جستجوی مقالات مرتبط با کلیدواژه "پیشرفت ژنتیکی" در نشریات گروه "زراعت"

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. 

Oat, as a dual-purpose cereal, has an important role to provide human food and animal feed and fodder regarding to its high amounts of beta-glucan, protein, vitamins, minerals, fatty acids and valuable antioxidants. Oat breeding programs have been steadily decreasing compared to other cereals due to decrease in cultivated area. Therefore, identifying and studying sources of diversity in oats is critical and valuable regarding to release new cultivars with better quality and higher grain yield per unit area. Thus, this experiment was carried out with the aim of evaluating different genetic parameters and principal component analysis in order to determine the amount of genetic diversity in oat genotypes.

In this study, 361 oat genotypes of seven species belong to 50 countries from five continents which were received from Australian Grain Genebank (AGG) and kept in the genebank of the Campus of Agriculture and Natural Resources, Razi University were investigated. Estimation of the genetic parameters related to plant height, panicle length, days to 50% flowering, days to 50% physiological maturity, biological yield, grain yield, straw yield, harvest index, thousand seed weight, number of seeds per panicle and number of panicle per square meter of the genotypes were performed. This experiment was conducted in a simple square lattice design with two replications under normal irrigation condition, in two cropping years 2017-2019 in the research farm of the Agriculture and Natural Resources Campus, Razi University, Kermanshah.

Based on the results of the one-year variance analysis, there was a highly significant difference between genotypes regarding all the measured traits which indicates the presence of considerable genetic diversity between these genotypes. The results of mean comparison based on LSD method showed (NILE), (KENT), (LA PREVISION), (ZLATAK), SDO-185), OX87:080-2), (ACACIA), AND (DUNNART) genotypes had the highest grain yield for two years, while, Genotypes (LIGOWA), (NILE), (VENTURA), (YULAF), (NMO-712), (SDO-185), (VDO-931.1), (SLAVUGE), and (no.9278) had the highest mean for biomass in two cropping years. The results of the descriptive statistics showed the wide range of changes for the most of the investigated traits, as it was variable for grain yield from 56.30 to 789.81 g/m2 in the first year and from 39.59 to 627.28 g/m2 in the second year. Based on the results of correlation analysis, the most positive and significant phenotypic correlation was calculated between biological yield and straw yield in both years. The result of phenotypic and genotypic correlation also, showed a significant relationship between grain yield and all studied traits except plant height, panicle length, days to heading, and days to maturity in the first year. Also, it had a significant phenotypic correlation with all traits except plant height and straw yield in the second year. The traits of 1000- kernel weight, plant height, days to heading, and number of panicles per square meter had the highest genetic variance in both years. The range of general heritability in the first year was variable from 70.06 to 95.87%, respectively, for the traits of days to physiological maturity and 1000 seed weight, and in the second year, from 77.85 to 94.91% for biological yield and 1000 seed weight. Grain yield, biological yield, straw yield, number of panicles per square meter, and number of grains per panicle had a high percentage of heritability and genetic advance simultaneously. Based on the principal component analysis the first two main components explained 63.3 and 67.8 percent of the total changes in each year, respectively.

The results of variance analysis of the data obtained from this study indicated the existence of significant genetic diversity among the evaluated genotypes in terms of all measured traits, which can be attributed to the existence of different species with different geographical origins. Comparing the average data, genotypes 336, 349, 356 and 360 were introduced as the genotypes with the highest average grain yield in both years. Based on the results of Principal Component Analysis and Correlations Analysis, it can be found that the attributes of the number of panicles per square meter, the number of grains per panicle, 1000-kernel weight, and biological performance are very effective in breeding programs to achieve superior varieties. The genotypes NILE, LA PREVISION, OX87:080-2 and DUNNART were the superior genotypes in terms of the mentioned traits and grain yield. The estimation of genetic parameters showed that the selection based on the number of panicles per plot, the number of grains per panicle, and plant height plays a significant role in improving grain yield because of having a high broad heritability and significant genetic advance at the same time. According to the results of this study, it is possible to separate the superior genotypes in terms of grain yield and biological yield, and perform subsequent tests for grain and fodder genotypes, separately. Also, valuable traits for easier access to this important issue in subsequent oat improvement programs could be identified.

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.

