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Showing 3 results for Zaynali Nezhad
Fatemeh Darvishnia, Mohammadhadi Pahlevani, Khalil Zaynali Nezhad, Khosro Azizi, Saied Bagherikia,
Volume 7, Issue 1 (9-2020)
Abstract
In order to determine the most effective indices for quantifying drought tolerance and identify genotypes that are tolerant to water stress in bread wheat, 50 bread wheat genotypes were compared in a randomized complete block design with three replications under both the non-stress dry farming with two complementary irrigation and the water stress dry farming conditions in Khorramabad, Iran. Analysis of variance showed that there was a significant difference among the genotypes in terms of all of the traits except the number of spike per area. In this study, eight indices including: Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), Mean Productivity (MP), Yield Index (YI), Harmonic Mean (HM), Yield Stability Index (YSI), Stress Susceptibility Index (SSI), and Tolerance index (TOL) were calculated by using of seed yield of the genotypes under both conditions. Indices that selection based on them will improve the yield in both conditions, are considered as suitable index. STI, GMP, MP and HM were introduced as suitable index for drought resistance selection. Genotypes Shiroodi and S-90-5 were determined as the most appropriate based on 3D plot. Based on positive correlation between water stress resistance indices and yield under stress and non-stress environments, STI and GMP were the best indices. By using the Biplot method, Shiroodi, S-90-5 and Oroum genotypes were considered as high yielding potential genotypes under the both conditions. According to the results of cluster analysis, genotypes were classified into three groups based on drought tolerance indices. Graphical analysis of genotypes also showed that genotypes Shiroodi and S-90-5 were more profitable than others under both drought stress and non-drought stress conditions. These genotypes could also be used as parents caring desirable genes in the crossing programs and selection of tolerate genotypes.
Esmaeil Dasturani, Khalil Zaynali Nezhad, Masood Soltani Najafabadi, Mohammadhadi Pahlevani, Hassan Soltanlo, Saeed Bagherikia,
Volume 8, Issue 1 (8-2021)
Abstract
The aim of this study was to determine the haplotype groups and identify the specific alleles associated with desirable agronomic characteristics in bread wheat. For this purpose, 42 local bread wheat genotypes belong to Iran region and nine commercial cultivars along with Chinese Spring variety (reference genotype) were cultivated in the format of augmented design and evaluated based on their 13 phenotypic traits. The results of descriptive statistics showed that awn length and day to flowering had the highest and lowest phenotypic coefficient of variation, respectively. Eight microsatellite markers were used to investigate the haplotype variation of QTLs associated with phenotypic traits located on wheat chromosomes 4B and 7D. The result showed that the genotypes were classified into 13 and 6 haplotype groups according to the allelic comparison with the reference genotype on chromosome 4B and 7D, respectively. In order to investigate the relationship between traits and markers, analysis of variance was performed based on completely randomized design with unequal numbers of replications for each marker. In general, of the 13 traits studied, there was a statistically significant linkage for eight traits and for the three traits, an allele-specific was introduced simultaneously. If the breeders are interested in genotype selection that simultaneously have three desirable characteristics such as early anthesis, semi-dwarfing and a greater number of grains per spike, they can use an allele-specific (153 bp) of Xgwm149-4B marker.
Kaveh Sadeghi, Mohammadhadi Pahlevani, Mohsen Esmeilzadeh Moghaddam, Khalil Zaynali Nezhad,
Volume 8, Issue 2 (3-2022)
Abstract
Identifying selection indices is the most important step of a breeding project that aims to improve grain yield. The definition of the selection index is usually done by evaluating the variables in multivariate statistical methods. In the present study, the relationship between grain yield and its components in bread wheat genotypes was determined by multivariate statistical methods. The experiment was conducted in a randomized complete block design with 3 replications in the research farm of Gorgan University of Agricultural Sciences and Natural Resources in the 2018-19 crop years. Ten commercial cultivars of bread wheat along with their offspring from direct and inverse crosses in a dialysis arrangement were evaluated for morphological and phenological traits, especially grain yield and its components. The results of genotypic and phenotypic correlation coefficients showed a positive and significant correlation (at 1% probability level) between grain yield and spike length, spike weight, number of fertile tillers, number of seeds per spike, number of spikes per spike, 1000-seed weight, biological yield and harvest index. Based on the results of stepwise regression analysis, biological yield, harvest index, number of grains per main spike and main spike weight were entered into the regression model, respectively, and explained a total of 98% of the variation in grain yield. Based on the results of path analysis, biological yield had the highest direct effect on grain yield. After biological yield, the most direct effect on grain yield was related to the weight of main spike. Also, by considering eigenvalues greater than one in factor analysis, 8 hidden factors were identified that explained a total of 75.18% of the data changes. In general, it can be concluded that biological yield, harvest index, number of seeds per spike and weight of spike compared to other traits can be used as appropriate indicators in breeding programs to select high-yield genotypes in field conditions. Genotypes Alo, Ehsan♂ × Gonbad♀ and Ehsan had the highest value for the studied traits, which can be used in future breeding researches.
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