and TMS genotypes were identified as the most tolerant and AGS 363, Hermen and Kuban as the most sensitive genotypes.

Wheat performance is always affected by climate change and environmental stresses such as drought stress. Development of high-yielding cultivars requires genetic diversity. Awareness about heritability of traits can be helpful in determining the appropriate breeding strategy for any environmental conditions. By progeny trial after a diallel crossing, the function of genes and inheritance of quantitative traits can be estimated. This increases the ability to select parental lines, to participate in crosses, and determines the management of generations in the segregating populations.

In order to understand the genetic structure of grain yield and some morphological traits of bread wheat under normal and drought stress conditions, eight bread wheat cultivars including Star; Tirgan; Ehsan; Shirodi; Bam; Tajan, Yang and Akbari were planted in the crossing block and direct crosses were performed among the eight cultivars to produce F1 generation. This research carries out in Gorgan agricultural research station in 2020-2021 cropping season, under normal and drought stress conditions. The progenies of the crosses with their parents were evaluated based on a randomized complete block design (RCBD) with three replications. Imposing stress by terminating irrigation was initiated at the Zadoks 60 (full heading emergence) stage.

Combined analysis of variance under normal and drought stress conditions showed that the simple effects of genotype and environment were statistically significant in all traits. Also, the interaction effects of genotype×environment was statistically significant for grain yield, biological yield and 100-kernel weight. In fact, for these traits the response of genotypes was different under normal and stress conditions. Analysis of variance of Griffing's diallel method showed a statistically significant difference between genotypes in all studied traits. Therefore, among the progenies of the crosses it is possible to select superior genotypes. In biological yield and grain yield under both normal and drought stress conditions, Tirgan cultivar had the highest general combining ability, while Star cultivar showed the lowest general combining ability. Tirgan cultivar can be used to increase grain yield and biological yield under both conditions. In plant height, peduncle length and harvest index, Tajan×Yang, Ehsan×Shirodi and Bam×Yang crosses had the maximum specific combining ability, respectively. In other traits, in each condition, an individual cross had the highest specific combining ability. Under normal conditions, Tajan×Akbari cross had the highest specific combining ability in grain yield. Under drought stress conditions, Bam×Akbari cross had the highest specific combining ability in biological yield and grain yield, it simultaneously had a high specific combinability in 100-grain weight, harvest index and number of grains per spike. Therefore, Bam×Akbari cross was determined as the best cross in genetic improvement of desirable agronomic traits with high specific combining ability in yield and yield components, under drought stress conditions. The ratio of additive variance from genetic variance for plant height and peduncle length was greater than dominance variance. Subsequently, the highest narrow-sense heritability in both normal and drought stress conditions was related to plant height and peduncle length. In both normal and drought stress conditions, the highest degree of dominance was related to harvest index traits and number of grains per spike, respectively. Therefore, in these traits the lowest narrow-sense heritability, the lowest Baker's genetic ratio and the highest ratio of dominance variance from genetic variance were observed in both normal and drought stress conditions. In grain yield, a high ratio of dominance variance from genetic variance was assigned under normal (84%) and drought stress (88%) conditions, hence low narrow-sense heritability was observed under normal (8%) and drought stress (5%) conditions. In general, in grain yield, biological yield and 100-kernel weight, narrow-sense heritability was lower under drought stress conditions, compared to normal conditions, which indicates a greater ratio of non-additive effects under drought stress conditions.

The results of this study showed that under both conditions, Tirgan cultivar had the highest general combining ability in grain yield and biological yield. Tajan×Akbari and Bam×Akbari crosses were determined as the best cross in genetic improvement of desirable agronomic traits with high specific combining ability in yield and yield components, under normal and drought stress conditions, respectively. In grain yield, biological yield and 100-kernel weight, narrow-sense heritability was lower under drought stress conditions, compared to normal conditions. Based our results under both conditions in the progenies of the crosses, genetic improvement can be done in plant height and peduncle length in the initial generations, but for other traits including grain yield and its components, selection should be postponed to more advanced generations.