In plant breeding programs, selection is one of the most important steps, and its efficiency is highly depends on the genetic diversity of the population and the heritability of traits. Due to the complexity of grain yield inheritance, direct selection is not very effective to improve it, so it is possible to obtain the necessary information for indirect selection to improve selection for grain yield by using multivariate statistical methods. The purpose of this research was to investigate the relationships between important agricultural traits, evaluate basic selection indices and provide the best indices to improve grain yield and identify the best quinoa genotypes to continue the breeding program to introduce the cultivar. For this purpose, 60 quinoa genotypes received from IPK Institute of Germany and were evaluated in the frame of randomized complete block design with 3 replications in 2022 in the research farm located in Kohdasht city. The results of phenotypic and genotypic path analysis of grain yield showed that the two traits of 1000-grain weight and number of panicle per plant had the most positive and significant direct effect on the grain yield of the studied genotypes. Also, the use of phenotypic and genotypic correlation coefficients and the first row traits included in the path analysis model of grain yield as economic value led to the highest genetic benefit of the traits and therefore, they can be good and suitable indicators for the selection of superior quinoa genotypes.

One of the methods that has been used in recent years to deal with dehydration and drought stress in many plants is the use of root symbiotic fungi (mycorrhiza). Ecological and physiological studies have shown that mycorrhizal symbiosis often results in better absorption of water and nutrients from the soil. Due to the importance of oilseeds and especially sesame, the study of commercial cultivars in terms of genetic variation, phenotypic components and heritability of traits is important. Sesame due to its high oil content (52-42 Percentage) and its proper quality (low cholesterol and the presence of some antioxidants) play an important role in human health and on the other hand the plant tolerates dehydration and drought stress. Currently, water stress is the most important and common factor in reducing yield in arid and semi-arid regions. High heritability for a trait indicates that the major part of phenotypic variance is due to genetic variance, while in low heritability, genetic factors have a smaller share in phototypic diversity. The aim of this study was to estimate the variance components and heritability of grain yield and related traits in 8 commercial sesame cultivars under different irrigation conditions.

In order to investigate the genetic diversity and the heritability of grain yield and yield components in sesame, 8 commercial cultivars were studied in three separate experiments using factorial split plot based on randomized block complete design with three replications in research field of Agricultural Research Center, West-Azerbaijan in 2015-2016 and 2016-2017 cropping seasons. The main plots (factor A and B) consisted of three different levels of irrigations (normal irrigation: irrigation after 70 mm evapotraspiration of crop or ETc, moderate drought stress: irrigation after 90 mm ETc and severe drought stress: irrigation after 110 mm ETc) and factor B included three levels: two species of mycorrhiza fungi Glomus mosseae, Glomus intraradices and non-inoculated (control). Sub plots (factor C) consisted of eight commercial cultivars of sesame.

The results of analysis of variance showed that the effect of environment, genotype and the interaction of environment × genotype on most of the studied traits were significant. In optimal irrigation regimes, moderate and severe drought stress under inoculation and non-inoculation conditions with mycorrhiza, the highest genetic variance was observed in biological yield, number of seeds per square meter and seed yield, respectively. The highest heritability in optimum irrigation conditions without mycorrhiza inoculation of traits (seed yield and number of grains per capsule), in optimum irrigation conditions and inoculation with mycorrhiza (both two species) (seed yield and 1000 seed weight), in moderate drought stress conditions and no inoculation with mycorrhiza (seed yield, 1000 seed weight and number of seeds per capsule), under moderate drought stress and inoculation with mycorrhiza G. mosseae (1000 seed weight and number of grains per capsule), under moderate stress conditions and inoculation with mycorrhiza G. intradices (seed yield, 1000 seed weight and number of grains per capsule), under severe drought stress conditions and without inoculation with mycorrhiza (stem diameter and 1000 seed weight), under severe drought stress conditions and inoculation with mycorrhiza G. mosseae (stem diameter, number of seeds per capsule and number of seeds per square meter) and in conditions of severe drought stress and inoculation with mycorrhiza G. intraradices (stem diameter, number of seeds per square meter and 1000 seed weight) were observed. Seed yield, biological yield and seed yield components had high genetic gain and genetic advance in all three different irrigation conditions. Among the components of grain yield, considering that the heritability of number of seeds per capsule and 1000 seed weight in all three different irrigation conditions is higher compared to the number of capsules per plant, so selection through number of seeds per capsule and 1000 seed weight to increase seed yield will be more efficient.

