جستجوی مقالات مرتبط با کلیدواژه « Indirect selection » در نشریات گروه « زراعت »

Wheat, as one of the most important crop on earth, is the main supplier of human food. This research was conducted to investigate the wheat recombinant inbred lines based on the germination components and compare them with the control varieties of the region to select the best lines using the selection index of the multi-trait genotype-ideotype distance (MGIDI). For this purpose, 40 wheat inbred lines (F8) were evaluated along with six control varieties (Arman, Araz, Ehsan, Tirgan, Meraj and Kalateh). According to the results of the analysis of variance, a significant difference between the studied lines was observed for all traits (P<.01). The results of factor analysis for the studied traits identified three factors that explained 86.93% of the total variation. Based on the MGIDI index, seven lines L3-4, L7-5, L7-4, L8-5, L4-4, L5-3, and L3-3 were selected as the superior genotypes with the lowest distance to the ideal genotype. Based on the cluster analysis, the genotypes were divided into five groups, and the genotypes of the fifth group were identified as the best genotypes in terms of all germination components and seedling traits, and were consistent with the genotypes identified based on the MGIDI index. The highest percentage of differential selection and genetic gain was assigned to the fresh weight vigour index (49.16% and 29.14%, respectively), which shows that the superiority of the selected genotypes is more prominent in terms of this trait. Based on the results, the recombinant inbred lines were significantly superior to the control cultivars in terms of the studied traits. Also, the results of this study showed that the use of the MGIDI index can efficiently identify superior genotypes.

Maize as a tropical cereal is a main source of food for humans and livestock, as well as biofuels and fiber in some regions of the world. Increasing maize production is one of the main priorities of the country, Iran. One of the columns of increasing production is development of new high-yielding cultivars. To improve a complex trait such as grain yield that has low heritability, indirect selection by other traits or developing a suitable index based on several traits can be used. In this study, linear phenotypic selection index (LPSI) and linear molecular selection index (LMSI) were prepared using the combination of morphological traits and informative ISSR molecular markers. The objective of the present study was to prepare appropriate selection indices in maize to improve grain yield.

The plant materials of this research were 97 maize genotypes that were cultivated in a randomized complete block design with six replications in the research field of the Faculty of Agriculture, Urmia University, Urmia, Iran. Morphological traits were measured from the tasseling stage to the physiological maturity. Sixty ISSR primer combinations were also used to prepare the molecular profile of the studied maize genotypes. To select the suitable genotypes, two indices including linear phenotypic selection index and linear molecular selection index were used, and the efficiency of the indices was compared with the estimation of different parameters such as the rate of genetic gain and response to selection.

The results of the linear phenotypic selection index showed that the highest rate of genetic gain based on the index (DG) was observed for chlorophyll content (99.15) and the lowest one for number of ears per plant (0.01). The expected genetic gain for all studied traits (DH) and response to selection was estimated at 163.2234 and 0.774, respectively. Based on the linear molecular selection index, the highest rate of genetic gain (DG) was observed for leaf area (99.31) and the lowest one was observed for number of ears per plant (0.02). The expected genetic gain for all studied traits (DH) and response to selection was also estimated at 50.972 and 0.774, respectively. The results showed that the correlation between index and breeding value (rHI) in the LPSI index was relatively favorable (less than one), and in the LMSI index was optimal (one), but both correlations were significant at 0.05 probability level according to the t-test. However, the efficiency of selection based on the index (ΔH) was 163.22 for the LPSI index and 50.97 for the LMSI index. On the other hand, the degree of genetic gain of trait (DG) was different depending on the type of index. For example, the ratio of genetic gain (DG) derived from molecular to phenotypic index for the number of ears per plant and grain yield (2.00 and 1.28, respectively) was higher than the other traits. Also, the best genotype based on both indices was genotype number of 61.

According to the results obtained from the present study and the review of sources in this field, it seems that it is possible to benefit from the advantages of development of the LMSI index in the breeding programs in early generations, but in advanced generations, it is better to select genotypes using the LPSI index, in which case the cost of molecular evaluations will be reduced.