In Iran, as in most poor and developing countries, wheat is the most important food in the diet of the people. Therefore, the field of study and research on various aspects of this important and strategic crop is still open to relevant researchers and experts. Given that the achievement of yield potential in crops, including wheat, is influenced by genetics, environmental conditions, their interaction and the application of proper management in the optimal use of available resources, so the genetic capacity of the existing germplasm should be used to produce suitable breeding lines in order to make the most of natural and climatic resources. Therefore, screening genotypes, selecting the proper parents, and modifying them through conventional and new methods can still be helpful. Estimating genetic effects and studying the inheritance pattern of important agronomic traits and in general knowledge of germplasm genetic information and knowledge of the genetic system of the studied trait is one of the most useful tools in designing breeding methods to improve target traits. This study aimed to estimate the genetic model controlling important agronomic traits and also to estimate heterosis and heritability in two bread wheat cross under normal and terminal drought stress conditions using generation mean analysis method and multivariate regression analysis.

A field investigation materials consisted of basic generations obtained from the crosses of a local cultivar “Marvdasht” (female parent) with two cultivars “Sistan” and “Norstar” (male parents). Both the crosses and resultant progenies were performed and developed under field conditions. All the six generations derived from the above two crosses were sown under two distinct conditions, normal (non-stress) and terminal drought stress in a randomized complete blocks design with three replicates at the Research Farm of Razi University, Kermanshah, Iran during the next cropping season (2015-2016). Terminal drought stress was imposed in Mid-May; while non-stress plots were irrigated whenever required. Weeds were controlled manually when necessary. The rainfall in 2015-2016 was 653 mm. Data from 10 plants in each of P1, P2 and F1 generations, 30 plants in F2 and 15 plants in each of BC1 and BC2 were randomly recorded per replication. Statistical analyses were done using different methods and software.

Significant differences between the generations were found for most of the traits which indicated the presence of genetic variation in the plant populations and scope of improvement through breeding methods such as selection and expression of heterosis. The scaling and joint scaling tests revealed that the simple additive-dominance model was not sufficient to explain the genetic variation in the crosses for all the studied traits apart from the number of spike per plant, main stem diameter and number of spikelet per spike at Marvdasht × Sistan, and hundred kernel weight and peduncle length at Marvdasht × Norstar. It could be concluded that the inheritance of these traits is governed by epistasis gene action. The results of analysis of variance obtained by regression method showed that fixable genetic effects had the highest relative contribution of the generation sum of squares for most of the traits in both crosses and under both normal and drought stress conditions. High estimates of broad-sense heritability for hundred kernel weight (0.67) in normal conditions at Marvdasht × Sistan cross and plant height (normal: 0.76 and stress: 0.67) and peduncle length (normal: 0.72 and stress: 0.67) at the Marvdasht × Norstar cross shows that the effects of dominance have a greater role in the inheritance pattern of these traits and therefore it is possible to produce hybrid varieties to improve these traits.

The results of generation mean analysis showed that the type and action of genetic effects were variable in both crosses and for different traits and indicate the need to adopt a special breeding method to improve them. The presence of duplicate mode of gene interactions signified the involvement of epistatic effects for most of the traits. Based on the present investigation, it could be inferred that the genetic control model was somewhat similar for most of the traits under both conditions at both crosses, and it has not been largely affected by drought stress.

Alfalfa (Medicago sativa L.), as the "queen of forage plants", is the most important fodder plant all over the world, including Iran. One of the common methods in alfalfa breeding is the improvement of synthetic verities. Numerous research activities for breeding and cultivation of alfalfa have been done in Iran, but so far only two improved populations have been introduced. This research was done to introduce the first synthetic variety of alfalfa using alfalfa-rich germplasm.

For evaluation of the general combining ability of Azarbaijan alfalfa ecotypes with polycross test and selection of synthetic variety parents, 30 native ecotypes were collected from the Azarbaijan region, and polycross nurseries were conducted in East Azarbaijan Agricultural and Natural Resources Research and Education Center, AREEO, Tabriz, Iran. The 30 half-sib families resulting from polycross nurseries were planted individually in pots and 30- day old seedlings were transplanted to the field and various traits were measured for 3 years. Based on 30 half-sib family's evaluation, 11 ecotypes were selected as parents for synthetic variety. The selected superior ecotypes were polycrossed under controlled conditions and the synthetic variety was produced. The synthetic cultivar was evaluated in several projects and several locations over several years along with parental ecotypes and control cultivars.

Statistical analyses showed significant differences among alfalfa half-sib families and it is possible to select parents. The narrow sense heritability values of fresh and dry forage yield, plant height, and ratios of the fresh and dry weight of leaves to the fresh and dry weight of stem were estimated as 51%, 50%, 46%, 11%, and 19% respectively. According to the ability of the general combination of ecotypes and especially based on fresh and dry forage yield, the top eleven ecotypes were selected for synthetic seed production. Considering 30% selection intensity, the expected genetic gain response for fresh and dry forage yield was calculated as 3.2 and 1.58 tons, respectively, which was expected to be 18% and 17.5% for fresh and dry forage yield, respectively. The ratios of fresh and dry weight of leaves to fresh and dry weight of stem showed low narrow sense heritability, so the expected genetic gain responses for them were very low.