Therefore, commercial sesame cultivars that have more seeds per capsule and a 1000 seed weight can be used in breeding programs to produce cultivars with high seed yield. According to the information of this study, only general heritability can be calculated, but since many studies on commercial sesame cultivars in interaction with different conditions of irrigation and inoculation and non-inoculation with mycorrhiza have not been done, so this study can useful for researchers.

Grain filling period and grain filling rate are among the traits that affect plant response to heat stress. Our knowledge about the the status of these traits in Iranian commercial bread wheat cultivars under normal and heat stress conditions is so rare if not available. The purpose of this study was to evaluate grain filling duration and grain filling rate of Iranian commercial bread wheat cultivars and to study genetic diversity under normal and heat stress of the earth's hottest places, Ahvaz condition.

The experiments were conducted during 2017 and 2018 under normal (optimal planting date) and terminal heat stress (delayed cultivation) conditions on 33 commercial bread wheat cultivars including: Kaz (international heat tolerant), Montana (international heat sensitive), two other international cultivars, weebill and babax and 29 commercial varieties in Iran, namely Roshan, Arvand, Ghods, Flat, Hirmand, Alvand, Verinac, Zagros, Kavir, Chamran, Marvdasht, Shiraz, Dez, Pishtaz, Hamoon, Bam, Sistan, Neyshabur, Sepahan, Arta, Bahar, Arg, Pars, Aflak, Chamran 2, Mehregan, Shosh, Barat and Khalil. The experiment was conducted as a randomized complete block design with three replications at the experimental field of Shahid Chamran University of Ahvaz.

The results of combined analysis showed significant differences (P≤0.01) between genotypes, environment (heat stress) and also genotype-environment interaction for grain yield, grain filling duration and grain filling rate. In general, grain yield and grain filling period of cultivars were significantly reduced under stress condition compared to non-stress condition. However, grain filling rate decreased in most cultivars and almost increased in tolerant cultivars such as kaz. Results of principal component analysis showed that Hamoon, Kaz, Chamran 2, Arvand, Chamran, Falat, Verinac, Alvand, Mehregan and Shosh had high yield and yield stability under heat stress condition. The coefficient of genotypic and phenotypic variation for different traits indicated significant variation for all traits. In addition, significant heritability and genetic improvement were estimated for grain filling rate. This trait showed a high correlation with grain yield under both stress and non-stress conditions.

Among the commercial bread wheat varieties Chamran 2, Shoush and Alvand showed considerable heat tolerance compared to the international heat tolerant cultivar, Kaz. Grain filling rate was identified as an important trait in optimal response of plants to terminal heat stress. The results showed good genetic variation among commercial bread wheat varieties for grain filling rate. This trait can be used to identify and enhance heat tolerant varieties in breeding programs.

In order to study of intra-cultivar variation and genetic gain of yield, yield components and fiber quality traits of cotton (cv. Latif) an experiment was conducted for three years (2015-2017) at Hashemabad cotton research station in Gorgan, Iran. Selection was performed by Pedigree- mass method and selected individual plants were grown in single row plot during experimental years. Analysis of data revealed significant difference between the three populations derived from selection during experimental years by the years. The highest coefficient of variation (CV) estimated for yield (23.8), seed weight (10.7), boll weight, lint percentage and fiber strength (8-8.6), respectively, which confirmed intra-cultivar variation. Boll weight, grain weight and lint weight had the highest heritability and genetic advance. Boll number and seed weight have identified as the most effective components and selection index for yield improvement. Correlation values revealed that micronair index positively correlated with lint percentage (r = 0.40 **) and negatively correlated with seed weight, which indicates importance of them as selection criteria for latif cultivar improvement. We conclude the short term improvements may be achieved through indirect selection for yield and lint percentage. Future efforts should be placed in increasing earliness and fiber strength rates.

Festuca species grow in Iran and widespread occurrence of polyploidy has an important role in the evolution of this group. Festuca arundinacea belong to the grass family and include different species that used as forage, turf grass and for soil conservation. The aim of this work was the study of changing in DNA content morphological and phenological traits in different genotypes of F. arundinacea which collected from different regions.