Early vigor, stress resistance, uniformity, high yield, and breeder right protection have turned hybrid cultivar development into the most successful breeding strategy in rapeseed (Brassica napus L.). The goals of this research were to develop the first CMS based rapeseed hybrids in Iran and to evaluate their performance and fertility. The effect of different traits on yield increasing of hybrids was also studied. Seven CMS lines were crossed with R2000 (a restorer-line) and the seed yield of hybrids was tested using a randomized complete block design with three replications in 2019-2020 and 2020-2021. Three of hybrids with 4.64, 4.40, and 4.38 tons per hectare, showed considerable yield and were significantly different than Nilufar, Neptune, and Nima (3.44, 3.37, and 3.30 tons per hectare, respectively), as check cultivars. R2000×A8 demonstrated the highest heterosis (34.71%) to high-check cultivar. All hybrids obtained were normal in terms of fertility, having no male-sterile flowers. Based on the results of principal component analysis and cluster analysis, the simultaneous increase in the number of pods per plant and the thousand seed weight, together with crossing the more distant parents will lead to more high yielding hybrids. The promising hybrids with high yield and remarkable fertility could be released as new cultivars after passing adaptability and stability experiments.

Due to the increasing need of the country to imported edible oil and rapeseed importance among oilseeds, efforts to increase its grain yield and oil content are of high importance. Therefore, recognizing the traits that increase grain yield of rapeseed has an important role in the success of breeding programs. Thus, sixteen rapeseed genotypes were evaluated in a randomized complete block design with three replications in three regions with different climatic conditions in Iran, including Karaj, Isfahan, and Hamadan in 2016-2017. Traits such as number of pods per plant, number of seeds per pod, grain yield, 1000-grain weight, plant height, height of the first branch, stem diameter, oil percent, number of days to flowering, number of days to the end of flowering, duration of flowering, and number of days to maturity were measured. Stepwise regression analysis showed that number of grain/pod, number of days to maturity and number of pods/plant (R2 = 97.7), number of pods/plant and number of days to maturity (R2 =78.4) and number of days to maturity and number of grains/pod (R2 = 45.5) accounted for total variations of grain yield in Karaj, Isfahan and Hamadan, respectively. The results showed that the number of days to maturity, number of pods/plant, number of grain/pods, stem diameter and plant height had the greatest positive effect on grain yield and oil content. Therefore, these traits can be used as suitable selection tools for increasing grain and oil yield in winter rapeseed breeding programs

Tomato (Solanum lycopersicum L.) is one of the important horticultural crop species world-wide. Identifying superior genotypes with a high yield and acceptable fruit quality can pave the way for breeding programs. In order to identify the best tomato cultivars for some of fruit quality and yield related traits, a 3-replicate experiment with 20 commercial tomato hybrids in randomized complete block design was conducted in research field of Tarbiat Modares University in Tehran, in 2017. The examined traits included number of days to flowering, number of days to first fruit-set, plant height, number of primary branches, number of primary clusters, number of fruits per plant, fruit yield per plant, leaf chlorophyll index, fruit juice acidity, fruit electrical conductivity, water salinity, total dissolved solids, percentage of brix and fruit lycopene content. Hybrids were compared by two methods of the heatmap clustering and the analytical hierarchy process as a multivariate indicator. Among the 14 tested traits, four traits including number of days to flowering, leaf chlorophyll index, water salinity, and total dissolved solids, indicated low heritability and genotypic/phenotypic correlation with fruit yield and hence were denied for multivariate analysis. Hybrids Hypeel 108 and Queenty were superior to the other hybrids in fruit lycopene content and fruit yield, respectively, and both hybrids had an acceptable fruit juice acidity for processing in the food industry. Hybrids Queenty, Adora, Berlina, and Hypeel 108 indicated the highest AHP values and the highest genetic distances. Thus, they were found to be the most suitable genotypes for cultivating in areas with similar climatic conditions and formation of next breeding generation. These hybrids were superior to other hybrids, not only in fruit yield but also in a great majority of the traits.

Phaseolous vulgaris is highly important among bean species. China, Iran and Japan are the most important countries producing bean in Asia. According to reported information, cultivated area of bean was 94000 ha in Iran which 17841 ha located in Lorestan province. Improvement of new cultivar with high genetic potential for grain yield is the final goal in many breeding programs. To achieve this goal, many characteristics should be considered. Positive and negative significant correlation has been reported between traits in common bean. Various, traits had different direct and indirect effects on grain yield which should be considered. In addition to path analysis, evaluation and relationship of traits by other multivariate statistical methods such as cluster and factor analysis have been studied for better understanding of these relationships. This study aimed to investigate superior lines, study the relationship between important traits with seed yield by some univariate and multivariate statistical methods, and provide functional recommendation to breeding programs.
 