Based on the results of several studies, the average yield of fresh and dry forage yield of the synthetic variety was 38609 and 10231 (Kg/ha), respectively. The superiority of this variety for fresh and dry forage yield in comparison with control cultivar was about 22%. The results of several research projects showed that the improved modified synthetic variety has the necessary superiority to be introduced as a new agricultural variety to the farmers for widespread cultivation and introduced and it was introduced as the first synthetic variety named Nafis.

Coriander is one of the important medicinal plants in the world which has been used widely in medicinal, cosmetic and health care industries.

In order to investigate the genetic diversity of this plant in Iran, 20 Coriander populations were collected from different parts of the country and evaluated out using randomized complete block design with three replications in Karaj Vegetable Research Center of Horticultural Sciences Research Institute in 2018-2019 and 2019-2020 crop years. During the growth period, the phenological, morphological and physiological characteristics were recorded. Days to generation, Largest basal leaf length, Basal leaf number, Days to full flowering, Days to Maturity, Plant height, Umbel number per plant, Fertile umbel number per plant, Unfertile umbel number per plant, Umbellate number per umbel, Seed number per umbel, thousand seed weight, Grain yeild per plant, Biomass per plant, Harvest index per plant, Grain yield, Biomass and Harvest index traits were investigated. Data were analyzed using SAS and SPSS software and for Grouping of the population, the cluster analysis was performed by Ward’s method and factor analysis was done using the Variomax rotation method.

According to the results of analysis of variance, there were significant differences between the studied populations in terms of most traits include the largest basal leaf length, basal leaf number, plant height, umbel number per plant, fertile umbel number per plant, unfertile umbel number per plant, umbellate number per umbel, grain number per umbel, 1000-seed weight, seed weight per plant, biomass per plant, harvest index per plant, grain yield, biomass and harvest index. Phenotypic and genotypic coefficients of variation were high for most of the traits which indicated the high diversity of these traits in the studied populations. The heritability in broad-sense of the traits largest basal leaf length, basal leaf number, plant height, umbel number per plant, fertile umbel number per plant, umbellate number per umbel, seed number per umbel, 1000-seed weight, seed weight per plant, biomass per plant, harvest index per plant, grain yield, biomass and harvest index were high, which makes the response to the selection of these traits expected in breeding programs. Cluster analysis classified 20 studied populations into five groups.

According to the results, the Kermanshah population had the highest grain yield in two years. The higher yield of this populaion was due to having the highest number of umbels per plant, number of fertile umbels, number of umbels per umbel and weight of 1000 seeds. Also, the traits of the length of the longest basal leaf, the number of basal leaves, the number of umbels per plant, the number of fertile umbels per plant, the number of umbels per umbel, the number of seeds per umbel, the weight of 1000 seeds, the yield of seeds per plant, the biomass of a single plant, the harvest index of a single plant, seed yield, biomass and harvest index had high heritability, which indicates the high role of genetic factors and the low influence of environmental factors on the control of these traits.

Crop yield products reduction due to abiotic stress is estimated at 51 to 82%. Most plants are exposed to environmental stresses, and water deficit is one of the most important non-abiotic stresses in limiting and producing crops around the world, especially in arid and semi-arid regions. Plants have developed various strategies to cope with water deficit stress, including morpho-physiological and biochemical.Wheat is one of the most important crops in the world, which in 2020 had the highest area under cultivation at the rate of 221.33 million hectares (with a total production of 766.03 million tons) worldwide. In the same year in Iran, the area under wheat cultivation was 6.70 million hectares and its production was 16.75 million tons.