This experiment was conducted using a complete block design with 3 replications. Genetic parameters were estimated for all traits including Day to head emergence, Flowering date, Plant height, Number of. stem per plant, Spike length, 1000-seed weight, Germination percentage, Germination rate, Germination vigor, Stability, Forage yield, Seed yield, Seed weight per stem, Harvest Index, Number of seed per plant. Three-week-old plants, fluorochrome DAPI and Hordeum vulgare L. cv. Sultan (2C= 11.12 pg) as an internal standard for DNA content measurement were used.

Evaluation of genetic parameters indicated that the difference between PCV and GCV was low for days to head emergence, flowering date, number of stem per plant, germination percentage, number of seed per plant, 1000-seed weight, germination rate, germination vigor and plant height, which clearly indicated the role of genetic variance was higher than the environmental variance. On the other hand, heritability was ranged between 66-95%. High broad-sense heritability was also observed for all the characters except spike length which indicate selection-based methods have high efficiency for these traits. Due to the low difference between PCV and GCV, high heritability and high genetic advance for days to head emergence, flowering date and germination vigor, it can be concluded that these traits are controlled by additive genetic action and can be improved through selective breeding programs. ANOVA results for relative nuclear DNA amount showed a significant difference between studied genotypes which suggest there is a high intraspecies variation for various genotypes in the different regions. The results of the mean comparison showed that the genotypes can be categorized into 7 separate groups. The highest and lowest relative amount of nuclear DNA was in (G13, G20, G21) and (G22, G16) genotypes respectively. According to previous studies, the change in the relative amount of nuclear DNA can be attributed to the presence of chromosome B and change the length of the chromosome.

It is suggested that day to head emergence, flowering date and germination vigor traits to be used for plant breeding programs. Moreover, the change in relative DNA content and morphological-phenological traits can be considered factors in the evolution of F.arundinacea and adaptation to varying environmental condition.

As the world's population grows, increasing demand for edible oils is inevitable. In addition to plant genetics, environmental variability plays a key role in plant yield. Drought is one of the most important environmental stresses that reduce the productivity of sunflower and other crops. Understanding the nature of phenotypic traits that improve performance under stress conditions and identifying the complex physiological and genetically mechanisms is fundamental to plant stress. Improving drought tolerance and increasing water productivity in plants is one of the most important goals of the breeders. Gaining knowledge of the amount of phenotypic and genetic parameters in the plant species for genetic and plant breeding studies is very important for the exact selection of the genotypes according to the objectives of the breeding programs. Understanding the nature of morphological, physiological, genetic and molecular mechanisms under the influence of drought tolerance can play an important role in the development of drought tolerant genotypes for cultivation in arid and semi-arid areas. The main aims of this study included investigation of genetic diversity of sunflower germplasm (to understand the relationships between morphological traits and their heritability) and accurate identification of the most important traits that affect the sunflower yield in each of the normal conditions and drought stress.

An experiment was conducted in a randomized complete block design with three replications in normal and drought stress conditions in 2014 growing season on 12 sunflower genotypes in a research field of Islamic Azad University, Karaj Branch. Each block consisted of 12 plots and each plot contained five rows. Each row was 5 meters length with 60 cm spacing, and plant spacing on rows was 20 cm. The studied traits included grain yield, seed length, seed width, seed diameter, leaf length, leaf width, plant height and stem diameter.

The results of combined analysis of variance confirmed the significant diversity among genotypes for most traits. Grain yield showed higher values for parameters of genetic efficiency, genotypic and phenotypic variation coefficients under drought stress and non-stress conditions compared to other traits. While the highest percentage of heritability in the normal condition belonged to grain yield, it belonged to plant height in the stress conditions. Plant height, leaf width, stem diameter and leaf length showed the highest change in terms of traits in stress conditions compared to normal conditions. Dendrograms derived from cluster analysis classified genotypes into three groups based on studied traits under both drought stress and non-stress conditions. According to the cluster analysis, under drought stress condition, the Sor and Progress genotypes were identified as tolerant genotypes and, in contrast, genotypes of Favorite, Record, SHF81-90, Master and Lakomka were recognized as sensitive genotypes.