Elite lines obtained from red common bean (Phaseolus vulgaris L.) local populations of Lorestan province and suburbs, Iran, including 14 lines belonged to Azna (2 lines), Aligudarz (4 lines), Aleshtar (1 line), Borujerd (1 lines), Durood (2 lines), Shazand (2 line) and Nourabad (2 lines), with two control cultivars Goli and Sayyad were evaluated in randomized complete block design (RCBD) with 4 replications in Borujerd station, Lorestan, Iran, in 2011. Plant height, node number, stem number, pod length, pod number per plant, seed number per plant, 100 seed weight and seed yield characteristics were measured. Data were normalized by Kolmogorov-Smirnov test at 0.01 probability level. Error, genetic and phenotypic variances, and broad sense heritability pertreatment mean were estimated. Pearson correlation coefficient was used to determine the relationship between traits. Cluster analysis based on UPGMA was performed and Wilks' lambda statistic was used for cutting dendrogram. Then, a code was allocated to each group and these groups were compared. However, in order to fix type I error, Hotelling’s T2 test was used at 0.05 probability level. Before that, the assumption of homogeneous variance-covariance matrix was tested by BOX test at 0.01 probability level. Then, traits were compared. Seed yield was considered as dependent variable (y) and regression analysis was performed by stepwise method. Traits, that had significant standardized coefficient, were used in path analysis. For statistical analysis, Excel, SPSS and MSTAT-C software were used.
 

The results of ANOVA showed that the lines had significant difference for all studied traits. Mean comparison by Duncan test showed the highest and lowest seed yield belonged to Aligodarz-3 line (6058 Kg ha-1) and Goli cultivar (3175 Kg ha-1), respectively. All of the genotypes that were located in high seed yield group by cluster analysis belonged to elite lines that indicated the local red common bean populations, as a heterozygote germplasm source that been mixed of homozygous genotypes, had high potential to selection of superior lines in the breeding program. Comparison between groups by Hotelling-T2 statistics indicated seed number per plant and had significant difference at 0.01 probability level. The highest and lowest significant correlation coefficient was observed for seed number per plant with seed yield (0.91**) and node number with stem number (0.27*), respectively. The results of multiple regression for seed yield as dependent variable showed that seed number per plant and 100 seed weight had significant standardized regression coefficient. While, 100 seed weight had no significant correlation coefficient with seed yield that breeders should be considered different aspect of trait relationships. Path analysis results showed seed number per plant with direct effect 1.03 had more effect on seed yield than 100 seed weight with direct effect 0.43. While, both seed number per plant and 100 seed weight had negative indirect effect on seed yield by each other. The results of factor analysis showed four factors explained 93% of total variation. The first and second factor were called yield and yield component, and phenological type explained 60% of total variation. The lines that located in high yield group had the highest value for yield and yield components factor. While, the lowest score for mentioned factor belonged to Goli cultivar that showed factor analysis can be used both to summarize many dependent variables (traits) into little independent variables (factors) and to selective genotypes based on factor value. According to reports, the genetic base of bean cultivars has been limited. One of the useful results of multivariate analysis is the investigation of genotypes that locate at the end of distribution for several traits and these genotypes can be used as parents for better utilizing of probably heterosis. Heterosis and crossing one of the sustainable agricultural goals would improve germplasm, increase human food, promotion of farmer’s livelihoods and provide food.
 

Local populations of red common bean should be considered by breeders to select superior lines because of its potential and adaptation. Some studied traits had high diversity that could be exploited in breeding programs. While, other traits need to increase diversity by breeding strategies. Considering that each of studied analysis showed the different aspects of traits relationships and genotypes potential. So, the results should be considered simultaneously by breeders to better interpretation. Among the studied traits seed number per plant, according to high heritability, the identification of groups with different grain yield, high correlation and positive direct effect on grain yield was appropriate to increase seed yield. Multivariate analysis can be used to evaluate desirable genotypes and accumulate favorable alleles in breeding programs. The results of this study can be useful for breeders to investigate and utilize both traits and genotypes in breeding programs.

