Document Type : Research Paper

Authors

• Nasrin Akbari ¹
• Reza Darvishzadeh ²

¹ Department of Plant Production and Genetics, Faculty of Agriculture Urmia University. Urmia, Iran

² Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia. Iran

Abstract

Introduction
Given the multigenic nature of drought tolerance and its susceptibility to environmental factors, successful germplasm selection and identification of superior genotypes are major challenges in drought tolerance breeding programs. Evaluation of drought tolerance is performed indirectly through multiple traits evaluated simultaneously in multiple environments.
Materials and Methods
In this study, 100 oilseed sunflower genotypes were evaluated for 13 traits under two normal and limited irrigations (drought stress) conditions in a simple 10×10 lattice design during 2013 and 2014 in the village of Qezeljeh, Salmas. To apply drought stress at the 8-leaf stage, a class A evaporation pan was used. Irrigation was performed under normal conditions after 90 mm of evaporation from the evaporation pan and under drought stress conditions after 180 ml of evaporation. After flowering, plant height (cm), leaf length (cm), leaf width (cm), petiole length (cm), stem diameter (cm), head diameter (cm), number of leaves, greenness index (SPAD), days to flowering (days), days to maturity (days), relative water content (percent), seed oil content (percent) and seed yield (gr-plant) in each one of field plots was measured. In order to benefit from the multiple selection method, the multi-traits selection index based on the distance from the ideal genotype was used. metan package in R software was used to analyze the data.
Results and Discussion
Based on the results of multivariate analysis of variance, the main effects of environment and genotype as well as the interaction effects of environment × genotype were significant in both normal and drought stress conditions, indicating a wide variation among genotypes. In the main effects component analysis under normal and drought stress conditions, five and four factors had eigenvalues greater than one, respectively, and explained 75% and 69.1% of the total traits variation, respectively. Under normal conditions, in the first factor with an eigenvalue of 4.8, the traits including leaf length, leaf width, petiole length, stem diameter, head diameter and seed yield had the most effect. In the second factor with an eigenvalue of 1.73, the traits including relative water content, days to flowering and days to maturity, in the third factor with an eigenvalue of 1.11, the greenness index, in the fourth factor with an eigenvalue of 1.07, the traits including leaf number and plant height, and in the fifth factor with an eigenvalue of 1.03, the oil content had the most effect. Under drought stress conditions, in the first factor with an eigenvalue of 4.45, the traits including leaf length, leaf width, petiole length, stem diameter, head diameter and seed yield had the most effect. In the second factor with an eigenvalue of 2.24, the traits including relative water content, days to flowering and days to maturity, in the third factor with an eigenvalue of 1.23, the traits including leaf number, plant height, seed oil content and in the fourth factor with an eigenvalue of 1.06, the traits including greenness index and oil content had the most effect. In principal component analysis for interaction effects, three and four factors had eigenvalues greater than one under normal and drought stress conditions, respectively, and these factors explained 62.3 and 71.4% of the total traits variation, respectively. Under normal conditions, the eigenvalues of the first three factors were 1.81, 1.07, and 1.03, respectively, and under drought stress conditions, the eigenvalues of the first four factors were 4.5, 2.24, 1.23, and 1.06, respectively. Based on the results of the multivariate index, five genotypes, (254-ENSAT), (AS3232), (ENSAT699), (HA304), and (SDB1), were evaluated as desirable genotypes under both normal and drought stress conditions.
Conclusion
MGIDI multivariate analysis is a comprehensive method for grouping genotypes according to all traits, which determines the contribution of each trait to variation. In this research, two genotypes 8 (ENSAT-254) and 17 (PAC2) had the highest genetic distance under both normal and drought stress conditions. Superior genotypes with the greatest genetic distance can be used to develop drought tolerant hybrid varieties in order to benefiting from the phenomenon of heterosis.

Keywords

• Genetic diversity
• Multivariate analysis of variance
• Simultaneous selection
• Oilseed plants
• Water deficit stress

Main Subjects

• B: Plant Breeding