In the combined analysis of variance the significance of the environmental effect shows that drought stress has significantly affected all traits. Therefore, the applied stress reveals the differences between the cultivars and the evaluation of the cultivars in the stress environment can lead to the selection of suitable cultivars. The effect of genotype was not significant for some traits, which suggests that the selection of cultivars for these traits is complex because the differences between the cultivars are not clearly defined. Selection is more reliable for traits that are significant, such as grain yield. The interaction between genotype and environment also increases the complexity of selection, which was significant only for plant height in this study. The high coefficient of phenotypic variation for traits indicates that the expression of these traits is greatly affected by the environment. Also, the high coefficient of genotypic and phenotypic variation for some traits indicates the wide range of changes for these traits. In general, the correspondence of the phenotypic coefficient and the genotypic coefficient in some traits indicates that the environmental effects on trait expression are negligible. However, when the phenotypic variation coefficient is higher than the genotypic variation coefficient, it indicates a high environmental effect. The low difference between the phenotypic and genotypic coefficient of variation for some traits suggests that these traits are more controlled by genetic factors. Therefore, the selection of parents for these traits is appropriate for hybridization programs.

The most important breeding objective in most crop plants is to increase grain yield, however, the complex genetic nature of grain yield and the influence of other traits make direct selection based on grain yield less successful. Therefor, it is necessary to introduce the other traits with simpler inheritance and higher heritability than grain yield as selection criteria, so that indirect selection based on them can lead to improve grain yield in the studied population. The objective of this study was to identify and introduce appropriate selection criteria to improve grain yield in an F11 rice population using base selection index. The plant materials of this study were 141 recombinant inbred lines of F11 generation derived from a cross between two Iranian rice cultivars, Gharib and Sepidrood, which were planted in a randomized complete block design with three replications at research field of Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran, in 2018. The studied traits were included days to 50% flowering, days to maturity, plant height, number of total tiller and panicle per plant, panicle length, number of filled and unfilled grain per panicle, number of spikelet per panicle, panicle fertility percentage, 1000 grain weight, grain length, width and shape and grain yield. The results of phenotypic and genotypic path analysis showed that number of panicle per plant, number of grain per panicle and 1000-grain weight had the most positive and significant direct effects on grain yield. Assessing the base selection indices and comparing them based on different evaluated criteria, specially genetic advance of each trait and relative efficiency of index- based selection than direct selection of grain yield also showed that the use of base selection indices based on phenotypic and genotypic correlation cefficients as well as path coefficients of number of panicle per plant, number of filled grain per panicle and 1000-grain weight were the most appropriate indices for selecting high yielding lines in the studied F11 population.

Potato (Solanum tuberosum L.) is an important food and cash crop ranking fourth after maize, wheat and rice annual production in the world. It is a high biological value crop that gives an exceptionally high yield with more nutritious content per unit area per unit time than any other major crops. Thus, it can play a remarkable role in human diet as a supplement to other food crops such as wheat and rice. The main objective of the breeding program is to increase yield production. One of the major factors contributing to potato yield reduction is limited number of cultivars with wide range of adaptability and stability in tuber yield. Thus, evaluating genotypes across various environments for their stability of performance and range of adaptation is crucial and is an important component of the research activity of the national as well as regional research program. 20 potato hybrids along with five commercial cultivars (Savalan, Agria, Caesar, Luta and Satina) were evaluated in randomized complete block design with three replications at Agricultural and Natural Resources Research Station of Ardebil, Khorasan razavi, Karaj, Isfahan and Hamedan in 2016.  In this investigation each of the hybrids and control cultivars were planted in 2 rows of six meters. Row spacing of 75 cm and plant spacing of 25 cm was considered. There were 25 tubers in each row. Pest control was performed using 250 ml of Ha-1 Confidor. During growing period and after harvest the traits such as: plant height, day of tuberization, main stem number per plant, tuber number and weight per plant, total tuber yield and percentage of tuber dry matter were measured. Combined analysis of variances was done and comparison of means was done by LSD at five percent probability level. The linear correlation between traits was also calculated. In order to understand the inter-relationships of attributes and determine the variables with the highest correlation, factor analysis with Varimax rotation of factors was used. Grouping of the hybrids was performed based on the first three factors. In order to study the genetic diversity and heritability of traits, some genetic parameters of the traits in potato cultivars and hybrids were calculated. All analyses were carried out using the SAS9 and SPSS16 softwares. Combined analysis of variance for traits showed significant differences among potato hybrids for all traits. The hybrids and environment interaction was significant for plant height, day of tuberization, tuber number and weight per plant, total tuber yield and tuber dry matter percent. Hybrids with number of 5, 9, 17 and 19 had the highest total tuber yield and the hybrid 20 and Satina cultivar had the lowest total tuber yield. The hybrids number 1, 3 and 20 had the highest amount of dry matter percentage compared to other hybrids suggesting that these hybrids are suitable for chips production. In factor analysis, three independent factors totally explained 75.744 percent of the variations. According to the results of factor analysis the following factors were nomenclature: the first factor as yield, the second factor as tuberization and third factor as plant. The weight per plant and tuber number per plant had the highest heritability, genetic gain, genotypic and phenotypic coefficient of variation. These traits can be improved through selection in breeding programs. In general, the results of the mean comparison and grouping of hybrids based on the first three factors showed that hybrids 5, 17 and 19 were better than the other hybrids. Hybrids 1, 3 and 20 with the highest percentage of dry matter are recommended for processing as chips. The weight per plant and the number of tubers per plant had the highest genetic gain and heritability rates, and these two traits could be improved through selection in breeding programs.