Introduction Coriander is an annual herb belongs to the umbel family and is native from North Africa to south-western of Asia. Coriander is one of the important medicinal plants that used in the pharmaceutical industry and it mainly cultivated and widely distributed for the fruits. The dried fruits are widely employed as a condiment, especially for flavoring of sauces, meat products and bakery and confectionery items. Also, coriander fruits are as a source of essential oils and fatty oil. Water deficit stress is one of the most important factors limiting the growth and survival of the plants in arid and semi-arid regions in the world. Water is a major component of the plant materials and significantly influence the quantity and quality of plant production. Drought stress leads to significant changes in the yield and composition of essential oils in aromatic and medicine plants. So that, it was reported that water deficit increased essential oil content but decreased essential oil yield in coriander. Iran with an average annual rainfall of 240 mm is classified as arid and semi-arid regions of the world. However, Iran is one of the world’s commercial coriander producers. Coriander has been cultivated for many years in different parts of Iran. Therefore, development of drought-tolerant cultivars with high essential oil and fatty oil yield is important in coriander. Indirect selection through yield components and yield-related traits is one of the most effective methods for improving complex traits such as fruit yield. Therefore, this research was conducted in order to understand the genetic association between quantitative and qualitative traits and also to identify the indirect selection indices for selection appropriate genotypes in coriander. Materials and Methods F1 and F2 generations derived from half-diallel crosses between six endemic coriander genotypes including Isfahan, Hamedan, Bushehr, Mazandaran, Markazi and Alborz, along with with their parents were evaluated in three irrigation regimes through randomized complete block design with three replications in each experiment during the growing season in 2016. Plants were grown in different irrigation regimes: well-watered (WW), moderate drought stress (MDS) and severe drought stress (SDS). The plant height, leaf number, branch number per plant, umbel number per plant, fertile umbel number per plant, fruit number per plant, thousand fruit weight, fruit yield, biological yield, essential oil content, fatty oil content, essential oil yield, fatty oil yield, SPAD chlorophyll content, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, relative water content and ion leakage were measured. Results and Discussion Results showed that fruit yield had the significant positive genetic correlation with days to flowering, SPAD chlorophyll content, relative water content, fruit number per plant and thousand fruit weight. Therefore, these traits could be used as suitable criterion for selection to increase fruit yield in drought stressed conditions. Consideration, the genetics of early ripening and fruit yield and a significant positive genetic correlation between days to ripening and fruit yield, improving coriander fruit yield under drought stress may be possible through breeding for drought escape. There were the positive genetic correlations between fruit yield and other economical traits in different irrigation regimes. Therefore, improving fruit yield can simultaneously be led to improve in the economical traits. Conclusion Generally, the results indicated that traits of days to flowering, SPAD chlorophyll content, relative water content, fruit number per plant and thousand fruit weight could be used as suitable criterion for selection to increase fruit yield in drought stressed conditions. Also, improving fruit yield can simultaneously be led to improve in the economical traits in both the non-stressed and drought stressed conditions

To improve a complex characters such as grain yield with low heritability, indirect selection through other characters and selection index based on different effective traits were used. For this purpose, 96 F3 families derived from Roshan and Kavir crossing, together with parents, F1 and F2 progenies were cultivated. In lattice design with 2 replications under drought stress conditions in research field of Shahid Bahonar University of Kerman at growing season of 2012-2013. In present study, the Smith-Hazel and Pesek-Baker selection indices were computed based on five traits including main spike weight, awn length, flag leaf width, 1000-grain weight and yield. In addition, direct and correlated responses were calculated for the mentioned traits. In Smith-Hazel index awn length and in Pesek-Baker index main spike weight had the highest selection response. The highest estimated relative selection efficiency for improvement of grain yield was obtained via selection for main spike weight and awn length. Main spike weight, awn length and 1000-grain weight showed positive response in all indices, while, flag leaf width revealed negative responses. Thus, selection based on these indices will resulting selection of families with high awn length, grain weight and low flag leaf width. Results showed that Pesek-Baker index had the highest selection efficiency and can be used to select appropriate genotypes in the present cross and bread wheat breeding programs.

One of the effective indirect selections methods for improving grain yield and its components is the selection index. In order to develop a suitable selection index for simultaneously increasing yield and its related traits, 100 sunflower inbred lines from different geographical origins were evaluated in randomized complete block designs with three replications at Urmia University in 2015 under normal and salt stress (8 dS/m) conditions. Smith-Hazel and Pesek-Baker indices based on 6 traits including plant high, head diameter, leaf number, one hundred seed weight, head dried weight and grain yield, as well as direct and correlated response of these traits were calculated in each one of salt stress conditions. Correlations between grain yield and selection indices were computed. The highest correlated responses were observed for plant height via seed yield (32.16) and for grain yield via head diameter (14.21) at normal and salt stress conditions, respectively. Head diameter with the highest correlated response for seed yield at normal and salt stress conditions can be considered as a suitable indirect trait for improving seed yield under both conditions. Smith-Hazel’s third indices and Pesek-Bakker’s third indices showed high heritability (0.76, 0.78), genetic correlations (0.87, 0.88) and relative efficiency (0.87, 0.88) and they help to identify the most superior genotypes same to direct selection by grain yield (16, 18) under both conditions. So, selection based on these indices potentially screens the high yielding lines. Based on results, the line ’71’ is introduced as superior line in normal and salt stress conditions.