The research was performed in research farm of Rainfed Agricultural Research Station Gachsaran, Iran, over 2020-2021 cropping years. In this study, 100 lines obtained from the landrace bread wheat of different origins from several continents and several countries were studied. The experiment was performed in a simple lattice design 10×10 with two replications and separately in two environmental conditions of stress and non-stress. The operation planting is done in January after conventional tillage implementation of the area by hand. The source of moisture supply for both rain fed (water deficit stress) and irrigation (no stress) test conditions was rainfall and sprinkler irrigation before the phonological stage of flowering (pollination (Zadocs scale 61)). Irrigation interruption was applied at the beginning of flowering in a stress environment (water deficit stress conditions) which continued until harvest, but the environment without stress in two times when wheat plants to early reproductive stage, flowering stages, and the beginning of grain filling (Grain paste stage (Zadocs scale 61-83)) Irrigation was performed. In this study, 16 morphological traits and grain yield were measured under both stress and non-stress conditions, including flag leaf length and width (cm), flag leaf pod length (cm), and flag leaf area (cm2), number of nodes and leaves per stem, internodes number, peduncle length (cm), plant height (cm), tiller number, fertile and infertile tillers of number, length of awn (cm), spike length (cm) and spike yield (g).

The results of the analysis of variance showed high and significant variability in both non-stress and deficit water stress. TRI 3492 was the most tolerant of geographical origin in Nepal and TRI 4549 had the lowest STI relative to deficit water stress of geographical origin in China. The highest and lowest heritability in stress conditions were related to plant height (98.02%) and the number of intermediate nodes (25.00%), respectively. The greatest decrease in heritability (66%) due to stress conditions was the leaf sheath length of the flag leaf. Among the traits studied in this study, flag leaf area with 31.41%, flag leaf length with 25.25% and grain yield with 23.53% had the highest percentage of stress reduction. The results of cluster analysis of the studied genotypes in both environmental conditions are in six separate and different groups so that the greatest difference in genetic distance and grain yield in both environmental conditions was observed between the first and sixth clusters.

Using the genotypes of first cluster (TRI 403, TRI 4013, TRI 3981, TRI 10340, TRI 5262, TRI 4549, TRI 2513, TRI 2656, TRI 3477, TRI 3242, TRI 3526, TRI 3513, TRI 4116 and TRI 4113) with 6TH cluster (TRI 10296, TRI657, TRI755, TRI752, TRI757, TRI 11020, TRI691, TRI 6129 and TRI754) Can be used in crossbreeding programs as well as genetic studies (such as recombinant populations and association mapping) and to increase the rate of heterosis used in water-deficit stress conditions.

Drought is one of the most important abiotic stresses limiting plant survival, growth, and production in many regions of the world. Approximately one-thirds of the world's agricultural lands are in arid and semi-arid regions, including Iran. Therefore, there is a need to improve plant cultivars with high adaptability and low water requirement. This study was conducted to evaluate the drought tolerance of Bromus inermis and Dactylis glomerata genotypes and investigate the relationship between seed yield and forage yield to select better genotypes in terms of these traits, simultaneously. In this study, 36 genotypes selected from polycross populations of both species were clonally propagated and evaluated under normal and drought-stressed conditions during 2014 and 2015 at the Research Farm of Isfahan University of Technology, Isfahan, Iran. In both species, high genetic variation was observed among genotypes for seed yield and its components indicating high potential for improving these traits through targeted selection in breeding programs. Drought stress negatively affected seed yield and its components and reduced the genetic diversity of most traits. Most of the studied traits had relatively high heritability; therefore, improvement of these traits is possible through recurrent selection in breeding programs. The significant association between seed and forage yield indicated that it is possible to select superior genotypes based on seed and forage yield in both normal and water stress conditions, simultaneously. However, the intensity of this association was higher in Dactylis glomerata than Bromus inermis. In both species and under both normal and drought stress conditions, better genotypes were identified in terms of seed and forage yield. These genotypes can be used in developing genetic populations for simultaneous improvement of seed and forage yield in future studies and also for the development of synthetic varieties in both species.

Wheat coleoptile protects the plumule and the first leaf so they can move from the embryo to the soil surface. Coleoptile is essential for plant establishment. Cultivars with longer coleoptiles and mesocotyls are sown deeper and are more successful under drought stress conditions. However, there is not much information about their genetics. The objective of the present study was to evaluate the coleoptile and mesocotyl of Iranian, overseas and the lines developed as a part of Shahid Bahonar University breeding program, and estimate of genetic parameters of these traits.
 

In this research, 30 bread wheat genotypes originated from Iran, CIMMYT, ICARDA, USA, and Australia and five lines from Shahid Bahonar University of Kerman breeding programs were sown at a 10 cm depth of soil in the research field of Shahid Bahonar University in a randomized complete block design with seven replications. Each plot consisted of three rows with two meters long and a 5 cm intra-row spacing. At harvest, the plants were gently removed from the soil, and after removing the soil from the root area, the roots were washed. In this study, coleoptile and mesocotyl length, number of seminal roots, root length, root and shoot dry weight were measured.