It is of great importance in breeding strategies to know the relationship between grain yield and main agronomic traits and understand the trend of changes in traits during breeding history. To meet these objectives, 313 Iranian wheat genotypes including 203 Iranian landraces and 110 Iranian cultivars were planted in an augmented design along with three check cultivars repeated in seven blocks in 2014 on the research field of Agronomy and Plant Breeding, University of Tehran. In order to increase accuracy and decrease environmental variation, the experiment has been replicated in three different location. Linear regression analysis between investigated characteristics and year of cultivar release and year of collection of landraces showed that the grain yield and thousand grain weight were significantly increased in both cultivars and landraces while spike weight was only significantly increased in the cultivars. Plant height and spike length were significantly decreased only in the cultivars during 74 years of breeding programs. No significant changes, however, was observed in the landraces. Although the number of grain/spike was known as the most important and effective traits on grain yield based on the results of correlation and path analyses, there was no any significant change for this trait during breeding programs. Since there were high phenotypic and genetic coefficient of variation for this trait, it could be one the most important traits in future breeding programs.

Chickpea production in Iran is less than half of world average yield. Genetic studies on yield and yield component may provide to select an effective breeding method for enhancing seed yield productivity. The current study was undertaken to estimate genetic parameters of yield and yield component of P1، P2، F1، F2، BC1P1، BC1P2 from a cross between chickpea varieties kabuli type ICCV2 and desi type JG62 and also P1، P2، F1، F2 a cross between Bivanij (kabuli type) and ICCV96029 (desi type) in ICRISAT and Sararood station during 1998-1999، 1999-2000 and 2003-2004. High heritability along with high genetic advance for 100-seed weight، leaf weight and specific leaf weight indicated the substantial contribution of additive genetic advance for the expression of these characters. Genotypic variation for number of days to first flower، number of days to first pod، number of secondary and primary branches per plant، plant width، plant height، number of seeds per pod and number of days to maturity was probably due to nonadditive gene effects. Both additive and nonadditive gene effects had important role for the expression of number of pods per plant، number of seeds per plant and seed yield per plant.

One of the most important purpose in breeding program is increasing grain yield per hectare. Using selection indices is the most effective methods of selection for simultaneous improvement of grain yield and related traits, which often have a quantitative inheritance. In this study, 29 rice genotypes (9 parents and 20 progenies) were evaluated. The numbers of filled grains in panicle and panicle fertility percentage traits have the highest Broad-sense heritability and highest positive and significant correlation with yield. The number of grain in panicle has the highest direct genotypic effect on grain yield. Analysis of regression showed that number of grain in panicle, panicle fertility percentage, number of filled grains in panicle and number of days to complete panicle have the highest affect on yield variation and therefore, using these 4 traits with grain yield, was considered as Selection indices. Results of selection indices showed that the phenotypic direct effect, genotypic correlation and Additive variance indices via optimum index and genotypic correlation, Broad-sense heritability and regression coefficient via Base index are the best indices of increasing yield trait. Selection for number of grain in panicle, panicle fertility percentage, number of filled grains in panicle and number of days to complete panicle by using Genotypic correlation coefficient as the economic weight would be effective selection criteria in each of the base or optimum method.