In order to evaluate the competitive ability of rice genotypes against weeds in direct seeding system and determination the traits that may confer such attributes, a field experiment was conducted at the Rice Research Institute of Iran in Rasht during 2016-17 cropping season. The experiment was laid out in a split plot based on randomized complete blocks design with three replications. The treatments included two levels of weed management (weedy (under natural weed flora) and weed-free) as the main plots, and ten rice genotypes (Hashemi, Abjiboji, Tazeh Hasani, Gilaneh, Shiroodi, Saleh, RI18430-1, RI18430-60, RI18430-72, RI18430-77) as subplots. The results showed genotypic differences in competitive ability against weeds. Under weed- free conditions, grain yield varied from 3293.5 in Saleh to 6796.1 kg.ha-1 in Shiroodi. Under weedy conditions, grain yield was also registered from 260.6 in breeding line RI18430-72 to 1291.2 kg.ha-1 in Hashemi. The highest and lowest amounts of weed biomass at flowering were also observed in Abjiboji and shiroodi, respectively. Average yield loss due to weed competition ranged from 73.55 to 94.1% in different rice genotypes. The results also indicated a positive significant correlation between competitive ability and grain yield, thus Hashemi, Shiroodi and the breeding line RI18430-60 had the highest competitive ability against weeds and also grain yield (the basis for direct selection under weedy condition). This method can be applied in integrated weed management programs to reduce herbicide use. The study revealed that early growth (vigor), leaf area index, crop biomass and height had significant positive correlation with competitive ability and hence, can be used as useful indirect selection criteria of genotypes with high competitive ability.

In order to determine the most important components of anise grain yield using regression analysis and path analysis, an experiment was conducted with 12 anise population in a randomized complete block design with three replications at research farm of the agricultural faculty, University of Zanjan in 2014 and 2015. The evaluated traits were days to flowering, days to maturity, grain filling period, plant height, number of primary branches per plant, number of secondary branches per plant, 1000-grain weight, number of umbels per plant, umbelet numbers per umbel, number of grains per umbel, grain yield, biological yield and harvest index. Combined analysis of variance showed significant differences between the populations from the all of studied traits. Days to maturity, number of umbels per plant, number of grains per umbel, biological yield and harvest index had significant positive correlations with grain yield. Stepwise regression analysis showed that the number of umbels per plant and number of grains per umbel justify 53 percent of the grain yield variations. Also, path analysis showed that direct effects include the main portion of correlation of these traits with grain yield. Since the traits have not negative relationship together, selection of anise genotypes using these two traits can be recommended to indirect improve grain yield.

In this study 36 canola genotypes from seven different species including Brassica. napus, B. rapa, B. oleracea, B. juncea, B. carinata, B. nigra and B. friticulosa were evaluated under non-stressed, moderate and sever drought stress conditions during 2011-2012 in a field experiment. The relationships among different traits were assessed. Results of analysis of variance (ANOVA) indicated high variation among genotypes for most of the studied traits. Cultivar by environment interaction was significant for most of the traits, suggesting differential genotypic responses to moistures conditions. The correlation results for the three B. napus, B. rapa and B. oleracea were divided in three levels of watering regime and the coefficients were found to be species-specific but overall correlation coefficients showed that there was significant and positive correlations between grain yield and number of pods per plant and 1000 grain weight, irrespective of watering regime. Results of stepwise regression were suggestive of species and watering-specificity. Under non-stress conditions the greatest direct effect on grain yield belonged to pod length for B. napus and number of pods per plant for B. rapa and B. oleracea. Results indicated that in order to improve grain yield indirectly, breeding strategies should be specific for each Brassica species.

In order to evaluate and determine the most effective traits for improvement of grain yield in bread wheat genotypes, an experiment was conducted with 567 genotypes. The experiment was conducted using augmented with two replications in which cv. Karadj1 and cv. Sardari were used as control. Analysis of variance indicated non-significant difference between blocks for all the traits. Results of correlation analysis showed that majority of the traits had positive and significant correlation with single plant kernel yield. Step-wise regression analysis indicated that seven traits (spike grain yield, biological yield, harvest index, 1000 kernel weight, grain no./plant, grain no./spike and spike length) entered to the model and estimated 99% of grain yield varation in plant. Path analysis determined that grain no./plant, biological yield and 1000 kernel weight had the most positive direct effect on plant grain yield. Therefore, results indicated that indirect selection for these traits under irrigation condition will lead to improvement in plant grain yield.