mona arefkhani; Ali Rahemi Karizaki; َAbbas Biabani; hossein sabouri; ghorbanali rassam
Abstract
Objective: The purpose of this experiment was to study the trend of yield fluctuations and related traits in released wheat cultivars in Iran from 1968 to 2016.Methods: This experiment was conducted with 16 wheat cultivars based on a Randomized Complete Block Design with three replications at Shirvan ...
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Objective: The purpose of this experiment was to study the trend of yield fluctuations and related traits in released wheat cultivars in Iran from 1968 to 2016.Methods: This experiment was conducted with 16 wheat cultivars based on a Randomized Complete Block Design with three replications at Shirvan Higher Education Complex in North Khorasan during the 2018-2019 and 2019-2020 growing seasons.Results: The findings indicated that the Iranian cultivars released do not have significant differences in terms of the number of seeds per spike, plant height, spike length, biological yield and gluten percentage, but grain yield, harvest index, 1000-seeds weight and protein percentage have improved by 61.84, 63.54, 62.37 and 14.4%, respectively, during the last 48 years. Additionally, wheat breeding in Iran has progressed towards single-spike formation. Path analysis showed that the plant height, biological yield, number of fertile tillers/m2 and harvest index explain more than 96% of yield changes and that traits such as the harvest index and number of fertile tillers are considered the most important traits in increasing and decreasing grain yield in Iranian wheat.Conclusion: According to the results of the causality analysis, it can be concluded that the selection for grain yield, based on other traits and without considering the relationships between them, may not provide accurate results. It is necessary to obtain a correct understanding of the role of the relationships between traits in breeding programs to increase selection efficiency.
Borzo Kazerani; Saied Navabpour; Hossein Sabouri; Seyedeh Sanaz Ramezanpour; Khalil Zaynali Nezhad; Ali Eskandari
Abstract
To determine the best selection indices for facilitating the selection procedure in a reproductive stage of 96 mutant lines (M2) of rice under different moisture conditions, an experiment was carried out in two environments at the research farm of Gonbad Kavous University in 2016 base on randomized complete ...
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To determine the best selection indices for facilitating the selection procedure in a reproductive stage of 96 mutant lines (M2) of rice under different moisture conditions, an experiment was carried out in two environments at the research farm of Gonbad Kavous University in 2016 base on randomized complete block design with three replications. Evaluating the reduction percentage in the average values of traits showed that the most damages as affected by drought stress was due to decreases in numbers of filled grains, numbers of tillers, and 1000-grain weight. Results of stepwise regression analysis indicated that 1000-grain weight, plant height, numbers of filled grains, numbers of days to flowering, flag leaf rolling, numbers of tillers, and panicle length traits were respectively entered into the final multivariate regression model as important traits affecting grain yield under a flooded condition, and 1000-grain weight, numbers of days to flowering, plant height, fertility percentage, panicle length, flag leaf frying, and numbers of tillers were respectively entered under drought stress. Evaluation of direct and indirect effects of studied traits on the grain yield using a path analysis showed that, 1000-grain weight, due to a positive and high direct effect, and numbers of filled grains, due to an indirect effect via 1000-grain weight, can be considered as the most important traits for increasing the grain yield under flooded condition. However, 1000-grain weight and fertility percentage can be introduced as appropriate selection criteria for the grain yield under a drought condition.