Coleoptile and mesocotyl are important traits for increasing drought tolerance in bread wheat. In the present research, mesocotyl length varied from 5.20 for Excalibur to 2.08 for Zagros, and showed a high heritability (0.48) and response to selection (11.61%). Furthermore, this trait had a positive significant correlation with coleoptile length (r=0.53**), root weight (r=0.38*) and shoot weight (r=0.36*). Seminal and nodal root number had the highest (0.59), while root length had the lowest (0.13) narrow-sense heritability. Overall, suitable cultivars for rain-fed conditions had higher coleoptile and mesocotyl than the others. Breeding lines in Shahid Bahonar University of Kerman suitable for rain-fed conditions had longer coleoptile and mesocotyl lengths. Root and shoot dry weight had a significant positive correlation (r=0.82**).

In general, breeding programs to increase grain yield differ under rain-fed and irrigated conditions. In wheat breeding programs under rain-fed conditions, special attention should be paid to coleoptile and mesocotyl traits. These traits were not influenced by the plant growth habit.

Mesocotyl of the Iranian cultivars was evaluated for the first time.
Breeding lines developed by Shahid Bahonar University of Kerman suitable for rain-fed had appropriate coleoptiles and mesocotyls.
Coleoptile and mesocotyl had a significant and positive correlation.

Barley (Hordeum vulgare) as one of the small grain cereals is widely cultivated in Iran and the world. Hence, the achievement of high-yielding and stable varieties is one of the main breeding proposed. The present study aimed to investigate a set of international genotypes of barley in terms of grain yield and some agronomic traits using the best linear unbiased predictor (BLUP) model under climatic conditions in Iran.

In this study, a set of genotypes including 24 international barley genotypes provided from ICARDA were investigated for grain yield and some agronomic traits including the number of days to heading, number of days to physiological maturity, grain filling period, plant high, spike length, and thousand grains weight in a randomized block design in the three research stations located at Karaj, Birjand, and Zabol during the 2020-2021 cropping season. After collecting and analyzing the experimental data, the best genotypes were identified based on BLUP model.

The results obtained from experimental data showed that the genotype and genotype-by-environment interaction effects were significant for grain yield and other measured traits (except days to heading and spike length). The highest values of genetic variance and heritability were estimated for spike length, 1000-grains weight, grain yield, and plant height. The results of the based-BLUP (best linear unbiased predictor) statistics revealed that genotypes G3, G6, G10, and G23 had the highest yield performance and stability compared with other genotypes across different environments. Taking into account the role of each measured trait on grain yield stability, genotypes G10, G16, G22, and G24 were identified as the best barley genotypes using the MTSI index. 

In conclusion, it can be stated that the MTSI index has high efficiency in breeding programs to use other traits related to grain yield to select stable and high-yield genotypes.

oilseed rape is one of the most important oilseed plants for supplying required oil and its products. To extent its cultivation area, the introduction of new cultivars with higher genetic diversity is necessary via breeding programs.

To establish of new genetic diversity and evaluation of genetic parameters, the 11 oilseed rape genotypes were crossed in full diallel method; consequently, different traits of parents and their F1 offspring were evaluated in a randomized complete block design replicated thrice.

Analysis of variance revealed that traits including days to flower initiation, physiological maturing, plant height, number of pods per plant, number of grain per pod, thousand-grain weight, and grain yield were significant. The genetic parameters analysis by Griffing's method I model II showed significant GCA, SCA, and REC effects of different traits which represent the evaluated traits were controlled by additive, non-additive, and cytoplasmic gene action effects. Analysis of combining ability represented that among parents, genotype SRL-97-1 had the highest GCA for physiological maturing, number of pod per plant, thousand-grain weight, and grain yield. Also, cross SRL-97-4×SRL-96-20 and SRL-97-15×SRL-97-3had the highest SCA and REC for grain yield, respectively. Besides, the broad sense heritability was higher in traits such as plant height, number of pod per plant and grain yield (H2=0.99); meanwhile, grain yield had a higher narrow sense heritability (h2=0.39).

Consequently, results showed that there was sufficient genetic diversity among evaluated genotypes in which the achieved diversity from the crossing of these genotypes could be applied in cultivar introduction. It is recommended that, genotypes with higher GCA and SCA are suitable for the foundation of a desirable population for selection of promising pure lines with higher yield attributes.