Document Type : Research Paper
Authors
1
Graduate M. Sc., Department of Plant Breeding and Biotechnology, Faculty of Plant Production, Agriculture and Natural Resources University of Gorgan, Gorgan, Iran
2
Associate Professor, Department of Plant Breeding and Biotechnology, Faculty of Plant Production, Agriculture and Natural Resources University of Gorgan, Gorgan, Iran
3
Graduate Ph. D., Department of Plant Breeding and Biotechnology, Faculty of Plant Production, Agriculture and Natural Resources University of Gorgan, Gorgan, Iran
10.22124/cr.2024.26168.1800
Abstract
Introduction
The water deficit is one of the most important problems in rice cultivation, particularly when the dry season coincides with the affected growth period. Drought stress is known as a reduced factor on yield, based on this introducing tolerant genotypes is a good way to cope with the matter. In order to find out the tolerant genotypes in response to drought stress, some indices have been suggested.
Materials and methods
The experiment was conducted on split plot order with RCB design with three replicates in Azadshahr aria. The main factor has two levels of irrigation included (drought stress and flooding as control) and the sub-factor included eight rice cultivars. In each plot (1 times 2 m) six rows of each cultivar with 25 cm space between rows cultivated. Irrigation was carried out in normal conditions until the last stage, but in the drought-stress condition, it was only carried out 40 days after tillering and then was done at 25d intervals until the end season. Samples were taken from 2-4 rows by removing border rows. All data was statistically analyzed by SAS software and By plot curve drawn by Stat-Graphic software.
Research findings
Analysis of variance for all traits studied showed a significant difference for cultivars in both irrigation conditions. Mean comparison of cultivars showed that in control and stress conditions, the highest average yield belonged to Fajr, IRAT216, sangjo, and Taromgardeh genotypes and the lowest yield in control belonged to the Sepidrood cultivar. The results of correlation coefficients for tolerance indices showed that performance in control conditions had a positive and significant correlation with mean production (MP), geometric mean productivity (GMP), harmonic mean (HARM), and drought tolerance (TOL), respectively, most of which were related. It was correlated with the mean index (r = 0.918) and in stress conditions the harmonic mean (HARM), geometric mean productivity (GMP) and mean production (MP) indices showed a high correlation with performance, most of which was related to the mean index. It was harmonic (r = 0.933). The results of the principal component analysis showed that most of the changes between data were justified by the first two main components so these two components explained 94.31% of the data changes. Cluster analysis based on drought tolerant indices also divided the cultivars into three groups, which had the highest drought tolerance of the first cluster.
Conclusion
Considering the results obtained from biplot analysis and the correlation between tolerant indices, it can be said that GMP, MP, and HM indices are the best indices for selecting high-yielding genotypes in both stress and non-stress conditions in this Based on the mentioned indices and biplot drawing, Fajr, Taromgardeh, sangjo and IRAT216 genotypes had high yield and drought tolerance and Sepidrood and Gharib Siah Reyhani cultivars had low yield and drought sensitive.
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