Meta-Analysis of the Effect of Drought Stress on Quantitative and Qualitative Yield of Nigella Sativa

Meta-Analysis of the Effect of Drought Stress on Quantitative and Qualitative Yield of Nigella Sativa  Sadegh Bahamin*۱, Abbas Maleki ۲۱- PhD in Agroecology, Department of Agrotechnology, Faculty Agriculture, Ferdowsi University of Mashhad, Iran.۳-Department of agronomy and plant breeding, Ilam Branch, Islamic Azad University. Ilam, Iran.  ⃰ Corresponding author: [e-mail] Received: ۲۰ March ۲۰۱۹                                                                                Accepted:  ۱ Janu ۲۰۲۰  AbstractThis study was conducted in order to investigate the effect of drought stress on the quantitative and qualitative yield of black seed with meta-analysis method. The research sample included a collection of domestic articles and theses between ۱۹۹۱ and ۲۰۲۱, and a total of ۱۸ articles and theses were found to be appropriate. Of these, ۱۸ articles had a control treatment or no drought stress. ۱۲ articles were in the range of ۹۰-۸۱ and ۴۰-۶۰% and ۱۴ articles were ۸۰-۶۱% of farm capacity. Mean and mean square of ۶ traits including seed yield, biological yield, seed protein, seed oil, protein yield and oil yield were extracted. All statistical calculations and graphs were done with Excel software. The results showed that according to the standardized values, the effect of drought stress on grain yield and dry matter yield was significant. Regarding the percentage of oil and percentage of protein, the results showed that the average effect size was not significantly different from the control treatment and therefore drought stress did not have a significant effect on increasing or decreasing the percentage of oil and percentage of protein compared to the control treatment. The standardized values ​​of the effect of drought stress on oil yield were significant compared to the control treatment and the control treatment with ۴۰-۶۰% of crop capacity. There was no significant difference between the control treatment and the ۸۱-۹۰% crop capacity treatment. Combining the data of the investigated experiments with the regression method showed that the reaction of grain yield to drought stress is consistent with the first-order model. With the increase of drought stress up to ۴۰% of the crop capacity, the grain yield decreased linearly. The correlation coefficient between drought stress and black seed yield was ۰.۴۶. The correlation results also showed that the relationship between these two dependent and independent variables is significant. The results of this research showed that despite numerous studies on the effect of drought stress on the performance of black seed plant in the country, the results are very diverse and highly scattered. This has led to the fact that the effect of drought stress, especially on the percentage of oil and black seed, is still unclear. As a powerful statistical method, meta-analysis provided a suitable and accurate tool for combining the results of independent experiments and defined specific ranges for the effect of drought stress on the characteristics of black currents. Drought stress has harmful effects on the quality of black seed and it is necessary to think of appropriate solutions to reduce the effect of drought stress on the quality of this valuable medicinal plant.

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Keywords: Stress , meta-analysis , Nigella sativa , Oil